Add translations

* Non blocking improvements

* Test fix

* Background thread re-queue

* Nonblockimg improvements, run tasks in background, add warning about CPU cores

* Misc fixes

.github/test/Dockerfile-alpine

@@ -7,6 +7,8 @@ ENV PYTHONUNBUFFERED=1
 
 COPY requirements.txt /requirements.txt
 
+ARG TARGETPLATFORM
+
 RUN \
  apk add --update --no-cache --virtual=build-dependencies \
     build-base \
@@ -27,7 +29,19 @@ RUN \
     file \
     nodejs \
     poppler-utils \
-    python3 && \
+    python3 \
+    glib \
+    libsm \
+    libxext \
+    libxrender && \
+  case "$TARGETPLATFORM" in \
+    linux/arm/v7|linux/arm/v8) \
+      echo "INFO: Skipping py3-opencv on $TARGETPLATFORM (using pixelmatch fallback)" \
+      ;; \
+    *) \
+      apk add --update --no-cache py3-opencv || echo "WARN: py3-opencv install failed, using pixelmatch fallback" \
+      ;; \
+  esac && \
   echo "**** pip3 install test of changedetection.io ****" && \
   python3 -m venv /lsiopy  && \
   pip install -U pip wheel setuptools && \

.github/workflows/codeql-analysis.yml

@@ -30,7 +30,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL

.github/workflows/containers.yml

@@ -39,14 +39,14 @@ jobs:
     # Or if we are in a tagged release scenario.
     if: ${{ github.event.workflow_run.conclusion == 'success' }} || ${{ github.event.release.tag_name }} != ''
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Set up Python 3.11
         uses: actions/setup-python@v6
         with:
           python-version: 3.11
 
       - name: Cache pip packages
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ~/.cache/pip
           key: ${{ runner.os }}-pip-${{ hashFiles('requirements.txt') }}
@@ -93,16 +93,27 @@ jobs:
           driver-opts: image=moby/buildkit:master
 
       # master branch -> :dev container tag
+      - name: Docker meta :dev
+        if: ${{ github.ref == 'refs/heads/master' && github.event_name != 'release' }}
+        uses: docker/metadata-action@v5
+        id: meta_dev
+        with:
+          images: |
+            ${{ secrets.DOCKER_HUB_USERNAME }}/changedetection.io
+            ghcr.io/${{ github.repository }}
+          tags: |
+            type=raw,value=dev
+
       - name: Build and push :dev
         id: docker_build
-        if: ${{ github.ref }} == "refs/heads/master"
+        if: ${{ github.ref == 'refs/heads/master' && github.event_name != 'release' }}
         uses: docker/build-push-action@v6
         with:
           context: ./
           file: ./Dockerfile
           push: true
-          tags: |
-            ${{ secrets.DOCKER_HUB_USERNAME }}/changedetection.io:dev,ghcr.io/${{ github.repository }}:dev
+          tags: ${{ steps.meta_dev.outputs.tags }}
+          labels: ${{ steps.meta_dev.outputs.labels }}
           platforms: linux/amd64,linux/arm64,linux/arm/v7,linux/arm/v8
           cache-from: type=gha
           cache-to: type=gha,mode=max
@@ -141,6 +152,7 @@ jobs:
           file: ./Dockerfile
           push: true
           tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
           platforms: linux/amd64,linux/arm64,linux/arm/v7,linux/arm/v8
           cache-from: type=gha
           cache-to: type=gha,mode=max

.github/workflows/pypi-release.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Set up Python
       uses: actions/setup-python@v6
       with:
@@ -21,7 +21,7 @@ jobs:
     - name: Build a binary wheel and a source tarball
       run: python3 -m build
     - name: Store the distribution packages
-      uses: actions/upload-artifact@v5
+      uses: actions/upload-artifact@v6
       with:
         name: python-package-distributions
         path: dist/
@@ -34,7 +34,7 @@ jobs:
     - build
     steps:
     - name: Download all the dists
-      uses: actions/download-artifact@v6
+      uses: actions/download-artifact@v7
       with:
         name: python-package-distributions
         path: dist/
@@ -93,7 +93,7 @@ jobs:
 
     steps:
     - name: Download all the dists
-      uses: actions/download-artifact@v6
+      uses: actions/download-artifact@v7
       with:
         name: python-package-distributions
         path: dist/

.github/workflows/test-container-build.yml

@@ -44,14 +44,14 @@ jobs:
           - platform: linux/arm64
             dockerfile: ./.github/test/Dockerfile-alpine
     steps:
-        - uses: actions/checkout@v5
+        - uses: actions/checkout@v6
         - name: Set up Python 3.11
           uses: actions/setup-python@v6
           with:
             python-version: 3.11
 
         - name: Cache pip packages
-          uses: actions/cache@v4
+          uses: actions/cache@v5
           with:
             path: ~/.cache/pip
             key: ${{ runner.os }}-pip-${{ hashFiles('requirements.txt') }}

.github/workflows/test-only.yml

@@ -7,7 +7,7 @@ jobs:
   lint-code:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Lint with Ruff
         run: |
           pip install ruff

.github/workflows/test-stack-reusable-workflow.yml

@@ -21,7 +21,7 @@ jobs:
     env:
       PYTHON_VERSION: ${{ inputs.python-version }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Set up Python ${{ env.PYTHON_VERSION }}
         uses: actions/setup-python@v6
@@ -29,7 +29,7 @@ jobs:
           python-version: ${{ env.PYTHON_VERSION }}
 
       - name: Cache pip packages
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ~/.cache/pip
           key: ${{ runner.os }}-pip-py${{ env.PYTHON_VERSION }}-${{ hashFiles('requirements.txt') }}
@@ -52,7 +52,7 @@ jobs:
           docker save test-changedetectionio -o /tmp/test-changedetectionio.tar
 
       - name: Upload Docker image artifact
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: test-changedetectionio-${{ env.PYTHON_VERSION }}
           path: /tmp/test-changedetectionio.tar
@@ -66,10 +66,10 @@ jobs:
     env:
       PYTHON_VERSION: ${{ inputs.python-version }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Download Docker image artifact
-        uses: actions/download-artifact@v6
+        uses: actions/download-artifact@v7
         with:
           name: test-changedetectionio-${{ env.PYTHON_VERSION }}
           path: /tmp
@@ -84,6 +84,7 @@ jobs:
           docker run test-changedetectionio bash -c 'python3 -m unittest changedetectionio.tests.unit.test_watch_model'
           docker run test-changedetectionio bash -c 'python3 -m unittest changedetectionio.tests.unit.test_jinja2_security'
           docker run test-changedetectionio bash -c 'python3 -m unittest changedetectionio.tests.unit.test_semver'
+          docker run test-changedetectionio bash -c 'python3 -m unittest changedetectionio.tests.unit.test_html_to_text'
 
   # Basic pytest tests with ancillary services
   basic-tests:
@@ -93,10 +94,10 @@ jobs:
     env:
       PYTHON_VERSION: ${{ inputs.python-version }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Download Docker image artifact
-        uses: actions/download-artifact@v6
+        uses: actions/download-artifact@v7
         with:
           name: test-changedetectionio-${{ env.PYTHON_VERSION }}
           path: /tmp
@@ -119,7 +120,7 @@ jobs:
 
       - name: Store test artifacts
         if: always()
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: test-cdio-basic-tests-output-py${{ env.PYTHON_VERSION }}
           path: output-logs
@@ -132,10 +133,10 @@ jobs:
     env:
       PYTHON_VERSION: ${{ inputs.python-version }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Download Docker image artifact
-        uses: actions/download-artifact@v6
+        uses: actions/download-artifact@v7
         with:
           name: test-changedetectionio-${{ env.PYTHON_VERSION }}
           path: /tmp
@@ -174,10 +175,10 @@ jobs:
     env:
       PYTHON_VERSION: ${{ inputs.python-version }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Download Docker image artifact
-        uses: actions/download-artifact@v6
+        uses: actions/download-artifact@v7
         with:
           name: test-changedetectionio-${{ env.PYTHON_VERSION }}
           path: /tmp
@@ -214,10 +215,10 @@ jobs:
     env:
       PYTHON_VERSION: ${{ inputs.python-version }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Download Docker image artifact
-        uses: actions/download-artifact@v6
+        uses: actions/download-artifact@v7
         with:
           name: test-changedetectionio-${{ env.PYTHON_VERSION }}
           path: /tmp
@@ -250,10 +251,10 @@ jobs:
     env:
       PYTHON_VERSION: ${{ inputs.python-version }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Download Docker image artifact
-        uses: actions/download-artifact@v6
+        uses: actions/download-artifact@v7
         with:
           name: test-changedetectionio-${{ env.PYTHON_VERSION }}
           path: /tmp
@@ -279,10 +280,10 @@ jobs:
     env:
       PYTHON_VERSION: ${{ inputs.python-version }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Download Docker image artifact
-        uses: actions/download-artifact@v6
+        uses: actions/download-artifact@v7
         with:
           name: test-changedetectionio-${{ env.PYTHON_VERSION }}
           path: /tmp
@@ -319,10 +320,10 @@ jobs:
     env:
       PYTHON_VERSION: ${{ inputs.python-version }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Download Docker image artifact
-        uses: actions/download-artifact@v6
+        uses: actions/download-artifact@v7
         with:
           name: test-changedetectionio-${{ env.PYTHON_VERSION }}
           path: /tmp
@@ -350,10 +351,10 @@ jobs:
     env:
       PYTHON_VERSION: ${{ inputs.python-version }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Download Docker image artifact
-        uses: actions/download-artifact@v6
+        uses: actions/download-artifact@v7
         with:
           name: test-changedetectionio-${{ env.PYTHON_VERSION }}
           path: /tmp
@@ -395,10 +396,10 @@ jobs:
     env:
       PYTHON_VERSION: ${{ inputs.python-version }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Download Docker image artifact
-        uses: actions/download-artifact@v6
+        uses: actions/download-artifact@v7
         with:
           name: test-changedetectionio-${{ env.PYTHON_VERSION }}
           path: /tmp

.gitignore

@@ -21,6 +21,7 @@ venv/
 # IDEs
 .idea
 .vscode/settings.json
+*~
 
 # Datastore files
 datastore/

Dockerfile

@@ -34,6 +34,7 @@ ENV OPENSSL_LIB_DIR="/usr/lib/arm-linux-gnueabihf"
 ENV OPENSSL_INCLUDE_DIR="/usr/include/openssl"
 # Additional environment variables for cryptography Rust build
 ENV CRYPTOGRAPHY_DONT_BUILD_RUST=1
+
 RUN --mount=type=cache,id=pip,sharing=locked,target=/tmp/pip-cache \
   pip install \
   --prefer-binary \
@@ -43,7 +44,6 @@ RUN --mount=type=cache,id=pip,sharing=locked,target=/tmp/pip-cache \
   --target=/dependencies \
   -r /requirements.txt
 
-
 # Playwright is an alternative to Selenium
 # Excluded this package from requirements.txt to prevent arm/v6 and arm/v7 builds from failing
 # https://github.com/dgtlmoon/changedetection.io/pull/1067 also musl/alpine (not supported)
@@ -52,13 +52,38 @@ RUN --mount=type=cache,id=pip,sharing=locked,target=/tmp/pip-cache \
   --prefer-binary \
   --cache-dir=/tmp/pip-cache \
   --target=/dependencies \
-  playwright~=1.48.0 \
+  playwright~=1.56.0 \
   || echo "WARN: Failed to install Playwright. The application can still run, but the Playwright option will be disabled."
 
+# OpenCV is optional for fast image comparison (pixelmatch is the fallback)
+# Skip on arm/v7 and arm/v8 where builds take weeks - excluded from requirements.txt
+ARG TARGETPLATFORM
+RUN --mount=type=cache,id=pip,sharing=locked,target=/tmp/pip-cache \
+  case "$TARGETPLATFORM" in \
+    linux/arm/v7|linux/arm/v8) \
+      echo "INFO: Skipping OpenCV on $TARGETPLATFORM (build takes too long), using pixelmatch fallback" \
+      ;; \
+    *) \
+      pip install \
+        --prefer-binary \
+        --extra-index-url https://www.piwheels.org/simple \
+        --cache-dir=/tmp/pip-cache \
+        --target=/dependencies \
+        opencv-python-headless>=4.8.0.76 \
+        || echo "WARN: OpenCV install failed, will use pixelmatch fallback" \
+      ;; \
+  esac
+
 
 # Final image stage
 FROM python:${PYTHON_VERSION}-slim-bookworm
 LABEL org.opencontainers.image.source="https://github.com/dgtlmoon/changedetection.io"
+LABEL org.opencontainers.image.url="https://changedetection.io"
+LABEL org.opencontainers.image.documentation="https://changedetection.io/tutorials"
+LABEL org.opencontainers.image.title="changedetection.io"
+LABEL org.opencontainers.image.description="Self-hosted web page change monitoring and notification service"
+LABEL org.opencontainers.image.licenses="Apache-2.0"
+LABEL org.opencontainers.image.vendor="changedetection.io"
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
     libxslt1.1 \
@@ -69,6 +94,11 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     # favicon type detection and other uses
     file \
     zlib1g \
+    # OpenCV dependencies for image processing
+    libglib2.0-0 \
+    libsm6 \
+    libxext6 \
+    libxrender-dev \
     && apt-get clean && rm -rf /var/lib/apt/lists/*
 
 
@@ -89,6 +119,9 @@ EXPOSE 5000
 # The actual flask app module
 COPY changedetectionio /app/changedetectionio
 
+# Compile translation files for i18n support
+RUN pybabel compile -d /app/changedetectionio/translations
+
 # Also for OpenAPI validation wrapper - needs the YML
 RUN [ ! -d "/app/docs" ] && mkdir /app/docs
 COPY docs/api-spec.yaml /app/docs/api-spec.yaml

MANIFEST.in

@@ -11,10 +11,12 @@ recursive-include changedetectionio/realtime *
 recursive-include changedetectionio/static *
 recursive-include changedetectionio/templates *
 recursive-include changedetectionio/tests *
+recursive-include changedetectionio/translations *
 recursive-include changedetectionio/widgets *
 prune changedetectionio/static/package-lock.json
 prune changedetectionio/static/styles/node_modules
 prune changedetectionio/static/styles/package-lock.json
+include changedetectionio/favicon_utils.py
 include changedetection.py
 include requirements.txt
 include README-pip.md

README-pip.md

@@ -14,7 +14,7 @@ Ideal for monitoring price changes, content edits, conditional changes and more.
 [<img src="https://raw.githubusercontent.com/dgtlmoon/changedetection.io/master/docs/screenshot.png" style="max-width:100%;" alt="Self-hosted web page change monitoring, list of websites with changes"  title="Self-hosted web page change monitoring, list of websites with changes"  />](https://changedetection.io)
 
 
-[**Don't have time? Try our extremely affordable subscription use our proxies and support!**](https://changedetection.io) 
+[**Don't have time? Try our extremely affordable subscription use our proxies and support!**](https://changedetection.io)
 
 
 
@@ -31,7 +31,7 @@ Available when connected to a <a href="https://github.com/dgtlmoon/changedetecti
 
 ### Perform interactive browser steps
 
-Fill in text boxes, click buttons and more, setup your changedetection scenario. 
+Fill in text boxes, click buttons and more, setup your changedetection scenario.
 
 Using the **Browser Steps** configuration, add basic steps before performing change detection, such as logging into websites, adding a product to a cart, accept cookie logins, entering dates and refining searches.
 
@@ -54,7 +54,7 @@ Requires Playwright to be enabled.
 - Know when your favourite whiskey is on sale, or other special deals are announced before anyone else
 - COVID related news from government websites
 - University/organisation news from their website
-- Detect and monitor changes in JSON API responses 
+- Detect and monitor changes in JSON API responses
 - JSON API monitoring and alerting
 - Changes in legal and other documents
 - Trigger API calls via notifications when text appears on a website
@@ -86,7 +86,7 @@ _Need an actual Chrome runner with Javascript support? We support fetching via W
 
 We [recommend and use Bright Data](https://brightdata.grsm.io/n0r16zf7eivq) global proxy services, Bright Data will match any first deposit up to $100 using our signup link.
 
-[Oxylabs](https://oxylabs.go2cloud.org/SH2d) is also an excellent proxy provider and well worth using, they offer Residental, ISP, Rotating and many other proxy types to suit your project. 
+[Oxylabs](https://oxylabs.go2cloud.org/SH2d) is also an excellent proxy provider and well worth using, they offer Residential, ISP, Rotating and many other proxy types to suit your project.
 
 Please :star: star :star: this project and help it grow! https://github.com/dgtlmoon/changedetection.io/
 
@@ -106,4 +106,3 @@ $ changedetection.io -d /path/to/empty/data/dir -p 5000
 Then visit http://127.0.0.1:5000 , You should now be able to access the UI.
 
 See https://changedetection.io for more information.
-

README.md

@@ -183,6 +183,9 @@ docker compose pull && docker compose up -d
 
 See the wiki for more information https://github.com/dgtlmoon/changedetection.io/wiki
 
+## Different browser viewport sizes (mobile, desktop etc)
+
+If you are using the recommended `sockpuppetbrowser` (which is in the docker-compose.yml as a setting to be uncommented) you can easily set different viewport sizes for your web page change detection, [see more information here about setting up different viewport sizes](https://github.com/dgtlmoon/sockpuppetbrowser?tab=readme-ov-file#setting-viewport-size).
 
 ## Filters
 

babel.cfg

@@ -0,0 +1,5 @@
+[python: **.py]
+keywords = _:1,_l:1,gettext:1
+
+[jinja2: **/templates/**.html]
+encoding = utf-8

changedetectionio/PLUGIN_README.md

@@ -64,7 +64,7 @@ def count_words_in_history(watch):
             return 0
             
         latest_key = list(watch.history.keys())[-1]
-        latest_content = watch.get_history_snapshot(latest_key)
+        latest_content = watch.get_history_snapshot(timestamp=latest_key)
         return len(latest_content.split())
     except Exception as e:
         logger.error(f"Error counting words: {str(e)}")

changedetectionio/__init__.py

@@ -1,11 +1,12 @@
 #!/usr/bin/env python3
 
 # Read more https://github.com/dgtlmoon/changedetection.io/wiki
-
-__version__ = '0.50.39'
+# Semver means never use .01, or 00. Should be .1.
+__version__ = '0.52.8'
 
 from changedetectionio.strtobool import strtobool
 from json.decoder import JSONDecodeError
+import logging
 import os
 import getopt
 import platform
@@ -19,6 +20,58 @@ from changedetectionio import store
 from changedetectionio.flask_app import changedetection_app
 from loguru import logger
 
+# ==============================================================================
+# Multiprocessing Configuration - CRITICAL for Thread Safety
+# ==============================================================================
+#
+# PROBLEM: Python 3.12+ warns about fork() with multi-threaded processes:
+#   "This process is multi-threaded, use of fork() may lead to deadlocks"
+#
+# WHY IT'S DANGEROUS:
+#   1. This Flask app has multiple threads (HTTP handlers, workers, SocketIO)
+#   2. fork() copies ONLY the calling thread to the child process
+#   3. BUT fork() also copies all locks/mutexes in their current state
+#   4. If another thread held a lock during fork() → child has locked lock with no owner
+#   5. Result: PERMANENT DEADLOCK if child tries to acquire that lock
+#
+# SOLUTION: Use 'spawn' instead of 'fork'
+#   - spawn starts a fresh Python interpreter (no inherited threads or locks)
+#   - Slower (~200ms vs ~1ms) but safe with multi-threaded parent
+#   - Consistent across all platforms (Windows already uses spawn by default)
+#
+# IMPLEMENTATION:
+#   1. Explicit contexts everywhere (primary protection):
+#      - playwright.py: ctx = multiprocessing.get_context('spawn')
+#      - puppeteer.py: ctx = multiprocessing.get_context('spawn')
+#      - isolated_opencv.py: ctx = multiprocessing.get_context('spawn')
+#      - isolated_libvips.py: ctx = multiprocessing.get_context('spawn')
+#
+#   2. Global default (defense-in-depth, below):
+#      - Safety net if future code forgets explicit context
+#      - Protects against third-party libraries using Process()
+#      - Costs nothing (explicit contexts always override it)
+#
+# WHY BOTH?
+#   - Explicit contexts: Clear, self-documenting, always works
+#   - Global default: Safety net for forgotten contexts or library code
+#   - If someone writes "Process()" instead of "ctx.Process()", still safe!
+#
+# See: https://docs.python.org/3/library/multiprocessing.html#contexts-and-start-methods
+# ==============================================================================
+
+import multiprocessing
+import sys
+
+# Set spawn as global default (safety net - all our code uses explicit contexts anyway)
+# Skip in tests to avoid breaking pytest-flask's LiveServer fixture (uses unpicklable local functions)
+if 'pytest' not in sys.modules:
+    try:
+        if multiprocessing.get_start_method(allow_none=True) is None:
+            multiprocessing.set_start_method('spawn', force=False)
+            logger.debug("Set multiprocessing default to 'spawn' for thread safety (explicit contexts used everywhere)")
+    except RuntimeError:
+        logger.debug(f"Multiprocessing start method already set: {multiprocessing.get_start_method()}")
+
 # Only global so we can access it in the signal handler
 app = None
 datastore = None
@@ -74,6 +127,12 @@ def main():
 
     datastore_path = None
     do_cleanup = False
+    # Optional URL to watch since start
+    default_url = None
+    # Set a default logger level
+    logger_level = 'DEBUG'
+    include_default_watches = True
+
     host = os.environ.get("LISTEN_HOST", "0.0.0.0").strip()
     port = int(os.environ.get('PORT', 5000))
     ssl_mode = False
@@ -87,15 +146,13 @@ def main():
         datastore_path = os.path.join(os.getcwd(), "../datastore")
 
     try:
-        opts, args = getopt.getopt(sys.argv[1:], "6Ccsd:h:p:l:", "port")
+        opts, args = getopt.getopt(sys.argv[1:], "6Ccsd:h:p:l:u:", "port")
     except getopt.GetoptError:
-        print('backend.py -s SSL enable -h [host] -p [port] -d [datastore path] -l [debug level - TRACE, DEBUG(default), INFO, SUCCESS, WARNING, ERROR, CRITICAL]')
+        print('backend.py -s SSL enable -h [host] -p [port] -d [datastore path] -u [default URL to watch] -l [debug level - TRACE, DEBUG(default), INFO, SUCCESS, WARNING, ERROR, CRITICAL]')
         sys.exit(2)
 
     create_datastore_dir = False
 
-    # Set a default logger level
-    logger_level = 'DEBUG'
     # Set a logger level via shell env variable
     # Used: Dockerfile for CICD
     # To set logger level for pytest, see the app function in tests/conftest.py
@@ -116,6 +173,10 @@ def main():
         if opt == '-d':
             datastore_path = arg
 
+        if opt == '-u':
+            default_url = arg
+            include_default_watches = False
+
         # Cleanup (remove text files that arent in the index)
         if opt == '-c':
             do_cleanup = True
@@ -157,6 +218,11 @@ def main():
               " WARNING, ERROR, CRITICAL")
         sys.exit(2)
 
+    # Disable verbose pyppeteer logging to prevent memory leaks from large CDP messages
+    # Set both parent and child loggers since pyppeteer hardcodes DEBUG level
+    logging.getLogger('pyppeteer.connection').setLevel(logging.WARNING)
+    logging.getLogger('pyppeteer.connection.Connection').setLevel(logging.WARNING)
+
     # isnt there some @thingy to attach to each route to tell it, that this route needs a datastore
     app_config = {'datastore_path': datastore_path}
 
@@ -172,13 +238,20 @@ def main():
             sys.exit(2)
 
     try:
-        datastore = store.ChangeDetectionStore(datastore_path=app_config['datastore_path'], version_tag=__version__)
+        datastore = store.ChangeDetectionStore(datastore_path=app_config['datastore_path'], version_tag=__version__, include_default_watches=include_default_watches)
     except JSONDecodeError as e:
         # Dont' start if the JSON DB looks corrupt
         logger.critical(f"ERROR: JSON DB or Proxy List JSON at '{app_config['datastore_path']}' appears to be corrupt, aborting.")
         logger.critical(str(e))
         return
 
+    # Inject datastore into plugins that need access to settings
+    from changedetectionio.pluggy_interface import inject_datastore_into_plugins
+    inject_datastore_into_plugins(datastore)
+
+    if default_url:
+        datastore.add_watch(url = default_url)
+
     app = changedetection_app(app_config, datastore)
 
     # Get the SocketIO instance from the Flask app (created in flask_app.py)
@@ -214,7 +287,9 @@ def main():
         return dict(right_sticky="v{}".format(datastore.data['version_tag']),
                     new_version_available=app.config['NEW_VERSION_AVAILABLE'],
                     has_password=datastore.data['settings']['application']['password'] != False,
-                    socket_io_enabled=datastore.data['settings']['application']['ui'].get('socket_io_enabled', True)
+                    socket_io_enabled=datastore.data['settings']['application']['ui'].get('socket_io_enabled', True),
+                    all_paused=datastore.data['settings']['application'].get('all_paused', False),
+                    all_muted=datastore.data['settings']['application'].get('all_muted', False)
                     )
 
     # Monitored websites will not receive a Referer header when a user clicks on an outgoing link.

changedetectionio/api/Tags.py

@@ -2,7 +2,9 @@ from changedetectionio import queuedWatchMetaData
 from changedetectionio import worker_handler
 from flask_expects_json import expects_json
 from flask_restful import abort, Resource
+from loguru import logger
 
+import threading
 from flask import request
 from . import auth
 
@@ -28,18 +30,36 @@ class Tag(Resource):
             abort(404, message=f'No tag exists with the UUID of {uuid}')
 
         if request.args.get('recheck'):
-            # Recheck all, including muted
-            # Get most overdue first
-            i=0
+            # Recheck all watches with this tag, including muted
+            # First collect watches to queue
+            watches_to_queue = []
             for k in sorted(self.datastore.data['watching'].items(), key=lambda item: item[1].get('last_checked', 0)):
                 watch_uuid = k[0]
                 watch = k[1]
-                if not watch['paused'] and tag['uuid'] not in watch['tags']:
-                    continue
-                worker_handler.queue_item_async_safe(self.update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': watch_uuid}))
-                i+=1
+                if not watch['paused'] and tag['uuid'] in watch['tags']:
+                    watches_to_queue.append(watch_uuid)
 
-            return f"OK, {i} watches queued", 200
+            # If less than 20 watches, queue synchronously for immediate feedback
+            if len(watches_to_queue) < 20:
+                for watch_uuid in watches_to_queue:
+                    worker_handler.queue_item_async_safe(self.update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': watch_uuid}))
+                return {'status': f'OK, queued {len(watches_to_queue)} watches for rechecking'}, 200
+            else:
+                # 20+ watches - queue in background thread to avoid blocking API response
+                def queue_watches_background():
+                    """Background thread to queue watches - discarded after completion."""
+                    try:
+                        for watch_uuid in watches_to_queue:
+                            worker_handler.queue_item_async_safe(self.update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': watch_uuid}))
+                        logger.info(f"Background queueing complete for tag {tag['uuid']}: {len(watches_to_queue)} watches queued")
+                    except Exception as e:
+                        logger.error(f"Error in background queueing for tag {tag['uuid']}: {e}")
+
+                # Start background thread and return immediately
+                thread = threading.Thread(target=queue_watches_background, daemon=True, name=f"QueueTag-{tag['uuid'][:8]}")
+                thread.start()
+
+                return {'status': f'OK, queueing {len(watches_to_queue)} watches in background'}, 202
 
         if request.args.get('muted', '') == 'muted':
             self.datastore.data['settings']['application']['tags'][uuid]['notification_muted'] = True

changedetectionio/api/Watch.py

@@ -1,17 +1,22 @@
 import os
+import threading
 
 from changedetectionio.validate_url import is_safe_valid_url
+from changedetectionio.favicon_utils import get_favicon_mime_type
 
-from flask_expects_json import expects_json
-from changedetectionio import queuedWatchMetaData
-from changedetectionio import worker_handler
-from flask_restful import abort, Resource
-from flask import request, make_response, send_from_directory
 from . import auth
+from changedetectionio import queuedWatchMetaData, strtobool
+from changedetectionio import worker_handler
+from flask import request, make_response, send_from_directory
+from flask_expects_json import expects_json
+from flask_restful import abort, Resource
+from loguru import logger
 import copy
 
 # Import schemas from __init__.py
 from . import schema, schema_create_watch, schema_update_watch, validate_openapi_request
+from ..notification import valid_notification_formats
+from ..notification.handler import newline_re
 
 
 def validate_time_between_check_required(json_data):
@@ -61,8 +66,21 @@ class Watch(Resource):
     @validate_openapi_request('getWatch')
     def get(self, uuid):
         """Get information about a single watch, recheck, pause, or mute."""
+        import time
         from copy import deepcopy
-        watch = deepcopy(self.datastore.data['watching'].get(uuid))
+        watch = None
+        # Retry up to 20 times if dict is being modified
+        # With sleep(0), this is fast: ~200µs best case, ~20ms worst case under heavy load
+        for attempt in range(20):
+            try:
+                watch = deepcopy(self.datastore.data['watching'].get(uuid))
+                break
+            except RuntimeError:
+                # Dict changed during deepcopy, retry after yielding to scheduler
+                # sleep(0) releases GIL and yields - no fixed delay, just lets other threads run
+                if attempt < 19:  # Don't yield on last attempt
+                    time.sleep(0)  # Yield to scheduler (microseconds, not milliseconds)
+
         if not watch:
             abort(404, message='No watch exists with the UUID of {}'.format(uuid))
 
@@ -113,19 +131,86 @@ class Watch(Resource):
 
         if request.json.get('proxy'):
             plist = self.datastore.proxy_list
-            if not request.json.get('proxy') in plist:
-                return "Invalid proxy choice, currently supported proxies are '{}'".format(', '.join(plist)), 400
+            if not plist or request.json.get('proxy') not in plist:
+                proxy_list_str = ', '.join(plist) if plist else 'none configured'
+                return f"Invalid proxy choice, currently supported proxies are '{proxy_list_str}'", 400
 
         # Validate time_between_check when not using defaults
         validation_error = validate_time_between_check_required(request.json)
         if validation_error:
             return validation_error, 400
 
-        # XSS etc protection
-        if request.json.get('url') and not is_safe_valid_url(request.json.get('url')):
-            return "Invalid URL", 400
+        # XSS etc protection - validate URL if it's being updated
+        if 'url' in request.json:
+            new_url = request.json.get('url')
 
-        watch.update(request.json)
+            # URL must be a non-empty string
+            if new_url is None:
+                return "URL cannot be null", 400
+
+            if not isinstance(new_url, str):
+                return "URL must be a string", 400
+
+            if not new_url.strip():
+                return "URL cannot be empty or whitespace only", 400
+
+            if not is_safe_valid_url(new_url.strip()):
+                return "Invalid or unsupported URL format. URL must use http://, https://, or ftp:// protocol", 400
+
+        # Handle processor-config-* fields separately (save to JSON, not datastore)
+        from changedetectionio import processors
+        processor_config_data = {}
+        regular_data = {}
+
+        for key, value in request.json.items():
+            if key.startswith('processor_config_'):
+                config_key = key.replace('processor_config_', '')
+                if value:  # Only save non-empty values
+                    processor_config_data[config_key] = value
+            else:
+                regular_data[key] = value
+
+        # Update watch with regular (non-processor-config) fields
+        watch.update(regular_data)
+
+        # Save processor config to JSON file if any config data exists
+        if processor_config_data:
+            try:
+                processor_name = request.json.get('processor', watch.get('processor'))
+                if processor_name:
+                    # Create a processor instance to access config methods
+                    from changedetectionio.processors import difference_detection_processor
+                    processor_instance = difference_detection_processor(self.datastore, uuid)
+                    # Use processor name as filename so each processor keeps its own config
+                    config_filename = f'{processor_name}.json'
+                    processor_instance.update_extra_watch_config(config_filename, processor_config_data)
+                    logger.debug(f"API: Saved processor config to {config_filename}: {processor_config_data}")
+
+                    # Call optional edit_hook if processor has one
+                    try:
+                        import importlib
+                        edit_hook_module_name = f'changedetectionio.processors.{processor_name}.edit_hook'
+
+                        try:
+                            edit_hook = importlib.import_module(edit_hook_module_name)
+                            logger.debug(f"API: Found edit_hook module for {processor_name}")
+
+                            if hasattr(edit_hook, 'on_config_save'):
+                                logger.info(f"API: Calling edit_hook.on_config_save for {processor_name}")
+                                # Call hook and get updated config
+                                updated_config = edit_hook.on_config_save(watch, processor_config_data, self.datastore)
+                                # Save updated config back to file
+                                processor_instance.update_extra_watch_config(config_filename, updated_config)
+                                logger.info(f"API: Edit hook updated config: {updated_config}")
+                            else:
+                                logger.debug(f"API: Edit hook module found but no on_config_save function")
+                        except ModuleNotFoundError:
+                            logger.debug(f"API: No edit_hook module for processor {processor_name} (this is normal)")
+                    except Exception as hook_error:
+                        logger.error(f"API: Edit hook error (non-fatal): {hook_error}", exc_info=True)
+
+            except Exception as e:
+                logger.error(f"API: Failed to save processor config: {e}")
 
         return "OK", 200
 
@@ -166,6 +251,10 @@ class WatchSingleHistory(Resource):
         if timestamp == 'latest':
             timestamp = list(watch.history.keys())[-1]
 
+        # Validate that the timestamp exists in history
+        if timestamp not in watch.history:
+            abort(404, message=f"No history snapshot found for timestamp '{timestamp}'")
+
         if request.args.get('html'):
             content = watch.get_fetched_html(timestamp)
             if content:
@@ -175,12 +264,130 @@ class WatchSingleHistory(Resource):
                 response = make_response("No content found", 404)
                 response.mimetype = "text/plain"
         else:
-            content = watch.get_history_snapshot(timestamp)
+            content = watch.get_history_snapshot(timestamp=timestamp)
             response = make_response(content, 200)
             response.mimetype = "text/plain"
 
         return response
 
+class WatchHistoryDiff(Resource):
+    """
+    Generate diff between two historical snapshots.
+
+    Note: This API endpoint currently returns text-based diffs and works best
+    with the text_json_diff processor. Future processor types (like image_diff,
+    restock_diff) may want to implement their own specialized API endpoints
+    for returning processor-specific data (e.g., price charts, image comparisons).
+
+    The web UI diff page (/diff/<uuid>) is processor-aware and delegates rendering
+    to processors/{type}/difference.py::render() for processor-specific visualizations.
+    """
+    def __init__(self, **kwargs):
+        # datastore is a black box dependency
+        self.datastore = kwargs['datastore']
+
+    @auth.check_token
+    @validate_openapi_request('getWatchHistoryDiff')
+    def get(self, uuid, from_timestamp, to_timestamp):
+        """Generate diff between two historical snapshots."""
+        from changedetectionio import diff
+        from changedetectionio.notification.handler import apply_service_tweaks
+
+        watch = self.datastore.data['watching'].get(uuid)
+        if not watch:
+            abort(404, message=f"No watch exists with the UUID of {uuid}")
+
+        if not len(watch.history):
+            abort(404, message=f"Watch found but no history exists for the UUID {uuid}")
+
+        history_keys = list(watch.history.keys())
+
+        # Handle 'latest' keyword for to_timestamp
+        if to_timestamp == 'latest':
+            to_timestamp = history_keys[-1]
+
+        # Handle 'previous' keyword for from_timestamp (second-most-recent)
+        if from_timestamp == 'previous':
+            if len(history_keys) < 2:
+                abort(404, message=f"Not enough history entries. Need at least 2 snapshots for 'previous'")
+            from_timestamp = history_keys[-2]
+
+        # Validate timestamps exist
+        if from_timestamp not in watch.history:
+            abort(404, message=f"From timestamp {from_timestamp} not found in watch history")
+        if to_timestamp not in watch.history:
+            abort(404, message=f"To timestamp {to_timestamp} not found in watch history")
+
+        # Get the format parameter (default to 'text')
+        output_format = request.args.get('format', 'text').lower()
+
+        # Validate format
+        if output_format not in valid_notification_formats.keys():
+            abort(400, message=f"Invalid format. Must be one of: {', '.join(valid_notification_formats.keys())}")
+
+        # Get the word_diff parameter (default to False - line-level mode)
+        word_diff = strtobool(request.args.get('word_diff', 'false'))
+
+        # Get the no_markup parameter (default to False)
+        no_markup = strtobool(request.args.get('no_markup', 'false'))
+
+        # Retrieve snapshot contents
+        from_version_file_contents = watch.get_history_snapshot(from_timestamp)
+        to_version_file_contents = watch.get_history_snapshot(to_timestamp)
+
+        # Get diff preferences from query parameters (matching UI preferences in DIFF_PREFERENCES_CONFIG)
+        # Support both 'type' (UI parameter) and 'word_diff' (API parameter) for backward compatibility
+        diff_type = request.args.get('type', 'diffLines')
+        if diff_type == 'diffWords':
+            word_diff = True
+
+        # Get boolean diff preferences with defaults from DIFF_PREFERENCES_CONFIG
+        changes_only = strtobool(request.args.get('changesOnly', 'true'))
+        ignore_whitespace = strtobool(request.args.get('ignoreWhitespace', 'false'))
+        include_removed = strtobool(request.args.get('removed', 'true'))
+        include_added = strtobool(request.args.get('added', 'true'))
+        include_replaced = strtobool(request.args.get('replaced', 'true'))
+
+        # Generate the diff with all preferences
+        content = diff.render_diff(
+            previous_version_file_contents=from_version_file_contents,
+            newest_version_file_contents=to_version_file_contents,
+            ignore_junk=ignore_whitespace,
+            include_equal=changes_only,
+            include_removed=include_removed,
+            include_added=include_added,
+            include_replaced=include_replaced,
+            word_diff=word_diff,
+        )
+
+        # Skip formatting if no_markup is set
+        if no_markup:
+            mimetype = "text/plain"
+        else:
+            # Apply formatting based on the requested format
+            if output_format == 'htmlcolor':
+                from changedetectionio.notification.handler import apply_html_color_to_body
+                content = apply_html_color_to_body(n_body=content)
+                mimetype = "text/html"
+            else:
+                # Apply service tweaks for text/html formats
+                # Pass empty URL and title as they're not used for the placeholder replacement we need
+                _, content, _ = apply_service_tweaks(
+                    url='',
+                    n_body=content,
+                    n_title='',
+                    requested_output_format=output_format
+                )
+                mimetype = "text/html" if output_format == 'html' else "text/plain"
+
+            if 'html' in output_format:
+                content = newline_re.sub('<br>\r\n', content)
+
+        response = make_response(content, 200)
+        response.mimetype = mimetype
+        return response
+
+
 class WatchFavicon(Resource):
     def __init__(self, **kwargs):
         # datastore is a black box dependency
@@ -196,16 +403,9 @@ class WatchFavicon(Resource):
 
         favicon_filename = watch.get_favicon_filename()
         if favicon_filename:
-            try:
-                import magic
-                mime = magic.from_file(
-                    os.path.join(watch.watch_data_dir, favicon_filename),
-                    mime=True
-                )
-            except ImportError:
-                # Fallback, no python-magic
-                import mimetypes
-                mime, encoding = mimetypes.guess_type(favicon_filename)
+            # Use cached MIME type detection
+            filepath = os.path.join(watch.watch_data_dir, favicon_filename)
+            mime = get_favicon_mime_type(filepath)
 
             response = make_response(send_from_directory(watch.watch_data_dir, favicon_filename))
             response.headers['Content-type'] = mime
@@ -235,8 +435,9 @@ class CreateWatch(Resource):
 
         if json_data.get('proxy'):
             plist = self.datastore.proxy_list
-            if not json_data.get('proxy') in plist:
-                return "Invalid proxy choice, currently supported proxies are '{}'".format(', '.join(plist)), 400
+            if not plist or json_data.get('proxy') not in plist:
+                proxy_list_str = ', '.join(plist) if plist else 'none configured'
+                return f"Invalid proxy choice, currently supported proxies are '{proxy_list_str}'", 400
 
         # Validate time_between_check when not using defaults
         validation_error = validate_time_between_check_required(json_data)
@@ -255,7 +456,8 @@ class CreateWatch(Resource):
 
         new_uuid = self.datastore.add_watch(url=url, extras=extras, tag=tags)
         if new_uuid:
-            worker_handler.queue_item_async_safe(self.update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': new_uuid}))
+# Dont queue because the scheduler will check that it hasnt been checked before anyway
+#            worker_handler.queue_item_async_safe(self.update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': new_uuid}))
             return {'uuid': new_uuid}, 201
         else:
             return "Invalid or unsupported URL", 400
@@ -285,8 +487,58 @@ class CreateWatch(Resource):
             }
 
         if request.args.get('recheck_all'):
-            for uuid in self.datastore.data['watching'].keys():
-                worker_handler.queue_item_async_safe(self.update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': uuid}))
-            return {'status': "OK"}, 200
+            # Collect all watches to queue
+            watches_to_queue = self.datastore.data['watching'].keys()
+
+            # If less than 20 watches, queue synchronously for immediate feedback
+            if len(watches_to_queue) < 20:
+                # Get already queued/running UUIDs once (efficient)
+                queued_uuids = set(self.update_q.get_queued_uuids())
+                running_uuids = set(worker_handler.get_running_uuids())
+
+                # Filter out watches that are already queued or running
+                watches_to_queue_filtered = [
+                    uuid for uuid in watches_to_queue
+                    if uuid not in queued_uuids and uuid not in running_uuids
+                ]
+
+                # Queue only the filtered watches
+                for uuid in watches_to_queue_filtered:
+                    worker_handler.queue_item_async_safe(self.update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': uuid}))
+
+                # Provide feedback about skipped watches
+                skipped_count = len(watches_to_queue) - len(watches_to_queue_filtered)
+                if skipped_count > 0:
+                    return {'status': f'OK, queued {len(watches_to_queue_filtered)} watches for rechecking ({skipped_count} already queued or running)'}, 200
+                else:
+                    return {'status': f'OK, queued {len(watches_to_queue_filtered)} watches for rechecking'}, 200
+            else:
+                # 20+ watches - queue in background thread to avoid blocking API response
+                # Capture queued/running state before background thread
+                queued_uuids = set(self.update_q.get_queued_uuids())
+                running_uuids = set(worker_handler.get_running_uuids())
+
+                def queue_all_watches_background():
+                    """Background thread to queue all watches - discarded after completion."""
+                    try:
+                        queued_count = 0
+                        skipped_count = 0
+                        for uuid in watches_to_queue:
+                            # Check if already queued or running (state captured at start)
+                            if uuid not in queued_uuids and uuid not in running_uuids:
+                                worker_handler.queue_item_async_safe(self.update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': uuid}))
+                                queued_count += 1
+                            else:
+                                skipped_count += 1
+
+                        logger.info(f"Background queueing complete: {queued_count} watches queued, {skipped_count} skipped (already queued/running)")
+                    except Exception as e:
+                        logger.error(f"Error in background queueing all watches: {e}")
+
+                # Start background thread and return immediately
+                thread = threading.Thread(target=queue_all_watches_background, daemon=True, name="QueueAllWatches-Background")
+                thread.start()
+
+                return {'status': f'OK, queueing {len(watches_to_queue)} watches in background'}, 202
 
         return list, 200

changedetectionio/api/__init__.py

@@ -41,7 +41,7 @@ def get_openapi_spec():
         # Possibly for pip3 packages
         spec_path = os.path.join(os.path.dirname(__file__), '../docs/api-spec.yaml')
 
-    with open(spec_path, 'r') as f:
+    with open(spec_path, 'r', encoding='utf-8') as f:
         spec_dict = yaml.safe_load(f)
     _openapi_spec = OpenAPI.from_dict(spec_dict)
     return _openapi_spec
@@ -51,6 +51,7 @@ def validate_openapi_request(operation_id):
     def decorator(f):
         @functools.wraps(f)
         def wrapper(*args, **kwargs):
+            from werkzeug.exceptions import BadRequest
             try:
                 # Skip OpenAPI validation for GET requests since they don't have request bodies
                 if request.method.upper() != 'GET':
@@ -61,7 +62,6 @@ def validate_openapi_request(operation_id):
                     openapi_request = FlaskOpenAPIRequest(request)
                     result = spec.unmarshal_request(openapi_request)
                     if result.errors:
-                        from werkzeug.exceptions import BadRequest
                         error_details = []
                         for error in result.errors:
                             error_details.append(str(error))
@@ -78,7 +78,7 @@ def validate_openapi_request(operation_id):
     return decorator
 
 # Import all API resources
-from .Watch import Watch, WatchHistory, WatchSingleHistory, CreateWatch, WatchFavicon
+from .Watch import Watch, WatchHistory, WatchSingleHistory, WatchHistoryDiff, CreateWatch, WatchFavicon
 from .Tags import Tags, Tag
 from .Import import Import
 from .SystemInfo import SystemInfo

changedetectionio/async_update_worker.py

@@ -1,3 +1,4 @@
+from blinker import signal
 from .processors.exceptions import ProcessorException
 import changedetectionio.content_fetchers.exceptions as content_fetchers_exceptions
 from changedetectionio.processors.text_json_diff.processor import FilterNotFoundInResponse
@@ -7,7 +8,7 @@ from changedetectionio.flask_app import watch_check_update
 import asyncio
 import importlib
 import os
-import queue
+import sys
 import time
 
 from loguru import logger
@@ -15,38 +16,67 @@ from loguru import logger
 # Async version of update_worker
 # Processes jobs from AsyncSignalPriorityQueue instead of threaded queue
 
-async def async_update_worker(worker_id, q, notification_q, app, datastore):
+IN_PYTEST = "pytest" in sys.modules or "PYTEST_CURRENT_TEST" in os.environ
+DEFER_SLEEP_TIME_ALREADY_QUEUED = 0.3 if IN_PYTEST else 10.0
+
+async def async_update_worker(worker_id, q, notification_q, app, datastore, executor=None):
     """
     Async worker function that processes watch check jobs from the queue.
-    
+
     Args:
         worker_id: Unique identifier for this worker
         q: AsyncSignalPriorityQueue containing jobs to process
         notification_q: Standard queue for notifications
         app: Flask application instance
         datastore: Application datastore
+        executor: ThreadPoolExecutor for queue operations (optional)
+
+    Returns:
+        "restart" if worker should restart, "shutdown" for clean exit
     """
     # Set a descriptive name for this task
     task = asyncio.current_task()
     if task:
         task.set_name(f"async-worker-{worker_id}")
-    
-    logger.info(f"Starting async worker {worker_id}")
-    
+
+    # Read restart policy from environment
+    max_jobs = int(os.getenv("WORKER_MAX_JOBS", "10"))
+    max_runtime_seconds = int(os.getenv("WORKER_MAX_RUNTIME", "3600"))  # 1 hour default
+
+    jobs_processed = 0
+    start_time = time.time()
+
+    logger.info(f"Starting async worker {worker_id} (max_jobs={max_jobs}, max_runtime={max_runtime_seconds}s)")
+
     while not app.config.exit.is_set():
         update_handler = None
         watch = None
 
         try:
-            # Use native janus async interface - no threads needed!
-            queued_item_data = await asyncio.wait_for(q.async_get(), timeout=1.0)
-            
+            # Use sync interface via run_in_executor since each worker has its own event loop
+            loop = asyncio.get_event_loop()
+            queued_item_data = await asyncio.wait_for(
+                loop.run_in_executor(executor, q.get, True, 1.0),  # block=True, timeout=1.0
+                timeout=1.5
+            )
+
         except asyncio.TimeoutError:
-            # No jobs available, continue loop
+            # No jobs available - check if we should restart based on time while idle
+            runtime = time.time() - start_time
+            if runtime >= max_runtime_seconds:
+                logger.info(f"Worker {worker_id} idle and reached max runtime ({runtime:.0f}s), restarting")
+                return "restart"
             continue
         except Exception as e:
+            # Handle expected Empty exception from queue timeout
+            import queue
+            if isinstance(e, queue.Empty):
+                # Queue is empty, normal behavior - just continue
+                continue
+
+            # Unexpected exception - log as critical
             logger.critical(f"CRITICAL: Worker {worker_id} failed to get queue item: {type(e).__name__}: {e}")
-            
+
             # Log queue health for debugging
             try:
                 queue_size = q.qsize()
@@ -54,16 +84,30 @@ async def async_update_worker(worker_id, q, notification_q, app, datastore):
                 logger.critical(f"CRITICAL: Worker {worker_id} queue health - size: {queue_size}, empty: {is_empty}")
             except Exception as health_e:
                 logger.critical(f"CRITICAL: Worker {worker_id} queue health check failed: {health_e}")
-            
+
             await asyncio.sleep(0.1)
             continue
-        
+
         uuid = queued_item_data.item.get('uuid')
-        fetch_start_time = round(time.time())
-        
-        # Mark this UUID as being processed
+        # RACE CONDITION FIX: Check if this UUID is already being processed by another worker
         from changedetectionio import worker_handler
-        worker_handler.set_uuid_processing(uuid, processing=True)
+        from changedetectionio.queuedWatchMetaData import PrioritizedItem
+        if worker_handler.is_watch_running_by_another_worker(uuid, worker_id):
+            logger.trace(f"Worker {worker_id} detected UUID {uuid} already being processed by another worker - deferring")
+            # Sleep to avoid tight loop and give the other worker time to finish
+            await asyncio.sleep(DEFER_SLEEP_TIME_ALREADY_QUEUED)
+
+            # Re-queue with lower priority so it gets checked again after current processing finishes
+            deferred_priority = max(1000, queued_item_data.priority * 10)
+            deferred_item = PrioritizedItem(priority=deferred_priority, item=queued_item_data.item)
+            worker_handler.queue_item_async_safe(q, deferred_item, silent=True)
+            logger.debug(f"Worker {worker_id} re-queued UUID {uuid} for subsequent check")
+            continue
+
+        fetch_start_time = round(time.time())
+
+        # Mark this UUID as being processed by this worker
+        worker_handler.set_uuid_processing(uuid, worker_id=worker_id, processing=True)
         
         try:
             if uuid in list(datastore.data['watching'].keys()) and datastore.data['watching'][uuid].get('url'):
@@ -87,9 +131,8 @@ async def async_update_worker(worker_id, q, notification_q, app, datastore):
                     processor = watch.get('processor', 'text_json_diff')
 
                     # Init a new 'difference_detection_processor'
-                    processor_module_name = f"changedetectionio.processors.{processor}.processor"
                     try:
-                        processor_module = importlib.import_module(processor_module_name)
+                        processor_module = importlib.import_module(f"changedetectionio.processors.{processor}.processor")
                     except ModuleNotFoundError as e:
                         print(f"Processor module '{processor}' not found.")
                         raise e
@@ -97,11 +140,20 @@ async def async_update_worker(worker_id, q, notification_q, app, datastore):
                     update_handler = processor_module.perform_site_check(datastore=datastore,
                                                                          watch_uuid=uuid)
 
+                    update_signal = signal('watch_small_status_comment')
+                    update_signal.send(watch_uuid=uuid, status="Fetching page..")
+
                     # All fetchers are now async, so call directly
                     await update_handler.call_browser()
 
-                    # Run change detection (this is synchronous)
-                    changed_detected, update_obj, contents = update_handler.run_changedetection(watch=watch)
+                    # Run change detection in executor to avoid blocking event loop
+                    # This includes CPU-intensive operations like HTML parsing (lxml/inscriptis)
+                    # which can take 2-10ms and cause GIL contention across workers
+                    loop = asyncio.get_event_loop()
+                    changed_detected, update_obj, contents = await loop.run_in_executor(
+                        executor,
+                        lambda: update_handler.run_changedetection(watch=watch)
+                    )
 
                 except PermissionError as e:
                     logger.critical(f"File permission error updating file, watch: {uuid}")
@@ -309,6 +361,7 @@ async def async_update_worker(worker_id, q, notification_q, app, datastore):
                 if not datastore.data['watching'].get(uuid):
                     continue
 
+                logger.debug(f"Processing watch UUID: {uuid} - xpath_data length returned {len(update_handler.xpath_data) if update_handler.xpath_data else 'empty.'}")
                 if process_changedetection_results:
                     try:
                         datastore.update_watch(uuid=uuid, update_obj=update_obj)
@@ -326,7 +379,7 @@ async def async_update_worker(worker_id, q, notification_q, app, datastore):
                                 fetch_start_time += 1
                                 await asyncio.sleep(1)
 
-                            watch.save_history_text(contents=contents,
+                            watch.save_history_blob(contents=contents,
                                                     timestamp=int(fetch_start_time),
                                                     snapshot_id=update_obj.get('previous_md5', 'none'))
 
@@ -353,12 +406,15 @@ async def async_update_worker(worker_id, q, notification_q, app, datastore):
                 count = watch.get('check_count', 0) + 1
 
                 # Always record page title (used in notifications, and can change even when the content is the same)
-                try:
-                    page_title = html_tools.extract_title(data=update_handler.fetcher.content)
-                    logger.debug(f"UUID: {uuid} Page <title> is '{page_title}'")
-                    datastore.update_watch(uuid=uuid, update_obj={'page_title': page_title})
-                except Exception as e:
-                    logger.warning(f"UUID: {uuid} Exception when extracting <title> - {str(e)}")
+                if update_obj.get('content-type') and 'html' in update_obj.get('content-type'):
+                    try:
+                        page_title = html_tools.extract_title(data=update_handler.fetcher.content)
+                        if page_title:
+                            page_title = page_title.strip()[:2000]
+                            logger.debug(f"UUID: {uuid} Page <title> is '{page_title}'")
+                            datastore.update_watch(uuid=uuid, update_obj={'page_title': page_title})
+                    except Exception as e:
+                        logger.warning(f"UUID: {uuid} Exception when extracting <title> - {str(e)}")
 
                 # Record server header
                 try:
@@ -394,8 +450,13 @@ async def async_update_worker(worker_id, q, notification_q, app, datastore):
             # Always cleanup - this runs whether there was an exception or not
             if uuid:
                 try:
-                    # Mark UUID as no longer being processed
-                    worker_handler.set_uuid_processing(uuid, processing=False)
+                    if update_handler and hasattr(update_handler, 'fetcher') and update_handler.fetcher:
+                        await update_handler.fetcher.quit(watch=watch)
+                except Exception as e:
+                    logger.error(f"Exception while cleaning/quit after calling browser: {e}")
+                try:
+                    # Mark UUID as no longer being processed by this worker
+                    worker_handler.set_uuid_processing(uuid, worker_id=worker_id, processing=False)
                     
                     # Send completion signal
                     if watch:
@@ -424,10 +485,16 @@ async def async_update_worker(worker_id, q, notification_q, app, datastore):
                     # 3. GC can't collect the object anyway (still referenced by datastore)
                     # 4. It would just cause confusion
 
+                    # Force garbage collection after cleanup
+                    import gc
+                    gc.collect()
+
                     logger.debug(f"Worker {worker_id} completed watch {uuid} in {time.time()-fetch_start_time:.2f}s")
                 except Exception as cleanup_error:
                     logger.error(f"Worker {worker_id} error during cleanup: {cleanup_error}")
-            
+
+            del(uuid)
+
             # Brief pause before continuing to avoid tight error loops (only on error)
             if 'e' in locals():
                 await asyncio.sleep(1.0)
@@ -435,6 +502,19 @@ async def async_update_worker(worker_id, q, notification_q, app, datastore):
                 # Small yield for normal completion
                 await asyncio.sleep(0.01)
 
+            # Job completed - increment counter and check restart conditions
+            jobs_processed += 1
+            runtime = time.time() - start_time
+
+            # Check if we should restart (only when idle, between jobs)
+            should_restart_jobs = jobs_processed >= max_jobs
+            should_restart_time = runtime >= max_runtime_seconds
+
+            if should_restart_jobs or should_restart_time:
+                reason = f"{jobs_processed} jobs" if should_restart_jobs else f"{runtime:.0f}s runtime"
+                logger.info(f"Worker {worker_id} restarting after {reason} ({jobs_processed} jobs, {runtime:.0f}s runtime)")
+                return "restart"
+
         # Check if we should exit
         if app.config.exit.is_set():
             break
@@ -442,10 +522,12 @@ async def async_update_worker(worker_id, q, notification_q, app, datastore):
     # Check if we're in pytest environment - if so, be more gentle with logging
     import sys
     in_pytest = "pytest" in sys.modules or "PYTEST_CURRENT_TEST" in os.environ
-    
+
     if not in_pytest:
         logger.info(f"Worker {worker_id} shutting down")
 
+    return "shutdown"
+
 
 def cleanup_error_artifacts(uuid, datastore):
     """Helper function to clean up error artifacts"""

changedetectionio/blueprint/backups/__init__.py

@@ -3,6 +3,7 @@ import glob
 import threading
 
 from flask import Blueprint, render_template, send_from_directory, flash, url_for, redirect, abort
+from flask_babel import gettext
 import os
 
 from changedetectionio.store import ChangeDetectionStore
@@ -82,19 +83,24 @@ def construct_blueprint(datastore: ChangeDetectionStore):
     @backups_blueprint.route("/request-backup", methods=['GET'])
     def request_backup():
         if any(thread.is_alive() for thread in backup_threads):
-            flash("A backup is already running, check back in a few minutes", "error")
+            flash(gettext("A backup is already running, check back in a few minutes"), "error")
             return redirect(url_for('backups.index'))
 
         if len(find_backups()) > int(os.getenv("MAX_NUMBER_BACKUPS", 100)):
-            flash("Maximum number of backups reached, please remove some", "error")
+            flash(gettext("Maximum number of backups reached, please remove some"), "error")
             return redirect(url_for('backups.index'))
 
         # Be sure we're written fresh
         datastore.sync_to_json()
-        zip_thread = threading.Thread(target=create_backup, args=(datastore.datastore_path, datastore.data.get("watching")))
+        zip_thread = threading.Thread(
+            target=create_backup,
+            args=(datastore.datastore_path, datastore.data.get("watching")),
+            daemon=True,
+            name="BackupCreator"
+        )
         zip_thread.start()
         backup_threads.append(zip_thread)
-        flash("Backup building in background, check back in a few minutes.")
+        flash(gettext("Backup building in background, check back in a few minutes."))
 
         return redirect(url_for('backups.index'))
 
@@ -157,7 +163,7 @@ def construct_blueprint(datastore: ChangeDetectionStore):
         for backup in backups:
             os.unlink(backup)
 
-        flash("Backups were deleted.")
+        flash(gettext("Backups were deleted."))
 
         return redirect(url_for('backups.index'))
 

changedetectionio/blueprint/backups/templates/overview.html

@@ -3,31 +3,31 @@
     {% from '_helpers.html' import render_simple_field, render_field %}
     <div class="edit-form">
         <div class="box-wrap inner">
-            <h4>Backups</h4>
+            <h4>{{ _('Backups') }}</h4>
             {% if backup_running %}
                 <p>
-                    <strong>A backup is running!</strong>
+                    <strong>{{ _('A backup is running!') }}</strong>
                 </p>
             {% endif %}
             <p>
-                Here you can download and request a new backup, when a backup is completed you will see it listed below.
+                {{ _('Here you can download and request a new backup, when a backup is completed you will see it listed below.') }}
             </p>
             <br>
                 {% if available_backups %}
                     <ul>
                     {% for backup in available_backups %}
-                        <li><a href="{{ url_for('backups.download_backup', filename=backup["filename"]) }}">{{ backup["filename"] }}</a> {{  backup["filesize"] }} Mb</li>
+                        <li><a href="{{ url_for('backups.download_backup', filename=backup["filename"]) }}">{{ backup["filename"] }}</a> {{  backup["filesize"] }} {{ _('Mb') }}</li>
                     {% endfor %}
                     </ul>
                 {% else %}
                     <p>
-                    <strong>No backups found.</strong>
+                    <strong>{{ _('No backups found.') }}</strong>
                     </p>
                 {% endif %}
 
-            <a class="pure-button pure-button-primary" href="{{ url_for('backups.request_backup') }}">Create backup</a>
+            <a class="pure-button pure-button-primary" href="{{ url_for('backups.request_backup') }}">{{ _('Create backup') }}</a>
             {% if available_backups %}
-                <a class="pure-button button-small button-error " href="{{ url_for('backups.remove_backups') }}">Remove backups</a>
+                <a class="pure-button button-small button-error " href="{{ url_for('backups.remove_backups') }}">{{ _('Remove backups') }}</a>
             {% endif %}
         </div>
     </div>

changedetectionio/blueprint/browser_steps/__init__.py

@@ -21,31 +21,154 @@ from changedetectionio.flask_app import login_optionally_required
 from loguru import logger
 
 browsersteps_sessions = {}
+browsersteps_watch_to_session = {}  # Maps watch_uuid -> browsersteps_session_id
 io_interface_context = None
 import json
 import hashlib
 from flask import Response
 import asyncio
 import threading
+import time
 
-def run_async_in_browser_loop(coro):
-    """Run async coroutine using the existing async worker event loop"""
-    from changedetectionio import worker_handler
-    
-    # Use the existing async worker event loop instead of creating a new one
-    if worker_handler.USE_ASYNC_WORKERS and worker_handler.async_loop and not worker_handler.async_loop.is_closed():
-        logger.debug("Browser steps using existing async worker event loop")
-        future = asyncio.run_coroutine_threadsafe(coro, worker_handler.async_loop)
-        return future.result()
-    else:
-        # Fallback: create a new event loop (for sync workers or if async loop not available)
-        logger.debug("Browser steps creating temporary event loop")
-        loop = asyncio.new_event_loop()
-        asyncio.set_event_loop(loop)
+# Dedicated event loop for ALL browser steps sessions
+_browser_steps_loop = None
+_browser_steps_thread = None
+_browser_steps_loop_lock = threading.Lock()
+
+def _start_browser_steps_loop():
+    """Start a dedicated event loop for browser steps in its own thread"""
+    global _browser_steps_loop
+
+    # Create and set the event loop for this thread
+    loop = asyncio.new_event_loop()
+    asyncio.set_event_loop(loop)
+    _browser_steps_loop = loop
+
+    logger.debug("Browser steps event loop started")
+
+    try:
+        # Run the loop forever - handles all browsersteps sessions
+        loop.run_forever()
+    except Exception as e:
+        logger.error(f"Browser steps event loop error: {e}")
+    finally:
         try:
-            return loop.run_until_complete(coro)
+            # Cancel all remaining tasks
+            pending = asyncio.all_tasks(loop)
+            for task in pending:
+                task.cancel()
+
+            # Wait for tasks to finish cancellation
+            if pending:
+                loop.run_until_complete(asyncio.gather(*pending, return_exceptions=True))
+        except Exception as e:
+            logger.debug(f"Error during browser steps loop cleanup: {e}")
         finally:
             loop.close()
+            logger.debug("Browser steps event loop closed")
+
+def _ensure_browser_steps_loop():
+    """Ensure the browser steps event loop is running"""
+    global _browser_steps_loop, _browser_steps_thread
+
+    with _browser_steps_loop_lock:
+        if _browser_steps_thread is None or not _browser_steps_thread.is_alive():
+            logger.debug("Starting browser steps event loop thread")
+            _browser_steps_thread = threading.Thread(
+                target=_start_browser_steps_loop,
+                daemon=True,
+                name="BrowserStepsEventLoop"
+            )
+            _browser_steps_thread.start()
+
+            # Wait for the loop to be ready
+            timeout = 5.0
+            start_time = time.time()
+            while _browser_steps_loop is None:
+                if time.time() - start_time > timeout:
+                    raise RuntimeError("Browser steps event loop failed to start")
+                time.sleep(0.01)
+
+            logger.debug("Browser steps event loop thread started and ready")
+
+def run_async_in_browser_loop(coro):
+    """Run async coroutine using the dedicated browser steps event loop"""
+    _ensure_browser_steps_loop()
+
+    if _browser_steps_loop and not _browser_steps_loop.is_closed():
+        logger.debug("Browser steps using dedicated event loop")
+        future = asyncio.run_coroutine_threadsafe(coro, _browser_steps_loop)
+        return future.result()
+    else:
+        raise RuntimeError("Browser steps event loop is not available")
+
+def cleanup_expired_sessions():
+    """Remove expired browsersteps sessions and cleanup their resources"""
+    global browsersteps_sessions, browsersteps_watch_to_session
+
+    expired_session_ids = []
+
+    # Find expired sessions
+    for session_id, session_data in browsersteps_sessions.items():
+        browserstepper = session_data.get('browserstepper')
+        if browserstepper and browserstepper.has_expired:
+            expired_session_ids.append(session_id)
+
+    # Cleanup expired sessions
+    for session_id in expired_session_ids:
+        logger.debug(f"Cleaning up expired browsersteps session {session_id}")
+        session_data = browsersteps_sessions[session_id]
+
+        # Cleanup playwright resources asynchronously
+        browserstepper = session_data.get('browserstepper')
+        if browserstepper:
+            try:
+                run_async_in_browser_loop(browserstepper.cleanup())
+            except Exception as e:
+                logger.error(f"Error cleaning up session {session_id}: {e}")
+
+        # Remove from sessions dict
+        del browsersteps_sessions[session_id]
+
+        # Remove from watch mapping
+        for watch_uuid, mapped_session_id in list(browsersteps_watch_to_session.items()):
+            if mapped_session_id == session_id:
+                del browsersteps_watch_to_session[watch_uuid]
+                break
+
+    if expired_session_ids:
+        logger.info(f"Cleaned up {len(expired_session_ids)} expired browsersteps session(s)")
+
+def cleanup_session_for_watch(watch_uuid):
+    """Cleanup a specific browsersteps session for a watch UUID"""
+    global browsersteps_sessions, browsersteps_watch_to_session
+
+    session_id = browsersteps_watch_to_session.get(watch_uuid)
+    if not session_id:
+        logger.debug(f"No browsersteps session found for watch {watch_uuid}")
+        return
+
+    logger.debug(f"Cleaning up browsersteps session {session_id} for watch {watch_uuid}")
+
+    session_data = browsersteps_sessions.get(session_id)
+    if session_data:
+        browserstepper = session_data.get('browserstepper')
+        if browserstepper:
+            try:
+                run_async_in_browser_loop(browserstepper.cleanup())
+            except Exception as e:
+                logger.error(f"Error cleaning up session {session_id} for watch {watch_uuid}: {e}")
+
+        # Remove from sessions dict
+        del browsersteps_sessions[session_id]
+
+    # Remove from watch mapping
+    del browsersteps_watch_to_session[watch_uuid]
+
+    logger.debug(f"Cleaned up session for watch {watch_uuid}")
+
+    # Opportunistically cleanup any other expired sessions
+    cleanup_expired_sessions()
 
 def construct_blueprint(datastore: ChangeDetectionStore):
     browser_steps_blueprint = Blueprint('browser_steps', __name__, template_folder="templates")
@@ -123,6 +246,9 @@ def construct_blueprint(datastore: ChangeDetectionStore):
         if not watch_uuid:
             return make_response('No Watch UUID specified', 500)
 
+        # Cleanup any existing session for this watch
+        cleanup_session_for_watch(watch_uuid)
+
         logger.debug("Starting connection with playwright")
         logger.debug("browser_steps.py connecting")
 
@@ -131,6 +257,10 @@ def construct_blueprint(datastore: ChangeDetectionStore):
             browsersteps_sessions[browsersteps_session_id] = run_async_in_browser_loop(
                 start_browsersteps_session(watch_uuid)
             )
+
+            # Store the mapping of watch_uuid -> browsersteps_session_id
+            browsersteps_watch_to_session[watch_uuid] = browsersteps_session_id
+
         except Exception as e:
             if 'ECONNREFUSED' in str(e):
                 return make_response('Unable to start the Playwright Browser session, is sockpuppetbrowser running? Network configuration is OK?', 401)

changedetectionio/blueprint/browser_steps/browser_steps.py

@@ -439,7 +439,7 @@ class browsersteps_live_ui(steppable_browser_interface):
             logger.warning("Attempted to get current state after cleanup")
             return (None, None)
 
-        xpath_element_js = importlib.resources.files("changedetectionio.content_fetchers.res").joinpath('xpath_element_scraper.js').read_text()
+        xpath_element_js = importlib.resources.files("changedetectionio.content_fetchers.res").joinpath('xpath_element_scraper.js').read_text(encoding="utf-8")
 
         now = time.time()
         await self.page.wait_for_timeout(1 * 1000)

changedetectionio/blueprint/imports/__init__.py

@@ -1,13 +1,8 @@
 from flask import Blueprint, request, redirect, url_for, flash, render_template
+from loguru import logger
+
 from changedetectionio.store import ChangeDetectionStore
 from changedetectionio.auth_decorator import login_optionally_required
-from changedetectionio import worker_handler
-from changedetectionio.blueprint.imports.importer import (
-    import_url_list, 
-    import_distill_io_json, 
-    import_xlsx_wachete, 
-    import_xlsx_custom
-)
 
 def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMetaData):
     import_blueprint = Blueprint('imports', __name__, template_folder="templates")
@@ -17,15 +12,26 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMe
     def import_page():
         remaining_urls = []
         from changedetectionio import forms
-
+#
         if request.method == 'POST':
+#            from changedetectionio import worker_handler
+
+            from changedetectionio.blueprint.imports.importer import (
+                import_url_list,
+                import_distill_io_json,
+                import_xlsx_wachete,
+                import_xlsx_custom
+            )
+
             # URL List import
             if request.values.get('urls') and len(request.values.get('urls').strip()):
                 # Import and push into the queue for immediate update check
                 importer_handler = import_url_list()
                 importer_handler.run(data=request.values.get('urls'), flash=flash, datastore=datastore, processor=request.values.get('processor', 'text_json_diff'))
-                for uuid in importer_handler.new_uuids:
-                    worker_handler.queue_item_async_safe(update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': uuid}))
+                logger.debug(f"Imported {len(importer_handler.new_uuids)} new UUIDs")
+                # Dont' add to queue because scheduler can see that they haven't been checked and will add them to the queue
+#                for uuid in importer_handler.new_uuids:
+#                    worker_handler.queue_item_async_safe(update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': uuid}))
 
                 if len(importer_handler.remaining_data) == 0:
                     return redirect(url_for('watchlist.index'))
@@ -37,8 +43,10 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMe
                 # Import and push into the queue for immediate update check
                 d_importer = import_distill_io_json()
                 d_importer.run(data=request.values.get('distill-io'), flash=flash, datastore=datastore)
-                for uuid in d_importer.new_uuids:
-                    worker_handler.queue_item_async_safe(update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': uuid}))
+                # Dont' add to queue because scheduler can see that they haven't been checked and will add them to the queue
+#                for uuid in importer_handler.new_uuids:
+#                    worker_handler.queue_item_async_safe(update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': uuid}))
+
 
             # XLSX importer
             if request.files and request.files.get('xlsx_file'):
@@ -60,8 +68,10 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMe
                     w_importer.import_profile = map
                     w_importer.run(data=file, flash=flash, datastore=datastore)
 
-                for uuid in w_importer.new_uuids:
-                    worker_handler.queue_item_async_safe(update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': uuid}))
+                # Dont' add to queue because scheduler can see that they haven't been checked and will add them to the queue
+#                for uuid in importer_handler.new_uuids:
+#                    worker_handler.queue_item_async_safe(update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': uuid}))
+
 
         # Could be some remaining, or we could be on GET
         form = forms.importForm(formdata=request.form if request.method == 'POST' else None)

changedetectionio/blueprint/imports/importer.py

@@ -2,6 +2,7 @@ from abc import abstractmethod
 import time
 from wtforms import ValidationError
 from loguru import logger
+from flask_babel import gettext
 
 from changedetectionio.forms import validate_url
 
@@ -41,7 +42,7 @@ class import_url_list(Importer):
         now = time.time()
 
         if (len(urls) > 5000):
-            flash("Importing 5,000 of the first URLs from your list, the rest can be imported again.")
+            flash(gettext("Importing 5,000 of the first URLs from your list, the rest can be imported again."))
 
         for url in urls:
             url = url.strip()
@@ -74,7 +75,7 @@ class import_url_list(Importer):
                 self.remaining_data = []
             self.remaining_data.append(url)
 
-        flash("{} Imported from list in {:.2f}s, {} Skipped.".format(good, time.time() - now, len(self.remaining_data)))
+        flash(gettext("{} Imported from list in {:.2f}s, {} Skipped.").format(good, time.time() - now, len(self.remaining_data)))
 
 
 class import_distill_io_json(Importer):
@@ -94,11 +95,11 @@ class import_distill_io_json(Importer):
         try:
             data = json.loads(data.strip())
         except json.decoder.JSONDecodeError:
-            flash("Unable to read JSON file, was it broken?", 'error')
+            flash(gettext("Unable to read JSON file, was it broken?"), 'error')
             return
 
         if not data.get('data'):
-            flash("JSON structure looks invalid, was it broken?", 'error')
+            flash(gettext("JSON structure looks invalid, was it broken?"), 'error')
             return
 
         for d in data.get('data'):
@@ -135,7 +136,7 @@ class import_distill_io_json(Importer):
                     self.new_uuids.append(new_uuid)
                     good += 1
 
-        flash("{} Imported from Distill.io in {:.2f}s, {} Skipped.".format(len(self.new_uuids), time.time() - now, len(self.remaining_data)))
+        flash(gettext("{} Imported from Distill.io in {:.2f}s, {} Skipped.").format(len(self.new_uuids), time.time() - now, len(self.remaining_data)))
 
 
 class import_xlsx_wachete(Importer):
@@ -156,7 +157,7 @@ class import_xlsx_wachete(Importer):
             wb = load_workbook(data)
         except Exception as e:
             # @todo correct except
-            flash("Unable to read export XLSX file, something wrong with the file?", 'error')
+            flash(gettext("Unable to read export XLSX file, something wrong with the file?"), 'error')
             return
 
         row_id = 2
@@ -196,7 +197,7 @@ class import_xlsx_wachete(Importer):
                         validate_url(data.get('url'))
                     except ValidationError as e:
                         logger.error(f">> Import URL error {data.get('url')} {str(e)}")
-                        flash(f"Error processing row number {row_id}, URL value was incorrect, row was skipped.", 'error')
+                        flash(gettext("Error processing row number {}, URL value was incorrect, row was skipped.").format(row_id), 'error')
                         # Don't bother processing anything else on this row
                         continue
 
@@ -210,12 +211,11 @@ class import_xlsx_wachete(Importer):
                         good += 1
             except Exception as e:
                 logger.error(e)
-                flash(f"Error processing row number {row_id}, check all cell data types are correct, row was skipped.", 'error')
+                flash(gettext("Error processing row number {}, check all cell data types are correct, row was skipped.").format(row_id), 'error')
             else:
                 row_id += 1
 
-        flash(
-            "{} imported from Wachete .xlsx in {:.2f}s".format(len(self.new_uuids), time.time() - now))
+        flash(gettext("{} imported from Wachete .xlsx in {:.2f}s").format(len(self.new_uuids), time.time() - now))
 
 
 class import_xlsx_custom(Importer):
@@ -236,7 +236,7 @@ class import_xlsx_custom(Importer):
             wb = load_workbook(data)
         except Exception as e:
             # @todo correct except
-            flash("Unable to read export XLSX file, something wrong with the file?", 'error')
+            flash(gettext("Unable to read export XLSX file, something wrong with the file?"), 'error')
             return
 
         # @todo cehck atleast 2 rows, same in other method
@@ -265,7 +265,7 @@ class import_xlsx_custom(Importer):
                             validate_url(url)
                         except ValidationError as e:
                             logger.error(f">> Import URL error {url} {str(e)}")
-                            flash(f"Error processing row number {row_i}, URL value was incorrect, row was skipped.", 'error')
+                            flash(gettext("Error processing row number {}, URL value was incorrect, row was skipped.").format(row_i), 'error')
                             # Don't bother processing anything else on this row
                             url = None
                             break
@@ -294,9 +294,8 @@ class import_xlsx_custom(Importer):
                         good += 1
         except Exception as e:
             logger.error(e)
-            flash(f"Error processing row number {row_i}, check all cell data types are correct, row was skipped.", 'error')
+            flash(gettext("Error processing row number {}, check all cell data types are correct, row was skipped.").format(row_i), 'error')
         else:
             row_i += 1
 
-        flash(
-            "{} imported from custom .xlsx in {:.2f}s".format(len(self.new_uuids), time.time() - now))
+        flash(gettext("{} imported from custom .xlsx in {:.2f}s").format(len(self.new_uuids), time.time() - now))

changedetectionio/blueprint/imports/templates/import.html

@@ -6,9 +6,9 @@
 
     <div class="tabs collapsable">
         <ul>
-            <li class="tab" id=""><a href="#url-list">URL List</a></li>
-            <li class="tab"><a href="#distill-io">Distill.io</a></li>
-            <li class="tab"><a href="#xlsx">.XLSX &amp; Wachete</a></li>
+            <li class="tab" id=""><a href="#url-list">{{ _('URL List') }}</a></li>
+            <li class="tab"><a href="#distill-io">{{ _('Distill.io') }}</a></li>
+            <li class="tab"><a href="#xlsx">{{ _('.XLSX & Wachete') }}</a></li>
         </ul>
     </div>
 
@@ -17,11 +17,10 @@
             <input type="hidden" name="csrf_token" value="{{ csrf_token() }}">
             <div class="tab-pane-inner" id="url-list">
                 <div class="pure-control-group">
-                        Enter one URL per line, and optionally add tags for each URL after a space, delineated by comma
-                        (,):
+                        {{ _('Enter one URL per line, and optionally add tags for each URL after a space, delineated by comma (,):') }}
                         <br>
-                        <p><strong>Example:  </strong><code>https://example.com tag1, tag2, last tag</code></p>
-                        URLs which do not pass validation will stay in the textarea.
+                        <p><strong>{{ _('Example:') }}  </strong><code>https://example.com tag1, tag2, last tag</code></p>
+                        {{ _('URLs which do not pass validation will stay in the textarea.') }}
                 </div>
                 {{ render_field(form.processor, class="processor") }}
                 
@@ -42,12 +41,12 @@
 
 
                     <div class="pure-control-group">
-                        Copy and Paste your Distill.io watch 'export' file, this should be a JSON file.<br>
-                        This is <i>experimental</i>, supported fields are <code>name</code>, <code>uri</code>, <code>tags</code>, <code>config:selections</code>, the rest (including <code>schedule</code>) are ignored.
+                        {{ _('Copy and Paste your Distill.io watch \'export\' file, this should be a JSON file.') }}<br>
+                        {{ _('This is') }} <i>{{ _('experimental') }}</i>, {{ _('supported fields are') }} <code>name</code>, <code>uri</code>, <code>tags</code>, <code>config:selections</code>, {{ _('the rest (including') }} <code>schedule</code>) {{ _('are ignored.') }}
                         <br>
                         <p>
-                        How to export? <a href="https://distill.io/docs/web-monitor/how-export-and-import-monitors/">https://distill.io/docs/web-monitor/how-export-and-import-monitors/</a><br>
-                        Be sure to set your default fetcher to Chrome if required.<br>
+                        {{ _('How to export?') }} <a href="https://distill.io/docs/web-monitor/how-export-and-import-monitors/">https://distill.io/docs/web-monitor/how-export-and-import-monitors/</a><br>
+                        {{ _('Be sure to set your default fetcher to Chrome if required.') }}<br>
                         </p>
                     </div>
 
@@ -89,32 +88,32 @@
             </fieldset>
                 <div class="pure-control-group">
                 <span class="pure-form-message-inline">
-                    Table of custom column and data types mapping for the <strong>Custom mapping</strong> File mapping type.
+                    {{ _('Table of custom column and data types mapping for the') }} <strong>{{ _('Custom mapping') }}</strong> {{ _('File mapping type.') }}
                 </span>
                     <table style="border: 1px solid #aaa; padding: 0.5rem; border-radius: 4px;">
                         <tr>
-                            <td><strong>Column #</strong></td>
+                            <td><strong>{{ _('Column #') }}</strong></td>
                             {% for n in range(4) %}
                                 <td><input type="number" name="custom_xlsx[col_{{n}}]" style="width: 4rem;" min="1"></td>
                             {%  endfor %}
                         </tr>
                         <tr>
-                            <td><strong>Type</strong></td>
+                            <td><strong>{{ _('Type') }}</strong></td>
                             {% for n in range(4) %}
                                 <td><select name="custom_xlsx[col_type_{{n}}]">
-                                    <option value="" style="color: #aaa"> -- none --</option>
-                                    <option value="url">URL</option>
-                                    <option value="title">Title</option>
-                                    <option value="include_filters">CSS/xPath filter</option>
-                                    <option value="tag">Group / Tag name(s)</option>
-                                    <option value="interval_minutes">Recheck time (minutes)</option>
+                                    <option value="" style="color: #aaa"> -- {{ _('none') }} --</option>
+                                    <option value="url">{{ _('URL') }}</option>
+                                    <option value="title">{{ _('Title') }}</option>
+                                    <option value="include_filters">{{ _('CSS/xPath filter') }}</option>
+                                    <option value="tag">{{ _('Group / Tag name(s)') }}</option>
+                                    <option value="interval_minutes">{{ _('Recheck time (minutes)') }}</option>
                                 </select></td>
                             {%  endfor %}
                         </tr>
                     </table>
                 </div>
             </div>
-            <button type="submit" class="pure-button pure-input-1-2 pure-button-primary">Import</button>
+            <button type="submit" class="pure-button pure-input-1-2 pure-button-primary">{{ _('Import') }}</button>
         </form>
 
     </div>

changedetectionio/blueprint/rss/__init__.py

@@ -1 +1,27 @@
-RSS_FORMAT_TYPES = [('plaintext', 'Plain text'), ('html', 'HTML Color')]
+from copy import deepcopy
+from loguru import logger
+
+from changedetectionio.model import USE_SYSTEM_DEFAULT_NOTIFICATION_FORMAT_FOR_WATCH
+from changedetectionio.notification import valid_notification_formats
+
+RSS_CONTENT_FORMAT_DEFAULT = 'text'
+
+# Some stuff not related
+RSS_FORMAT_TYPES = deepcopy(valid_notification_formats)
+if RSS_FORMAT_TYPES.get('markdown'):
+    del RSS_FORMAT_TYPES['markdown']
+
+if RSS_FORMAT_TYPES.get(USE_SYSTEM_DEFAULT_NOTIFICATION_FORMAT_FOR_WATCH):
+    del RSS_FORMAT_TYPES[USE_SYSTEM_DEFAULT_NOTIFICATION_FORMAT_FOR_WATCH]
+
+if not RSS_FORMAT_TYPES.get(RSS_CONTENT_FORMAT_DEFAULT):
+    logger.critical(f"RSS_CONTENT_FORMAT_DEFAULT not in the acceptable list {RSS_CONTENT_FORMAT_DEFAULT}")
+
+RSS_TEMPLATE_TYPE_OPTIONS = {'system_default': 'System default', 'notification_body': 'Notification body'}
+
+# @note: We use <pre> because nearly all RSS readers render only HTML (Thunderbird for example cant do just plaintext)
+RSS_TEMPLATE_PLAINTEXT_DEFAULT = "<pre>{{watch_label}} had a change.\n\n{{diff}}\n</pre>"
+
+# @todo add some [edit]/[history]/[goto] etc links
+# @todo need {{watch_edit_link}} + delete + history link token
+RSS_TEMPLATE_HTML_DEFAULT = "<html><body>\n<h4><a href=\"{{watch_url}}\">{{watch_label}}</a></h4>\n<p>{{diff}}</p>\n</body></html>\n"

changedetectionio/blueprint/rss/_util.py

@@ -0,0 +1,156 @@
+"""
+Utility functions for RSS feed generation.
+"""
+
+from changedetectionio.notification.handler import process_notification
+from changedetectionio.notification_service import NotificationContextData, _check_cascading_vars
+from loguru import logger
+import datetime
+import pytz
+import re
+
+
+BAD_CHARS_REGEX = r'[\x00-\x08\x0B\x0C\x0E-\x1F]'
+
+
+def scan_invalid_chars_in_rss(content):
+    """
+    Scan for invalid characters in RSS content.
+    Returns True if invalid characters are found.
+    """
+    for match in re.finditer(BAD_CHARS_REGEX, content):
+        i = match.start()
+        bad_char = content[i]
+        hex_value = f"0x{ord(bad_char):02x}"
+        # Grab context
+        start = max(0, i - 20)
+        end = min(len(content), i + 21)
+        context = content[start:end].replace('\n', '\\n').replace('\r', '\\r')
+        logger.warning(f"Invalid char {hex_value} at pos {i}: ...{context}...")
+        # First match is enough
+        return True
+
+    return False
+
+
+def clean_entry_content(content):
+    """
+    Remove invalid characters from RSS content.
+    """
+    cleaned = re.sub(BAD_CHARS_REGEX, '', content)
+    return cleaned
+
+
+def generate_watch_guid(watch, timestamp):
+    """
+    Generate a unique GUID for a watch RSS entry.
+
+    Args:
+        watch: The watch object
+        timestamp: The timestamp of the specific change this entry represents
+    """
+    return f"{watch['uuid']}/{timestamp}"
+
+
+def validate_rss_token(datastore, request):
+    """
+    Validate the RSS access token from the request.
+
+    Returns:
+        tuple: (is_valid, error_response) where error_response is None if valid
+    """
+    app_rss_token = datastore.data['settings']['application'].get('rss_access_token')
+    rss_url_token = request.args.get('token')
+
+    if rss_url_token != app_rss_token:
+        return False, ("Access denied, bad token", 403)
+
+    return True, None
+
+
+def get_rss_template(datastore, watch, rss_content_format, default_html, default_plaintext):
+    """Get the appropriate template for RSS content."""
+    if datastore.data['settings']['application'].get('rss_template_type') == 'notification_body':
+        return _check_cascading_vars(datastore=datastore, var_name='notification_body', watch=watch)
+
+    override = datastore.data['settings']['application'].get('rss_template_override')
+    if override and override.strip():
+        return override
+    elif 'text' in rss_content_format:
+        return default_plaintext
+    else:
+        return default_html
+
+
+def get_watch_label(datastore, watch):
+    """Get the label for a watch based on settings."""
+    if datastore.data['settings']['application']['ui'].get('use_page_title_in_list') or watch.get('use_page_title_in_list'):
+        return watch.label
+    else:
+        return watch.get('url')
+
+
+def add_watch_categories(fe, watch, datastore):
+    """Add category tags to a feed entry based on watch tags."""
+    for tag_uuid in watch.get('tags', []):
+        tag = datastore.data['settings']['application'].get('tags', {}).get(tag_uuid)
+        if tag and tag.get('title'):
+            fe.category(term=tag.get('title'))
+
+
+def build_notification_context(watch, timestamp_from, timestamp_to, watch_label,
+                               n_body_template, rss_content_format):
+    """Build the notification context object."""
+    return NotificationContextData(initial_data={
+        'notification_urls': ['null://just-sending-a-null-test-for-the-render-in-RSS'],
+        'notification_body': n_body_template,
+        'timestamp_to': timestamp_to,
+        'timestamp_from': timestamp_from,
+        'watch_label': watch_label,
+        'notification_format': rss_content_format
+    })
+
+
+def render_notification(n_object, notification_service, watch, datastore,
+                       date_index_from=None, date_index_to=None):
+    """Process and render the notification content."""
+    kwargs = {'n_object': n_object, 'watch': watch}
+
+    if date_index_from is not None and date_index_to is not None:
+        kwargs['date_index_from'] = date_index_from
+        kwargs['date_index_to'] = date_index_to
+
+    n_object = notification_service.queue_notification_for_watch(**kwargs)
+    n_object['watch_mime_type'] = None
+
+    res = process_notification(n_object=n_object, datastore=datastore)
+    return res[0]
+
+
+def populate_feed_entry(fe, watch, content, guid, timestamp, link=None, title_suffix=None):
+    """Populate a feed entry with content and metadata."""
+    watch_label = watch.get('url')  # Already determined by caller
+
+    # Set link
+    if link:
+        fe.link(link=link)
+
+    # Set title
+    if title_suffix:
+        fe.title(title=f"{watch_label} - {title_suffix}")
+    else:
+        fe.title(title=watch_label)
+
+    # Clean and set content
+    if scan_invalid_chars_in_rss(content):
+        content = clean_entry_content(content)
+    fe.content(content=content, type='CDATA')
+
+    # Set GUID
+    fe.guid(guid, permalink=False)
+
+    # Set pubDate using the timestamp of this specific change
+    dt = datetime.datetime.fromtimestamp(int(timestamp))
+    dt = dt.replace(tzinfo=pytz.UTC)
+    fe.pubDate(dt)
+

changedetectionio/blueprint/rss/blueprint.py

@@ -1,155 +1,26 @@
 
-from changedetectionio.jinja2_custom import render as jinja_render
-from changedetectionio.notification.handler import apply_service_tweaks
 from changedetectionio.store import ChangeDetectionStore
-from feedgen.feed import FeedGenerator
-from flask import Blueprint, make_response, request, url_for, redirect
-from loguru import logger
-import datetime
-import pytz
-import re
-import time
+from flask import Blueprint
 
-
-BAD_CHARS_REGEX=r'[\x00-\x08\x0B\x0C\x0E-\x1F]'
-
-# Anything that is not text/UTF-8 should be stripped before it breaks feedgen (such as binary data etc)
-def scan_invalid_chars_in_rss(content):
-    for match in re.finditer(BAD_CHARS_REGEX, content):
-        i = match.start()
-        bad_char = content[i]
-        hex_value = f"0x{ord(bad_char):02x}"
-        # Grab context
-        start = max(0, i - 20)
-        end = min(len(content), i + 21)
-        context = content[start:end].replace('\n', '\\n').replace('\r', '\\r')
-        logger.warning(f"Invalid char {hex_value} at pos {i}: ...{context}...")
-        # First match is enough
-        return True
-
-    return False
-
-
-def clean_entry_content(content):
-    cleaned = re.sub(BAD_CHARS_REGEX, '', content)
-    return cleaned
+from . import tag as tag_routes
+from . import main_feed
+from . import single_watch
 
 def construct_blueprint(datastore: ChangeDetectionStore):
+    """
+    Construct and configure the RSS blueprint with all routes.
+
+    Args:
+        datastore: The ChangeDetectionStore instance
+
+    Returns:
+        The configured Flask blueprint
+    """
     rss_blueprint = Blueprint('rss', __name__)
 
-    # Some RSS reader situations ended up with rss/ (forward slash after RSS) due
-    # to some earlier blueprint rerouting work, it should goto feed.
-    @rss_blueprint.route("/", methods=['GET'])
-    def extraslash():
-        return redirect(url_for('rss.feed'))
-
-    # Import the login decorator if needed
-    # from changedetectionio.auth_decorator import login_optionally_required
-    @rss_blueprint.route("", methods=['GET'])
-    def feed():
-        now = time.time()
-        # Always requires token set
-        app_rss_token = datastore.data['settings']['application'].get('rss_access_token')
-        rss_url_token = request.args.get('token')
-        if rss_url_token != app_rss_token:
-            return "Access denied, bad token", 403
-
-        from changedetectionio import diff
-        limit_tag = request.args.get('tag', '').lower().strip()
-        # Be sure limit_tag is a uuid
-        for uuid, tag in datastore.data['settings']['application'].get('tags', {}).items():
-            if limit_tag == tag.get('title', '').lower().strip():
-                limit_tag = uuid
-
-        # Sort by last_changed and add the uuid which is usually the key..
-        sorted_watches = []
-
-        # @todo needs a .itemsWithTag() or something - then we can use that in Jinaj2 and throw this away
-        for uuid, watch in datastore.data['watching'].items():
-            # @todo tag notification_muted skip also (improve Watch model)
-            if datastore.data['settings']['application'].get('rss_hide_muted_watches') and watch.get('notification_muted'):
-                continue
-            if limit_tag and not limit_tag in watch['tags']:
-                continue
-            watch['uuid'] = uuid
-            sorted_watches.append(watch)
-
-        sorted_watches.sort(key=lambda x: x.last_changed, reverse=False)
-
-        fg = FeedGenerator()
-        fg.title('changedetection.io')
-        fg.description('Feed description')
-        fg.link(href='https://changedetection.io')
-
-        html_colour_enable = False
-        if datastore.data['settings']['application'].get('rss_content_format') == 'html':
-            html_colour_enable = True
-
-        for watch in sorted_watches:
-
-            dates = list(watch.history.keys())
-            # Re #521 - Don't bother processing this one if theres less than 2 snapshots, means we never had a change detected.
-            if len(dates) < 2:
-                continue
-
-            if not watch.viewed:
-                # Re #239 - GUID needs to be individual for each event
-                # @todo In the future make this a configurable link back (see work on BASE_URL https://github.com/dgtlmoon/changedetection.io/pull/228)
-                guid = "{}/{}".format(watch['uuid'], watch.last_changed)
-                fe = fg.add_entry()
-
-                # Include a link to the diff page, they will have to login here to see if password protection is enabled.
-                # Description is the page you watch, link takes you to the diff JS UI page
-                # Dict val base_url will get overriden with the env var if it is set.
-                ext_base_url = datastore.data['settings']['application'].get('active_base_url')
-                # @todo fix
-
-                # Because we are called via whatever web server, flask should figure out the right path (
-                diff_link = {'href': url_for('ui.ui_views.diff_history_page', uuid=watch['uuid'], _external=True)}
-
-                fe.link(link=diff_link)
-
-                # Same logic as watch-overview.html
-                if datastore.data['settings']['application']['ui'].get('use_page_title_in_list') or watch.get('use_page_title_in_list'):
-                    watch_label = watch.label
-                else:
-                    watch_label = watch.get('url')
-
-                fe.title(title=watch_label)
-                try:
-
-                    html_diff = diff.render_diff(previous_version_file_contents=watch.get_history_snapshot(dates[-2]),
-                                                 newest_version_file_contents=watch.get_history_snapshot(dates[-1]),
-                                                 include_equal=False,
-                                                 line_feed_sep="<br>"
-                                                 )
-
-
-                    requested_output_format = 'htmlcolor' if html_colour_enable else 'html'
-                    html_diff = apply_service_tweaks(url='', n_body=html_diff, n_title=None, requested_output_format=requested_output_format)
-
-                except FileNotFoundError as e:
-                    html_diff = f"History snapshot file for watch {watch.get('uuid')}@{watch.last_changed} - '{watch.get('title')} not found."
-
-                # @todo Make this configurable and also consider html-colored markup
-                # @todo User could decide if <link> goes to the diff page, or to the watch link
-                rss_template = "<html><body>\n<h4><a href=\"{{watch_url}}\">{{watch_title}}</a></h4>\n<p>{{html_diff}}</p>\n</body></html>\n"
-
-                content = jinja_render(template_str=rss_template, watch_title=watch_label, html_diff=html_diff, watch_url=watch.link)
-
-                # Out of range chars could also break feedgen
-                if scan_invalid_chars_in_rss(content):
-                    content = clean_entry_content(content)
-
-                fe.content(content=content, type='CDATA')
-                fe.guid(guid, permalink=False)
-                dt = datetime.datetime.fromtimestamp(int(watch.newest_history_key))
-                dt = dt.replace(tzinfo=pytz.UTC)
-                fe.pubDate(dt)
-
-        response = make_response(fg.rss_str())
-        response.headers.set('Content-Type', 'application/rss+xml;charset=utf-8')
-        logger.trace(f"RSS generated in {time.time() - now:.3f}s")
-        return response
+    # Register all route modules
+    main_feed.construct_main_feed_routes(rss_blueprint, datastore)
+    single_watch.construct_single_watch_routes(rss_blueprint, datastore)
+    tag_routes.construct_tag_routes(rss_blueprint, datastore)
 
     return rss_blueprint

changedetectionio/blueprint/rss/main_feed.py

@@ -0,0 +1,105 @@
+from flask import make_response, request, url_for, redirect
+
+
+
+def construct_main_feed_routes(rss_blueprint, datastore):
+    """
+    Construct the main RSS feed routes.
+
+    Args:
+        rss_blueprint: The Flask blueprint to add routes to
+        datastore: The ChangeDetectionStore instance
+    """
+
+    # Some RSS reader situations ended up with rss/ (forward slash after RSS) due
+    # to some earlier blueprint rerouting work, it should goto feed.
+    @rss_blueprint.route("/", methods=['GET'])
+    def extraslash():
+        return redirect(url_for('rss.feed'))
+
+    # Import the login decorator if needed
+    # from changedetectionio.auth_decorator import login_optionally_required
+    @rss_blueprint.route("", methods=['GET'])
+    def feed():
+        from feedgen.feed import FeedGenerator
+        from loguru import logger
+        import time
+
+        from . import RSS_TEMPLATE_HTML_DEFAULT, RSS_TEMPLATE_PLAINTEXT_DEFAULT
+        from ._util import (validate_rss_token, generate_watch_guid, get_rss_template,
+                           get_watch_label, build_notification_context, render_notification,
+                           populate_feed_entry, add_watch_categories)
+        from ...notification_service import NotificationService
+
+        now = time.time()
+
+        # Validate token
+        is_valid, error = validate_rss_token(datastore, request)
+        if not is_valid:
+            return error
+
+        rss_content_format = datastore.data['settings']['application'].get('rss_content_format')
+
+        limit_tag = request.args.get('tag', '').lower().strip()
+        # Be sure limit_tag is a uuid
+        for uuid, tag in datastore.data['settings']['application'].get('tags', {}).items():
+            if limit_tag == tag.get('title', '').lower().strip():
+                limit_tag = uuid
+
+        # Sort by last_changed and add the uuid which is usually the key..
+        sorted_watches = []
+
+        # @todo needs a .itemsWithTag() or something - then we can use that in Jinaj2 and throw this away
+        for uuid, watch in datastore.data['watching'].items():
+            # @todo tag notification_muted skip also (improve Watch model)
+            if datastore.data['settings']['application'].get('rss_hide_muted_watches') and watch.get('notification_muted'):
+                continue
+            if limit_tag and not limit_tag in watch['tags']:
+                continue
+            sorted_watches.append(watch)
+
+        sorted_watches.sort(key=lambda x: x.last_changed, reverse=False)
+
+        fg = FeedGenerator()
+        fg.title('changedetection.io')
+        fg.description('Feed description')
+        fg.link(href='https://changedetection.io')
+        notification_service = NotificationService(datastore=datastore, notification_q=False)
+
+        for watch in sorted_watches:
+
+            dates = list(watch.history.keys())
+            # Re #521 - Don't bother processing this one if theres less than 2 snapshots, means we never had a change detected.
+            if len(dates) < 2:
+                continue
+
+            if not watch.viewed:
+                # Re #239 - GUID needs to be individual for each event
+                # @todo In the future make this a configurable link back (see work on BASE_URL https://github.com/dgtlmoon/changedetection.io/pull/228)
+                watch_label = get_watch_label(datastore, watch)
+                timestamp_to = dates[-1]
+                timestamp_from = dates[-2]
+                guid = generate_watch_guid(watch, timestamp_to)
+                # Because we are called via whatever web server, flask should figure out the right path
+                diff_link = {'href': url_for('ui.ui_diff.diff_history_page', uuid=watch['uuid'], _external=True)}
+
+                # Get template and build notification context
+                n_body_template = get_rss_template(datastore, watch, rss_content_format,
+                                                   RSS_TEMPLATE_HTML_DEFAULT, RSS_TEMPLATE_PLAINTEXT_DEFAULT)
+
+                n_object = build_notification_context(watch, timestamp_from, timestamp_to,
+                                                     watch_label, n_body_template, rss_content_format)
+
+                # Render notification
+                res = render_notification(n_object, notification_service, watch, datastore)
+
+                # Create and populate feed entry
+                fe = fg.add_entry()
+                populate_feed_entry(fe, watch, res['body'], guid, timestamp_to, link=diff_link)
+                fe.title(title=watch_label)  # Override title to not include suffix
+                add_watch_categories(fe, watch, datastore)
+
+        response = make_response(fg.rss_str())
+        response.headers.set('Content-Type', 'application/rss+xml;charset=utf-8')
+        logger.trace(f"RSS generated in {time.time() - now:.3f}s")
+        return response

changedetectionio/blueprint/rss/single_watch.py

@@ -0,0 +1,112 @@
+
+
+def construct_single_watch_routes(rss_blueprint, datastore):
+    """
+    Construct RSS feed routes for single watches.
+
+    Args:
+        rss_blueprint: The Flask blueprint to add routes to
+        datastore: The ChangeDetectionStore instance
+    """
+
+    @rss_blueprint.route("/watch/<string:uuid>", methods=['GET'])
+    def rss_single_watch(uuid):
+        import time
+
+        from flask import make_response, request
+        from feedgen.feed import FeedGenerator
+        from loguru import logger
+
+        from . import RSS_TEMPLATE_HTML_DEFAULT, RSS_TEMPLATE_PLAINTEXT_DEFAULT
+        from ._util import (validate_rss_token, get_rss_template, get_watch_label,
+                           build_notification_context, render_notification,
+                           populate_feed_entry, add_watch_categories)
+        from ...notification_service import NotificationService
+
+        """
+        Display the most recent changes for a single watch as RSS feed.
+        Returns RSS XML with multiple entries showing diffs between consecutive snapshots.
+        The number of entries is controlled by the rss_diff_length setting.
+        """
+        now = time.time()
+
+        # Validate token
+        is_valid, error = validate_rss_token(datastore, request)
+        if not is_valid:
+            return error
+
+        rss_content_format = datastore.data['settings']['application'].get('rss_content_format')
+
+        # Get the watch by UUID
+        watch = datastore.data['watching'].get(uuid)
+        if not watch:
+            return f"Watch with UUID {uuid} not found", 404
+
+        # Check if watch has at least 2 history snapshots
+        dates = list(watch.history.keys())
+        if len(dates) < 2:
+            return f"Watch {uuid} does not have enough history snapshots to show changes (need at least 2)", 400
+
+        # Get the number of diffs to include (default: 5)
+        rss_diff_length = datastore.data['settings']['application'].get('rss_diff_length', 5)
+
+        # Calculate how many diffs we can actually show (limited by available history)
+        # We need at least 2 snapshots to create 1 diff
+        max_possible_diffs = len(dates) - 1
+        num_diffs = min(rss_diff_length, max_possible_diffs) if rss_diff_length > 0 else max_possible_diffs
+
+        # Create RSS feed
+        fg = FeedGenerator()
+
+        # Set title: use "label (url)" if label differs from url, otherwise just url
+        watch_url = watch.get('url', '')
+        watch_label = get_watch_label(datastore, watch)
+
+        if watch_label != watch_url:
+            feed_title = f'changedetection.io - {watch_label} ({watch_url})'
+        else:
+            feed_title = f'changedetection.io - {watch_url}'
+
+        fg.title(feed_title)
+        fg.description('Changes')
+        fg.link(href='https://changedetection.io')
+
+        # Loop through history and create RSS entries for each diff
+        # Add entries in reverse order because feedgen reverses them
+        # This way, the newest change appears first in the final RSS
+
+        notification_service = NotificationService(datastore=datastore, notification_q=False)
+        for i in range(num_diffs - 1, -1, -1):
+            # Calculate indices for this diff (working backwards from newest)
+            # i=0: compare dates[-2] to dates[-1] (most recent change)
+            # i=1: compare dates[-3] to dates[-2] (previous change)
+            # etc.
+            date_index_to = -(i + 1)
+            date_index_from = -(i + 2)
+            timestamp_to = dates[date_index_to]
+            timestamp_from = dates[date_index_from]
+
+            # Get template and build notification context
+            n_body_template = get_rss_template(datastore, watch, rss_content_format,
+                                               RSS_TEMPLATE_HTML_DEFAULT, RSS_TEMPLATE_PLAINTEXT_DEFAULT)
+
+            n_object = build_notification_context(watch, timestamp_from, timestamp_to,
+                                                 watch_label, n_body_template, rss_content_format)
+
+            # Render notification with date indices
+            res = render_notification(n_object, notification_service, watch, datastore,
+                                     date_index_from, date_index_to)
+
+            # Create and populate feed entry
+            guid = f"{uuid}/{timestamp_to}"
+            fe = fg.add_entry()
+            title_suffix = f"Change @ {res['original_context']['change_datetime']}"
+            populate_feed_entry(fe, watch, res.get('body', ''), guid, timestamp_to,
+                              link={'href': watch.get('url')}, title_suffix=title_suffix)
+            add_watch_categories(fe, watch, datastore)
+
+        response = make_response(fg.rss_str())
+        response.headers.set('Content-Type', 'application/rss+xml;charset=utf-8')
+        logger.debug(f"RSS Single watch built in {time.time()-now:.2f}s")
+
+        return response

changedetectionio/blueprint/rss/tag.py

@@ -0,0 +1,95 @@
+def construct_tag_routes(rss_blueprint, datastore):
+    """
+    Construct RSS feed routes for tags.
+
+    Args:
+        rss_blueprint: The Flask blueprint to add routes to
+        datastore: The ChangeDetectionStore instance
+    """
+
+    @rss_blueprint.route("/tag/<string:tag_uuid>", methods=['GET'])
+    def rss_tag_feed(tag_uuid):
+
+        from flask import make_response, request, url_for
+        from feedgen.feed import FeedGenerator
+
+        from . import RSS_TEMPLATE_HTML_DEFAULT, RSS_TEMPLATE_PLAINTEXT_DEFAULT
+        from ._util import (validate_rss_token, generate_watch_guid, get_rss_template,
+                           get_watch_label, build_notification_context, render_notification,
+                           populate_feed_entry, add_watch_categories)
+        from ...notification_service import NotificationService
+
+        """
+        Display an RSS feed for all unviewed watches that belong to a specific tag.
+        Returns RSS XML with entries for each unviewed watch with sufficient history.
+        """
+        # Validate token
+        is_valid, error = validate_rss_token(datastore, request)
+        if not is_valid:
+            return error
+
+        rss_content_format = datastore.data['settings']['application'].get('rss_content_format')
+
+        # Verify tag exists
+        tag = datastore.data['settings']['application'].get('tags', {}).get(tag_uuid)
+        if not tag:
+            return f"Tag with UUID {tag_uuid} not found", 404
+
+        tag_title = tag.get('title', 'Unknown Tag')
+
+        # Create RSS feed
+        fg = FeedGenerator()
+        fg.title(f'changedetection.io - {tag_title}')
+        fg.description(f'Changes for watches tagged with {tag_title}')
+        fg.link(href='https://changedetection.io')
+        notification_service = NotificationService(datastore=datastore, notification_q=False)
+        # Find all watches with this tag
+        for uuid, watch in datastore.data['watching'].items():
+            #@todo  This is wrong, it needs to sort by most recently changed and then limit it  datastore.data['watching'].items().sorted(?)
+            # So get all watches in this tag then sort
+
+            # Skip if watch doesn't have this tag
+            if tag_uuid not in watch.get('tags', []):
+                continue
+
+            # Skip muted watches if configured
+            if datastore.data['settings']['application'].get('rss_hide_muted_watches') and watch.get('notification_muted'):
+                continue
+
+            # Check if watch has at least 2 history snapshots
+            dates = list(watch.history.keys())
+            if len(dates) < 2:
+                continue
+
+            # Only include unviewed watches
+            if not watch.viewed:
+                # Include a link to the diff page (use uuid from loop, don't modify watch dict)
+                diff_link = {'href': url_for('ui.ui_diff.diff_history_page', uuid=uuid, _external=True)}
+
+                # Get watch label
+                watch_label = get_watch_label(datastore, watch)
+
+                # Get template and build notification context
+                timestamp_to = dates[-1]
+                timestamp_from = dates[-2]
+
+                # Generate GUID for this entry
+                guid = generate_watch_guid(watch, timestamp_to)
+                n_body_template = get_rss_template(datastore, watch, rss_content_format,
+                                                   RSS_TEMPLATE_HTML_DEFAULT, RSS_TEMPLATE_PLAINTEXT_DEFAULT)
+
+                n_object = build_notification_context(watch, timestamp_from, timestamp_to,
+                                                     watch_label, n_body_template, rss_content_format)
+
+                # Render notification
+                res = render_notification(n_object, notification_service, watch, datastore)
+
+                # Create and populate feed entry
+                fe = fg.add_entry()
+                title_suffix = f"Change @ {res['original_context']['change_datetime']}"
+                populate_feed_entry(fe, watch, res['body'], guid, timestamp_to, link=diff_link, title_suffix=title_suffix)
+                add_watch_categories(fe, watch, datastore)
+
+        response = make_response(fg.rss_str())
+        response.headers.set('Content-Type', 'application/rss+xml;charset=utf-8')
+        return response

changedetectionio/blueprint/settings/__init__.py

@@ -5,6 +5,7 @@ from zoneinfo import ZoneInfo, available_timezones
 import secrets
 import flask_login
 from flask import Blueprint, render_template, request, redirect, url_for, flash
+from flask_babel import gettext
 
 from changedetectionio.store import ChangeDetectionStore
 from changedetectionio.auth_decorator import login_optionally_required
@@ -17,6 +18,12 @@ def construct_blueprint(datastore: ChangeDetectionStore):
     @login_optionally_required
     def settings_page():
         from changedetectionio import forms
+        from changedetectionio.pluggy_interface import (
+            get_plugin_settings_tabs,
+            load_plugin_settings,
+            save_plugin_settings
+        )
+
 
         default = deepcopy(datastore.data['settings'])
         if datastore.proxy_list is not None:
@@ -54,7 +61,7 @@ def construct_blueprint(datastore: ChangeDetectionStore):
                 # SALTED_PASS means the password is "locked" to what we set in the Env var
                 if not os.getenv("SALTED_PASS", False):
                     datastore.remove_password()
-                    flash("Password protection removed.", 'notice')
+                    flash(gettext("Password protection removed."), 'notice')
                     flask_login.logout_user()
                     return redirect(url_for('settings.settings_page'))
 
@@ -71,14 +78,20 @@ def construct_blueprint(datastore: ChangeDetectionStore):
                 # Handle dynamic worker count adjustment
                 old_worker_count = datastore.data['settings']['requests'].get('workers', 1)
                 new_worker_count = form.data['requests'].get('workers', 1)
-                
+
                 datastore.data['settings']['requests'].update(form.data['requests'])
-                
+
                 # Adjust worker count if it changed
                 if new_worker_count != old_worker_count:
                     from changedetectionio import worker_handler
                     from changedetectionio.flask_app import update_q, notification_q, app, datastore as ds
-                    
+
+                    # Check CPU core availability and warn if worker count is high
+                    cpu_count = os.cpu_count()
+                    if cpu_count and new_worker_count >= (cpu_count * 0.9):
+                        flash(gettext("Warning: Worker count ({}) is close to or exceeds available CPU cores ({})").format(
+                            new_worker_count, cpu_count), 'warning')
+
                     result = worker_handler.adjust_async_worker_count(
                         new_count=new_worker_count,
                         update_q=update_q,
@@ -86,32 +99,68 @@ def construct_blueprint(datastore: ChangeDetectionStore):
                         app=app,
                         datastore=ds
                     )
-                    
+
                     if result['status'] == 'success':
-                        flash(f"Worker count adjusted: {result['message']}", 'notice')
+                        flash(gettext("Worker count adjusted: {}").format(result['message']), 'notice')
                     elif result['status'] == 'not_supported':
-                        flash("Dynamic worker adjustment not supported for sync workers", 'warning')
+                        flash(gettext("Dynamic worker adjustment not supported for sync workers"), 'warning')
                     elif result['status'] == 'error':
-                        flash(f"Error adjusting workers: {result['message']}", 'error')
+                        flash(gettext("Error adjusting workers: {}").format(result['message']), 'error')
 
                 if not os.getenv("SALTED_PASS", False) and len(form.application.form.password.encrypted_password):
                     datastore.data['settings']['application']['password'] = form.application.form.password.encrypted_password
                     datastore.needs_write_urgent = True
-                    flash("Password protection enabled.", 'notice')
+                    flash(gettext("Password protection enabled."), 'notice')
                     flask_login.logout_user()
                     return redirect(url_for('watchlist.index'))
 
                 datastore.needs_write_urgent = True
-                flash("Settings updated.")
+
+                # Also save plugin settings from the same form submission
+                plugin_tabs_list = get_plugin_settings_tabs()
+                for tab in plugin_tabs_list:
+                    plugin_id = tab['plugin_id']
+                    form_class = tab['form_class']
+
+                    # Instantiate plugin form with POST data
+                    plugin_form = form_class(formdata=request.form)
+
+                    # Save plugin settings (validation is optional for plugins)
+                    if plugin_form.data:
+                        save_plugin_settings(datastore.datastore_path, plugin_id, plugin_form.data)
+
+                flash(gettext("Settings updated."))
 
             else:
-                flash("An error occurred, please see below.", "error")
+                flash(gettext("An error occurred, please see below."), "error")
 
         # Convert to ISO 8601 format, all date/time relative events stored as UTC time
         utc_time = datetime.now(ZoneInfo("UTC")).isoformat()
 
+        # Get active plugins
+        from changedetectionio.pluggy_interface import get_active_plugins
+        import sys
+        active_plugins = get_active_plugins()
+        python_version = f"{sys.version_info.major}.{sys.version_info.minor}.{sys.version_info.micro}"
+
+        # Get plugin settings tabs and instantiate forms
+        plugin_tabs = get_plugin_settings_tabs()
+        plugin_forms = {}
+
+        for tab in plugin_tabs:
+            plugin_id = tab['plugin_id']
+            form_class = tab['form_class']
+
+            # Load existing settings
+            settings = load_plugin_settings(datastore.datastore_path, plugin_id)
+
+            # Instantiate the form with existing settings
+            plugin_forms[plugin_id] = form_class(data=settings)
+
         output = render_template("settings.html",
+                                active_plugins=active_plugins,
                                 api_key=datastore.data['settings']['application'].get('api_access_token'),
+                                python_version=python_version,
                                 available_timezones=sorted(available_timezones()),
                                 emailprefix=os.getenv('NOTIFICATION_MAIL_BUTTON_PREFIX', False),
                                 extra_notification_token_placeholder_info=datastore.get_unique_notification_token_placeholders_available(),
@@ -121,6 +170,8 @@ def construct_blueprint(datastore: ChangeDetectionStore):
                                 settings_application=datastore.data['settings']['application'],
                                 timezone_default_config=datastore.data['settings']['application'].get('scheduler_timezone_default'),
                                 utc_time=utc_time,
+                                plugin_tabs=plugin_tabs,
+                                plugin_forms=plugin_forms,
                                 )
 
         return output
@@ -131,7 +182,7 @@ def construct_blueprint(datastore: ChangeDetectionStore):
         secret = secrets.token_hex(16)
         datastore.data['settings']['application']['api_access_token'] = secret
         datastore.needs_write_urgent = True
-        flash("API Key was regenerated.")
+        flash(gettext("API Key was regenerated."))
         return redirect(url_for('settings.settings_page')+'#api')
         
     @settings_blueprint.route("/notification-logs", methods=['GET'])
@@ -142,4 +193,32 @@ def construct_blueprint(datastore: ChangeDetectionStore):
                                logs=notification_debug_log if len(notification_debug_log) else ["Notification logs are empty - no notifications sent yet."])
         return output
 
+    @settings_blueprint.route("/toggle-all-paused", methods=['GET'])
+    @login_optionally_required
+    def toggle_all_paused():
+        current_state = datastore.data['settings']['application'].get('all_paused', False)
+        datastore.data['settings']['application']['all_paused'] = not current_state
+        datastore.needs_write_urgent = True
+
+        if datastore.data['settings']['application']['all_paused']:
+            flash(gettext("Automatic scheduling paused - checks will not be queued."), 'notice')
+        else:
+            flash(gettext("Automatic scheduling resumed - checks will be queued normally."), 'notice')
+
+        return redirect(url_for('watchlist.index'))
+
+    @settings_blueprint.route("/toggle-all-muted", methods=['GET'])
+    @login_optionally_required
+    def toggle_all_muted():
+        current_state = datastore.data['settings']['application'].get('all_muted', False)
+        datastore.data['settings']['application']['all_muted'] = not current_state
+        datastore.needs_write_urgent = True
+
+        if datastore.data['settings']['application']['all_muted']:
+            flash(gettext("All notifications muted."), 'notice')
+        else:
+            flash(gettext("All notifications unmuted."), 'notice')
+
+        return redirect(url_for('watchlist.index'))
+
     return settings_blueprint

changedetectionio/blueprint/settings/templates/notification-log.html

@@ -4,7 +4,7 @@
 <div class="edit-form">
      <div class="inner">
 
-         <h4 style="margin-top: 0px;">Notification debug log</h4>
+         <h4 style="margin-top: 0px;">{{ _('Notification debug log') }}</h4>
                 <div id="notification-error-log">
                 <ul style="font-size: 80%; margin:0px; padding: 0 0 0 7px">
                 {% for log in logs|reverse %}

changedetectionio/blueprint/settings/templates/settings.html

@@ -2,7 +2,7 @@
 
 {% block content %}
 {% from '_helpers.html' import render_field, render_checkbox_field, render_button, render_time_schedule_form, render_ternary_field, render_fieldlist_with_inline_errors %}
-{% from '_common_fields.html' import render_common_settings_form %}
+{% from '_common_fields.html' import render_common_settings_form, show_token_placeholders %}
 <script>
     const notification_base_url="{{url_for('ui.ui_notification.ajax_callback_send_notification_test', mode="global-settings")}}";
 {% if emailprefix %}
@@ -18,14 +18,22 @@
 <div class="edit-form">
     <div class="tabs collapsable">
         <ul>
-            <li class="tab" id=""><a href="#general">General</a></li>
-            <li class="tab"><a href="#notifications">Notifications</a></li>
-            <li class="tab"><a href="#fetching">Fetching</a></li>
-            <li class="tab"><a href="#filters">Global Filters</a></li>
-            <li class="tab"><a href="#ui-options">UI Options</a></li>
-            <li class="tab"><a href="#api">API</a></li>
-            <li class="tab"><a href="#timedate">Time &amp Date</a></li>
-            <li class="tab"><a href="#proxies">CAPTCHA &amp; Proxies</a></li>
+            <li class="tab" id=""><a href="#general">{{ _('General') }}</a></li>
+            <li class="tab"><a href="#notifications">{{ _('Notifications') }}</a></li>
+            <li class="tab"><a href="#fetching">{{ _('Fetching') }}</a></li>
+            <li class="tab"><a href="#filters">{{ _('Global Filters') }}</a></li>
+            <li class="tab"><a href="#ui-options">{{ _('UI Options') }}</a></li>
+            <li class="tab"><a href="#api">{{ _('API') }}</a></li>
+            <li class="tab"><a href="#rss">{{ _('RSS') }}</a></li>
+            <li class="tab"><a href="{{ url_for('backups.index') }}" class="pure-menu-link">{{ _('Backups') }}</a></li>
+            <li class="tab"><a href="#timedate">{{ _('Time & Date') }}</a></li>
+            <li class="tab"><a href="#proxies">{{ _('CAPTCHA & Proxies') }}</a></li>
+            {% if plugin_tabs %}
+                {% for tab in plugin_tabs %}
+            <li class="tab"><a href="#plugin-{{ tab.plugin_id }}">{{ tab.tab_label }}</a></li>
+                {% endfor %}
+            {% endif %}
+            <li class="tab"><a href="#info">{{ _('Info') }}</a></li>
         </ul>
     </div>
     <div class="box-wrap inner">
@@ -35,23 +43,20 @@
                 <fieldset>
                     <div class="pure-control-group">
                         {{ render_field(form.requests.form.time_between_check, class="time-check-widget") }}
-                        <span class="pure-form-message-inline">Default recheck time for all watches, current system minimum is <i>{{min_system_recheck_seconds}}</i> seconds (<a href="https://github.com/dgtlmoon/changedetection.io/wiki/Misc-system-settings#enviroment-variables">more info</a>).</span>
+
+                        <span class="pure-form-message-inline">{{ _('Default recheck time for all watches, current system minimum is') }} <i>{{min_system_recheck_seconds}}</i> {{ _('seconds') }} (<a href="https://github.com/dgtlmoon/changedetection.io/wiki/Misc-system-settings#enviroment-variables">{{ _('more info') }}</a>).</span>
                             <div id="time-between-check-schedule">
-                                <!-- Start Time and End Time -->
+                                <!-- Start Time and End Time {{ timezone_default_config }} -->
                                 <div id="limit-between-time">
-                                    {{ render_time_schedule_form(form.requests, available_timezones, timezone_default_config) }}
+                                   {{ render_time_schedule_form(form.requests, available_timezones, timezone_default_config) }}
                                 </div>
                         </div>
                     </div>
-                    <div class="pure-control-group">
-                        {{ render_field(form.requests.form.jitter_seconds, class="jitter_seconds") }}
-                        <span class="pure-form-message-inline">Example - 3 seconds random jitter could trigger up to 3 seconds earlier or up to 3 seconds later</span>
-                    </div>
                     <div class="pure-control-group">
                         {{ render_field(form.application.form.filter_failure_notification_threshold_attempts, class="filter_failure_notification_threshold_attempts") }}
-                        <span class="pure-form-message-inline">After this many consecutive times that the CSS/xPath filter is missing, send a notification
+                        <span class="pure-form-message-inline">{{ _('After this many consecutive times that the CSS/xPath filter is missing, send a notification') }}
                             <br>
-                        Set to <strong>0</strong> to disable
+                        {{ _('Set to') }} <strong>0</strong> {{ _('to disable') }}
                         </span>
                     </div>
                     <div class="pure-control-group">
@@ -60,49 +65,33 @@
                                 {{ render_button(form.application.form.removepassword_button) }}
                             {% else %}
                             {{ render_field(form.application.form.password) }}
-                            <span class="pure-form-message-inline">Password protection for your changedetection.io application.</span>
+                            <span class="pure-form-message-inline">{{ _('Password protection for your changedetection.io application.') }}</span>
                             {% endif %}
                         {% else %}
-                            <span class="pure-form-message-inline">Password is locked.</span>
+                            <span class="pure-form-message-inline">{{ _('Password is locked.') }}</span>
                         {% endif %}
                     </div>
 
                     <div class="pure-control-group">
                         {{ render_checkbox_field(form.application.form.shared_diff_access, class="shared_diff_access") }}
-                        <span class="pure-form-message-inline">Allow access to view watch diff page when password is enabled (Good for sharing the diff page)
-                        </span>
+                        <span class="pure-form-message-inline">{{ _('Allow access to the watch change history page when password is enabled (Good for sharing the diff page)') }}</span>
                     </div>
                     <div class="pure-control-group">
                         {{ render_checkbox_field(form.application.form.empty_pages_are_a_change) }}
-                        <span class="pure-form-message-inline">When a request returns no content, or the HTML does not contain any text, is this considered a change?</span>
-                    </div>
-                    <div class="grey-form-border">
-                        <div class="pure-control-group">
-                            {{ render_checkbox_field(form.application.form.rss_hide_muted_watches) }}
-                        </div>
-                        <div class="pure-control-group">
-                            {{ render_field(form.application.form.rss_content_format) }}
-                            <span class="pure-form-message-inline">Love RSS? Does your reader support HTML? Set it here</span>
-                        </div>
-                        <div class="pure-control-group">
-                            {{ render_checkbox_field(form.application.form.rss_reader_mode) }}
-                            <span class="pure-form-message-inline">Transforms RSS/RDF feed watches into beautiful text only</span>
-                        </div>
+                        <span class="pure-form-message-inline">{{ _('When a request returns no content, or the HTML does not contain any text, is this considered a change?') }}</span>
                     </div>
                 </fieldset>
             </div>
 
             <div class="tab-pane-inner" id="notifications">
                 <fieldset>
-                    <div class="field-group">
-                        {{ render_common_settings_form(form.application.form, emailprefix, settings_application, extra_notification_token_placeholder_info) }}
-                    </div>
+                    {{ render_common_settings_form(form.application.form, emailprefix, settings_application, extra_notification_token_placeholder_info) }}
                 </fieldset>
                 <div class="pure-control-group" id="notification-base-url">
                     {{ render_field(form.application.form.base_url, class="m-d") }}
                     <span class="pure-form-message-inline">
-                        Base URL used for the <code>{{ '{{ base_url }}' }}</code> token in notification links.<br>
-                        Default value is the system environment variable '<code>BASE_URL</code>' - <a href="https://github.com/dgtlmoon/changedetection.io/wiki/Configurable-BASE_URL-setting">read more here</a>.
+                        {{ _('Base URL used for the') }} <code>{{ '{{ base_url }}' }}</code> {{ _('token in notification links.') }}<br>
+                        {{ _('Default value is the system environment variable') }} '<code>BASE_URL</code>' - <a href="https://github.com/dgtlmoon/changedetection.io/wiki/Configurable-BASE_URL-setting">{{ _('read more here') }}</a>.
                     </span>
                 </div>
             </div>
@@ -111,15 +100,15 @@
                 <div class="pure-control-group inline-radio">
                     {{ render_field(form.application.form.fetch_backend, class="fetch-backend") }}
                     <span class="pure-form-message-inline">
-                        <p>Use the <strong>Basic</strong> method (default) where your watched sites don't need Javascript to render.</p>
-                        <p>The <strong>Chrome/Javascript</strong> method requires a network connection to a running WebDriver+Chrome server, set by the ENV var 'WEBDRIVER_URL'. </p>
+                        <p>{{ _('Use the') }} <strong>{{ _('Basic') }}</strong> {{ _('method (default) where your watched sites don\'t need Javascript to render.') }}</p>
+                        <p>{{ _('The') }} <strong>{{ _('Chrome/Javascript') }}</strong> {{ _('method requires a network connection to a running WebDriver+Chrome server, set by the ENV var') }} 'WEBDRIVER_URL'. </p>
                     </span>
                 </div>
                 <fieldset class="pure-group" id="webdriver-override-options" data-visible-for="application-fetch_backend=html_webdriver">
                     <div class="pure-form-message-inline">
-                        <strong>If you're having trouble waiting for the page to be fully rendered (text missing etc), try increasing the 'wait' time here.</strong>
+                        <strong>{{ _('If you\'re having trouble waiting for the page to be fully rendered (text missing etc), try increasing the \'wait\' time here.') }}</strong>
                         <br>
-                        This will wait <i>n</i> seconds before extracting the text.
+                        {{ _('This will wait') }} <i>n</i> {{ _('seconds before extracting the text.') }}
                     </div>
                     <div class="pure-control-group">
                         {{ render_field(form.application.form.webdriver_delay) }}
@@ -128,23 +117,27 @@
                 <div class="pure-control-group">
                     {{ render_field(form.requests.form.workers) }}
                     {% set worker_info = get_worker_status_info() %}
-                    <span class="pure-form-message-inline">Number of concurrent workers to process watches. More workers = faster processing but higher memory usage.<br>
-                    Currently running: <strong>{{ worker_info.count }}</strong> operational {{ worker_info.type }} workers{% if worker_info.active_workers > 0 %} ({{ worker_info.active_workers }} actively processing){% endif %}.</span>
+                    <span class="pure-form-message-inline">{{ _('Number of concurrent workers to process watches. More workers = faster processing but higher memory usage.') }}<br>
+                    {{ _('Currently running:') }} <strong>{{ worker_info.count }}</strong> {{ _('operational') }} {{ worker_info.type }} {{ _('workers') }}{% if worker_info.active_workers > 0 %} ({{ worker_info.active_workers }} {{ _('actively processing') }}){% endif %}.</span>
+                </div>
+                <div class="pure-control-group">
+                    {{ render_field(form.requests.form.jitter_seconds, class="jitter_seconds") }}
+                    <span class="pure-form-message-inline">{{ _('Example - 3 seconds random jitter could trigger up to 3 seconds earlier or up to 3 seconds later') }}</span>
                 </div>
                 <div class="pure-control-group">
                     {{ render_field(form.requests.form.timeout) }}
-                    <span class="pure-form-message-inline">For regular plain requests (not chrome based), maximum number of seconds until timeout, 1-999.<br>
+                    <span class="pure-form-message-inline">{{ _('For regular plain requests (not chrome based), maximum number of seconds until timeout, 1-999.') }}</span><br>
                 </div>
                 <div class="pure-control-group inline-radio">
                     {{ render_field(form.requests.form.default_ua) }}
                     <span class="pure-form-message-inline">
-                        Applied to all requests.<br><br>
-                        Note: Simply changing the User-Agent often does not defeat anti-robot technologies, it's important to consider <a href="https://changedetection.io/tutorial/what-are-main-types-anti-robot-mechanisms">all of the ways that the browser is detected</a>.
+                        {{ _('Applied to all requests.') }}<br><br>
+                        {{ _('Note: Simply changing the User-Agent often does not defeat anti-robot technologies, it\'s important to consider') }} <a href="https://changedetection.io/tutorial/what-are-main-types-anti-robot-mechanisms">{{ _('all of the ways that the browser is detected') }}</a>.
                     </span>
                 </div>
                 <div class="pure-control-group">
                                         <br>
-                    Tip: <a href="https://github.com/dgtlmoon/changedetection.io/wiki/Proxy-configuration#brightdata-proxy-support">Connect using Bright Data and Oxylabs Proxies, find out more here.</a>
+                    {{ _('Tip:') }} <a href="https://github.com/dgtlmoon/changedetection.io/wiki/Proxy-configuration#brightdata-proxy-support">{{ _('Connect using Bright Data and Oxylabs Proxies, find out more here.') }}</a>
 
                 </div>
             </div>
@@ -153,15 +146,15 @@
 
                     <fieldset class="pure-group">
                     {{ render_checkbox_field(form.application.form.ignore_whitespace) }}
-                    <span class="pure-form-message-inline">Ignore whitespace, tabs and new-lines/line-feeds when considering if a change was detected.<br>
-                    <i>Note:</i> Changing this will change the status of your existing watches, possibly trigger alerts etc.
+                    <span class="pure-form-message-inline">{{ _('Ignore whitespace, tabs and new-lines/line-feeds when considering if a change was detected.') }}<br>
+                    <i>{{ _('Note:') }}</i> {{ _('Changing this will change the status of your existing watches, possibly trigger alerts etc.') }}
                     </span>
                     </fieldset>
                 <fieldset class="pure-group">
                     {{ render_checkbox_field(form.application.form.render_anchor_tag_content) }}
-                    <span class="pure-form-message-inline">Render anchor tag content, default disabled, when enabled renders links as <code>(link text)[https://somesite.com]</code>
+                    <span class="pure-form-message-inline">{{ _('Render anchor tag content, default disabled, when enabled renders links as') }} <code>(link text)[https://somesite.com]</code>
                         <br>
-                    <i>Note:</i> Changing this could affect the content of your existing watches, possibly trigger alerts etc.
+                    <i>{{ _('Note:') }}</i> {{ _('Changing this could affect the content of your existing watches, possibly trigger alerts etc.') }}
                     </span>
                     </fieldset>
                     <fieldset class="pure-group">
@@ -172,9 +165,9 @@ nav
 //*[contains(text(), 'Advertisement')]") }}
                       <span class="pure-form-message-inline">
                         <ul>
-                          <li> Remove HTML element(s) by CSS and XPath selectors before text conversion. </li>
-                          <li> Don't paste HTML here, use only CSS and XPath selectors </li>
-                          <li> Add multiple elements, CSS or XPath selectors per line to ignore multiple parts of the HTML. </li>
+                          <li> {{ _('Remove HTML element(s) by CSS and XPath selectors before text conversion.') }} </li>
+                          <li> {{ _('Don\'t paste HTML here, use only CSS and XPath selectors') }} </li>
+                          <li> {{ _('Add multiple elements, CSS or XPath selectors per line to ignore multiple parts of the HTML.') }} </li>
                         </ul>
                       </span>
                     </fieldset>
@@ -182,88 +175,118 @@ nav
                     {{ render_field(form.application.form.global_ignore_text, rows=5, placeholder="Some text to ignore in a line
 /some.regex\d{2}/ for case-INsensitive regex
                     ") }}
-                    <span class="pure-form-message-inline">Note: This is applied globally in addition to the per-watch rules.</span><br>
+                    <span class="pure-form-message-inline">{{ _('Note: This is applied globally in addition to the per-watch rules.') }}</span><br>
                     <span class="pure-form-message-inline">
                         <ul>
-                            <li>Matching text will be <strong>ignored</strong> in the text snapshot (you can still see it but it wont trigger a change)</li>
-                            <li>Note: This is applied globally in addition to the per-watch rules.</li>
-                            <li>Each line processed separately, any line matching will be ignored (removed before creating the checksum)</li>
-                            <li>Regular Expression support, wrap the entire line in forward slash <code>/regex/</code></li>
-                            <li>Changing this will affect the comparison checksum which may trigger an alert</li>
+                            <li>{{ _('Matching text will be') }} <strong>{{ _('ignored') }}</strong> {{ _('in the text snapshot (you can still see it but it wont trigger a change)') }}</li>
+                            <li>{{ _('Note: This is applied globally in addition to the per-watch rules.') }}</li>
+                            <li>{{ _('Each line processed separately, any line matching will be ignored (removed before creating the checksum)') }}</li>
+                            <li>{{ _('Regular Expression support, wrap the entire line in forward slash') }} <code>/regex/</code></li>
+                            <li>{{ _('Changing this will affect the comparison checksum which may trigger an alert') }}</li>
                         </ul>
                      </span>
                     </fieldset>
                     <fieldset class="pure-group">
                         {{ render_checkbox_field(form.application.form.strip_ignored_lines) }}
-                        <span class="pure-form-message-inline">Remove any text that appears in the "Ignore text" from the output (otherwise its just ignored for change-detection)<br>
-                        <i>Note:</i> Changing this will change the status of your existing watches, possibly trigger alerts etc.
+                        <span class="pure-form-message-inline">{{ _('Remove any text that appears in the "Ignore text" from the output (otherwise its just ignored for change-detection)') }}<br>
+                        <i>{{ _('Note:') }}</i> {{ _('Changing this will change the status of your existing watches, possibly trigger alerts etc.') }}
                         </span>
                     </fieldset>
            </div>
 
             <div class="tab-pane-inner" id="api">
-                <h4>API Access</h4>
-                <p>Drive your changedetection.io via API, More about <a href="https://changedetection.io/docs/api_v1/index.html">API access and examples here</a>.</p>
+                <h4>{{ _('API Access') }}</h4>
+                <p>{{ _('Drive your changedetection.io via API, More about') }} <a href="https://changedetection.io/docs/api_v1/index.html">{{ _('API access and examples here') }}</a>.</p>
 
                 <div class="pure-control-group">
                     {{ render_checkbox_field(form.application.form.api_access_token_enabled) }}
-                    <div class="pure-form-message-inline">Restrict API access limit by using <code>x-api-key</code> header - required for the Chrome Extension to work</div><br>
-                    <div class="pure-form-message-inline"><br>API Key <span id="api-key">{{api_key}}</span>
-                        <span style="display:none;" id="api-key-copy" >copy</span>
+                    <div class="pure-form-message-inline">{{ _('Restrict API access limit by using') }} <code>x-api-key</code> {{ _('header - required for the Chrome Extension to work') }}</div><br>
+                    <div class="pure-form-message-inline"><br>{{ _('API Key') }} <span id="api-key">{{api_key}}</span>
+                        <span style="display:none;" id="api-key-copy" >{{ _('copy') }}</span>
                     </div>
                 </div>
                 <div class="pure-control-group">
-                    <a href="{{url_for('settings.settings_reset_api_key')}}" class="pure-button button-small button-cancel">Regenerate API key</a>
+                    <a href="{{url_for('settings.settings_reset_api_key')}}" class="pure-button button-small button-cancel">{{ _('Regenerate API key') }}</a>
                 </div>
                 <div class="pure-control-group">
-                    <h4>Chrome Extension</h4>
-                    <p>Easily add any web-page to your changedetection.io installation from within Chrome.</p>
-                    <strong>Step 1</strong> Install the extension, <strong>Step 2</strong> Navigate to this page,
-                    <strong>Step 3</strong> Open the extension from the toolbar and click "<i>Sync API Access</i>"
+                    <h4>{{ _('Chrome Extension') }}</h4>
+                    <p>{{ _('Easily add any web-page to your changedetection.io installation from within Chrome.') }}</p>
+                    <strong>{{ _('Step 1') }}</strong> {{ _('Install the extension,') }} <strong>{{ _('Step 2') }}</strong> {{ _('Navigate to this page,') }}
+                    <strong>{{ _('Step 3') }}</strong> {{ _('Open the extension from the toolbar and click') }} "<i>{{ _('Sync API Access') }}</i>"
                     <p>
                         <a id="chrome-extension-link"
-                           title="Try our new Chrome Extension!"
+                           title="{{ _('Try our new Chrome Extension!') }}"
                            href="https://chromewebstore.google.com/detail/changedetectionio-website/kefcfmgmlhmankjmnbijimhofdjekbop">
-                            <img alt="Chrome store icon" src="{{ url_for('static_content', group='images', filename='google-chrome-icon.png') }}" alt="Chrome">
-                            Chrome Webstore
+                            <img alt="{{ _('Chrome store icon') }}" src="{{ url_for('static_content', group='images', filename='google-chrome-icon.png') }}" >
+                            {{ _('Chrome Webstore') }}
                         </a>
                     </p>
                 </div>
             </div>
-            <div class="tab-pane-inner" id="timedate">
+            <div class="tab-pane-inner" id="rss">
                 <div class="pure-control-group">
-                    Ensure the settings below are correct, they are used to manage the time schedule for checking your web page watches.
+                    {{ render_checkbox_field(form.application.form.rss_hide_muted_watches) }}
                 </div>
                 <div class="pure-control-group">
-                    <p><strong>UTC Time &amp Date from Server:</strong> <span id="utc-time" >{{ utc_time }}</span></p>
-                    <p><strong>Local Time &amp Date in Browser:</strong> <span class="local-time" data-utc="{{ utc_time }}"></span></p>
-                    <p>
+                    {{ render_field(form.application.form.rss_diff_length) }}
+                    <span class="pure-form-message-inline">{{ _('Maximum number of history snapshots to include in the watch specific RSS feed.') }}</span>
+                </div>
+                <div class="pure-control-group">
+                    {{ render_checkbox_field(form.application.form.rss_reader_mode) }}
+                    <span class="pure-form-message-inline">{{ _('For watching other RSS feeds - When watching RSS/Atom feeds, convert them into clean text for better change detection.') }}</span>
+                </div>
+                <div class="pure-control-group grey-form-border">
+                    <div class="pure-control-group">
+                        {{ render_field(form.application.form.rss_content_format) }}
+                        <span class="pure-form-message-inline">{{ _('Does your reader support HTML? Set it here') }}</span>
+                    </div>
+                    <div class="pure-control-group">
+                        {{ render_field(form.application.form.rss_template_type) }}
+                        <span class="pure-form-message-inline">{{ _('\'System default\' for the same template for all items, or re-use your "Notification Body" as the template.') }}</span>
+                    </div>
+                    <div>
+                       {{ render_field(form.application.form.rss_template_override) }}
+                        {{ show_token_placeholders(extra_notification_token_placeholder_info=extra_notification_token_placeholder_info, suffix="-rss") }}
+                    </div>
+                </div>
+                <br>
+
+
+            </div>
+                <div class="tab-pane-inner" id="timedate">
+                <div class="pure-control-group">
+                    {{ _('Ensure the settings below are correct, they are used to manage the time schedule for checking your web page watches.') }}
+                </div>
+                <div class="pure-control-group">
+                    <p><strong>{{ _('UTC Time & Date from Server:') }}</strong> <span id="utc-time" >{{ utc_time }}</span></p>
+                    <p><strong>{{ _('Local Time & Date in Browser:') }}</strong> <span class="local-time" data-utc="{{ utc_time }}"></span></p>
+                    <div>
                        {{ render_field(form.application.form.scheduler_timezone_default) }}
                         <datalist id="timezones" style="display: none;">
                             {%- for timezone in available_timezones -%}<option value="{{ timezone }}">{{ timezone }}</option>{%- endfor -%}
                         </datalist>
-                    </p>
+                    </div>
                 </div>
             </div>
             <div class="tab-pane-inner" id="ui-options">
                 <div class="pure-control-group">
                     {{ render_checkbox_field(form.application.form.ui.form.open_diff_in_new_tab, class="open_diff_in_new_tab") }}
-                    <span class="pure-form-message-inline">Enable this setting to open the diff page in a new tab. If disabled, the diff page will open in the current tab.</span>
+                    <span class="pure-form-message-inline">{{ _('Enable this setting to open the diff page in a new tab. If disabled, the diff page will open in the current tab.') }}</span>
                 </div>
                 <div class="pure-control-group">
                     {{ render_checkbox_field(form.application.form.ui.form.socket_io_enabled, class="socket_io_enabled") }}
-                    <span class="pure-form-message-inline">Realtime UI Updates Enabled - (Restart required if this is changed)</span>
+                    <span class="pure-form-message-inline">{{ _('Realtime UI Updates Enabled - (Restart required if this is changed)') }}</span>
                 </div>
                 <div class="pure-control-group">
                     {{ render_checkbox_field(form.application.form.ui.form.favicons_enabled, class="") }}
-                    <span class="pure-form-message-inline">Enable or Disable Favicons next to the watch list</span>
+                    <span class="pure-form-message-inline">{{ _('Enable or Disable Favicons next to the watch list') }}</span>
                 </div>
                 <div class="pure-control-group">
                     {{ render_checkbox_field(form.application.form.ui.use_page_title_in_list) }}
                 </div>
                 <div class="pure-control-group">
                     {{ render_field(form.application.form.pager_size) }}
-                    <span class="pure-form-message-inline">Number of items per page in the watch overview list, 0 to disable.</span>
+                    <span class="pure-form-message-inline">{{ _('Number of items per page in the watch overview list, 0 to disable.') }}</span>
                 </div>
 
             </div>
@@ -311,18 +334,18 @@ nav
                     </div>
                 </div>
 
-               <p><strong>Tip</strong>: "Residential" and "Mobile" proxy type can be more successfull than "Data Center" for blocked websites.
+                <p><strong>{{ _('Tip') }}</strong>: {{ _('"Residential" and "Mobile" proxy type can be more successfull than "Data Center" for blocked websites.') }}</p>
 
                 <div class="pure-control-group" id="extra-proxies-setting">
                 {{ render_fieldlist_with_inline_errors(form.requests.form.extra_proxies) }}
-                <span class="pure-form-message-inline">"Name" will be used for selecting the proxy in the Watch Edit settings</span><br>
-                <span class="pure-form-message-inline">SOCKS5 proxies with authentication are only supported with 'plain requests' fetcher, for other fetchers you should whitelist the IP access instead</span>
+                <span class="pure-form-message-inline">{{ _('"Name" will be used for selecting the proxy in the Watch Edit settings') }}</span><br>
+                <span class="pure-form-message-inline">{{ _('SOCKS5 proxies with authentication are only supported with \'plain requests\' fetcher, for other fetchers you should whitelist the IP access instead') }}</span>
                 {% if form.requests.proxy %}
                 <div>
                 <br>
                     <div class="inline-radio">
                         {{ render_field(form.requests.form.proxy, class="fetch-backend-proxy") }}
-                        <span class="pure-form-message-inline">Choose a default proxy for all watches</span>
+                        <span class="pure-form-message-inline">{{ _('Choose a default proxy for all watches') }}</span>
                     </div>
                 </div>
                 {% endif %}
@@ -334,13 +357,51 @@ nav
                     </p>
                     {{ render_fieldlist_with_inline_errors(form.requests.form.extra_browsers) }}
                 </div>
-            
+            </div>
+            {% if plugin_tabs %}
+                {% for tab in plugin_tabs %}
+            <div class="tab-pane-inner" id="plugin-{{ tab.plugin_id }}">
+                {% set plugin_form = plugin_forms[tab.plugin_id] %}
+                {% if tab.template_path %}
+                    {# Plugin provides custom template - include it directly (no separate form) #}
+                    {% include tab.template_path with context %}
+                {% else %}
+                    {# Default form rendering - fields only, no submit button #}
+                    <fieldset>
+                        {% for field in plugin_form %}
+                            {% if field.type != 'CSRFToken' and field.type != 'SubmitField' %}
+                        <div class="pure-control-group">
+                                {% if field.type == 'BooleanField' %}
+                            {{ render_checkbox_field(field) }}
+                                {% else %}
+                            {{ render_field(field) }}
+                                {% endif %}
+                        </div>
+                            {% endif %}
+                        {% endfor %}
+                    </fieldset>
+                {% endif %}
+            </div>
+                {% endfor %}
+            {% endif %}
+            <div class="tab-pane-inner" id="info">
+                <p><strong>{{ _('Python version:') }}</strong> {{ python_version }}</p>
+                <p><strong>{{ _('Plugins active:') }}</strong></p>
+                {% if active_plugins %}
+                <ul>
+                    {% for plugin in active_plugins %}
+                    <li><strong>{{ plugin.name }}</strong> - {{ plugin.description }}</li>
+                    {% endfor %}
+                </ul>
+                {% else %}
+                <p>{{ _('No plugins active') }}</p>
+                {% endif %}
             </div>
             <div id="actions">
                 <div class="pure-control-group">
                     {{ render_button(form.save_button) }}
-                    <a href="{{url_for('watchlist.index')}}" class="pure-button button-cancel">Back</a>
-                    <a href="{{url_for('ui.clear_all_history')}}" class="pure-button button-error">Clear Snapshot History</a>
+                    <a href="{{url_for('watchlist.index')}}" class="pure-button button-cancel">{{ _('Back') }}</a>
+                    <a href="{{url_for('ui.clear_all_history')}}" class="pure-button button-error">{{ _('Clear Snapshot History') }}</a>
                 </div>
             </div>
         </form>

changedetectionio/blueprint/tags/__init__.py

@@ -1,5 +1,7 @@
+import threading
 from flask import Blueprint, request, render_template, flash, url_for, redirect
-
+from flask_babel import gettext
+from loguru import logger
 
 from changedetectionio.store import ChangeDetectionStore
 from changedetectionio.flask_app import login_optionally_required
@@ -21,9 +23,10 @@ def construct_blueprint(datastore: ChangeDetectionStore):
         tag_count = Counter(tag for watch in datastore.data['watching'].values() if watch.get('tags') for tag in watch['tags'])
 
         output = render_template("groups-overview.html",
+                                 app_rss_token=datastore.data['settings']['application'].get('rss_access_token'),
                                  available_tags=sorted_tags,
                                  form=add_form,
-                                 tag_count=tag_count
+                                 tag_count=tag_count,
                                  )
 
         return output
@@ -42,11 +45,11 @@ def construct_blueprint(datastore: ChangeDetectionStore):
         title = request.form.get('name').strip()
 
         if datastore.tag_exists_by_name(title):
-            flash(f'The tag "{title}" already exists', "error")
+            flash(gettext('The tag "{}" already exists').format(title), "error")
             return redirect(url_for('tags.tags_overview_page'))
 
         datastore.add_tag(title)
-        flash("Tag added")
+        flash(gettext("Tag added"))
 
 
         return redirect(url_for('tags.tags_overview_page'))
@@ -61,39 +64,73 @@ def construct_blueprint(datastore: ChangeDetectionStore):
     @tags_blueprint.route("/delete/<string:uuid>", methods=['GET'])
     @login_optionally_required
     def delete(uuid):
-        removed = 0
-        # Delete the tag, and any tag reference
+        # Delete the tag from settings immediately
         if datastore.data['settings']['application']['tags'].get(uuid):
             del datastore.data['settings']['application']['tags'][uuid]
 
-        for watch_uuid, watch in datastore.data['watching'].items():
-            if watch.get('tags') and uuid in watch['tags']:
-                removed += 1
-                watch['tags'].remove(uuid)
+        # Remove tag from all watches in background thread to avoid blocking
+        def remove_tag_background(tag_uuid):
+            """Background thread to remove tag from watches - discarded after completion."""
+            removed_count = 0
+            try:
+                for watch_uuid, watch in datastore.data['watching'].items():
+                    if watch.get('tags') and tag_uuid in watch['tags']:
+                        watch['tags'].remove(tag_uuid)
+                        removed_count += 1
+                logger.info(f"Background: Tag {tag_uuid} removed from {removed_count} watches")
+            except Exception as e:
+                logger.error(f"Error removing tag from watches: {e}")
 
-        flash(f"Tag deleted and removed from {removed} watches")
+        # Start daemon thread
+        threading.Thread(target=remove_tag_background, args=(uuid,), daemon=True).start()
+
+        flash(gettext("Tag deleted, removing from watches in background"))
         return redirect(url_for('tags.tags_overview_page'))
 
     @tags_blueprint.route("/unlink/<string:uuid>", methods=['GET'])
     @login_optionally_required
     def unlink(uuid):
-        unlinked = 0
-        for watch_uuid, watch in datastore.data['watching'].items():
-            if watch.get('tags') and uuid in watch['tags']:
-                unlinked += 1
-                watch['tags'].remove(uuid)
+        # Unlink tag from all watches in background thread to avoid blocking
+        def unlink_tag_background(tag_uuid):
+            """Background thread to unlink tag from watches - discarded after completion."""
+            unlinked_count = 0
+            try:
+                for watch_uuid, watch in datastore.data['watching'].items():
+                    if watch.get('tags') and tag_uuid in watch['tags']:
+                        watch['tags'].remove(tag_uuid)
+                        unlinked_count += 1
+                logger.info(f"Background: Tag {tag_uuid} unlinked from {unlinked_count} watches")
+            except Exception as e:
+                logger.error(f"Error unlinking tag from watches: {e}")
 
-        flash(f"Tag unlinked removed from {unlinked} watches")
+        # Start daemon thread
+        threading.Thread(target=unlink_tag_background, args=(uuid,), daemon=True).start()
+
+        flash(gettext("Unlinking tag from watches in background"))
         return redirect(url_for('tags.tags_overview_page'))
 
     @tags_blueprint.route("/delete_all", methods=['GET'])
     @login_optionally_required
     def delete_all():
-        for watch_uuid, watch in datastore.data['watching'].items():
-            watch['tags'] = []
+        # Clear all tags from settings immediately
         datastore.data['settings']['application']['tags'] = {}
 
-        flash(f"All tags deleted")
+        # Clear tags from all watches in background thread to avoid blocking
+        def clear_all_tags_background():
+            """Background thread to clear tags from all watches - discarded after completion."""
+            cleared_count = 0
+            try:
+                for watch_uuid, watch in datastore.data['watching'].items():
+                    watch['tags'] = []
+                    cleared_count += 1
+                logger.info(f"Background: Cleared tags from {cleared_count} watches")
+            except Exception as e:
+                logger.error(f"Error clearing tags from watches: {e}")
+
+        # Start daemon thread
+        threading.Thread(target=clear_all_tags_background, daemon=True).start()
+
+        flash(gettext("All tags deleted, clearing from watches in background"))
         return redirect(url_for('tags.tags_overview_page'))
 
     @tags_blueprint.route("/edit/<string:uuid>", methods=['GET'])
@@ -105,7 +142,7 @@ def construct_blueprint(datastore: ChangeDetectionStore):
 
         default = datastore.data['settings']['application']['tags'].get(uuid)
         if not default:
-            flash("Tag not found", "error")
+            flash(gettext("Tag not found"), "error")
             return redirect(url_for('watchlist.index'))
 
         form = group_restock_settings_form(
@@ -149,9 +186,9 @@ def construct_blueprint(datastore: ChangeDetectionStore):
             included_content = template.render(**template_args)
 
         output = render_template("edit-tag.html",
-                                 settings_application=datastore.data['settings']['application'],
-                                 extra_tab_content=form.extra_tab_content() if form.extra_tab_content() else None,
                                  extra_form_content=included_content,
+                                 extra_tab_content=form.extra_tab_content() if form.extra_tab_content() else None,
+                                 settings_application=datastore.data['settings']['application'],
                                  **template_args
                                  )
 
@@ -180,7 +217,7 @@ def construct_blueprint(datastore: ChangeDetectionStore):
         datastore.data['settings']['application']['tags'][uuid].update(form.data)
         datastore.data['settings']['application']['tags'][uuid]['processor'] = 'restock_diff'
         datastore.needs_write_urgent = True
-        flash("Updated")
+        flash(gettext("Updated"))
 
         return redirect(url_for('tags.tags_overview_page'))
 

changedetectionio/blueprint/tags/templates/edit-tag.html

@@ -24,12 +24,12 @@
 
     <div class="tabs collapsable">
         <ul>
-            <li class="tab" id=""><a href="#general">General</a></li>
-            <li class="tab"><a href="#filters-and-triggers">Filters &amp; Triggers</a></li>
+            <li class="tab" id=""><a href="#general">{{ _('General') }}</a></li>
+            <li class="tab"><a href="#filters-and-triggers">{{ _('Filters & Triggers') }}</a></li>
             {% if extra_tab_content %}
             <li class="tab"><a href="#extras_tab">{{ extra_tab_content }}</a></li>
             {% endif %}
-            <li class="tab"><a href="#notifications">Notifications</a></li>
+            <li class="tab"><a href="#notifications">{{ _('Notifications') }}</a></li>
         </ul>
     </div>
 
@@ -47,10 +47,10 @@
             </div>
 
             <div class="tab-pane-inner" id="filters-and-triggers">
-                <p>These settings are <strong><i>added</i></strong> to any existing watch configurations.</p>
+                <p>{{ _('These settings are') }} <strong><i>{{ _('added') }}</i></strong> {{ _('to any existing watch configurations.') }}</p>
                 {% include "edit/include_subtract.html" %}
                 <div class="text-filtering border-fieldset">
-                    <h3>Text filtering</h3>
+                    <h3>{{ _('Text filtering') }}</h3>
                     {% include "edit/text-options.html" %}
                 </div>
             </div>
@@ -70,18 +70,18 @@
                     <div class="pure-control-group inline-radio">
                       {{ render_checkbox_field(form.notification_screenshot) }}
                         <span class="pure-form-message-inline">
-                            <strong>Use with caution!</strong> This will easily fill up your email storage quota or flood other storages.
+                            <strong>{{ _('Use with caution!') }}</strong> {{ _('This will easily fill up your email storage quota or flood other storages.') }}
                         </span>
                     </div>
                     {% endif %}
                     <div class="field-group" id="notification-field-group">
                         {% if has_default_notification_urls %}
                         <div class="inline-warning">
-                            <img class="inline-warning-icon" src="{{url_for('static_content', group='images', filename='notice.svg')}}" alt="Look out!" title="Lookout!" >
-                            There are <a href="{{ url_for('settings.settings_page')}}#notifications">system-wide notification URLs enabled</a>, this form will override notification settings for this watch only &dash; an empty Notification URL list here will still send notifications.
+                            <img class="inline-warning-icon" src="{{url_for('static_content', group='images', filename='notice.svg')}}" alt="{{ _('Look out!') }}" title="{{ _('Lookout!') }}" >
+                            {{ _('There are') }} <a href="{{ url_for('settings.settings_page')}}#notifications">{{ _('system-wide notification URLs enabled') }}</a>, {{ _('this form will override notification settings for this watch only') }} &dash; {{ _('an empty Notification URL list here will still send notifications.') }}
                         </div>
                         {% endif %}
-                        <a href="#notifications" id="notification-setting-reset-to-default" class="pure-button button-xsmall" style="right: 20px; top: 20px; position: absolute; background-color: #5f42dd; border-radius: 4px; font-size: 70%; color: #fff">Use system defaults</a>
+                        <a href="#notifications" id="notification-setting-reset-to-default" class="pure-button button-xsmall" style="right: 20px; top: 20px; position: absolute; background-color: #5f42dd; border-radius: 4px; font-size: 70%; color: #fff">{{ _('Use system defaults') }}</a>
 
                         {{ render_common_settings_form(form, emailprefix, settings_application, extra_notification_token_placeholder_info) }}
                     </div>

changedetectionio/blueprint/tags/templates/groups-overview.html

@@ -2,22 +2,23 @@
 {% block content %}
 {% from '_helpers.html' import render_simple_field, render_field %}
 <script src="{{url_for('static_content', group='js', filename='jquery-3.6.0.min.js')}}"></script>
+<script src="{{url_for('static_content', group='js', filename='modal.js')}}"></script>
 
 <div class="box">
     <form class="pure-form" action="{{ url_for('tags.form_tag_add') }}" method="POST" id="new-watch-form">
         <input type="hidden" name="csrf_token" value="{{ csrf_token() }}" >
         <fieldset>
-            <legend>Add a new organisational tag</legend>
+            <legend>{{ _('Add a new organisational tag') }}</legend>
             <div id="watch-add-wrapper-zone">
                 <div>
-                    {{ render_simple_field(form.name, placeholder="Watch group / tag") }}
+                    {{ render_simple_field(form.name, placeholder=_("Watch group / tag")) }}
                 </div>
                 <div>
-                    {{ render_simple_field(form.save_button, title="Save" ) }}
+                    {{ render_simple_field(form.save_button, title=_("Save") ) }}
                 </div>
             </div>
             <br>
-            <div style="color: #fff;">Groups allows you to manage filters and notifications for multiple watches under a single organisational tag.</div>
+            <div style="color: #fff;">{{ _('Groups allows you to manage filters and notifications for multiple watches under a single organisational tag.') }}</div>
         </fieldset>
     </form>
     <!-- @todo maybe some overview matrix, 'tick' with which has notification, filter rules etc -->
@@ -27,8 +28,8 @@
             <thead>
             <tr>
                 <th></th>
-                <th># Watches</th>
-                <th>Tag / Label name</th>
+                <th>{{ _('# Watches') }}</th>
+                <th>{{ _('Tag / Label name') }}</th>
                 <th></th>
             </tr>
             </thead>
@@ -38,7 +39,7 @@
             --->
             {% if not available_tags|length %}
             <tr>
-                <td colspan="3">No website organisational tags/groups configured</td>
+                <td colspan="3">{{ _('No website organisational tags/groups configured') }}</td>
             </tr>
             {% endif %}
             {% for uuid, tag in available_tags  %}
@@ -49,9 +50,25 @@
                 <td>{{ "{:,}".format(tag_count[uuid]) if uuid in tag_count else 0 }}</td>
                 <td class="title-col inline"> <a href="{{url_for('watchlist.index', tag=uuid) }}">{{ tag.title }}</a></td>
                 <td>
-                    <a class="pure-button pure-button-primary" href="{{ url_for('tags.form_tag_edit', uuid=uuid) }}">Edit</a>&nbsp;
-                    <a class="pure-button pure-button-primary" href="{{ url_for('tags.delete', uuid=uuid) }}" title="Deletes and removes tag">Delete</a>
-                    <a class="pure-button pure-button-primary" href="{{ url_for('tags.unlink', uuid=uuid) }}" title="Keep the tag but unlink any watches">Unlink</a>
+                    <a class="pure-button pure-button-primary" href="{{ url_for('tags.form_tag_edit', uuid=uuid) }}">{{ _('Edit') }}</a>
+                    <a href="{{ url_for('ui.form_watch_checknow', tag=uuid) }}" class="pure-button pure-button-primary" >{{ _('Recheck') }}</a>
+                    <a class="pure-button button-error"
+                       href="{{ url_for('tags.delete', uuid=uuid) }}"
+                       data-requires-confirm
+                       data-confirm-type="danger"
+                       data-confirm-title="{{ _('Delete Group?') }}"
+                       data-confirm-message="{{ _('<p>Are you sure you want to delete group <strong>%(title)s</strong>?</p><p>This action cannot be undone.</p>', title=tag.title) }}"
+                       data-confirm-button="{{ _('Delete') }}"
+                       title="{{ _('Deletes and removes tag') }}">{{ _('Delete') }}</a>
+                    <a class="pure-button button-warning"
+                       href="{{ url_for('tags.unlink', uuid=uuid) }}"
+                       data-requires-confirm
+                       data-confirm-type="warning"
+                       data-confirm-title="{{ _('Unlink Group?') }}"
+                       data-confirm-message="{{ _('<p>Are you sure you want to unlink all watches from group <strong>%(title)s</strong>?</p><p>The tag will be kept but watches will be removed from it.</p>', title=tag.title) }}"
+                       data-confirm-button="{{ _('Unlink') }}"
+                       title="{{ _('Keep the tag but unlink any watches') }}">{{ _('Unlink') }}</a>
+                    <a href="{{ url_for('rss.rss_tag_feed', tag_uuid=uuid, token=app_rss_token)}}"><img alt="{{ _('RSS Feed for this watch') }}" style="padding-left: 1em;" src="{{url_for('static_content', group='images', filename='generic_feed-icon.svg')}}" height="15"></a>
                 </td>
             </tr>
             {% endfor %}

changedetectionio/blueprint/ui/__init__.py

@@ -1,11 +1,14 @@
 import time
-from flask import Blueprint, request, redirect, url_for, flash, render_template, session
+import threading
+from flask import Blueprint, request, redirect, url_for, flash, render_template, session, current_app
+from flask_babel import gettext
 from loguru import logger
 
 from changedetectionio.store import ChangeDetectionStore
 from changedetectionio.blueprint.ui.edit import construct_blueprint as construct_edit_blueprint
 from changedetectionio.blueprint.ui.notification import construct_blueprint as construct_notification_blueprint
 from changedetectionio.blueprint.ui.views import construct_blueprint as construct_views_blueprint
+from changedetectionio.blueprint.ui import diff, preview
 
 def _handle_operations(op, uuids, datastore, worker_handler, update_q, queuedWatchMetaData, watch_check_update, extra_data=None, emit_flash=True):
     from flask import request, flash
@@ -15,42 +18,42 @@ def _handle_operations(op, uuids, datastore, worker_handler, update_q, queuedWat
             if datastore.data['watching'].get(uuid):
                 datastore.delete(uuid)
         if emit_flash:
-            flash(f"{len(uuids)} watches deleted")
+            flash(gettext("{} watches deleted").format(len(uuids)))
 
     elif op == 'pause':
         for uuid in uuids:
             if datastore.data['watching'].get(uuid):
                 datastore.data['watching'][uuid]['paused'] = True
         if emit_flash:
-            flash(f"{len(uuids)} watches paused")
+            flash(gettext("{} watches paused").format(len(uuids)))
 
     elif op == 'unpause':
         for uuid in uuids:
             if datastore.data['watching'].get(uuid):
                 datastore.data['watching'][uuid.strip()]['paused'] = False
         if emit_flash:
-            flash(f"{len(uuids)} watches unpaused")
+            flash(gettext("{} watches unpaused").format(len(uuids)))
 
     elif (op == 'mark-viewed'):
         for uuid in uuids:
             if datastore.data['watching'].get(uuid):
                 datastore.set_last_viewed(uuid, int(time.time()))
         if emit_flash:
-            flash(f"{len(uuids)} watches updated")
+            flash(gettext("{} watches updated").format(len(uuids)))
 
     elif (op == 'mute'):
         for uuid in uuids:
             if datastore.data['watching'].get(uuid):
                 datastore.data['watching'][uuid]['notification_muted'] = True
         if emit_flash:
-            flash(f"{len(uuids)} watches muted")
+            flash(gettext("{} watches muted").format(len(uuids)))
 
     elif (op == 'unmute'):
         for uuid in uuids:
             if datastore.data['watching'].get(uuid):
                 datastore.data['watching'][uuid]['notification_muted'] = False
         if emit_flash:
-            flash(f"{len(uuids)} watches un-muted")
+            flash(gettext("{} watches un-muted").format(len(uuids)))
 
     elif (op == 'recheck'):
         for uuid in uuids:
@@ -58,21 +61,21 @@ def _handle_operations(op, uuids, datastore, worker_handler, update_q, queuedWat
                 # Recheck and require a full reprocessing
                 worker_handler.queue_item_async_safe(update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': uuid}))
         if emit_flash:
-            flash(f"{len(uuids)} watches queued for rechecking")
+            flash(gettext("{} watches queued for rechecking").format(len(uuids)))
 
     elif (op == 'clear-errors'):
         for uuid in uuids:
             if datastore.data['watching'].get(uuid):
                 datastore.data['watching'][uuid]["last_error"] = False
         if emit_flash:
-            flash(f"{len(uuids)} watches errors cleared")
+            flash(gettext("{} watches errors cleared").format(len(uuids)))
 
     elif (op == 'clear-history'):
         for uuid in uuids:
             if datastore.data['watching'].get(uuid):
                 datastore.clear_watch_history(uuid)
         if emit_flash:
-            flash(f"{len(uuids)} watches cleared/reset.")
+            flash(gettext("{} watches cleared/reset.").format(len(uuids)))
 
     elif (op == 'notification-default'):
         from changedetectionio.notification import (
@@ -85,7 +88,7 @@ def _handle_operations(op, uuids, datastore, worker_handler, update_q, queuedWat
                 datastore.data['watching'][uuid]['notification_urls'] = []
                 datastore.data['watching'][uuid]['notification_format'] = USE_SYSTEM_DEFAULT_NOTIFICATION_FORMAT_FOR_WATCH
         if emit_flash:
-            flash(f"{len(uuids)} watches set to use default notification settings")
+            flash(gettext("{} watches set to use default notification settings").format(len(uuids)))
 
     elif (op == 'assign-tag'):
         op_extradata = extra_data
@@ -100,7 +103,7 @@ def _handle_operations(op, uuids, datastore, worker_handler, update_q, queuedWat
 
                         datastore.data['watching'][uuid]['tags'].append(tag_uuid)
         if emit_flash:
-            flash(f"{len(uuids)} watches were tagged")
+            flash(gettext("{} watches were tagged").format(len(uuids)))
 
     if uuids:
         for uuid in uuids:
@@ -121,6 +124,13 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, worker_handle
     views_blueprint = construct_views_blueprint(datastore, update_q, queuedWatchMetaData, watch_check_update)
     ui_blueprint.register_blueprint(views_blueprint)
 
+    # Register diff and preview blueprints
+    diff_blueprint = diff.construct_blueprint(datastore)
+    ui_blueprint.register_blueprint(diff_blueprint)
+
+    preview_blueprint = preview.construct_blueprint(datastore)
+    ui_blueprint.register_blueprint(preview_blueprint)
+
     # Import the login decorator
     from changedetectionio.auth_decorator import login_optionally_required
 
@@ -130,9 +140,9 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, worker_handle
         try:
             datastore.clear_watch_history(uuid)
         except KeyError:
-            flash('Watch not found', 'error')
+            flash(gettext('Watch not found'), 'error')
         else:
-            flash("Cleared snapshot history for watch {}".format(uuid))
+            flash(gettext("Cleared snapshot history for watch {}").format(uuid))
         return redirect(url_for('watchlist.index'))
 
     @ui_blueprint.route("/clear_history", methods=['GET', 'POST'])
@@ -142,11 +152,26 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, worker_handle
             confirmtext = request.form.get('confirmtext')
 
             if confirmtext == 'clear':
-                for uuid in datastore.data['watching'].keys():
-                    datastore.clear_watch_history(uuid)
-                flash("Cleared snapshot history for all watches")
+                # Run in background thread to avoid blocking
+                def clear_history_background():
+                    # Capture UUIDs first to avoid race conditions
+                    watch_uuids = list(datastore.data['watching'].keys())
+                    logger.info(f"Background: Clearing history for {len(watch_uuids)} watches")
+
+                    for uuid in watch_uuids:
+                        try:
+                            datastore.clear_watch_history(uuid)
+                        except Exception as e:
+                            logger.error(f"Error clearing history for watch {uuid}: {e}")
+
+                    logger.info("Background: Completed clearing history")
+
+                # Start daemon thread
+                threading.Thread(target=clear_history_background, daemon=True).start()
+
+                flash(gettext("History clearing started in background"))
             else:
-                flash('Incorrect confirmation text.', 'error')
+                flash(gettext('Incorrect confirmation text.'), 'error')
 
             return redirect(url_for('watchlist.index'))
 
@@ -160,18 +185,32 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, worker_handle
         # Save the current newest history as the most recently viewed
         with_errors = request.args.get('with_errors') == "1"
         tag_limit = request.args.get('tag')
-        logger.debug(f"Limiting to tag {tag_limit}")
         now = int(time.time())
-        for watch_uuid, watch in datastore.data['watching'].items():
-            if with_errors and not watch.get('last_error'):
-                continue
 
-            if tag_limit and ( not watch.get('tags') or tag_limit not in watch['tags'] ):
-                logger.debug(f"Skipping watch {watch_uuid}")
-                continue
+        # Mark watches as viewed in background thread to avoid blocking
+        def mark_viewed_background():
+            """Background thread to mark watches as viewed - discarded after completion."""
+            marked_count = 0
+            try:
+                for watch_uuid, watch in datastore.data['watching'].items():
+                    if with_errors and not watch.get('last_error'):
+                        continue
 
-            datastore.set_last_viewed(watch_uuid, now)
+                    if tag_limit and (not watch.get('tags') or tag_limit not in watch['tags']):
+                        continue
 
+                    datastore.set_last_viewed(watch_uuid, now)
+                    marked_count += 1
+
+                logger.info(f"Background marking complete: {marked_count} watches marked as viewed")
+            except Exception as e:
+                logger.error(f"Error in background mark as viewed: {e}")
+
+        # Start background thread and return immediately
+        thread = threading.Thread(target=mark_viewed_background, daemon=True)
+        thread.start()
+
+        flash(gettext("Marking watches as viewed in background..."))
         return redirect(url_for('watchlist.index', tag=tag_limit))
 
     @ui_blueprint.route("/delete", methods=['GET'])
@@ -180,14 +219,14 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, worker_handle
         uuid = request.args.get('uuid')
 
         if uuid != 'all' and not uuid in datastore.data['watching'].keys():
-            flash('The watch by UUID {} does not exist.'.format(uuid), 'error')
+            flash(gettext('The watch by UUID {} does not exist.').format(uuid), 'error')
             return redirect(url_for('watchlist.index'))
 
         # More for testing, possible to return the first/only
         if uuid == 'first':
             uuid = list(datastore.data['watching'].keys()).pop()
         datastore.delete(uuid)
-        flash('Deleted.')
+        flash(gettext('Deleted.'))
 
         return redirect(url_for('watchlist.index'))
 
@@ -204,7 +243,7 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, worker_handle
         if not datastore.data['watching'].get(uuid).get('paused'):
             worker_handler.queue_item_async_safe(update_q, queuedWatchMetaData.PrioritizedItem(priority=5, item={'uuid': new_uuid}))
 
-        flash('Cloned, you are editing the new watch.')
+        flash(gettext('Cloned, you are editing the new watch.'))
 
         return redirect(url_for("ui.ui_edit.edit_page", uuid=new_uuid))
 
@@ -216,40 +255,83 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, worker_handle
         uuid = request.args.get('uuid')
         with_errors = request.args.get('with_errors') == "1"
 
-        i = 0
-
-        running_uuids = worker_handler.get_running_uuids()
-
         if uuid:
-            if uuid not in running_uuids:
+            # Single watch - check if already queued or running
+            if worker_handler.is_watch_running(uuid) or uuid in update_q.get_queued_uuids():
+                flash(gettext("Watch is already queued or being checked."))
+            else:
                 worker_handler.queue_item_async_safe(update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': uuid}))
-                i += 1
-
+                flash(gettext("Queued 1 watch for rechecking."))
         else:
-            # Recheck all, including muted
-            # Get most overdue first
+            # Multiple watches - first count how many need to be queued
+            watches_to_queue = []
             for k in sorted(datastore.data['watching'].items(), key=lambda item: item[1].get('last_checked', 0)):
                 watch_uuid = k[0]
                 watch = k[1]
-                if not watch['paused']:
-                    if watch_uuid not in running_uuids:
-                        if with_errors and not watch.get('last_error'):
-                            continue
+                if not watch['paused'] and watch_uuid:
+                    if with_errors and not watch.get('last_error'):
+                        continue
+                    if tag != None and tag not in watch['tags']:
+                        continue
+                    watches_to_queue.append(watch_uuid)
 
-                        if tag != None and tag not in watch['tags']:
-                            continue
+            # If less than 20 watches, queue synchronously for immediate feedback
+            if len(watches_to_queue) < 20:
+                # Get already queued/running UUIDs once (efficient)
+                queued_uuids = set(update_q.get_queued_uuids())
+                running_uuids = set(worker_handler.get_running_uuids())
 
-                        worker_handler.queue_item_async_safe(update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': watch_uuid}))
-                        i += 1
+                # Filter out watches that are already queued or running
+                watches_to_queue_filtered = []
+                for watch_uuid in watches_to_queue:
+                    if watch_uuid not in queued_uuids and watch_uuid not in running_uuids:
+                        watches_to_queue_filtered.append(watch_uuid)
 
-        if i == 1:
-            flash("Queued 1 watch for rechecking.")
-        if i > 1:
-            flash(f"Queued {i} watches for rechecking.")
-        if i == 0:
-            flash("No watches available to recheck.")
+                # Queue only the filtered watches
+                for watch_uuid in watches_to_queue_filtered:
+                    worker_handler.queue_item_async_safe(update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': watch_uuid}))
 
-        return redirect(url_for('watchlist.index'))
+                # Provide feedback about skipped watches
+                skipped_count = len(watches_to_queue) - len(watches_to_queue_filtered)
+                if skipped_count > 0:
+                    flash(gettext("Queued {} watches for rechecking ({} already queued or running).").format(
+                        len(watches_to_queue_filtered), skipped_count))
+                else:
+                    if len(watches_to_queue_filtered) == 1:
+                        flash(gettext("Queued 1 watch for rechecking."))
+                    else:
+                        flash(gettext("Queued {} watches for rechecking.").format(len(watches_to_queue_filtered)))
+            else:
+                # 20+ watches - queue in background thread to avoid blocking HTTP response
+                # Capture queued/running state before background thread
+                queued_uuids = set(update_q.get_queued_uuids())
+                running_uuids = set(worker_handler.get_running_uuids())
+
+                def queue_watches_background():
+                    """Background thread to queue watches - discarded after completion."""
+                    try:
+                        queued_count = 0
+                        skipped_count = 0
+                        for watch_uuid in watches_to_queue:
+                            # Check if already queued or running (state captured at start)
+                            if watch_uuid not in queued_uuids and watch_uuid not in running_uuids:
+                                worker_handler.queue_item_async_safe(update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': watch_uuid}))
+                                queued_count += 1
+                            else:
+                                skipped_count += 1
+
+                        logger.info(f"Background queueing complete: {queued_count} watches queued, {skipped_count} skipped (already queued/running)")
+                    except Exception as e:
+                        logger.error(f"Error in background queueing: {e}")
+
+                # Start background thread and return immediately
+                thread = threading.Thread(target=queue_watches_background, daemon=True, name="QueueWatches-Background")
+                thread.start()
+
+                # Return immediately with approximate message
+                flash(gettext("Queueing watches for rechecking in background..."))
+
+        return redirect(url_for('watchlist.index', **({'tag': tag} if tag else {})))
 
     @ui_blueprint.route("/form/checkbox-operations", methods=['POST'])
     @login_optionally_required
@@ -318,8 +400,29 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, worker_handle
 
         except Exception as e:
             logger.error(f"Error sharing -{str(e)}")
-            flash(f"Could not share, something went wrong while communicating with the share server - {str(e)}", 'error')
+            flash(gettext("Could not share, something went wrong while communicating with the share server - {}").format(str(e)), 'error')
 
         return redirect(url_for('watchlist.index'))
 
+    @ui_blueprint.route("/language/auto-detect", methods=['GET'])
+    def delete_locale_language_session_var_if_it_exists():
+        """Clear the session locale preference to auto-detect from browser Accept-Language header"""
+        if 'locale' in session:
+            session.pop('locale', None)
+            # Refresh Flask-Babel to clear cached locale
+            from flask_babel import refresh
+            refresh()
+            flash(gettext("Language set to auto-detect from browser"))
+
+        # Check if there's a redirect parameter to return to the same page
+        redirect_url = request.args.get('redirect')
+
+        # If redirect is provided and safe, use it
+        from changedetectionio.is_safe_url import is_safe_url
+        if redirect_url and is_safe_url(redirect_url, current_app):
+            return redirect(redirect_url)
+
+        # Otherwise redirect to watchlist
+        return redirect(url_for('watchlist.index'))
+
     return ui_blueprint

changedetectionio/blueprint/ui/diff.py

@@ -0,0 +1,317 @@
+from flask import Blueprint, request, redirect, url_for, flash, render_template, make_response, send_from_directory
+from flask_babel import gettext
+
+import re
+import importlib
+from loguru import logger
+from markupsafe import Markup
+
+from changedetectionio.diff import (
+    REMOVED_STYLE, ADDED_STYLE, REMOVED_INNER_STYLE, ADDED_INNER_STYLE,
+    REMOVED_PLACEMARKER_OPEN, REMOVED_PLACEMARKER_CLOSED,
+    ADDED_PLACEMARKER_OPEN, ADDED_PLACEMARKER_CLOSED,
+    CHANGED_PLACEMARKER_OPEN, CHANGED_PLACEMARKER_CLOSED,
+    CHANGED_INTO_PLACEMARKER_OPEN, CHANGED_INTO_PLACEMARKER_CLOSED
+)
+from changedetectionio.store import ChangeDetectionStore
+from changedetectionio.auth_decorator import login_optionally_required
+
+
+def construct_blueprint(datastore: ChangeDetectionStore):
+    diff_blueprint = Blueprint('ui_diff', __name__, template_folder="../ui/templates")
+
+    @diff_blueprint.app_template_filter('diff_unescape_difference_spans')
+    def diff_unescape_difference_spans(content):
+        """Emulate Jinja2's auto-escape, then selectively unescape our diff spans."""
+        from markupsafe import escape
+
+        if not content:
+            return Markup('')
+
+        # Step 1: Escape everything like Jinja2 would (this makes it XSS-safe)
+        escaped_content = escape(str(content))
+
+        # Step 2: Unescape only our exact diff spans generated by apply_html_color_to_body()
+        # Pattern matches the exact structure:
+        # <span style="{STYLE}" role="{ROLE}" aria-label="{LABEL}" title="{TITLE}">
+
+        # Unescape outer span opening tags with full attributes (role, aria-label, title)
+        # Matches removed/added/changed/changed_into spans
+        result = re.sub(
+            rf'&lt;span style=&#34;({re.escape(REMOVED_STYLE)}|{re.escape(ADDED_STYLE)})&#34; '
+            rf'role=&#34;(deletion|insertion|note)&#34; '
+            rf'aria-label=&#34;([^&]+?)&#34; '
+            rf'title=&#34;([^&]+?)&#34;&gt;',
+            r'<span style="\1" role="\2" aria-label="\3" title="\4">',
+            str(escaped_content),
+            flags=re.IGNORECASE
+        )
+
+        # Unescape inner span opening tags (without additional attributes)
+        # This matches the darker background styles for changed parts within lines
+        result = re.sub(
+            rf'&lt;span style=&#34;({re.escape(REMOVED_INNER_STYLE)}|{re.escape(ADDED_INNER_STYLE)})&#34;&gt;',
+            r'<span style="\1">',
+            result,
+            flags=re.IGNORECASE
+        )
+
+        # Unescape closing tags (but only as many as we opened)
+        open_count = result.count('<span style=')
+        close_count = str(escaped_content).count('&lt;/span&gt;')
+
+        # Replace up to the number of spans we opened
+        for _ in range(min(open_count, close_count)):
+            result = result.replace('&lt;/span&gt;', '</span>', 1)
+
+        return Markup(result)
+
+    @diff_blueprint.route("/diff/<string:uuid>", methods=['GET'])
+    @login_optionally_required
+    def diff_history_page(uuid):
+        """
+        Render the history/diff page for a watch.
+
+        This route is processor-aware: it delegates rendering to the processor's
+        difference.py module, allowing different processor types to provide
+        custom visualizations:
+        - text_json_diff: Text/HTML diff with syntax highlighting
+        - restock_diff: Could show price charts and stock history
+        - image_diff: Could show image comparison slider/overlay
+
+        Each processor implements processors/{type}/difference.py::render()
+        If a processor doesn't have a difference module, falls back to text_json_diff.
+        """
+
+        # More for testing, possible to return the first/only
+        if uuid == 'first':
+            uuid = list(datastore.data['watching'].keys()).pop()
+
+        try:
+            watch = datastore.data['watching'][uuid]
+        except KeyError:
+            flash(gettext("No history found for the specified link, bad link?"), "error")
+            return redirect(url_for('watchlist.index'))
+
+        dates = list(watch.history.keys())
+        if not dates or len(dates) < 2:
+            flash(gettext("Not enough history (2 snapshots required) to show difference page for this watch."), "error")
+            return redirect(url_for('watchlist.index'))
+
+        # Get the processor type for this watch
+        processor_name = watch.get('processor', 'text_json_diff')
+
+        try:
+            # Try to import the processor's difference module
+            processor_module = importlib.import_module(f'changedetectionio.processors.{processor_name}.difference')
+
+            # Call the processor's render() function
+            if hasattr(processor_module, 'render'):
+                return processor_module.render(
+                    watch=watch,
+                    datastore=datastore,
+                    request=request,
+                    url_for=url_for,
+                    render_template=render_template,
+                    flash=flash,
+                    redirect=redirect
+                )
+        except (ImportError, ModuleNotFoundError) as e:
+            logger.warning(f"Processor {processor_name} does not have a difference module, falling back to text_json_diff: {e}")
+
+        # Fallback: if processor doesn't have difference module, use text_json_diff as default
+        from changedetectionio.processors.text_json_diff.difference import render as default_render
+        return default_render(
+            watch=watch,
+            datastore=datastore,
+            request=request,
+            url_for=url_for,
+            render_template=render_template,
+            flash=flash,
+            redirect=redirect
+        )
+
+    @diff_blueprint.route("/diff/<string:uuid>/extract", methods=['GET'])
+    @login_optionally_required
+    def diff_history_page_extract_GET(uuid):
+        """
+        Render the data extraction form for a watch.
+
+        This route is processor-aware: it delegates to the processor's
+        extract.py module, allowing different processor types to provide
+        custom extraction interfaces.
+
+        Each processor implements processors/{type}/extract.py::render_form()
+        If a processor doesn't have an extract module, falls back to text_json_diff.
+        """
+        # More for testing, possible to return the first/only
+        if uuid == 'first':
+            uuid = list(datastore.data['watching'].keys()).pop()
+
+        try:
+            watch = datastore.data['watching'][uuid]
+        except KeyError:
+            flash(gettext("No history found for the specified link, bad link?"), "error")
+            return redirect(url_for('watchlist.index'))
+
+        # Get the processor type for this watch
+        processor_name = watch.get('processor', 'text_json_diff')
+
+        try:
+            # Try to import the processor's extract module
+            processor_module = importlib.import_module(f'changedetectionio.processors.{processor_name}.extract')
+
+            # Call the processor's render_form() function
+            if hasattr(processor_module, 'render_form'):
+                return processor_module.render_form(
+                    watch=watch,
+                    datastore=datastore,
+                    request=request,
+                    url_for=url_for,
+                    render_template=render_template,
+                    flash=flash,
+                    redirect=redirect
+                )
+        except (ImportError, ModuleNotFoundError) as e:
+            logger.warning(f"Processor {processor_name} does not have an extract module, falling back to base extractor: {e}")
+
+        # Fallback: if processor doesn't have extract module, use base processors.extract as default
+        from changedetectionio.processors.extract import render_form as default_render_form
+        return default_render_form(
+            watch=watch,
+            datastore=datastore,
+            request=request,
+            url_for=url_for,
+            render_template=render_template,
+            flash=flash,
+            redirect=redirect
+        )
+
+    @diff_blueprint.route("/diff/<string:uuid>/extract", methods=['POST'])
+    @login_optionally_required
+    def diff_history_page_extract_POST(uuid):
+        """
+        Process the data extraction request.
+
+        This route is processor-aware: it delegates to the processor's
+        extract.py module, allowing different processor types to provide
+        custom extraction logic.
+
+        Each processor implements processors/{type}/extract.py::process_extraction()
+        If a processor doesn't have an extract module, falls back to text_json_diff.
+        """
+        # More for testing, possible to return the first/only
+        if uuid == 'first':
+            uuid = list(datastore.data['watching'].keys()).pop()
+
+        try:
+            watch = datastore.data['watching'][uuid]
+        except KeyError:
+            flash(gettext("No history found for the specified link, bad link?"), "error")
+            return redirect(url_for('watchlist.index'))
+
+        # Get the processor type for this watch
+        processor_name = watch.get('processor', 'text_json_diff')
+
+        try:
+            # Try to import the processor's extract module
+            processor_module = importlib.import_module(f'changedetectionio.processors.{processor_name}.extract')
+
+            # Call the processor's process_extraction() function
+            if hasattr(processor_module, 'process_extraction'):
+                return processor_module.process_extraction(
+                    watch=watch,
+                    datastore=datastore,
+                    request=request,
+                    url_for=url_for,
+                    make_response=make_response,
+                    send_from_directory=send_from_directory,
+                    flash=flash,
+                    redirect=redirect
+                )
+        except (ImportError, ModuleNotFoundError) as e:
+            logger.warning(f"Processor {processor_name} does not have an extract module, falling back to base extractor: {e}")
+
+        # Fallback: if processor doesn't have extract module, use base processors.extract as default
+        from changedetectionio.processors.extract import process_extraction as default_process_extraction
+        return default_process_extraction(
+            watch=watch,
+            datastore=datastore,
+            request=request,
+            url_for=url_for,
+            make_response=make_response,
+            send_from_directory=send_from_directory,
+            flash=flash,
+            redirect=redirect
+        )
+
+    @diff_blueprint.route("/diff/<string:uuid>/processor-asset/<string:asset_name>", methods=['GET'])
+    @login_optionally_required
+    def processor_asset(uuid, asset_name):
+        """
+        Serve processor-specific binary assets (images, files, etc.).
+
+        This route is processor-aware: it delegates to the processor's
+        difference.py module, allowing different processor types to serve
+        custom assets without embedding them as base64 in templates.
+
+        This solves memory issues with large binary data (e.g., screenshots)
+        by streaming them as separate HTTP responses instead of embedding
+        in the HTML template.
+
+        Each processor implements processors/{type}/difference.py::get_asset()
+        which returns (binary_data, content_type, cache_control_header).
+
+        Example URLs:
+        - /diff/{uuid}/processor-asset/before
+        - /diff/{uuid}/processor-asset/after
+        - /diff/{uuid}/processor-asset/rendered_diff
+        """
+        # More for testing, possible to return the first/only
+        if uuid == 'first':
+            uuid = list(datastore.data['watching'].keys()).pop()
+
+        try:
+            watch = datastore.data['watching'][uuid]
+        except KeyError:
+            flash(gettext("No history found for the specified link, bad link?"), "error")
+            return redirect(url_for('watchlist.index'))
+
+        # Get the processor type for this watch
+        processor_name = watch.get('processor', 'text_json_diff')
+
+        try:
+            # Try to import the processor's difference module
+            processor_module = importlib.import_module(f'changedetectionio.processors.{processor_name}.difference')
+
+            # Call the processor's get_asset() function
+            if hasattr(processor_module, 'get_asset'):
+                result = processor_module.get_asset(
+                    asset_name=asset_name,
+                    watch=watch,
+                    datastore=datastore,
+                    request=request
+                )
+
+                if result is None:
+                    from flask import abort
+                    abort(404, description=f"Asset '{asset_name}' not found")
+
+                binary_data, content_type, cache_control = result
+
+                response = make_response(binary_data)
+                response.headers['Content-Type'] = content_type
+                if cache_control:
+                    response.headers['Cache-Control'] = cache_control
+                return response
+            else:
+                logger.warning(f"Processor {processor_name} does not implement get_asset()")
+                from flask import abort
+                abort(404, description=f"Processor '{processor_name}' does not support assets")
+
+        except (ImportError, ModuleNotFoundError) as e:
+            logger.warning(f"Processor {processor_name} does not have a difference module: {e}")
+            from flask import abort
+            abort(404, description=f"Processor '{processor_name}' not found")
+
+    return diff_blueprint

changedetectionio/blueprint/ui/edit.py

@@ -1,8 +1,8 @@
-import time
 from copy import deepcopy
 import os
 import importlib.resources
-from flask import Blueprint, request, redirect, url_for, flash, render_template, make_response, send_from_directory, abort
+from flask import Blueprint, request, redirect, url_for, flash, render_template, abort
+from flask_babel import gettext
 from loguru import logger
 from jinja2 import Environment, FileSystemLoader
 
@@ -32,14 +32,14 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMe
 
         # More for testing, possible to return the first/only
         if not datastore.data['watching'].keys():
-            flash("No watches to edit", "error")
+            flash(gettext("No watches to edit"), "error")
             return redirect(url_for('watchlist.index'))
 
         if uuid == 'first':
             uuid = list(datastore.data['watching'].keys()).pop()
 
         if not uuid in datastore.data['watching']:
-            flash("No watch with the UUID %s found." % (uuid), "error")
+            flash(gettext("No watch with the UUID {} found.").format(uuid), "error")
             return redirect(url_for('watchlist.index'))
 
         switch_processor = request.args.get('switch_processor')
@@ -47,12 +47,18 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMe
             for p in processors.available_processors():
                 if p[0] == switch_processor:
                     datastore.data['watching'][uuid]['processor'] = switch_processor
-                    flash(f"Switched to mode - {p[1]}.")
+                    flash(gettext("Switched to mode - {}.").format(p[1]))
                     datastore.clear_watch_history(uuid)
                     redirect(url_for('ui_edit.edit_page', uuid=uuid))
 
         # be sure we update with a copy instead of accidently editing the live object by reference
-        default = deepcopy(datastore.data['watching'][uuid])
+        default = None
+        while not default:
+            try:
+                default = deepcopy(datastore.data['watching'][uuid])
+            except RuntimeError as e:
+                # Dictionary changed
+                continue
 
         # Defaults for proxy choice
         if datastore.proxy_list is not None:  # When enabled
@@ -66,7 +72,7 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMe
         processor_name = datastore.data['watching'][uuid].get('processor', '')
         processor_classes = next((tpl for tpl in processors.find_processors() if tpl[1] == processor_name), None)
         if not processor_classes:
-            flash(f"Cannot load the edit form for processor/plugin '{processor_classes[1]}', plugin missing?", 'error')
+            flash(gettext("Cannot load the edit form for processor/plugin '{}', plugin missing?").format(processor_classes[1]), 'error')
             return redirect(url_for('watchlist.index'))
 
         parent_module = processors.get_parent_module(processor_classes[0])
@@ -96,6 +102,26 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMe
         form.datastore = datastore
         form.watch = default
 
+        # Load processor-specific config from JSON file for GET requests
+        if request.method == 'GET' and processor_name:
+            try:
+                from changedetectionio.processors.base import difference_detection_processor
+                # Create a processor instance to access config methods
+                processor_instance = difference_detection_processor(datastore, uuid)
+                # Use processor name as filename so each processor keeps its own config
+                config_filename = f'{processor_name}.json'
+                processor_config = processor_instance.get_extra_watch_config(config_filename)
+
+                if processor_config:
+                    # Populate processor-config-* fields from JSON
+                    for config_key, config_value in processor_config.items():
+                        field_name = f'processor_config_{config_key}'
+                        if hasattr(form, field_name):
+                            getattr(form, field_name).data = config_value
+                            logger.debug(f"Loaded processor config from {config_filename}: {field_name} = {config_value}")
+            except Exception as e:
+                logger.warning(f"Failed to load processor config: {e}")
+
         for p in datastore.extra_browsers:
             form.fetch_backend.choices.append(p)
 
@@ -114,11 +140,6 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMe
 
         if request.method == 'POST' and form.validate():
 
-            # If they changed processor, it makes sense to reset it.
-            if datastore.data['watching'][uuid].get('processor') != form.data.get('processor'):
-                datastore.data['watching'][uuid].clear_watch()
-                flash("Reset watch history due to change of processor")
-
             extra_update_obj = {
                 'consecutive_filter_failures': 0,
                 'last_error' : False
@@ -129,7 +150,60 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMe
 
             extra_update_obj['time_between_check'] = form.time_between_check.data
 
-             # Ignore text
+             # Handle processor-config-* fields separately (save to JSON, not datastore)
+            processor_config_data = {}
+            fields_to_remove = []
+            for field_name, field_value in form.data.items():
+                if field_name.startswith('processor_config_'):
+                    config_key = field_name.replace('processor_config_', '')
+                    if field_value:  # Only save non-empty values
+                        processor_config_data[config_key] = field_value
+                    fields_to_remove.append(field_name)
+
+            # Save processor config to JSON file if any config data exists
+            if processor_config_data:
+                try:
+                    processor_name = form.data.get('processor')
+                    # Create a processor instance to access config methods
+                    processor_instance = processors.difference_detection_processor(datastore, uuid)
+                    # Use processor name as filename so each processor keeps its own config
+                    config_filename = f'{processor_name}.json'
+                    processor_instance.update_extra_watch_config(config_filename, processor_config_data)
+                    logger.debug(f"Saved processor config to {config_filename}: {processor_config_data}")
+
+                    # Call optional edit_hook if processor has one
+                    try:
+                        # Try to import the edit_hook module from the processor package
+                        import importlib
+                        edit_hook_module_name = f'changedetectionio.processors.{processor_name}.edit_hook'
+
+                        try:
+                            edit_hook = importlib.import_module(edit_hook_module_name)
+                            logger.debug(f"Found edit_hook module for {processor_name}")
+
+                            if hasattr(edit_hook, 'on_config_save'):
+                                logger.info(f"Calling edit_hook.on_config_save for {processor_name}")
+                                watch_obj = datastore.data['watching'][uuid]
+                                # Call hook and get updated config
+                                updated_config = edit_hook.on_config_save(watch_obj, processor_config_data, datastore)
+                                # Save updated config back to file
+                                processor_instance.update_extra_watch_config(config_filename, updated_config)
+                                logger.info(f"Edit hook updated config: {updated_config}")
+                            else:
+                                logger.debug(f"Edit hook module found but no on_config_save function")
+                        except ModuleNotFoundError:
+                            logger.debug(f"No edit_hook module for processor {processor_name} (this is normal)")
+                    except Exception as hook_error:
+                        logger.error(f"Edit hook error (non-fatal): {hook_error}", exc_info=True)
+
+                except Exception as e:
+                    logger.error(f"Failed to save processor config: {e}")
+
+            # Remove processor-config-* fields from form.data before updating datastore
+            for field_name in fields_to_remove:
+                form.data.pop(field_name, None)
+
+            # Ignore text
             form_ignore_text = form.ignore_text.data
             datastore.data['watching'][uuid]['ignore_text'] = form_ignore_text
 
@@ -168,7 +242,14 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMe
             # Recast it if need be to right data Watch handler
             watch_class = processors.get_custom_watch_obj_for_processor(form.data.get('processor'))
             datastore.data['watching'][uuid] = watch_class(datastore_path=datastore.datastore_path, default=datastore.data['watching'][uuid])
-            flash("Updated watch - unpaused!" if request.args.get('unpause_on_save') else "Updated watch.")
+            flash(gettext("Updated watch - unpaused!") if request.args.get('unpause_on_save') else gettext("Updated watch."))
+
+            # Cleanup any browsersteps session for this watch
+            try:
+                from changedetectionio.blueprint.browser_steps import cleanup_session_for_watch
+                cleanup_session_for_watch(uuid)
+            except Exception as e:
+                logger.debug(f"Error cleaning up browsersteps session: {e}")
 
             # Re #286 - We wait for syncing new data to disk in another thread every 60 seconds
             # But in the case something is added we should save straight away
@@ -206,13 +287,13 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMe
 
             # Diff page [edit] link should go back to diff page
             if request.args.get("next") and request.args.get("next") == 'diff':
-                return redirect(url_for('ui.ui_views.diff_history_page', uuid=uuid))
+                return redirect(url_for('ui.ui_diff.diff_history_page', uuid=uuid))
 
             return redirect(url_for('watchlist.index', tag=request.args.get("tag",'')))
 
         else:
             if request.method == 'POST' and not form.validate():
-                flash("An error occurred, please see below.", "error")
+                flash(gettext("An error occurred, please see below."), "error")
 
             # JQ is difficult to install on windows and must be manually added (outside requirements.txt)
             jq_support = True
@@ -223,26 +304,25 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMe
 
             watch = datastore.data['watching'].get(uuid)
 
-            # if system or watch is configured to need a chrome type browser
-            system_uses_webdriver = datastore.data['settings']['application']['fetch_backend'] == 'html_webdriver'
-            watch_needs_selenium_or_playwright = False
-            if (watch.get('fetch_backend') == 'system' and system_uses_webdriver) or watch.get('fetch_backend') == 'html_webdriver' or watch.get('fetch_backend', '').startswith('extra_browser_'):
-                watch_needs_selenium_or_playwright = True
-
-
             from zoneinfo import available_timezones
 
-            # Only works reliably with Playwright
-
             # Import the global plugin system
-            from changedetectionio.pluggy_interface import collect_ui_edit_stats_extras
-            
+            from changedetectionio.pluggy_interface import collect_ui_edit_stats_extras, get_fetcher_capabilities
+
+            # Get fetcher capabilities instead of hardcoded logic
+            capabilities = get_fetcher_capabilities(watch, datastore)
+            app_rss_token = datastore.data['settings']['application'].get('rss_access_token'),
+
+            c = [f"processor-{watch.get('processor')}"]
+            if worker_handler.is_watch_running(uuid):
+                c.append('checking-now')
+
             template_args = {
                 'available_processors': processors.available_processors(),
                 'available_timezones': sorted(available_timezones()),
                 'browser_steps_config': browser_step_ui_config,
                 'emailprefix': os.getenv('NOTIFICATION_MAIL_BUTTON_PREFIX', False),
-                'extra_classes': 'checking-now' if worker_handler.is_watch_running(uuid) else '',
+                'extra_classes': ' '.join(c),
                 'extra_notification_token_placeholder_info': datastore.get_unique_notification_token_placeholders_available(),
                 'extra_processor_config': form.extra_tab_content(),
                 'extra_title': f" - Edit - {watch.label}",
@@ -252,16 +332,19 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMe
                 'has_special_tag_options': _watch_has_tag_options_set(watch=watch),
                 'jq_support': jq_support,
                 'playwright_enabled': os.getenv('PLAYWRIGHT_DRIVER_URL', False),
+                'app_rss_token': app_rss_token,
+                'rss_uuid_feed' : {
+                    'label': watch.label,
+                    'url': url_for('rss.rss_single_watch', uuid=watch['uuid'], token=app_rss_token)
+                },
                 'settings_application': datastore.data['settings']['application'],
-                'system_has_playwright_configured': os.getenv('PLAYWRIGHT_DRIVER_URL'),
-                'system_has_webdriver_configured': os.getenv('WEBDRIVER_URL'),
                 'ui_edit_stats_extras': collect_ui_edit_stats_extras(watch),
                 'visual_selector_data_ready': datastore.visualselector_data_is_ready(watch_uuid=uuid),
                 'timezone_default_config': datastore.data['settings']['application'].get('scheduler_timezone_default'),
                 'using_global_webdriver_wait': not default['webdriver_delay'],
                 'uuid': uuid,
                 'watch': watch,
-                'watch_needs_selenium_or_playwright': watch_needs_selenium_or_playwright,
+                'capabilities': capabilities
             }
 
             included_content = None
@@ -335,6 +418,6 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMe
                     s = re.sub(r'[0-9]+', r'\\d+', s)
                     datastore.data["watching"][uuid]['ignore_text'].append('/' + s + '/')
 
-        return f"<a href={url_for('ui.ui_views.preview_page', uuid=uuid)}>Click to preview</a>"
+        return f"<a href={url_for('ui.ui_preview.preview_page', uuid=uuid)}>Click to preview</a>"
     
     return edit_blueprint

changedetectionio/blueprint/ui/notification.py

@@ -2,7 +2,6 @@ from flask import Blueprint, request, make_response
 import random
 from loguru import logger
 
-from changedetectionio.notification_service import NotificationContextData, set_basic_notification_vars
 from changedetectionio.store import ChangeDetectionStore
 from changedetectionio.auth_decorator import login_optionally_required
 
@@ -15,7 +14,7 @@ def construct_blueprint(datastore: ChangeDetectionStore):
     @notification_blueprint.route("/notification/send-test/", methods=['POST'])
     @login_optionally_required
     def ajax_callback_send_notification_test(watch_uuid=None):
-
+        from changedetectionio.notification_service import NotificationContextData, set_basic_notification_vars
         # Watch_uuid could be unset in the case it`s used in tag editor, global settings
         import apprise
         from changedetectionio.notification.handler import process_notification
@@ -97,45 +96,29 @@ def construct_blueprint(datastore: ChangeDetectionStore):
             n_object['as_async'] = False
 
             #  Same like in notification service, should be refactored
-            dates = []
+            dates = list(watch.history.keys())
             trigger_text = ''
             snapshot_contents = ''
-            if watch:
-                watch_history = watch.history
-                dates = list(watch_history.keys())
-                trigger_text = watch.get('trigger_text', [])
-                # Add text that was triggered
-                if len(dates):
-                    snapshot_contents = watch.get_history_snapshot(dates[-1])
-                else:
-                    snapshot_contents = "No snapshot/history available, the watch should fetch atleast once."
-
-                if len(trigger_text):
-                    from . import html_tools
-                    triggered_text = html_tools.get_triggered_text(content=snapshot_contents, trigger_text=trigger_text)
-                    if triggered_text:
-                        triggered_text = '\n'.join(triggered_text)
 
             # Could be called as a 'test notification' with only 1 snapshot available
             prev_snapshot = "Example text: example test\nExample text: change detection is cool\nExample text: some more examples\n"
             current_snapshot = "Example text: example test\nExample text: change detection is fantastic\nExample text: even more examples\nExample text: a lot more examples"
 
-
-
             if len(dates) > 1:
-                prev_snapshot = watch.get_history_snapshot(dates[-2])
-                current_snapshot = watch.get_history_snapshot(dates[-1])
+                prev_snapshot = watch.get_history_snapshot(timestamp=dates[-2])
+                current_snapshot = watch.get_history_snapshot(timestamp=dates[-1])
 
-            n_object.update(set_basic_notification_vars(snapshot_contents=snapshot_contents,
-                                                        current_snapshot=current_snapshot,
+            n_object.update(set_basic_notification_vars(current_snapshot=current_snapshot,
                                                         prev_snapshot=prev_snapshot,
                                                         watch=watch,
-                                                        triggered_text=trigger_text))
+                                                        triggered_text=trigger_text,
+                                                        timestamp_changed=dates[-1] if dates else None))
 
 
             sent_obj = process_notification(n_object, datastore)
 
         except Exception as e:
+            logger.error(e)
             e_str = str(e)
             # Remove this text which is not important and floods the container
             e_str = e_str.replace(

changedetectionio/blueprint/ui/preview.py

@@ -0,0 +1,201 @@
+from flask import Blueprint, request, url_for, flash, render_template, redirect
+from flask_babel import gettext
+import time
+from loguru import logger
+
+from changedetectionio.store import ChangeDetectionStore
+from changedetectionio.auth_decorator import login_optionally_required
+from changedetectionio import html_tools
+
+def construct_blueprint(datastore: ChangeDetectionStore):
+    preview_blueprint = Blueprint('ui_preview', __name__, template_folder="../ui/templates")
+
+    @preview_blueprint.route("/preview/<string:uuid>", methods=['GET'])
+    @login_optionally_required
+    def preview_page(uuid):
+        """
+        Render the preview page for a watch.
+
+        This route is processor-aware: it delegates rendering to the processor's
+        preview.py module, allowing different processor types to provide
+        custom visualizations:
+        - text_json_diff: Text preview with syntax highlighting
+        - image_ssim_diff: Image preview with proper rendering
+        - restock_diff: Could show latest price/stock data
+
+        Each processor implements processors/{type}/preview.py::render()
+        If a processor doesn't have a preview module, falls back to default text preview.
+        """
+        # More for testing, possible to return the first/only
+        if uuid == 'first':
+            uuid = list(datastore.data['watching'].keys()).pop()
+
+        try:
+            watch = datastore.data['watching'][uuid]
+        except KeyError:
+            flash(gettext("No history found for the specified link, bad link?"), "error")
+            return redirect(url_for('watchlist.index'))
+
+        # Get the processor type for this watch
+        processor_name = watch.get('processor', 'text_json_diff')
+
+        try:
+            # Try to import the processor's preview module
+            import importlib
+            processor_module = importlib.import_module(f'changedetectionio.processors.{processor_name}.preview')
+
+            # Call the processor's render() function
+            if hasattr(processor_module, 'render'):
+                return processor_module.render(
+                    watch=watch,
+                    datastore=datastore,
+                    request=request,
+                    url_for=url_for,
+                    render_template=render_template,
+                    flash=flash,
+                    redirect=redirect
+                )
+        except (ImportError, ModuleNotFoundError) as e:
+            logger.debug(f"Processor {processor_name} does not have a preview module, using default preview: {e}")
+
+        # Fallback: if processor doesn't have preview module, use default text preview
+        content = []
+        versions = []
+        timestamp = None
+
+        system_uses_webdriver = datastore.data['settings']['application']['fetch_backend'] == 'html_webdriver'
+        extra_stylesheets = [url_for('static_content', group='styles', filename='diff.css')]
+
+        is_html_webdriver = False
+        if (watch.get('fetch_backend') == 'system' and system_uses_webdriver) or watch.get('fetch_backend') == 'html_webdriver' or watch.get('fetch_backend', '').startswith('extra_browser_'):
+            is_html_webdriver = True
+
+        triggered_line_numbers = []
+        ignored_line_numbers = []
+        blocked_line_numbers = []
+
+        if datastore.data['watching'][uuid].history_n == 0 and (watch.get_error_text() or watch.get_error_snapshot()):
+            flash(gettext("Preview unavailable - No fetch/check completed or triggers not reached"), "error")
+        else:
+            # So prepare the latest preview or not
+            preferred_version = request.args.get('version')
+            versions = list(watch.history.keys())
+            timestamp = versions[-1]
+            if preferred_version and preferred_version in versions:
+                timestamp = preferred_version
+
+            try:
+                versions = list(watch.history.keys())
+                content = watch.get_history_snapshot(timestamp=timestamp)
+
+                triggered_line_numbers = html_tools.strip_ignore_text(content=content,
+                                                                      wordlist=watch.get('trigger_text'),
+                                                                      mode='line numbers'
+                                                                      )
+                ignored_line_numbers = html_tools.strip_ignore_text(content=content,
+                                                                      wordlist=watch.get('ignore_text'),
+                                                                      mode='line numbers'
+                                                                      )
+                blocked_line_numbers = html_tools.strip_ignore_text(content=content,
+                                                                      wordlist=watch.get("text_should_not_be_present"),
+                                                                      mode='line numbers'
+                                                                      )
+            except Exception as e:
+                content.append({'line': f"File doesnt exist or unable to read timestamp {timestamp}", 'classes': ''})
+
+        from changedetectionio.pluggy_interface import get_fetcher_capabilities
+        capabilities = get_fetcher_capabilities(watch, datastore)
+
+        output = render_template("preview.html",
+                                 capabilities=capabilities,
+                                 content=content,
+                                 current_diff_url=watch['url'],
+                                 current_version=timestamp,
+                                 extra_stylesheets=extra_stylesheets,
+                                 extra_title=f" - Diff - {watch.label} @ {timestamp}",
+                                 highlight_ignored_line_numbers=ignored_line_numbers,
+                                 highlight_triggered_line_numbers=triggered_line_numbers,
+                                 highlight_blocked_line_numbers=blocked_line_numbers,
+                                 history_n=watch.history_n,
+                                 is_html_webdriver=is_html_webdriver,
+                                 last_error=watch['last_error'],
+                                 last_error_screenshot=watch.get_error_snapshot(),
+                                 last_error_text=watch.get_error_text(),
+                                 screenshot=watch.get_screenshot(),
+                                 uuid=uuid,
+                                 versions=versions,
+                                 watch=watch,
+                                 )
+
+        return output
+
+    @preview_blueprint.route("/preview/<string:uuid>/processor-asset/<string:asset_name>", methods=['GET'])
+    @login_optionally_required
+    def processor_asset(uuid, asset_name):
+        """
+        Serve processor-specific binary assets for preview (images, files, etc.).
+
+        This route is processor-aware: it delegates to the processor's
+        preview.py module, allowing different processor types to serve
+        custom assets without embedding them as base64 in templates.
+
+        This solves memory issues with large binary data by streaming them
+        as separate HTTP responses instead of embedding in the HTML template.
+
+        Each processor implements processors/{type}/preview.py::get_asset()
+        which returns (binary_data, content_type, cache_control_header).
+
+        Example URLs:
+        - /preview/{uuid}/processor-asset/screenshot?version=123456789
+        """
+        from flask import make_response
+
+        # More for testing, possible to return the first/only
+        if uuid == 'first':
+            uuid = list(datastore.data['watching'].keys()).pop()
+
+        try:
+            watch = datastore.data['watching'][uuid]
+        except KeyError:
+            flash(gettext("No history found for the specified link, bad link?"), "error")
+            return redirect(url_for('watchlist.index'))
+
+        # Get the processor type for this watch
+        processor_name = watch.get('processor', 'text_json_diff')
+
+        try:
+            # Try to import the processor's preview module
+            import importlib
+            processor_module = importlib.import_module(f'changedetectionio.processors.{processor_name}.preview')
+
+            # Call the processor's get_asset() function
+            if hasattr(processor_module, 'get_asset'):
+                result = processor_module.get_asset(
+                    asset_name=asset_name,
+                    watch=watch,
+                    datastore=datastore,
+                    request=request
+                )
+
+                if result is None:
+                    from flask import abort
+                    abort(404, description=f"Asset '{asset_name}' not found")
+
+                binary_data, content_type, cache_control = result
+
+                response = make_response(binary_data)
+                response.headers['Content-Type'] = content_type
+                if cache_control:
+                    response.headers['Cache-Control'] = cache_control
+                return response
+            else:
+                logger.warning(f"Processor {processor_name} does not implement get_asset()")
+                from flask import abort
+                abort(404, description=f"Processor '{processor_name}' does not support assets")
+
+        except (ImportError, ModuleNotFoundError) as e:
+            logger.warning(f"Processor {processor_name} does not have a preview module: {e}")
+            from flask import abort
+            abort(404, description=f"Processor '{processor_name}' not found")
+
+    return preview_blueprint

changedetectionio/blueprint/ui/templates/clear_all_history.html

@@ -9,13 +9,12 @@
       <input type="hidden" name="csrf_token" value="{{ csrf_token() }}" >
       <fieldset>
         <div class="pure-control-group">
-          This will remove version history (snapshots) for ALL watches, but keep
-          your list of URLs! <br />
-          You may like to use the <strong>BACKUP</strong> link first.<br />
+          {{ _('This will remove version history (snapshots) for ALL watches, but keep your list of URLs!') }} <br />
+          {{ _('You may like to use the') }} <strong>{{ _('BACKUP') }}</strong> {{ _('link first.') }}<br />
         </div>
         <br />
         <div class="pure-control-group">
-          <label for="confirmtext">Confirmation text</label>
+          <label for="confirmtext">{{ _('Confirmation text') }}</label>
           <input
             type="text"
             id="confirmtext"
@@ -25,20 +24,19 @@
             size="10"
           />
           <span class="pure-form-message-inline"
-            >Type in the word <strong>clear</strong> to confirm that you
-            understand.</span
+            >{{ _('Type in the word') }} <strong>{{ _('clear') }}</strong> {{ _('to confirm that you understand.') }}</span
           >
         </div>
         <br />
         <div class="pure-control-group">
           <button type="submit" class="pure-button pure-button-primary">
-            Clear History!
+            {{ _('Clear History!') }}
           </button>
         </div>
         <br />
         <div class="pure-control-group">
           <a href="{{url_for('watchlist.index')}}" class="pure-button button-cancel"
-            >Cancel</a
+            >{{ _('Cancel') }}</a
           >
         </div>
       </fieldset>

changedetectionio/blueprint/ui/templates/diff-offscreen-options.html

@@ -0,0 +1,12 @@
+<ul id="highlightSnippetActions">
+    <li>
+        <button class="pure-button pure-button-primary" onclick="diffToJpeg()" title="{{ _('Share diff as image') }}">{{ _('Share as Image') }}</button>
+    </li>
+    <li>
+        <a class="pure-button pure-button-primary" data-mode="exact" href="javascript:void(0);">{{ _('Ignore any lines matching') }}</a>
+    </li>
+    <li>
+        <a class="pure-button pure-button-primary" data-mode="digit-regex" href="javascript:void(0);" >{{ _('Ignore any lines matching excluding digits') }}</a>
+    </li>
+</ul>
+

changedetectionio/blueprint/ui/templates/diff.html

@@ -0,0 +1,166 @@
+{% extends 'base.html' %}
+{% from '_helpers.html' import render_field, render_checkbox_field, render_button %}
+{% block content %}
+<script>
+    const screenshot_url="{{url_for('static_content', group='screenshot', filename=uuid)}}";
+    {% if last_error_screenshot %}
+    const error_screenshot_url="{{url_for('static_content', group='screenshot', filename=uuid, error_screenshot=1) }}";
+    {% endif %}
+
+    const highlight_submit_ignore_url="{{url_for('ui.ui_edit.highlight_submit_ignore_url', uuid=uuid)}}";
+    const watch_url= {{watch_a.link|tojson}};
+
+    // Initial scroll position: if set, scroll to this line number in #difference on page load
+    const initialScrollToLineNumber = {{ initial_scroll_line_number|default('null') }};
+</script>
+<script src="https://cdn.jsdelivr.net/npm/html2canvas@1.4.1/dist/html2canvas.min.js"></script>
+<script src="{{url_for('static_content', group='js', filename='plugins.js')}}"></script>
+<script src="https://cdn.jsdelivr.net/npm/piexifjs@1.0.6/piexif.min.js"></script>
+<script src="{{url_for('static_content', group='js', filename='snippet-to-image.js')}}"></script>
+<script src="{{url_for('static_content', group='js', filename='diff-overview.js')}}" defer></script>
+
+
+<div id="settings">
+    <form class="pure-form " action="{{ url_for("ui.ui_diff.diff_history_page", uuid=uuid) }}" method="GET" id="diff-form">
+        <fieldset class="diff-fieldset">
+            {% if versions|length >= 1 %}
+                <span style="white-space: nowrap;">
+                <label id="change-from" for="diff-from-version" class="from-to-label">{{ _('From') }}</label>
+                <select id="diff-from-version" name="from_version" class="needs-localtime">
+                    {%- for version in versions|reverse -%}
+                        <option value="{{ version }}" {% if version== from_version %} selected="" {% endif %}>
+                            {{ version }}{#{% if loop.index == 2 %} (Previous){% endif %}#}
+                        </option>
+                    {%- endfor -%}
+                </select>
+                </span>
+                <span style="white-space: nowrap;">
+                <label id="change-to" for="diff-to-version" class="from-to-label">{{ _('To') }}</label>
+                <select id="diff-to-version" name="to_version" class="needs-localtime">
+                    {%- for version in versions|reverse -%}
+                        <option value="{{ version }}" {% if version== to_version %} selected="" {% endif %}>
+                            {{ version }}{#{% if loop.first %} (Current){% endif %}#}
+                        </option>
+                    {%- endfor -%}
+                </select>
+                </span>
+                {#<button type="submit" class="pure-button pure-button-primary reset-margin">Go</button>#}
+            {% endif %}
+        </fieldset>
+        <fieldset id="diff-style">
+            <span>
+                <label for="diffWords" class="pure-checkbox">
+                <input type="radio" name="type" id="diffWords" value="diffWords" {% if diff_prefs.type == 'diffWords' %}checked=""{% endif %}> {{ _('Words') }}</label>
+            </span>
+            <span>
+                <label for="diffLines" class="pure-checkbox">
+                <input type="radio" name="type" id="diffLines" value="diffLines" {% if diff_prefs.type == 'diffLines' %}checked=""{% endif %}> {{ _('Lines') }}</label>
+            </span>
+            <span>
+                <label for="ignoreWhitespace" class="pure-checkbox" id="label-diff-ignorewhitespace">
+                <input type="checkbox" id="ignoreWhitespace" name="ignoreWhitespace" {% if diff_prefs.ignoreWhitespace %}checked=""{% endif %}> {{ _('Ignore Whitespace') }}</label>
+            </span>
+            <span>
+                <label for="changesOnly" class="pure-checkbox" id="label-diff-changes">
+                <input type="checkbox" id="changesOnly" name="changesOnly" {% if diff_prefs.changesOnly %}checked=""{% endif %}> {{ _('Same/non-changed') }}</label>
+            </span>
+            <span>
+                <label for="removed" class="pure-checkbox" id="label-diff-removed">
+                <input type="checkbox" id="removed" name="removed" {% if diff_prefs.removed %}checked=""{% endif %}> {{ _('Removed') }}</label>
+            </span>
+            <span>
+                <label for="added" class="pure-checkbox" id="label-diff-added">
+                <input type="checkbox" id="added" name="added" {% if diff_prefs.added %}checked=""{% endif %}> {{ _('Added') }}</label>
+            </span>
+            <span>
+                <label for="replaced" class="pure-checkbox" id="label-diff-replaced">
+                <input type="checkbox" id="replaced"  name="replaced" {% if diff_prefs.replaced %}checked=""{% endif %}> {{ _('Replaced') }}</label>
+            </span>
+        </fieldset>
+        {%- if versions|length >= 2 -%}
+            <div id="keyboard-nav">
+                <strong>{{ _('Keyboard:') }} </strong>
+                <a href="" class="pure-button pure-button-primary" id="btn-previous"> &larr; {{ _('Previous') }}</a>
+                &nbsp; <a class="pure-button pure-button-primary" id="btn-next" href=""> &rarr; {{ _('Next') }}</a>
+            </div>
+        {%- endif -%}
+    </form>
+</div>
+
+<div id="diff-jump" style="display:none;"><!-- disabled for now -->
+    <a id="jump-next-diff" title="{{ _('Jump to next difference') }}">{{ _('Jump') }}</a>
+</div>
+
+<script src="{{url_for('static_content', group='js', filename='tabs.js')}}" defer></script>
+<div class="tabs">
+    <ul>
+        {% if last_error_text %}<li class="tab" id="error-text-tab"><a href="#error-text">{{ _('Error Text') }}</a></li> {% endif %}
+        {% if last_error_screenshot %}<li class="tab" id="error-screenshot-tab"><a href="#error-screenshot">{{ _('Error Screenshot') }}</a></li> {% endif %}
+        <li class="tab" id="text-tab"><a href="#text">{{ _('Text') }}</a></li>
+        <li class="tab" id="screenshot-tab"><a href="#screenshot">{{ _('Current screenshot') }}</a></li>
+        <li class="tab" id="extract-tab"><a href="{{ url_for('ui.ui_diff.diff_history_page_extract_GET', uuid=uuid)}}">{{ _('Extract Data') }}</a></li>
+    </ul>
+</div>
+
+<div id="diff-ui">
+    <div class="tab-pane-inner" id="error-text">
+        <div class="snapshot-age error">{{watch_a.error_text_ctime|format_seconds_ago}} {{ _('seconds ago.') }}</div>
+        <pre>
+            {{ last_error_text }}
+        </pre>
+    </div>
+
+    <div class="tab-pane-inner" id="error-screenshot">
+        <div class="snapshot-age error">{{watch_a.snapshot_error_screenshot_ctime|format_seconds_ago}} {{ _('seconds ago') }}</div>
+        <img id="error-screenshot-img"  style="max-width: 80%" alt="{{ _('Current error-ing screenshot from most recent request') }}" >
+    </div>
+
+    <div class="tab-pane-inner" id="text">
+    {%- if (content | default('')).split('\n') | length > 100 -%}
+        <div id="cell-diff-jump-visualiser"  style="user-select: none;">
+            {%- for cell in diff_cell_grid -%}
+            <div{% if cell.class %} class="{{ cell.class }}"{% endif %}></div>
+            {%- endfor -%}
+        </div>
+    {%- endif -%}
+        {%- if password_enabled_and_share_is_off -%}
+            <div class="tip">{{ _('Pro-tip: You can enable') }} <strong>{{ _('"share access when password is enabled"') }}</strong> {{ _('from settings.') }}
+            </div>
+        {%- endif -%}
+        <div id="text-diff-heading-area"  style="user-select: none;">
+            <div class="snapshot-age"><span>{{ from_version|format_timestamp_timeago }}</span>
+                {%- if note -%}<span class="note"><strong>{{ note }}</strong></span>{%- endif -%}
+                <a href="{{ url_for("ui.ui_preview.preview_page", uuid=uuid) }}">{{ _('Goto single snapshot') }}</a>
+            </div>
+        </div>
+        <pre id="difference" style="border-left: 2px solid #ddd;">{{ content| diff_unescape_difference_spans }}</pre>
+    <div id="diff-visualiser-area-after" style="user-select: none;">
+        <strong>{{ _('Tip:') }}</strong> {{ _('Highlight text to share or add to ignore lists.') }}
+    </div>
+    </div>
+
+    <div class="tab-pane-inner" id="screenshot">
+         <div class="tip">
+             {{ _('For now, Differences are performed on text, not graphically, only the latest screenshot is available.') }}
+         </div>
+         {% if is_html_webdriver %}
+           {% if screenshot %}
+            <div class="snapshot-age">{{watch_a.snapshot_screenshot_ctime|format_timestamp_timeago}}</div>
+            <img style="max-width: 80%" id="screenshot-img" alt="{{ _('Current screenshot from most recent request') }}" >
+           {% else %}
+              {{ _('No screenshot available just yet! Try rechecking the page.') }}
+           {% endif %}
+         {% else %}
+           <strong>{{ _('Screenshot requires Playwright/WebDriver enabled') }}</strong>
+         {% endif %}
+     </div>
+
+</div>
+
+<script>
+    const newest_version_timestamp = {{newest_version_timestamp}};
+</script>
+<script src="{{url_for('static_content', group='js', filename='diff-render.js')}}"></script>
+
+
+{% endblock %}

changedetectionio/blueprint/ui/templates/edit.html

@@ -1,12 +1,13 @@
 {% extends 'base.html' %}
 {% block content %}
-{% from '_helpers.html' import render_field, render_checkbox_field, render_button, render_time_schedule_form, playwright_warning, only_playwright_type_watches_warning, render_conditions_fieldlist_of_formfields_as_table, render_ternary_field %}
+{% from '_helpers.html' import render_field, render_checkbox_field, render_button, render_time_schedule_form, playwright_warning, only_playwright_type_watches_warning, highlight_trigger_ignored_explainer, render_conditions_fieldlist_of_formfields_as_table, render_ternary_field %}
 {% from '_common_fields.html' import render_common_settings_form %}
 <script src="{{url_for('static_content', group='js', filename='tabs.js')}}" defer></script>
 <script src="{{url_for('static_content', group='js', filename='vis.js')}}" defer></script>
 <script src="{{url_for('static_content', group='js', filename='global-settings.js')}}" defer></script>
 <script src="{{url_for('static_content', group='js', filename='scheduler.js')}}" defer></script>
 <script src="{{url_for('static_content', group='js', filename='conditions.js')}}" defer></script>
+<script src="{{url_for('static_content', group='js', filename='modal.js')}}"></script>
 
 
 <script>
@@ -43,20 +44,20 @@
 
     <div class="tabs collapsable">
         <ul>
-            <li class="tab"><a href="#general">General</a></li>
-            <li class="tab"><a href="#request">Request</a></li>
+            <li class="tab"><a href="#general">{{ _('General') }}</a></li>
+            <li class="tab"><a href="#request">{{ _('Request') }}</a></li>
             {% if extra_tab_content %}
             <li class="tab"><a href="#extras_tab">{{ extra_tab_content }}</a></li>
             {% endif %}
-            <li class="tab"><a id="browsersteps-tab" href="#browser-steps">Browser Steps</a></li>
+            <li class="tab"><a id="browsersteps-tab" href="#browser-steps">{{ _('Browser Steps') }}</a></li>
         <!-- should goto extra forms? -->
-            {% if watch['processor'] == 'text_json_diff' %}
-            <li class="tab"><a id="visualselector-tab" href="#visualselector">Visual Filter Selector</a></li>
-            <li class="tab" id="filters-and-triggers-tab"><a href="#filters-and-triggers">Filters &amp; Triggers</a></li>
-            <li class="tab" id="conditions-tab"><a href="#conditions">Conditions</a></li>
+            {% if watch['processor'] == 'text_json_diff' or watch['processor'] == 'image_ssim_diff' %}
+            <li class="tab"><a id="visualselector-tab" href="#visualselector">{{ _('Visual Filter Selector') }}</a></li>
+            <li class="tab" id="filters-and-triggers-tab"><a href="#filters-and-triggers">{{ _('Filters & Triggers') }}</a></li>
+            <li class="tab" id="conditions-tab"><a href="#conditions">{{ _('Conditions') }}</a></li>
             {% endif %}
-            <li class="tab"><a href="#notifications">Notifications</a></li>
-            <li class="tab"><a href="#stats">Stats</a></li>
+            <li class="tab"><a href="#notifications">{{ _('Notifications') }}</a></li>
+            <li class="tab"><a href="#stats">{{ _('Stats') }}</a></li>
         </ul>
     </div>
 
@@ -69,19 +70,19 @@
                 <fieldset>
                     <div class="pure-control-group">
                         {{ render_field(form.url, placeholder="https://...", required=true, class="m-d") }}
-                        <div class="pure-form-message">Some sites use JavaScript to create the content, for this you should <a href="https://github.com/dgtlmoon/changedetection.io/wiki/Fetching-pages-with-WebDriver">use the Chrome/WebDriver Fetcher</a></div>
-                        <div class="pure-form-message">Variables are supported in the URL (<a href="https://github.com/dgtlmoon/changedetection.io/wiki/Handling-variables-in-the-watched-URL">help and examples here</a>).</div>
+                        <div class="pure-form-message">{{ _('Some sites use JavaScript to create the content, for this you should') }} <a href="https://github.com/dgtlmoon/changedetection.io/wiki/Fetching-pages-with-WebDriver">{{ _('use the Chrome/WebDriver Fetcher') }}</a></div>
+                        <div class="pure-form-message">{{ _('Variables are supported in the URL') }} (<a href="https://github.com/dgtlmoon/changedetection.io/wiki/Handling-variables-in-the-watched-URL">{{ _('help and examples here') }}</a>).</div>
                     </div>
                     <div class="pure-control-group">
                         {{ render_field(form.tags) }}
-                        <span class="pure-form-message-inline">Organisational tag/group name used in the main listing page</span>
+                        <span class="pure-form-message-inline">{{ _('Organisational tag/group name used in the main listing page') }}</span>
                     </div>
                     <div class="pure-control-group inline-radio">
                         {{ render_field(form.processor) }}
                     </div>
                     <div class="pure-control-group">
                         {{ render_field(form.title, class="m-d", placeholder=watch.label) }}
-                        <span class="pure-form-message-inline">Automatically uses the page title if found, you can also use your own title/description here</span>
+                        <span class="pure-form-message-inline">{{ _('Automatically uses the page title if found, you can also use your own title/description here') }}</span>
                     </div>
                     <div class="pure-control-group time-between-check border-fieldset">
 
@@ -91,7 +92,7 @@
                             {{ render_field(form.time_between_check, class="time-check-widget") }}
 
                             <span class="pure-form-message-inline">
-                             The interval/amount of time between each check.
+                             {{ _('The interval/amount of time between each check.') }}
                             </span>
                         </div>
                         <div id="time-between-check-schedule">
@@ -106,7 +107,7 @@
                     <div class="pure-control-group">
                         {{ render_checkbox_field(form.filter_failure_notification_send) }}
                         <span class="pure-form-message-inline">
-                         Sends a notification when the filter can no longer be seen on the page, good for knowing when the page changed and your filter will not work anymore.
+                         {{ _('Sends a notification when the filter can no longer be seen on the page, good for knowing when the page changed and your filter will not work anymore.') }}
                         </span>
                     </div>
                     <div class="pure-control-group">
@@ -119,17 +120,17 @@
                     <div class="pure-control-group inline-radio">
                         {{ render_field(form.fetch_backend, class="fetch-backend") }}
                         <span class="pure-form-message-inline">
-                            <p>Use the <strong>Basic</strong> method (default) where your watched site doesn't need Javascript to render.</p>
-                            <p>The <strong>Chrome/Javascript</strong> method requires a network connection to a running WebDriver+Chrome server, set by the ENV var 'WEBDRIVER_URL'. </p>
-                            Tip: <a href="https://github.com/dgtlmoon/changedetection.io/wiki/Proxy-configuration#brightdata-proxy-support">Connect using Bright Data and Oxylabs Proxies, find out more here.</a>
+                            <p>{{ _('Use the') }} <strong>{{ _('Basic') }}</strong> {{ _('method (default) where your watched site doesn\'t need Javascript to render.') }}</p>
+                            <p>{{ _('The') }} <strong>{{ _('Chrome/Javascript') }}</strong> {{ _('method requires a network connection to a running WebDriver+Chrome server, set by the ENV var \'WEBDRIVER_URL\'.') }} </p>
+                            {{ _('Tip:') }} <a href="https://github.com/dgtlmoon/changedetection.io/wiki/Proxy-configuration#brightdata-proxy-support">{{ _('Connect using Bright Data and Oxylabs Proxies, find out more here.') }}</a>
                         </span>
                     </div>
                 {% if form.proxy %}
                     <div class="pure-control-group inline-radio">
-                          <div>{{ form.proxy.label }} <a href="" id="check-all-proxies" class="pure-button button-secondary button-xsmall" >Check/Scan all</a></div>
+                          <div>{{ form.proxy.label }} <a href="" id="check-all-proxies" class="pure-button button-secondary button-xsmall" >{{ _('Check/Scan all') }}</a></div>
                           <div>{{ form.proxy(class="fetch-backend-proxy") }}</div>
                         <span class="pure-form-message-inline">
-                        Choose a proxy for this watch
+                        {{ _('Choose a proxy for this watch') }}
                         </span>
                     </div>
                 {% endif %}
@@ -139,31 +140,29 @@
                     <div class="pure-control-group">
                         {{ render_field(form.webdriver_delay) }}
                         <div class="pure-form-message-inline">
-                            <strong>If you're having trouble waiting for the page to be fully rendered (text missing etc), try increasing the 'wait' time here.</strong>
+                            <strong>{{ _('If you\'re having trouble waiting for the page to be fully rendered (text missing etc), try increasing the \'wait\' time here.') }}</strong>
                             <br>
-                            This will wait <i>n</i> seconds before extracting the text.
+                            {{ _('This will wait') }} <i>n</i> {{ _('seconds before extracting the text.') }}
                             {% if using_global_webdriver_wait %}
-                            <br><strong>Using the current global default settings</strong>
+                            <br><strong>{{ _('Using the current global default settings') }}</strong>
                             {% endif %}
                         </div>
                     </div>
                     <div class="pure-control-group">
-                        <a class="pure-button button-secondary button-xsmall show-advanced">Show advanced options</a>
+                        <a class="pure-button button-secondary button-xsmall show-advanced">{{ _('Show advanced options') }}</a>
                     </div>
                     <div class="advanced-options"  style="display: none;">
                         {{ render_field(form.webdriver_js_execute_code) }}
                         <div class="pure-form-message-inline">
-                            Run this code before performing change detection, handy for filling in fields and other
-                            actions <a
-                                href="https://github.com/dgtlmoon/changedetection.io/wiki/Run-JavaScript-before-change-detection">More
-                            help and examples here</a>
+                            {{ _('Run this code before performing change detection, handy for filling in fields and other actions') }} <a
+                                href="https://github.com/dgtlmoon/changedetection.io/wiki/Run-JavaScript-before-change-detection">{{ _('More help and examples here') }}</a>
                         </div>
                     </div>
                 </fieldset>
                 <!-- html requests always -->
                 <fieldset data-visible-for="fetch_backend=html_requests">
                     <div class="pure-control-group">
-                        <a class="pure-button button-secondary button-xsmall show-advanced">Show advanced options</a>
+                        <a class="pure-button button-secondary button-xsmall show-advanced">{{ _('Show advanced options') }}</a>
                     </div>
                     <div class="advanced-options"  style="display: none;">
                         <div class="pure-control-group" id="request-method">
@@ -178,7 +177,7 @@
    \"year\":{% now 'Europe/Berlin', '%Y' %}
 }") }}
                         </div>
-                        <div class="pure-form-message">Variables are supported in the request body (<a href="https://github.com/dgtlmoon/changedetection.io/wiki/Handling-variables-in-the-watched-URL">help and examples here</a>).</div>
+                        <div class="pure-form-message">{{ _('Variables are supported in the request body') }} (<a href="https://github.com/dgtlmoon/changedetection.io/wiki/Handling-variables-in-the-watched-URL">{{ _('help and examples here') }}</a>).</div>
                     </div>
                 </fieldset>
             <!-- hmm -->
@@ -187,15 +186,15 @@
 Cookie: foobar
 User-Agent: wonderbra 1.0
 Math: {{ 1 + 1 }}") }}
-                        <div class="pure-form-message">Variables are supported in the request header values (<a href="https://github.com/dgtlmoon/changedetection.io/wiki/Handling-variables-in-the-watched-URL">help and examples here</a>).</div>
+                        <div class="pure-form-message">{{ _('Variables are supported in the request header values') }} (<a href="https://github.com/dgtlmoon/changedetection.io/wiki/Handling-variables-in-the-watched-URL">{{ _('help and examples here') }}</a>).</div>
                         <div class="pure-form-message-inline">
                             {% if has_extra_headers_file %}
-                                <strong>Alert! Extra headers file found and will be added to this watch!</strong>
+                                <strong>{{ _('Alert! Extra headers file found and will be added to this watch!') }}</strong>
                             {% else %}
-                                Headers can be also read from a file in your data-directory <a href="https://github.com/dgtlmoon/changedetection.io/wiki/Adding-headers-from-an-external-file">Read more here</a>
+                                {{ _('Headers can be also read from a file in your data-directory') }} <a href="https://github.com/dgtlmoon/changedetection.io/wiki/Adding-headers-from-an-external-file">{{ _('Read more here') }}</a>
                             {% endif %}
                             <br>
-                            (Not supported by Selenium browser)
+                            ({{ _('Not supported by Selenium browser') }})
                         </div>
                     </div>
             <fieldset data-visible-for="fetch_backend=html_requests fetch_backend=html_webdriver" >
@@ -206,9 +205,8 @@ Math: {{ 1 + 1 }}") }}
             </div>
 
             <div class="tab-pane-inner" id="browser-steps">
-            {% if watch_needs_selenium_or_playwright %}
-                {# Only works with playwright #}
-                {% if system_has_playwright_configured %}
+            {% if capabilities.supports_browser_steps %}
+               {% if true %}
                 <img class="beta-logo" src="{{url_for('static_content', group='images', filename='beta-logo.png')}}" alt="New beta functionality">
                 <fieldset>
                     <div class="pure-control-group">
@@ -220,19 +218,19 @@ Math: {{ 1 + 1 }}") }}
 
                         <!---  Do this later -->
                         <div class="checkbox" style="display: none;">
-                            <input type=checkbox id="include_text_elements" > <label for="include_text_elements">Turn on text finder</label>
+                            <input type=checkbox id="include_text_elements" > <label for="include_text_elements">{{ _('Turn on text finder') }}</label>
                         </div>
 
-                        <div id="loading-status-text" style="display: none;">Please wait, first browser step can take a little time to load..<div class="spinner"></div></div>
+                        <div id="loading-status-text" style="display: none;">{{ _('Please wait, first browser step can take a little time to load..') }}<div class="spinner"></div></div>
                         <div class="flex-wrapper" >
 
                             <div id="browser-steps-ui" class="noselect">
                                 <div class="noselect"  id="browsersteps-selector-wrapper" style="width: 100%">
                                     <span class="loader" >
                                         <span id="browsersteps-click-start">
-                                            <h2 >Click here to Start</h2>
+                                            <h2 >{{ _('Click here to Start') }}</h2>
                                             <svg style="height: 3.5rem;" version="1.1" viewBox="0 0 32 32"  xml:space="preserve" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g id="start"/><g id="play_x5F_alt"><path d="M16,0C7.164,0,0,7.164,0,16s7.164,16,16,16s16-7.164,16-16S24.836,0,16,0z M10,24V8l16.008,8L10,24z" style="fill: var(--color-grey-400);"/></g></svg><br>
-                                            Please allow 10-15 seconds for the browser to connect.<br>
+                                            {{ _('Please allow 10-15 seconds for the browser to connect.') }}<br>
                                         </span>
                                         <div class="spinner"  style="display: none;"></div>
                                     </span>
@@ -241,22 +239,20 @@ Math: {{ 1 + 1 }}") }}
                                 </div>
                             </div>
                             <div id="browser-steps-fieldlist" >
-                                <span id="browser-seconds-remaining">Press "Play" to start.</span> <span style="font-size: 80%;"> (<a target="newwindow" href="https://github.com/dgtlmoon/changedetection.io/pull/478/files#diff-1a79d924d1840c485238e66772391268a89c95b781d69091384cf1ea1ac146c9R4">?</a>) </span>
+                                <span id="browser-seconds-remaining">{{ _('Press "Play" to start.') }}</span> <span style="font-size: 80%;"> (<a target="newwindow" href="https://github.com/dgtlmoon/changedetection.io/pull/478/files#diff-1a79d924d1840c485238e66772391268a89c95b781d69091384cf1ea1ac146c9R4">?</a>) </span>
                                 {{ render_field(form.browser_steps) }}
                             </div>
                         </div>
                     </div>
                 </fieldset>
                 {% else %}
-                    {# it's configured to use selenium or chrome but system says its not configured #}
-                    {{ playwright_warning() }}
-                    {% if system_has_webdriver_configured %}
-                        <strong>Selenium/Webdriver cant be used here because it wont fetch screenshots reliably.</strong>
-                    {% endif %}
+                    <strong>{{ _('Visual Selector data is not ready, watch needs to be checked atleast once.') }}</strong>
                 {% endif %}
             {% else %}
-                {# "This functionality needs chrome.." #}
-                {{ only_playwright_type_watches_warning() }}
+                <p>
+                    <strong>{{ _('Sorry, this functionality only works with fetchers that support interactive Javascript (so far only Playwright based fetchers)') }}<br>
+                    {{ _('You need to') }} <a href="#request">{{ _('Set the fetch method') }}</a> {{ _('to one that supports interactive Javascript.') }}</strong>
+                </p>
             {% endif %}
             </div>
 
@@ -266,28 +262,28 @@ Math: {{ 1 + 1 }}") }}
                     <div  class="pure-control-group inline-radio">
                       {{ render_ternary_field(form.notification_muted, BooleanField=true) }}
                     </div>
-                    {% if watch_needs_selenium_or_playwright %}
+                    {% if capabilities.supports_screenshots %}
                     <div class="pure-control-group inline-radio">
                       {{ render_checkbox_field(form.notification_screenshot) }}
                         <span class="pure-form-message-inline">
-                            <strong>Use with caution!</strong> This will easily fill up your email storage quota or flood other storages.
+                            <strong>{{ _('Use with caution!') }}</strong> {{ _('This will easily fill up your email storage quota or flood other storages.') }}
                         </span>
                     </div>
                     {% endif %}
                     <div class="field-group" id="notification-field-group">
                         {% if has_default_notification_urls %}
                         <div class="inline-warning">
-                            <img class="inline-warning-icon" src="{{url_for('static_content', group='images', filename='notice.svg')}}" alt="Look out!" title="Lookout!" >
-                            There are <a href="{{ url_for('settings.settings_page')}}#notifications">system-wide notification URLs enabled</a>, this form will override notification settings for this watch only &dash; an empty Notification URL list here will still send notifications.
+                            <img class="inline-warning-icon" src="{{url_for('static_content', group='images', filename='notice.svg')}}" alt="{{ _('Look out!') }}" title="{{ _('Lookout!') }}" >
+                            {{ _('There are') }} <a href="{{ url_for('settings.settings_page')}}#notifications">{{ _('system-wide notification URLs enabled') }}</a>, {{ _('this form will override notification settings for this watch only') }} &dash; {{ _('an empty Notification URL list here will still send notifications.') }}
                         </div>
                         {% endif %}
-                        <a href="#notifications" id="notification-setting-reset-to-default" class="pure-button button-xsmall" style="right: 20px; top: 20px; position: absolute; background-color: #5f42dd; border-radius: 4px; font-size: 70%; color: #fff">Use system defaults</a>
+                        <a href="#notifications" id="notification-setting-reset-to-default" class="pure-button button-xsmall" style="right: 20px; top: 20px; position: absolute; background-color: #5f42dd; border-radius: 4px; font-size: 70%; color: #fff">{{ _('Use system defaults') }}</a>
                         {{ render_common_settings_form(form, emailprefix, settings_application, extra_notification_token_placeholder_info) }}
                     </div>
                 </fieldset>
             </div>
 
-            {% if watch['processor'] == 'text_json_diff' %}
+            {% if watch['processor'] == 'text_json_diff' or watch['processor'] == 'image_ssim_diff' %}
 
             <div class="tab-pane-inner" id="conditions">
                     <script>
@@ -298,23 +294,23 @@ Math: {{ 1 + 1 }}") }}
                     {{ render_conditions_fieldlist_of_formfields_as_table(form.conditions) }}
                     <div class="pure-form-message-inline">
 
-                        <p id="verify-state-text">Use the verify (✓) button to test if a condition passes against the current snapshot.</p>
-                       Read a quick tutorial about <a href="https://changedetection.io/tutorial/conditional-actions-web-page-changes">using conditional web page changes here</a>.<br>
+                        <p id="verify-state-text">{{ _('Use the verify (✓) button to test if a condition passes against the current snapshot.') }}</p>
+                       {{ _('Read a quick tutorial about') }} <a href="https://changedetection.io/tutorial/conditional-actions-web-page-changes">{{ _('using conditional web page changes here') }}</a>.<br>
                     </div>
                 </div>
             </div>
             <div class="tab-pane-inner" id="filters-and-triggers">
-                <span id="activate-text-preview" class="pure-button pure-button-primary button-xsmall">Activate preview</span>
+                <span id="activate-text-preview" class="pure-button pure-button-primary button-xsmall">{{ _('Activate preview') }}</span>
               <div>
               <div id="edit-text-filter">
                     <div class="pure-control-group" id="pro-tips">
-                            <strong>Pro-tips:</strong><br>
+                            <strong>{{ _('Pro-tips:') }}</strong><br>
                             <ul>
                                 <li>
-                                    Use the preview page to see your filters and triggers highlighted.
+                                    {{ _('Use the preview page to see your filters and triggers highlighted.') }}
                                 </li>
                                 <li>
-                                    Some sites use JavaScript to create the content, for this you should <a href="https://github.com/dgtlmoon/changedetection.io/wiki/Fetching-pages-with-WebDriver">use the Chrome/WebDriver Fetcher</a>
+                                    {{ _('Some sites use JavaScript to create the content, for this you should') }} <a href="https://github.com/dgtlmoon/changedetection.io/wiki/Fetching-pages-with-WebDriver">{{ _('use the Chrome/WebDriver Fetcher') }}</a>
                                 </li>
                             </ul>
                     </div>
@@ -322,50 +318,51 @@ Math: {{ 1 + 1 }}") }}
 {% include "edit/include_subtract.html" %}
                 <div class="text-filtering border-fieldset">
                 <fieldset class="pure-group" id="text-filtering-type-options">
-                    <h3>Text filtering</h3>
-                        Limit trigger/ignore/block/extract to;<br>
+                    <h3>{{ _('Text filtering') }}</h3>
+                        {{ _('Limit trigger/ignore/block/extract to;') }}<br>
                         {{ render_checkbox_field(form.filter_text_added) }}
                         {{ render_checkbox_field(form.filter_text_replaced) }}
                         {{ render_checkbox_field(form.filter_text_removed) }}
-                    <span class="pure-form-message-inline">Note: Depending on the length and similarity of the text on each line, the algorithm may consider an <strong>addition</strong> instead of <strong>replacement</strong> for example.</span><br>
-                    <span class="pure-form-message-inline">&nbsp;So it's always better to select <strong>Added</strong>+<strong>Replaced</strong> when you're interested in new content.</span><br>
-                    <span class="pure-form-message-inline">&nbsp;When content is merely moved in a list, it will also trigger an <strong>addition</strong>, consider enabling <code><strong>Only trigger when unique lines appear</strong></code></span>
+                    <span class="pure-form-message-inline">{{ _('Note: Depending on the length and similarity of the text on each line, the algorithm may consider an') }} <strong>{{ _('addition') }}</strong> {{ _('instead of') }} <strong>{{ _('replacement') }}</strong> {{ _('for example.') }}</span><br>
+                    <span class="pure-form-message-inline">&nbsp;{{ _('So it\'s always better to select') }} <strong>{{ _('Added') }}</strong>+<strong>{{ _('Replaced') }}</strong> {{ _('when you\'re interested in new content.') }}</span><br>
+                    <span class="pure-form-message-inline">&nbsp;{{ _('When content is merely moved in a list, it will also trigger an') }} <strong>{{ _('addition') }}</strong>, {{ _('consider enabling') }} <code><strong>{{ _('Only trigger when unique lines appear') }}</strong></code></span>
                 </fieldset>
                 <fieldset class="pure-control-group">
                     {{ render_checkbox_field(form.check_unique_lines) }}
-                    <span class="pure-form-message-inline">Good for websites that just move the content around, and you want to know when NEW content is added, compares new lines against all history for this watch.</span>
+                    <span class="pure-form-message-inline">{{ _('Good for websites that just move the content around, and you want to know when NEW content is added, compares new lines against all history for this watch.') }}</span>
                 </fieldset>
                 <fieldset class="pure-control-group">
                     {{ render_checkbox_field(form.remove_duplicate_lines) }}
-                    <span class="pure-form-message-inline">Remove duplicate lines of text</span>
+                    <span class="pure-form-message-inline">{{ _('Remove duplicate lines of text') }}</span>
                 </fieldset>
                 <fieldset class="pure-control-group">
                     {{ render_checkbox_field(form.sort_text_alphabetically) }}
-                    <span class="pure-form-message-inline">Helps reduce changes detected caused by sites shuffling lines around, combine with <i>check unique lines</i> below.</span>
+                    <span class="pure-form-message-inline">{{ _('Helps reduce changes detected caused by sites shuffling lines around, combine with') }} <i>{{ _('check unique lines') }}</i> {{ _('below.') }}</span>
                 </fieldset>
                 <fieldset class="pure-control-group">
                     {{ render_checkbox_field(form.trim_text_whitespace) }}
-                    <span class="pure-form-message-inline">Remove any whitespace before and after each line of text</span>
+                    <span class="pure-form-message-inline">{{ _('Remove any whitespace before and after each line of text') }}</span>
                 </fieldset>
                 {% include "edit/text-options.html" %}
                 </div>
               </div>
               <div id="text-preview" style="display: none;" >
-                    <script>
-                        const preview_text_edit_filters_url="{{url_for('ui.ui_edit.watch_get_preview_rendered', uuid=uuid)}}";
-                    </script>
-                    <br>
-                    {#<div id="text-preview-controls"><span id="text-preview-refresh" class="pure-button button-xsmall">Refresh</span></div>#}
-                    <div class="minitabs-wrapper">
-                      <div class="minitabs-content">
-                          <div id="text-preview-inner" class="monospace-preview">
-                              <p>Loading...</p>
-                          </div>
-                          <div id="text-preview-before-inner" style="display: none;" class="monospace-preview">
-                              <p>Loading...</p>
-                          </div>
+                <script>
+                    const preview_text_edit_filters_url="{{url_for('ui.ui_edit.watch_get_preview_rendered', uuid=uuid)}}";
+                </script>
+                <br>
+                {#<div id="text-preview-controls"><span id="text-preview-refresh" class="pure-button button-xsmall">Refresh</span></div>#}
+                <div class="minitabs-wrapper">
+                  <div class="minitabs-content">
+                      <div id="text-preview-inner" class="monospace-preview">
+                          <p>{{ _('Loading...') }}</p>
                       </div>
-                    </div>
+                      <div id="text-preview-before-inner" style="display: none;" class="monospace-preview">
+                          <p>{{ _('Loading...') }}</p>
+                      </div>
+                  </div>
+                </div>
+                {{ highlight_trigger_ignored_explainer() }}
             </div>
           </div>
         </div>
@@ -377,41 +374,55 @@ Math: {{ 1 + 1 }}") }}
             {{ extra_form_content|safe }}
             </div>
         {% endif %}
-            {% if watch['processor'] == 'text_json_diff' %}
+            {% if watch['processor'] == 'text_json_diff' or watch['processor'] == 'image_ssim_diff' %}
             <div class="tab-pane-inner visual-selector-ui" id="visualselector">
                 <img class="beta-logo" src="{{url_for('static_content', group='images', filename='beta-logo.png')}}" alt="New beta functionality">
 
                 <fieldset>
                     <div class="pure-control-group">
-                        {% if watch_needs_selenium_or_playwright %}
-                            {% if system_has_playwright_configured %}
-                            <span class="pure-form-message-inline" id="visual-selector-heading">
-                                The Visual Selector tool lets you select the <i>text</i> elements that will be used for the change detection. It automatically fills-in the filters in the "CSS/JSONPath/JQ/XPath Filters" box of the <a href="#filters-and-triggers">Filters & Triggers</a> tab. Use <strong>Shift+Click</strong> to select multiple items.
-                            </span>
+                        {% if capabilities.supports_screenshots and capabilities.supports_xpath_element_data %}
+                            {% if visual_selector_data_ready %}
+                                <span class="pure-form-message-inline" id="visual-selector-heading">
+                                    {{ _('The Visual Selector tool lets you select the') }} <i>{{ _('text') }}</i> {{ _('elements that will be used for the change detection. It automatically fills-in the filters in the "CSS/JSONPath/JQ/XPath Filters" box of the') }} <a href="#filters-and-triggers">{{ _('Filters & Triggers') }}</a> {{ _('tab. Use') }} <strong>{{ _('Shift+Click') }}</strong> {{ _('to select multiple items.') }}
+                                </span>
 
-                            <div id="selector-header">
-                                <a id="clear-selector" class="pure-button button-secondary button-xsmall" style="font-size: 70%">Clear selection</a>
-                                <!-- visual selector IMG will try to load, it will either replace this or on error replace it with some handy text -->
-                                <i class="fetching-update-notice" style="font-size: 80%;">One moment, fetching screenshot and element information..</i>
-                            </div>
-                            <div id="selector-wrapper" style="display: none">
-                                <!-- request the screenshot and get the element offset info ready -->
-                                <!-- use img src ready load to know everything is ready to map out -->
-                                <!-- @todo: maybe something interesting like a field to select 'elements that contain text... and their parents n' -->
-                                <img id="selector-background" >
-                                <canvas id="selector-canvas"></canvas>
-                            </div>
-                            <div id="selector-current-xpath" style="overflow-x: hidden"><strong>Currently:</strong>&nbsp;<span class="text">Loading...</span></div>
-                        {% else %}
-                            {# The watch needed chrome but system says that playwright is not ready #}
-                            {{ playwright_warning() }}
-                        {% endif %}
-                            {% if system_has_webdriver_configured %}
-                                <strong>Selenium/Webdriver cant be used here because it wont fetch screenshots reliably.</strong>
-                            {% endif %}
+                                {% if watch['processor'] == 'image_ssim_diff' %}
+                                <div id="selection-mode-controls" style="margin: 10px 0; padding: 10px; background: var(--color-background-tab); border-radius: 5px;">
+                                    <label style="font-weight: 600; margin-right: 15px;">{{ _('Selection Mode:') }}</label>
+                                    <label style="margin-right: 15px;">
+                                        <input type="radio" name="selector-mode" value="element" style="margin-right: 5px;">
+                                        {{ _('Select by element') }}
+                                    </label>
+                                    <label>
+                                        <input type="radio" name="selector-mode" value="draw" checked style="margin-right: 5px;">
+                                        {{ _('Draw area') }}
+                                    </label>
+                                    {{ render_field(form.processor_config_bounding_box) }}
+                                    {{ render_field(form.processor_config_selection_mode) }}
+                                </div>
+                                {% endif %}
+
+                                <div id="selector-header">
+                                    <a id="clear-selector" class="pure-button button-secondary button-xsmall" style="font-size: 70%">{{ _('Clear selection') }}</a>
+                                    <!-- visual selector IMG will try to load, it will either replace this or on error replace it with some handy text -->
+                                    <i class="fetching-update-notice" style="font-size: 80%;">{{ _('One moment, fetching screenshot and element information..') }}</i>
+                                </div>
+                                <div id="selector-wrapper" style="display: none">
+                                    <!-- request the screenshot and get the element offset info ready -->
+                                    <!-- use img src ready load to know everything is ready to map out -->
+                                    <!-- @todo: maybe something interesting like a field to select 'elements that contain text... and their parents n' -->
+                                    <img id="selector-background" >
+                                    <canvas id="selector-canvas"></canvas>
+                                </div>
+                                <div id="selector-current-xpath" style="overflow-x: hidden"><strong>{{ _('Currently:') }}</strong>&nbsp;<span class="text">{{ _('Loading...') }}</span></div>
+                            {%  else %}
+                                <strong>{{ _('Visual Selector data is not ready, watch needs to be checked atleast once.') }}</strong>
+                            {%  endif %}
                     {% else %}
-                        {# "This functionality needs chrome.." #}
-                        {{ only_playwright_type_watches_warning() }}
+                        <p>
+                            <strong>{{ _('Sorry, this functionality only works with fetchers that support Javascript and screenshots (such as playwright etc).') }}<br>
+                            {{ _('You need to') }} <a href="#request">{{ _('Set the fetch method') }}</a> {{ _('to one that supports Javascript and screenshots.') }}</strong>
+                        </p>
                     {% endif %}
                     </div>
                 </fieldset>
@@ -427,27 +438,27 @@ Math: {{ 1 + 1 }}") }}
                     <table class="pure-table" id="stats-table">
                         <tbody>
                         <tr>
-                            <td>Check count</td>
+                            <td>{{ _('Check count') }}</td>
                             <td>{{ "{:,}".format( watch.check_count) }}</td>
                         </tr>
                         <tr>
-                            <td>Consecutive filter failures</td>
+                            <td>{{ _('Consecutive filter failures') }}</td>
                             <td>{{ "{:,}".format( watch.consecutive_filter_failures) }}</td>
                         </tr>
                         <tr>
-                            <td>History length</td>
+                            <td>{{ _('History length') }}</td>
                             <td>{{ "{:,}".format(watch.history|length) }}</td>
                         </tr>
                         <tr>
-                            <td>Last fetch duration</td>
+                            <td>{{ _('Last fetch duration') }}</td>
                             <td>{{ watch.fetch_time }}s</td>
                         </tr>
                         <tr>
-                            <td>Notification alert count</td>
+                            <td>{{ _('Notification alert count') }}</td>
                             <td>{{ watch.notification_alert_count }}</td>
                         </tr>
                         <tr>
-                            <td>Server type reply</td>
+                            <td>{{ _('Server type reply') }}</td>
                             <td>{{ watch.get('remote_server_reply') }}</td>
                         </tr>
                         </tbody>
@@ -461,7 +472,7 @@ Math: {{ 1 + 1 }}") }}
 
                     {% if watch.history_n %}
                         <p>
-                             <a href="{{url_for('ui.ui_edit.watch_get_latest_html', uuid=uuid)}}" class="pure-button button-small">Download latest HTML snapshot</a>
+                             <a href="{{url_for('ui.ui_edit.watch_get_latest_html', uuid=uuid)}}" class="pure-button button-small">{{ _('Download latest HTML snapshot') }}</a>
                         </p>
                     {% endif %}
 
@@ -471,11 +482,22 @@ Math: {{ 1 + 1 }}") }}
                 <div class="pure-control-group">
                     {{ render_button(form.save_button) }}
                     <a href="{{url_for('ui.form_delete', uuid=uuid)}}"
-                       class="pure-button button-error ">Delete</a>
+                       class="pure-button button-error"
+                       data-requires-confirm
+                       data-confirm-type="danger"
+                       data-confirm-title="{{ _('Delete Watch?') }}"
+                       data-confirm-message="<p>{{ _('Are you sure you want to delete the watch for:') }}</p><p><strong>{{ watch.get('url', 'this watch') }}</strong></p><p>{{ _('This action cannot be undone.') }}</p>"
+                       data-confirm-button="{{ _('Delete') }}">{{ _('Delete') }}</a>
                     {% if watch.history_n %}<a href="{{url_for('ui.clear_watch_history', uuid=uuid)}}"
-                       class="pure-button button-error">Clear History</a>{% endif %}
+                       class="pure-button button-error"
+                       data-requires-confirm
+                       data-confirm-type="warning"
+                       data-confirm-title="{{ _('Clear History?') }}"
+                       data-confirm-message="<p>{{ _('Are you sure you want to clear all history for:') }}</p><p><strong>{{ watch.get('url', 'this watch') }}</strong></p><p>{{ _('This will remove all snapshots and previous versions. This action cannot be undone.') }}</p>"
+                       data-confirm-button="{{ _('Clear History') }}">{{ _('Clear History') }}</a>{% endif %}
                     <a href="{{url_for('ui.form_clone', uuid=uuid)}}"
-                       class="pure-button">Clone &amp; Edit</a>
+                       class="pure-button">{{ _('Clone & Edit') }}</a>
+                 <a href="{{ url_for('rss.rss_single_watch', uuid=uuid, token=app_rss_token)}}"><img alt="{{ _('RSS Feed for this watch') }}" style="padding: .5em 1em;" src="{{url_for('static_content', group='images', filename='generic_feed-icon.svg')}}" height="15"></a>
                 </div>
             </div>
         </form>

changedetectionio/blueprint/ui/templates/preview.html

@@ -1,9 +1,11 @@
 {% extends 'base.html' %}
-
+{% from '_helpers.html' import highlight_trigger_ignored_explainer %}
 {% block content %}
     <script>
         const screenshot_url = "{{url_for('static_content', group='screenshot', filename=uuid)}}";
-        const triggered_line_numbers = {{ triggered_line_numbers|tojson }};
+        const triggered_line_numbers = {{ highlight_triggered_line_numbers|tojson }};
+        const ignored_line_numbers = {{ highlight_ignored_line_numbers|tojson }};
+        const blocked_line_numbers = {{ highlight_blocked_line_numbers|tojson }};
         {% if last_error_screenshot %}
             const error_screenshot_url = "{{url_for('static_content', group='screenshot', filename=uuid, error_screenshot=1) }}";
         {% endif %}
@@ -14,10 +16,10 @@
     <script src="{{ url_for('static_content', group='js', filename='preview.js') }}" defer></script>
     <script src="{{ url_for('static_content', group='js', filename='tabs.js') }}" defer></script>
     {% if versions|length >= 2 %}
-        <div id="settings" style="text-align: center;">
+        <div id="diff-form" style="text-align: center;">
             <form class="pure-form " action="" method="POST">
                 <fieldset>
-                    <label for="preview-version">Select timestamp</label> <select id="preview-version"
+                    <label for="preview-version">{{ _('Select timestamp') }}</label> <select id="preview-version"
                                                                                  name="from_version"
                                                                                  class="needs-localtime">
                     {% for version in versions|reverse %}
@@ -26,27 +28,27 @@
                         </option>
                     {% endfor %}
                 </select>
-                    <button type="submit" class="pure-button pure-button-primary">Go</button>
+                    <button type="submit" class="pure-button pure-button-primary">{{ _('Go') }}</button>
 
                 </fieldset>
             </form>
                 <br>
-                <strong>Keyboard: </strong><a href="" class="pure-button pure-button-primary" id="btn-previous">
-                &larr; Previous</a> &nbsp; <a class="pure-button pure-button-primary" id="btn-next" href="">
-                &rarr; Next</a>
+                <strong>{{ _('Keyboard:') }} </strong><a href="" class="pure-button pure-button-primary" id="btn-previous">
+                &larr; {{ _('Previous') }}</a> &nbsp; <a class="pure-button pure-button-primary" id="btn-next" href="">
+                &rarr; {{ _('Next') }}</a>
         </div>
     {% endif %}
 
     <div class="tabs">
         <ul>
             {% if last_error_text %}
-                <li class="tab" id="error-text-tab"><a href="#error-text">Error Text</a></li> {% endif %}
+                <li class="tab" id="error-text-tab"><a href="#error-text">{{ _('Error Text') }}</a></li> {% endif %}
             {% if last_error_screenshot %}
-                <li class="tab" id="error-screenshot-tab"><a href="#error-screenshot">Error Screenshot</a>
+                <li class="tab" id="error-screenshot-tab"><a href="#error-screenshot">{{ _('Error Screenshot') }}</a>
                 </li> {% endif %}
             {% if history_n > 0 %}
-                <li class="tab" id="text-tab"><a href="#text">Text</a></li>
-                <li class="tab" id="screenshot-tab"><a href="#screenshot">Screenshot</a></li>
+                <li class="tab" id="text-tab"><a href="#text">{{ _('Text') }}</a></li>
+                <li class="tab" id="screenshot-tab"><a href="#screenshot">{{ _('Current screenshot') }}</a></li>
             {% endif %}
         </ul>
     </div>
@@ -54,50 +56,39 @@
 
     <div id="diff-ui">
         <div class="tab-pane-inner" id="error-text">
-            <div class="snapshot-age error">{{ watch.error_text_ctime|format_seconds_ago }} seconds ago</div>
+            <div class="snapshot-age error">{{ watch.error_text_ctime|format_seconds_ago }} {{ _('seconds ago') }}</div>
             <pre>
             {{ last_error_text }}
         </pre>
         </div>
 
         <div class="tab-pane-inner" id="error-screenshot">
-            <div class="snapshot-age error">{{ watch.snapshot_error_screenshot_ctime|format_seconds_ago }} seconds ago
+            <div class="snapshot-age error">{{ watch.snapshot_error_screenshot_ctime|format_seconds_ago }} {{ _('seconds ago') }}
             </div>
             <img id="error-screenshot-img" style="max-width: 80%"
-                 alt="Current erroring screenshot from most recent request">
+                 alt="{{ _('Current erroring screenshot from most recent request') }}">
         </div>
 
         <div class="tab-pane-inner" id="text">
+            {{ highlight_trigger_ignored_explainer() }}
             <div class="snapshot-age">{{ current_version|format_timestamp_timeago }}</div>
-            <span class="tip"><strong>Pro-tip</strong>: Highlight text to add to ignore filters</span>
-
-            <table>
-                <tbody>
-                <tr>
-                    <td id="diff-col" class="highlightable-filter">
-                        <pre style="border-left: 2px solid #ddd;">
-{{ content }}
-                        </pre>
-                    </td>
-                </tr>
-                </tbody>
-            </table>
+            <pre id="difference" style="border-left: 2px solid #ddd;">{{ content| diff_unescape_difference_spans }}</pre>
         </div>
 
         <div class="tab-pane-inner" id="screenshot">
             <div class="tip">
-                For now, Differences are performed on text, not graphically, only the latest screenshot is available.
+                {{ _('For now, Differences are performed on text, not graphically, only the latest screenshot is available.') }}
             </div>
             <br>
-            {% if is_html_webdriver %}
+            {% if capabilities.supports_screenshots %}
                 {% if screenshot %}
                     <div class="snapshot-age">{{ watch.snapshot_screenshot_ctime|format_timestamp_timeago }}</div>
-                    <img style="max-width: 80%" id="screenshot-img" alt="Current screenshot from most recent request">
+                    <img style="max-width: 80%" id="screenshot-img" alt="{{ _('Current screenshot from most recent request') }}">
                 {% else %}
-                    No screenshot available just yet! Try rechecking the page.
+                    {{ _('No screenshot available just yet! Try rechecking the page.') }}
                 {% endif %}
             {% else %}
-                <strong>Screenshot requires Playwright/WebDriver enabled</strong>
+                <strong>{{ _('Screenshot requires a Content Fetcher ( Sockpuppetbrowser, selenium, etc ) that supports screenshots.') }}</strong>
             {% endif %}
         </div>
     </div>

changedetectionio/blueprint/ui/views.py

@@ -1,207 +1,12 @@
-from flask import Blueprint, request, redirect, url_for, flash, render_template, make_response, send_from_directory, abort
-import os
-import time
-from loguru import logger
-
+from flask import Blueprint, request, redirect, url_for, flash
+from flask_babel import gettext
 from changedetectionio.store import ChangeDetectionStore
 from changedetectionio.auth_decorator import login_optionally_required
-from changedetectionio import html_tools
 from changedetectionio import worker_handler
 
+
 def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMetaData, watch_check_update):
     views_blueprint = Blueprint('ui_views', __name__, template_folder="../ui/templates")
-    
-    @views_blueprint.route("/preview/<string:uuid>", methods=['GET'])
-    @login_optionally_required
-    def preview_page(uuid):
-        content = []
-        versions = []
-        timestamp = None
-
-        # More for testing, possible to return the first/only
-        if uuid == 'first':
-            uuid = list(datastore.data['watching'].keys()).pop()
-
-        try:
-            watch = datastore.data['watching'][uuid]
-        except KeyError:
-            flash("No history found for the specified link, bad link?", "error")
-            return redirect(url_for('watchlist.index'))
-
-        system_uses_webdriver = datastore.data['settings']['application']['fetch_backend'] == 'html_webdriver'
-        extra_stylesheets = [url_for('static_content', group='styles', filename='diff.css')]
-
-        is_html_webdriver = False
-        if (watch.get('fetch_backend') == 'system' and system_uses_webdriver) or watch.get('fetch_backend') == 'html_webdriver' or watch.get('fetch_backend', '').startswith('extra_browser_'):
-            is_html_webdriver = True
-        triggered_line_numbers = []
-        if datastore.data['watching'][uuid].history_n == 0 and (watch.get_error_text() or watch.get_error_snapshot()):
-            flash("Preview unavailable - No fetch/check completed or triggers not reached", "error")
-        else:
-            # So prepare the latest preview or not
-            preferred_version = request.args.get('version')
-            versions = list(watch.history.keys())
-            timestamp = versions[-1]
-            if preferred_version and preferred_version in versions:
-                timestamp = preferred_version
-
-            try:
-                versions = list(watch.history.keys())
-                content = watch.get_history_snapshot(timestamp)
-
-                triggered_line_numbers = html_tools.strip_ignore_text(content=content,
-                                                                      wordlist=watch['trigger_text'],
-                                                                      mode='line numbers'
-                                                                      )
-
-            except Exception as e:
-                content.append({'line': f"File doesnt exist or unable to read timestamp {timestamp}", 'classes': ''})
-
-        output = render_template("preview.html",
-                                 content=content,
-                                 current_version=timestamp,
-                                 history_n=watch.history_n,
-                                 extra_stylesheets=extra_stylesheets,
-                                 extra_title=f" - Diff - {watch.label} @ {timestamp}",
-                                 triggered_line_numbers=triggered_line_numbers,
-                                 current_diff_url=watch['url'],
-                                 screenshot=watch.get_screenshot(),
-                                 watch=watch,
-                                 uuid=uuid,
-                                 is_html_webdriver=is_html_webdriver,
-                                 last_error=watch['last_error'],
-                                 last_error_text=watch.get_error_text(),
-                                 last_error_screenshot=watch.get_error_snapshot(),
-                                 versions=versions
-                                )
-
-        return output
-
-    @views_blueprint.route("/diff/<string:uuid>", methods=['POST'])
-    @login_optionally_required
-    def diff_history_page_build_report(uuid):
-        from changedetectionio import forms
-
-        # More for testing, possible to return the first/only
-        if uuid == 'first':
-            uuid = list(datastore.data['watching'].keys()).pop()
-
-        try:
-            watch = datastore.data['watching'][uuid]
-        except KeyError:
-            flash("No history found for the specified link, bad link?", "error")
-            return redirect(url_for('watchlist.index'))
-
-        # For submission of requesting an extract
-        extract_form = forms.extractDataForm(formdata=request.form,
-                                             data={'extract_regex': request.form.get('extract_regex', '')}
-                                             )
-        if not extract_form.validate():
-            flash("An error occurred, please see below.", "error")
-            return _render_diff_template(uuid, extract_form)
-
-        else:
-            extract_regex = request.form.get('extract_regex', '').strip()
-            output = watch.extract_regex_from_all_history(extract_regex)
-            if output:
-                watch_dir = os.path.join(datastore.datastore_path, uuid)
-                response = make_response(send_from_directory(directory=watch_dir, path=output, as_attachment=True))
-                response.headers['Content-type'] = 'text/csv'
-                response.headers['Cache-Control'] = 'no-cache, no-store, must-revalidate'
-                response.headers['Pragma'] = 'no-cache'
-                response.headers['Expires'] = "0"
-                return response
-
-            flash('No matches found while scanning all of the watch history for that RegEx.', 'error')
-        return redirect(url_for('ui.ui_views.diff_history_page', uuid=uuid) + '#extract')
-
-    def _render_diff_template(uuid, extract_form=None):
-        """Helper function to render the diff template with all required data"""
-        from changedetectionio import forms
-
-        # More for testing, possible to return the first/only
-        if uuid == 'first':
-            uuid = list(datastore.data['watching'].keys()).pop()
-
-        extra_stylesheets = [url_for('static_content', group='styles', filename='diff.css')]
-        try:
-            watch = datastore.data['watching'][uuid]
-        except KeyError:
-            flash("No history found for the specified link, bad link?", "error")
-            return redirect(url_for('watchlist.index'))
-
-        # Use provided form or create a new one
-        if extract_form is None:
-            extract_form = forms.extractDataForm(formdata=request.form,
-                                                 data={'extract_regex': request.form.get('extract_regex', '')}
-                                                 )
-
-        history = watch.history
-        dates = list(history.keys())
-
-        # If a "from_version" was requested, then find it (or the closest one)
-        # Also set "from version" to be the closest version to the one that was last viewed.
-
-        best_last_viewed_timestamp = watch.get_from_version_based_on_last_viewed
-        from_version_timestamp = best_last_viewed_timestamp if best_last_viewed_timestamp else dates[-2]
-        from_version = request.args.get('from_version', from_version_timestamp )
-
-        # Use the current one if nothing was specified
-        to_version = request.args.get('to_version', str(dates[-1]))
-
-        try:
-            to_version_file_contents = watch.get_history_snapshot(timestamp=to_version)
-        except Exception as e:
-            logger.error(f"Unable to read watch history to-version for version {to_version}: {str(e)}")
-            to_version_file_contents = f"Unable to read to-version at {to_version}.\n"
-
-        try:
-            from_version_file_contents = watch.get_history_snapshot(timestamp=from_version)
-        except Exception as e:
-            logger.error(f"Unable to read watch history from-version for version {from_version}: {str(e)}")
-            from_version_file_contents = f"Unable to read to-version {from_version}.\n"
-
-        screenshot_url = watch.get_screenshot()
-
-        system_uses_webdriver = datastore.data['settings']['application']['fetch_backend'] == 'html_webdriver'
-
-        is_html_webdriver = False
-        if (watch.get('fetch_backend') == 'system' and system_uses_webdriver) or watch.get('fetch_backend') == 'html_webdriver' or watch.get('fetch_backend', '').startswith('extra_browser_'):
-            is_html_webdriver = True
-
-        password_enabled_and_share_is_off = False
-        if datastore.data['settings']['application'].get('password') or os.getenv("SALTED_PASS", False):
-            password_enabled_and_share_is_off = not datastore.data['settings']['application'].get('shared_diff_access')
-
-        datastore.set_last_viewed(uuid, time.time())
-
-        return render_template("diff.html",
-                                 current_diff_url=watch['url'],
-                                 from_version=str(from_version),
-                                 to_version=str(to_version),
-                                 extra_stylesheets=extra_stylesheets,
-                                 extra_title=f" - Diff - {watch.label}",
-                                 extract_form=extract_form,
-                                 is_html_webdriver=is_html_webdriver,
-                                 last_error=watch['last_error'],
-                                 last_error_screenshot=watch.get_error_snapshot(),
-                                 last_error_text=watch.get_error_text(),
-                                 left_sticky=True,
-                                 newest=to_version_file_contents,
-                                 newest_version_timestamp=dates[-1],
-                                 password_enabled_and_share_is_off=password_enabled_and_share_is_off,
-                                 from_version_file_contents=from_version_file_contents,
-                                 to_version_file_contents=to_version_file_contents,
-                                 screenshot=screenshot_url,
-                                 uuid=uuid,
-                                 versions=dates, # All except current/last
-                                 watch_a=watch
-                                 )
-
-    @views_blueprint.route("/diff/<string:uuid>", methods=['GET'])
-    @login_optionally_required
-    def diff_history_page(uuid):
-        return _render_diff_template(uuid)
 
     @views_blueprint.route("/form/add/quickwatch", methods=['POST'])
     @login_optionally_required
@@ -216,7 +21,7 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMe
 
         url = request.form.get('url').strip()
         if datastore.url_exists(url):
-            flash(f'Warning, URL {url} already exists', "notice")
+            flash(gettext('Warning, URL {} already exists').format(url), "notice")
 
         add_paused = request.form.get('edit_and_watch_submit_button') != None
         processor = request.form.get('processor', 'text_json_diff')
@@ -224,12 +29,12 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMe
 
         if new_uuid:
             if add_paused:
-                flash('Watch added in Paused state, saving will unpause.')
+                flash(gettext('Watch added in Paused state, saving will unpause.'))
                 return redirect(url_for('ui.ui_edit.edit_page', uuid=new_uuid, unpause_on_save=1, tag=request.args.get('tag')))
             else:
                 # Straight into the queue.
                 worker_handler.queue_item_async_safe(update_q, queuedWatchMetaData.PrioritizedItem(priority=1, item={'uuid': new_uuid}))
-                flash("Watch added.")
+                flash(gettext("Watch added."))
 
         return redirect(url_for('watchlist.index', tag=request.args.get('tag','')))
 

changedetectionio/blueprint/watchlist/__init__.py

@@ -2,10 +2,11 @@ import os
 import time
 
 from flask import Blueprint, request, make_response, render_template, redirect, url_for, flash, session
-from flask_login import current_user
 from flask_paginate import Pagination, get_page_parameter
+from flask_babel import gettext as _
 
 from changedetectionio import forms
+from changedetectionio import processors
 from changedetectionio.store import ChangeDetectionStore
 from changedetectionio.auth_decorator import login_optionally_required
 
@@ -73,7 +74,10 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMe
 
         pagination = Pagination(page=page,
                                 total=total_count,
-                                per_page=datastore.data['settings']['application'].get('pager_size', 50), css_framework="semantic")
+                                per_page=datastore.data['settings']['application'].get('pager_size', 50),
+                                css_framework="semantic",
+                                display_msg=_('displaying <b>{start} - {end}</b> {record_name} in total <b>{total}</b>'),
+                                record_name=_('records'))
 
         sorted_tags = sorted(datastore.data['settings']['application'].get('tags').items(), key=lambda x: x[1]['title'])
 
@@ -84,13 +88,19 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, queuedWatchMe
             app_rss_token=datastore.data['settings']['application'].get('rss_access_token'),
             datastore=datastore,
             errored_count=errored_count,
+            extra_classes='has-queue' if not update_q.empty() else '',
             form=form,
+            generate_tag_colors=processors.generate_processor_badge_colors,
             guid=datastore.data['app_guid'],
             has_proxies=datastore.proxy_list,
             hosted_sticky=os.getenv("SALTED_PASS", False) == False,
             now_time_server=round(time.time()),
             pagination=pagination,
-            queued_uuids=[q_uuid.item['uuid'] for q_uuid in update_q.queue],
+            processor_badge_css=processors.get_processor_badge_css(),
+            processor_badge_texts=processors.get_processor_badge_texts(),
+            processor_descriptions=processors.get_processor_descriptions(),
+            queue_size=update_q.qsize(),
+            queued_uuids=update_q.get_queued_uuids(),
             search_q=request.args.get('q', '').strip(),
             sort_attribute=request.args.get('sort') if request.args.get('sort') else request.cookies.get('sort'),
             sort_order=request.args.get('order') if request.args.get('order') else request.cookies.get('order'),

changedetectionio/blueprint/watchlist/templates/watch-overview.html

@@ -3,6 +3,7 @@
 {%- from '_helpers.html' import render_simple_field, render_field, render_nolabel_field, sort_by_title -%}
 <script src="{{url_for('static_content', group='js', filename='jquery-3.6.0.min.js')}}"></script>
 <script src="{{url_for('static_content', group='js', filename='watch-overview.js')}}" defer></script>
+<script src="{{url_for('static_content', group='js', filename='modal.js')}}"></script>
 <script>let nowtimeserver={{ now_time_server }};</script>
 <script>let favicon_baseURL="{{ url_for('static_content', group='favicon', filename="PLACEHOLDER")}}";</script>
 <script>
@@ -18,27 +19,57 @@ document.addEventListener('DOMContentLoaded', function() {
     background-repeat: no-repeat;
     transition: background-size 0.9s ease
 }
+
+/* Auto-generated processor badge colors */
+{{ processor_badge_css|safe }}
+
+/* Auto-generated tag colors */
+{%- for uuid, tag in tags -%}
+{%- if tag and tag.title -%}
+{%- set class_name = tag.title|sanitize_tag_class -%}
+{%- set colors = generate_tag_colors(tag.title) -%}
+.button-tag.tag-{{ class_name }} {
+  background-color: {{ colors['light']['bg'] }};
+  color: {{ colors['light']['color'] }};
+}
+
+.watch-tag-list.tag-{{ class_name }} {
+  background-color: {{ colors['light']['bg'] }};
+  color: {{ colors['light']['color'] }};
+}
+
+html[data-darkmode="true"] .button-tag.tag-{{ class_name }} {
+  background-color: {{ colors['dark']['bg'] }};
+  color: {{ colors['dark']['color'] }};
+}
+
+html[data-darkmode="true"] .watch-tag-list.tag-{{ class_name }} {
+  background-color: {{ colors['dark']['bg'] }};
+  color: {{ colors['dark']['color'] }};
+}
+{%- endif -%}
+{%- endfor -%}
 </style>
 <div class="box" id="form-quick-watch-add">
 
     <form class="pure-form" action="{{ url_for('ui.ui_views.form_quick_watch_add', tag=active_tag_uuid) }}" method="POST" id="new-watch-form">
         <input type="hidden" name="csrf_token" value="{{ csrf_token() }}" >
         <fieldset>
-            <legend>Add a new web page change detection watch</legend>
+            <legend>{{ _('Add a new web page change detection watch') }}</legend>
             <div id="watch-add-wrapper-zone">
                     {{ render_nolabel_field(form.url, placeholder="https://...", required=true) }}
-                    {{ render_nolabel_field(form.watch_submit_button, title="Watch this URL!" ) }}
-                    {{ render_nolabel_field(form.edit_and_watch_submit_button, title="Edit first then Watch") }}
+                    {{ render_nolabel_field(form.watch_submit_button, title=_("Watch this URL!") ) }}
+                    {{ render_nolabel_field(form.edit_and_watch_submit_button, title=_("Edit first then Watch") ) }}
             </div>
             <div id="watch-group-tag">
-               {{ render_field(form.tags, value=active_tag.title if active_tag_uuid else '', placeholder="Watch group / tag", class="transparent-field") }}
+               {{ render_field(form.tags, value=active_tag.title if active_tag_uuid else '', placeholder=_("Watch group / tag"), class="transparent-field") }}
             </div>
             <div id="quick-watch-processor-type">
                 {{ render_simple_field(form.processor) }}
             </div>
 
         </fieldset>
-        <span style="color:#eee; font-size: 80%;"><img alt="Create a shareable link" style="height: 1em;display:inline-block;" src="{{url_for('static_content', group='images', filename='spread-white.svg')}}" > Tip: You can also add 'shared' watches. <a href="https://github.com/dgtlmoon/changedetection.io/wiki/Sharing-a-Watch">More info</a></span>
+        <span style="color:#eee; font-size: 80%;"><img alt="{{ _('Create a shareable link') }}" style="height: 1em;display:inline-block;" src="{{url_for('static_content', group='images', filename='spread-white.svg')}}" > {{ _("Tip: You can also add 'shared' watches.") }} <a href="https://github.com/dgtlmoon/changedetection.io/wiki/Sharing-a-Watch">{{ _('More info') }}</a></span>
     </form>
 </div>
 <div class="box">
@@ -46,29 +77,44 @@ document.addEventListener('DOMContentLoaded', function() {
     <input type="hidden" name="csrf_token" value="{{ csrf_token() }}" >
     <input type="hidden" id="op_extradata" name="op_extradata" value="" >
     <div id="checkbox-operations">
-        <button class="pure-button button-secondary button-xsmall"  name="op" value="pause"><i data-feather="pause" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>Pause</button>
-        <button class="pure-button button-secondary button-xsmall"  name="op" value="unpause"><i data-feather="play" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>UnPause</button>
-        <button class="pure-button button-secondary button-xsmall"  name="op" value="mute"><i data-feather="volume-x" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>Mute</button>
-        <button class="pure-button button-secondary button-xsmall"  name="op" value="unmute"><i data-feather="volume-2" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>UnMute</button>
-        <button class="pure-button button-secondary button-xsmall" name="op" value="recheck"><i data-feather="refresh-cw" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>Recheck</button>
-        <button class="pure-button button-secondary button-xsmall" name="op" value="assign-tag" id="checkbox-assign-tag"><i data-feather="tag" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>Tag</button>
-        <button class="pure-button button-secondary button-xsmall" name="op" value="mark-viewed"><i data-feather="eye" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>Mark viewed</button>
-        <button class="pure-button button-secondary button-xsmall" name="op" value="notification-default"><i data-feather="bell" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>Use default notification</button>
-        <button class="pure-button button-secondary button-xsmall" name="op" value="clear-errors"><i data-feather="x-circle" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>Clear errors</button>
-        <button class="pure-button button-secondary button-xsmall" style="background: #dd4242;" name="op" value="clear-history"><i data-feather="trash-2" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>Clear/reset history</button>
-        <button class="pure-button button-secondary button-xsmall" style="background: #dd4242;" name="op" value="delete"><i data-feather="trash" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>Delete</button>
+        <button class="pure-button button-secondary button-xsmall"  name="op" value="pause"><i data-feather="pause" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>{{ _('Pause') }}</button>
+        <button class="pure-button button-secondary button-xsmall"  name="op" value="unpause"><i data-feather="play" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>{{ _('UnPause') }}</button>
+        <button class="pure-button button-secondary button-xsmall"  name="op" value="mute"><i data-feather="volume-x" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>{{ _('Mute') }}</button>
+        <button class="pure-button button-secondary button-xsmall"  name="op" value="unmute"><i data-feather="volume-2" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>{{ _('UnMute') }}</button>
+        <button class="pure-button button-secondary button-xsmall" name="op" value="recheck"><i data-feather="refresh-cw" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>{{ _('Recheck') }}</button>
+        <button class="pure-button button-secondary button-xsmall" name="op" value="assign-tag" id="checkbox-assign-tag"><i data-feather="tag" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>{{ _('Tag') }}</button>
+        <button class="pure-button button-secondary button-xsmall" name="op" value="mark-viewed"><i data-feather="eye" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>{{ _('Mark viewed') }}</button>
+        <button class="pure-button button-secondary button-xsmall" name="op" value="notification-default"><i data-feather="bell" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>{{ _('Use default notification') }}</button>
+        <button class="pure-button button-secondary button-xsmall" name="op" value="clear-errors"><i data-feather="x-circle" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>{{ _('Clear errors') }}</button>
+        <button class="pure-button button-secondary button-xsmall" style="background: #dd4242;" name="op" value="clear-history"
+                       data-requires-confirm
+                       data-confirm-type="danger"
+                       data-confirm-title="{{ _('Clear Histories') }}"
+                       data-confirm-message="{{ _('<p>Are you sure you want to clear history for the selected items?</p><p>This action cannot be undone.</p>') }}"
+                       data-confirm-button="{{ _('OK') }}"><i data-feather="trash-2" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>{{ _('Clear/reset history') }}</button>
+        <button class="pure-button button-secondary button-xsmall" style="background: #dd4242;" name="op" value="delete"
+                       data-requires-confirm
+                       data-confirm-type="danger"
+                       data-confirm-title="{{ _('Delete Watches?') }}"
+                       data-confirm-message="{{ _('<p>Are you sure you want to delete the selected watches?</strong></p><p>This action cannot be undone.</p>') }}"
+                       data-confirm-button="{{ _('Delete') }}"><i data-feather="trash" style="width: 14px; height: 14px; stroke: white; margin-right: 4px;"></i>{{ _('Delete') }}</button>
     </div>
-    {%- if watches|length >= pagination.per_page -%}
-        {{ pagination.info }}
-    {%- endif -%}
-    {%- if search_q -%}<div id="search-result-info">Searching "<strong><i>{{search_q}}</i></strong>"</div>{%- endif -%}
+
+    <div id="stats_row">
+        <div class="left">{%- if watches|length >= pagination.per_page -%}{{ pagination.info }}{%- endif -%}</div>
+        <div class="right" >{{ _('Queued size') }}: <span id="queue-size-int">{{ queue_size }}</span></div>
+    </div>
+
+
+
+    {%- if search_q -%}<div id="search-result-info">{{ _('Searching') }} "<strong><i>{{search_q}}</i></strong>"</div>{%- endif -%}
     <div>
-        <a href="{{url_for('watchlist.index')}}" class="pure-button button-tag {{'active' if not active_tag_uuid }}">All</a>
+        <a href="{{url_for('watchlist.index')}}" class="pure-button button-tag {{'active' if not active_tag_uuid }}">{{ _('All') }}</a>
 
     <!-- tag list -->
     {%- for uuid, tag in tags -%}
         {%- if tag != "" -%}
-            <a href="{{url_for('watchlist.index', tag=uuid) }}" class="pure-button button-tag {{'active' if active_tag_uuid == uuid }}">{{ tag.title }}</a>
+            <a href="{{url_for('watchlist.index', tag=uuid) }}" class="pure-button button-tag tag-{{ tag.title|sanitize_tag_class }} {{'active' if active_tag_uuid == uuid }}">{{ tag.title }}</a>
         {%- endif -%}
     {%- endfor -%}
     </div>
@@ -101,19 +147,19 @@ document.addEventListener('DOMContentLoaded', function() {
                     &nbsp;
                     <a class="{{ 'active '+link_order if sort_attribute == 'notification_muted' else 'inactive' }}" href="{{url_for('watchlist.index', sort='notification_muted', order=link_order, tag=active_tag_uuid)}}"><i data-feather="volume-2" style="vertical-align: bottom; width: 14px; height: 14px;  margin-right: 4px;"></i><span class='arrow {{link_order}}'></span></a>
                 </th>
-                <th><a class="{{ 'active '+link_order if sort_attribute == 'label' else 'inactive' }}" href="{{url_for('watchlist.index', sort='label', order=link_order, tag=active_tag_uuid)}}">Website <span class='arrow {{link_order}}'></span></a></th>
+                <th><a class="{{ 'active '+link_order if sort_attribute == 'label' else 'inactive' }}" href="{{url_for('watchlist.index', sort='label', order=link_order, tag=active_tag_uuid)}}">{{ _('Website') }} <span class='arrow {{link_order}}'></span></a></th>
              {%- if any_has_restock_price_processor -%}
-                <th>Restock &amp; Price</th>
+                <th>{{ _('Restock & Price') }}</th>
              {%- endif -%}
-                <th><a class="{{ 'active '+link_order if sort_attribute == 'last_checked' else 'inactive' }}" href="{{url_for('watchlist.index', sort='last_checked', order=link_order, tag=active_tag_uuid)}}"><span class="hide-on-mobile">Last</span> Checked <span class='arrow {{link_order}}'></span></a></th>
-                <th><a class="{{ 'active '+link_order if sort_attribute == 'last_changed' else 'inactive' }}" href="{{url_for('watchlist.index', sort='last_changed', order=link_order, tag=active_tag_uuid)}}"><span class="hide-on-mobile">Last</span> Changed <span class='arrow {{link_order}}'></span></a></th>
+                <th><a class="{{ 'active '+link_order if sort_attribute == 'last_checked' else 'inactive' }}" href="{{url_for('watchlist.index', sort='last_checked', order=link_order, tag=active_tag_uuid)}}"><span class="hide-on-mobile">{{ _('Last') }}</span> {{ _('Checked') }} <span class='arrow {{link_order}}'></span></a></th>
+                <th><a class="{{ 'active '+link_order if sort_attribute == 'last_changed' else 'inactive' }}" href="{{url_for('watchlist.index', sort='last_changed', order=link_order, tag=active_tag_uuid)}}"><span class="hide-on-mobile">{{ _('Last') }}</span> {{ _('Changed') }} <span class='arrow {{link_order}}'></span></a></th>
                 <th class="empty-cell"></th>
             </tr>
             </thead>
             <tbody>
             {%- if not watches|length -%}
             <tr>
-                <td colspan="{{ cols_required }}" style="text-wrap: wrap;">No website watches configured, please add a URL in the box above, or <a href="{{ url_for('imports.import_page')}}" >import a list</a>.</td>
+                <td colspan="{{ cols_required }}" style="text-wrap: wrap;">{{ _('No web page change detection watches configured, please add a URL in the box above, or') }} <a href="{{ url_for('imports.import_page')}}" >{{ _('import a list') }}</a>.</td>
             </tr>
             {%- endif -%}
 
@@ -155,7 +201,7 @@ document.addEventListener('DOMContentLoaded', function() {
                     <div class="flex-wrapper">
                     {% if 'favicons_enabled' not in ui_settings or ui_settings['favicons_enabled'] %}
                         <div>{# A page might have hundreds of these images, set IMG options for lazy loading, don't set SRC if we dont have it so it doesnt fetch the placeholder'  #}
-                            <img alt="Favicon thumbnail" class="favicon" loading="lazy" decoding="async" fetchpriority="low" {% if favicon %} src="{{url_for('static_content', group='favicon', filename=watch.uuid)}}" {% else %} src='data:image/svg+xml;utf8,%3Csvg xmlns="http://www.w3.org/2000/svg" width="7.087" height="7.087" viewBox="0 0 7.087 7.087"%3E%3Ccircle cx="3.543" cy="3.543" r="3.279" stroke="%23e1e1e1" stroke-width="0.45" fill="none" opacity="0.74"/%3E%3C/svg%3E' {%  endif %} />
+                            <img alt="Favicon thumbnail" class="favicon" loading="lazy" decoding="async" fetchpriority="low" {% if favicon %} src="{{url_for('static_content', group='favicon', filename=watch.uuid)}}" {% else %} src='data:image/svg+xml;utf8,%3Csvg xmlns="http://www.w3.org/2000/svg" width="7.087" height="7.087" viewBox="0 0 7.087 7.087"%3E%3Ccircle cx="3.543" cy="3.543" r="3.279" stroke="%23e1e1e1" stroke-width="0.45" fill="none" opacity="0.74"/%3E%3C/svg%3E' {%  endif %} >
                         </div>
                     {%  endif %}
                         <div>
@@ -167,26 +213,24 @@ document.addEventListener('DOMContentLoaded', function() {
                             {% endif %}
                            <a class="external" target="_blank" rel="noopener" href="{{ watch.link.replace('source:','') }}">&nbsp;</a>
                         </span>
-                            <div class="error-text" style="display:none;">{{ watch.compile_error_texts(has_proxies=datastore.proxy_list) }}</div>
+                            <div class="error-text" style="display:none;">{{ watch.compile_error_texts(has_proxies=datastore.proxy_list)|safe }}</div>
                             {%- if watch['processor'] == 'text_json_diff'  -%}
                                 {%- if watch['has_ldjson_price_data'] and not watch['track_ldjson_price_data']  -%}
                                 <div class="ldjson-price-track-offer">Switch to Restock & Price watch mode? <a href="{{url_for('price_data_follower.accept', uuid=watch.uuid)}}" class="pure-button button-xsmall">Yes</a> <a href="{{url_for('price_data_follower.reject', uuid=watch.uuid)}}" class="">No</a></div>
                                 {%- endif -%}
                             {%- endif -%}
-                            {%- if watch['processor'] == 'restock_diff' -%}
-                                <span class="tracking-ldjson-price-data" title="Automatically following embedded price information"><img src="{{url_for('static_content', group='images', filename='price-tag-icon.svg')}}"  class="status-icon price-follow-tag-icon" > Price</span>
+                            {%- if watch['processor'] and watch['processor'] in processor_badge_texts -%}
+                                <span class="processor-badge processor-badge-{{ watch['processor'] }}" title="{{ processor_descriptions.get(watch['processor'], watch['processor']) }}">{{ processor_badge_texts[watch['processor']] }}</span>
                             {%- endif -%}
                             {%- for watch_tag_uuid, watch_tag in datastore.get_all_tags_for_watch(watch['uuid']).items() -%}
-                              <span class="watch-tag-list">{{ watch_tag.title }}</span>
+                              <span class="watch-tag-list tag-{{ watch_tag.title|sanitize_tag_class }}">{{ watch_tag.title }}</span>
                             {%- endfor -%}
                         </div>
                     <div class="status-icons">
                             <a class="link-spread" href="{{url_for('ui.form_share_put_watch', uuid=watch.uuid)}}"><img src="{{url_for('static_content', group='images', filename='spread.svg')}}" class="status-icon icon icon-spread" title="Create a link to share watch config with others" ></a>
-                            {%- if watch.get_fetch_backend == "html_webdriver"
-                                 or ( watch.get_fetch_backend == "system" and system_default_fetcher == 'html_webdriver'  )
-                                 or "extra_browser_" in watch.get_fetch_backend
-                            -%}
-                            <img class="status-icon" src="{{url_for('static_content', group='images', filename='google-chrome-icon.png')}}" alt="Using a Chrome browser" title="Using a Chrome browser" >
+                            {%- set effective_fetcher = watch.get_fetch_backend if watch.get_fetch_backend != "system" else system_default_fetcher -%}
+                            {%- if effective_fetcher and ("html_webdriver" in effective_fetcher or "html_" in effective_fetcher or "extra_browser_" in effective_fetcher) -%}
+                                {{ effective_fetcher|fetcher_status_icons }}
                             {%- endif -%}
                             {%- if watch.is_pdf  -%}<img class="status-icon" src="{{url_for('static_content', group='images', filename='pdf-icon.svg')}}" alt="Converting PDF to text" >{%- endif -%}
                             {%- if watch.has_browser_steps -%}<img class="status-icon status-browsersteps" src="{{url_for('static_content', group='images', filename='steps.svg')}}" alt="Browser Steps is enabled" >{%- endif -%}
@@ -198,20 +242,20 @@ document.addEventListener('DOMContentLoaded', function() {
                 <td class="restock-and-price">
                     {%- if watch['processor'] == 'restock_diff'  -%}
                         {%- if watch.has_restock_info -%}
-                            <span class="restock-label {{'in-stock' if watch['restock']['in_stock'] else 'not-in-stock' }}" title="Detecting restock and price">
+                            <span class="restock-label {{'in-stock' if watch['restock']['in_stock'] else 'not-in-stock' }}" title="{{ _('Detecting restock and price') }}">
                                 <!-- maybe some object watch['processor'][restock_diff] or.. -->
-                                 {%- if watch['restock']['in_stock']-%}  In stock {%- else-%}  Not in stock {%- endif -%}
+                                 {%- if watch['restock']['in_stock']-%}  {{ _('In stock') }} {%- else-%}  {{ _('Not in stock') }} {%- endif -%}
                             </span>
                         {%- endif -%}
 
                         {%- if watch.get('restock') and watch['restock']['price'] != None -%}
                             {%- if watch['restock']['price'] != None -%}
-                                <span class="restock-label price" title="Price">
-                                {{ watch['restock']['price']|format_number_locale }} {{ watch['restock']['currency'] }}
+                                <span class="restock-label price" title="{{ _('Price') }}">
+                                {{ watch['restock']['price']|format_number_locale if watch['restock'].get('price') else '' }} {{ watch['restock'].get('currency','') }}
                                 </span>
                             {%- endif -%}
                         {%- elif not watch.has_restock_info -%}
-                            <span class="restock-label error">No information</span>
+                            <span class="restock-label error">{{ _('No information') }}</span>
                         {%- endif -%}
                     {%- endif -%}
                 </td>
@@ -219,24 +263,24 @@ document.addEventListener('DOMContentLoaded', function() {
             {#last_checked becomes fetch-start-time#}
                 <td class="last-checked" data-timestamp="{{ watch.last_checked }}" data-fetchduration={{ watch.fetch_time }} data-eta_complete="{{ watch.last_checked+watch.fetch_time }}" >
                     <div class="spinner-wrapper" style="display:none;" >
-                        <span class="spinner"></span><span>&nbsp;Checking now</span>
+                        <span class="spinner"></span><span class="status-text">&nbsp;{{ _('Checking now') }}</span>
                     </div>
                     <span class="innertext">{{watch|format_last_checked_time|safe}}</span>
                 </td>
                 <td class="last-changed" data-timestamp="{{ watch.last_changed }}">{%- if watch.history_n >=2 and watch.last_changed >0 -%}
                     {{watch.last_changed|format_timestamp_timeago}}
                     {%- else -%}
-                    Not yet
+                    {{ _('Not yet') }}
                     {%- endif -%}
                 </td>
                 <td class="buttons">
                     <div>
                     {%- set target_attr = ' target="' ~ watch.uuid ~ '"' if datastore.data['settings']['application']['ui'].get('open_diff_in_new_tab') else '' -%}
-                    <a href="" class="already-in-queue-button recheck pure-button pure-button-primary" style="display: none;" disabled="disabled">Queued</a>
-                    <a href="{{ url_for('ui.form_watch_checknow', uuid=watch.uuid, tag=request.args.get('tag')) }}" data-op='recheck' class="ajax-op recheck pure-button pure-button-primary">Recheck</a>
-                    <a href="{{ url_for('ui.ui_edit.edit_page', uuid=watch.uuid, tag=active_tag_uuid)}}#general" class="pure-button pure-button-primary">Edit</a>
-                    <a href="{{ url_for('ui.ui_views.diff_history_page', uuid=watch.uuid)}}" {{target_attr}} class="pure-button pure-button-primary history-link" style="display: none;">History</a>
-                    <a href="{{ url_for('ui.ui_views.preview_page', uuid=watch.uuid)}}" {{target_attr}} class="pure-button pure-button-primary preview-link" style="display: none;">Preview</a>
+                    <a href="" class="already-in-queue-button recheck pure-button pure-button-primary" style="display: none;" disabled="disabled">{{ _('Queued') }}</a>
+                    <a href="{{ url_for('ui.form_watch_checknow', uuid=watch.uuid, tag=request.args.get('tag')) }}" data-op='recheck' class="ajax-op recheck pure-button pure-button-primary">{{ _('Recheck') }}</a>
+                    <a href="{{ url_for('ui.ui_edit.edit_page', uuid=watch.uuid, tag=active_tag_uuid)}}#general" class="pure-button pure-button-primary">{{ _('Edit') }}</a>
+                    <a href="{{ url_for('ui.ui_diff.diff_history_page', uuid=watch.uuid)}}" {{target_attr}} class="pure-button pure-button-primary history-link" style="display: none;">{{ _('History') }}</a>
+                    <a href="{{ url_for('ui.ui_preview.preview_page', uuid=watch.uuid)}}" {{target_attr}} class="pure-button pure-button-primary preview-link" style="display: none;">{{ _('Preview') }}</a>
                     </div>
                 </td>
             </tr>
@@ -245,22 +289,21 @@ document.addEventListener('DOMContentLoaded', function() {
         </table>
         <ul id="post-list-buttons">
             <li id="post-list-with-errors" style="display: none;" >
-                <a href="{{url_for('watchlist.index', with_errors=1, tag=request.args.get('tag')) }}" class="pure-button button-tag button-error">With errors ({{ errored_count }})</a>
+                <a href="{{url_for('watchlist.index', with_errors=1, tag=request.args.get('tag')) }}" class="pure-button button-tag button-error">{{ _('With errors') }} ({{ errored_count }})</a>
             </li>
             <li id="post-list-mark-views" style="display: none;" >
-                <a href="{{url_for('ui.mark_all_viewed',with_errors=request.args.get('with_errors',0)) }}" class="pure-button button-tag " id="mark-all-viewed">Mark all viewed</a>
+                <a href="{{url_for('ui.mark_all_viewed',with_errors=request.args.get('with_errors',0)) }}" class="pure-button button-tag " id="mark-all-viewed">{{ _('Mark all viewed') }}</a>
             </li>
         {%-  if active_tag_uuid -%}
             <li id="post-list-mark-views-tag">
-                <a href="{{url_for('ui.mark_all_viewed', tag=active_tag_uuid) }}" class="pure-button button-tag " id="mark-all-viewed">Mark all viewed in '{{active_tag.title}}'</a>
+                <a href="{{url_for('ui.mark_all_viewed', tag=active_tag_uuid) }}" class="pure-button button-tag " id="mark-all-viewed">{{ _("Mark all viewed in '%(title)s'", title=active_tag.title) }}</a>
             </li>
         {%-  endif -%}
             <li id="post-list-unread" style="display: none;" >
-                <a href="{{url_for('watchlist.index', unread=1, tag=request.args.get('tag')) }}" class="pure-button button-tag">Unread (<span id="unread-tab-counter">{{ unread_changes_count }}</span>)</a>
+                <a href="{{url_for('watchlist.index', unread=1, tag=request.args.get('tag')) }}" class="pure-button button-tag">{{ _('Unread') }} (<span id="unread-tab-counter">{{ unread_changes_count }}</span>)</a>
             </li>
             <li>
-               <a href="{{ url_for('ui.form_watch_checknow', tag=active_tag_uuid, with_errors=request.args.get('with_errors',0)) }}" class="pure-button button-tag" id="recheck-all">Recheck
-                all {% if active_tag_uuid %}  in '{{active_tag.title}}'{%endif%}</a>
+               <a href="{{ url_for('ui.form_watch_checknow', tag=active_tag_uuid, with_errors=request.args.get('with_errors',0)) }}" class="pure-button button-tag" id="recheck-all">{{ _('Recheck all') }} {% if active_tag_uuid %}  {{ _("in '%(title)s'", title=active_tag.title) }}{%endif%}</a>
             </li>
             <li>
                 <a href="{{ url_for('rss.feed', tag=active_tag_uuid, token=app_rss_token)}}"><img alt="RSS Feed" id="feed-icon" src="{{url_for('static_content', group='images', filename='generic_feed-icon.svg')}}" height="15"></a>

changedetectionio/conditions/plugins/levenshtein_plugin.py

@@ -1,3 +1,7 @@
+"""
+Levenshtein distance and similarity plugin for text change detection.
+Provides metrics for measuring text similarity between snapshots.
+"""
 import pluggy
 from loguru import logger
 

changedetectionio/conditions/plugins/wordcount_plugin.py

@@ -1,3 +1,7 @@
+"""
+Word count plugin for content analysis.
+Provides word count metrics for snapshot content.
+"""
 import pluggy
 from loguru import logger
 
@@ -14,7 +18,7 @@ def count_words_in_history(watch, incoming_text=None):
         elif watch.history.keys():
             # When called from UI extras to count latest snapshot
             latest_key = list(watch.history.keys())[-1]
-            latest_content = watch.get_history_snapshot(latest_key)
+            latest_content = watch.get_history_snapshot(timestamp=latest_key)
             return len(latest_content.split())
         return 0
     except Exception as e:

changedetectionio/content_fetchers/__init__.py

@@ -7,6 +7,9 @@ import os
 # Visual Selector scraper - 'Button' is there because some sites have <button>OUT OF STOCK</button>.
 visualselector_xpath_selectors = 'div,span,form,table,tbody,tr,td,a,p,ul,li,h1,h2,h3,h4,header,footer,section,article,aside,details,main,nav,section,summary,button'
 
+# Import hookimpl from centralized pluggy interface
+from changedetectionio.pluggy_interface import hookimpl
+
 SCREENSHOT_MAX_HEIGHT_DEFAULT = 20000
 SCREENSHOT_DEFAULT_QUALITY = 40
 
@@ -18,7 +21,9 @@ SCREENSHOT_MAX_TOTAL_HEIGHT = int(os.getenv("SCREENSHOT_MAX_HEIGHT", SCREENSHOT_
 # The size at which we will switch to stitching method, when below this (and
 # MAX_TOTAL_HEIGHT which can be set by a user) we will use the default
 # screenshot method.
-SCREENSHOT_SIZE_STITCH_THRESHOLD = 8000
+# Increased from 8000 to 10000 for better performance (fewer chunks = faster)
+# Most modern GPUs support 16384x16384 textures, so 1280x10000 is safe
+SCREENSHOT_SIZE_STITCH_THRESHOLD = int(os.getenv("SCREENSHOT_CHUNK_HEIGHT", 10000))
 
 # available_fetchers() will scan this implementation looking for anything starting with html_
 # this information is used in the form selections
@@ -35,17 +40,54 @@ def available_fetchers():
     # See the if statement at the bottom of this file for how we switch between playwright and webdriver
     import inspect
     p = []
+
+    # Get built-in fetchers (but skip plugin fetchers that were added via setattr)
     for name, obj in inspect.getmembers(sys.modules[__name__], inspect.isclass):
         if inspect.isclass(obj):
             # @todo html_ is maybe better as fetcher_ or something
             # In this case, make sure to edit the default one in store.py and fetch_site_status.py
             if name.startswith('html_'):
-                t = tuple([name, obj.fetcher_description])
-                p.append(t)
+                # Skip plugin fetchers that were already registered
+                if name not in _plugin_fetchers:
+                    t = tuple([name, obj.fetcher_description])
+                    p.append(t)
+
+    # Get plugin fetchers from cache (already loaded at module init)
+    for name, fetcher_class in _plugin_fetchers.items():
+        if hasattr(fetcher_class, 'fetcher_description'):
+            t = tuple([name, fetcher_class.fetcher_description])
+            p.append(t)
+        else:
+            logger.warning(f"Plugin fetcher '{name}' does not have fetcher_description attribute")
 
     return p
 
 
+def get_plugin_fetchers():
+    """Load and return all plugin fetchers from the centralized plugin manager."""
+    from changedetectionio.pluggy_interface import plugin_manager
+
+    fetchers = {}
+    try:
+        # Call the register_content_fetcher hook from all registered plugins
+        results = plugin_manager.hook.register_content_fetcher()
+        for result in results:
+            if result:
+                name, fetcher_class = result
+                fetchers[name] = fetcher_class
+                # Register in current module so hasattr() checks work
+                setattr(sys.modules[__name__], name, fetcher_class)
+                logger.info(f"Registered plugin fetcher: {name} - {getattr(fetcher_class, 'fetcher_description', 'No description')}")
+    except Exception as e:
+        logger.error(f"Error loading plugin fetchers: {e}")
+
+    return fetchers
+
+
+# Initialize plugins at module load time
+_plugin_fetchers = get_plugin_fetchers()
+
+
 # Decide which is the 'real' HTML webdriver, this is more a system wide config
 # rather than site-specific.
 use_playwright_as_chrome_fetcher = os.getenv('PLAYWRIGHT_DRIVER_URL', False)
@@ -62,3 +104,8 @@ else:
     logger.debug("Falling back to selenium as fetcher")
     from .webdriver_selenium import fetcher as html_webdriver
 
+
+# Register built-in fetchers as plugins after all imports are complete
+from changedetectionio.pluggy_interface import register_builtin_fetchers
+register_builtin_fetchers()
+

changedetectionio/content_fetchers/base.py

@@ -51,6 +51,7 @@ class Fetcher():
     favicon_blob = None
     instock_data = None
     instock_data_js = ""
+    screenshot_format = None
     status_code = None
     webdriver_js_execute_code = None
     xpath_data = None
@@ -64,6 +65,35 @@ class Fetcher():
     # Time ONTOP of the system defined env minimum time
     render_extract_delay = 0
 
+    # Fetcher capability flags - subclasses should override these
+    # These indicate what features the fetcher supports
+    supports_browser_steps = False      # Can execute browser automation steps
+    supports_screenshots = False        # Can capture page screenshots
+    supports_xpath_element_data = False # Can extract xpath element positions/data for visual selector
+
+    def __init__(self, **kwargs):
+        if kwargs and 'screenshot_format' in kwargs:
+            self.screenshot_format = kwargs.get('screenshot_format')
+
+
+    @classmethod
+    def get_status_icon_data(cls):
+        """Return data for status icon to display in the watch overview.
+
+        This method can be overridden by subclasses to provide custom status icons.
+
+        Returns:
+            dict or None: Dictionary with icon data:
+                {
+                    'filename': 'icon-name.svg',  # Icon filename
+                    'alt': 'Alt text',            # Alt attribute
+                    'title': 'Tooltip text',      # Title attribute
+                    'style': 'height: 1em;'       # Optional inline CSS
+                }
+                Or None if no icon
+        """
+        return None
+
     def clear_content(self):
         """
         Explicitly clear all content from memory to free up heap space.
@@ -92,12 +122,13 @@ class Fetcher():
                   request_method=None,
                   timeout=None,
                   url=None,
+                  watch_uuid=None,
                   ):
         # Should set self.error, self.status_code and self.content
         pass
 
     @abstractmethod
-    def quit(self, watch=None):
+    async def quit(self, watch=None):
         return
 
     @abstractmethod

changedetectionio/content_fetchers/playwright.py

@@ -1,3 +1,4 @@
+import gc
 import json
 import os
 from urllib.parse import urlparse
@@ -9,10 +10,10 @@ from changedetectionio.content_fetchers import SCREENSHOT_MAX_HEIGHT_DEFAULT, vi
 from changedetectionio.content_fetchers.base import Fetcher, manage_user_agent
 from changedetectionio.content_fetchers.exceptions import PageUnloadable, Non200ErrorCodeReceived, EmptyReply, ScreenshotUnavailable
 
-async def capture_full_page_async(page):
+async def capture_full_page_async(page, screenshot_format='JPEG'):
     import os
     import time
-    from multiprocessing import Process, Pipe
+    import multiprocessing
 
     start = time.time()
 
@@ -26,8 +27,20 @@ async def capture_full_page_async(page):
     step_size = SCREENSHOT_SIZE_STITCH_THRESHOLD # Size that won't cause GPU to overflow
     screenshot_chunks = []
     y = 0
+    elements_locked = False
 
     if page_height > page.viewport_size['height']:
+
+        # Lock all element dimensions BEFORE screenshot to prevent CSS media queries from resizing
+        # capture_full_page_async() changes viewport height which triggers @media (min-height) rules
+        lock_elements_js_path = os.path.join(os.path.dirname(__file__), 'res', 'lock-elements-sizing.js')
+        with open(lock_elements_js_path, 'r') as f:
+            lock_elements_js = f.read()
+        await page.evaluate(lock_elements_js)
+        elements_locked = True
+
+        logger.debug("Element dimensions locked before screenshot capture")
+
         if page_height < step_size:
             step_size = page_height # Incase page is bigger than default viewport but smaller than proposed step size
         logger.debug(f"Setting bigger viewport to step through large page width W{page.viewport_size['width']}xH{step_size} because page_height > viewport_size")
@@ -35,36 +48,68 @@ async def capture_full_page_async(page):
         await page.set_viewport_size({'width': page.viewport_size['width'], 'height': step_size})
 
     # Capture screenshots in chunks up to the max total height
+    # Use PNG for better quality (no compression artifacts), JPEG for smaller size
+    screenshot_type = screenshot_format.lower() if screenshot_format else 'jpeg'
+    # PNG should use quality 100, JPEG uses configurable quality
+    screenshot_quality = 100 if screenshot_type == 'png' else int(os.getenv("SCREENSHOT_QUALITY", 72))
+
     while y < min(page_height, SCREENSHOT_MAX_TOTAL_HEIGHT):
+        # Only scroll if not at the top (y > 0)
+        if y > 0:
+            await page.evaluate(f"window.scrollTo(0, {y})")
+
+        # Request GC only before screenshot (not 3x per chunk)
         await page.request_gc()
-        await page.evaluate(f"window.scrollTo(0, {y})")
-        await page.request_gc()
-        screenshot_chunks.append(await page.screenshot(
-            type="jpeg",
-            full_page=False,
-            quality=int(os.getenv("SCREENSHOT_QUALITY", 72))
-        ))
+
+        screenshot_kwargs = {
+            'type': screenshot_type,
+            'full_page': False
+        }
+        # Only pass quality parameter for jpeg (PNG doesn't support it in Playwright)
+        if screenshot_type == 'jpeg':
+            screenshot_kwargs['quality'] = screenshot_quality
+
+        screenshot_chunks.append(await page.screenshot(**screenshot_kwargs))
         y += step_size
-        await page.request_gc()
 
     # Restore original viewport size
     await page.set_viewport_size({'width': original_viewport['width'], 'height': original_viewport['height']})
 
+    # Unlock element dimensions if they were locked
+    if elements_locked:
+        unlock_elements_js_path = os.path.join(os.path.dirname(__file__), 'res', 'unlock-elements-sizing.js')
+        with open(unlock_elements_js_path, 'r') as f:
+            unlock_elements_js = f.read()
+        await page.evaluate(unlock_elements_js)
+        logger.debug("Element dimensions unlocked after screenshot capture")
+
     # If we have multiple chunks, stitch them together
     if len(screenshot_chunks) > 1:
-        from changedetectionio.content_fetchers.screenshot_handler import stitch_images_worker
         logger.debug(f"Screenshot stitching {len(screenshot_chunks)} chunks together")
-        parent_conn, child_conn = Pipe()
-        p = Process(target=stitch_images_worker, args=(child_conn, screenshot_chunks, page_height, SCREENSHOT_MAX_TOTAL_HEIGHT))
-        p.start()
-        screenshot = parent_conn.recv_bytes()
-        p.join()
+
+        # For small number of chunks (2-3), stitch inline to avoid multiprocessing overhead
+        # Only use separate process for many chunks (4+) to avoid blocking the event loop
+        if len(screenshot_chunks) <= 3:
+            from changedetectionio.content_fetchers.screenshot_handler import stitch_images_inline
+            screenshot = stitch_images_inline(screenshot_chunks, page_height, SCREENSHOT_MAX_TOTAL_HEIGHT)
+        else:
+            # Use separate process for many chunks to avoid blocking
+            # Always use spawn for thread safety - consistent behavior in tests and production
+            from changedetectionio.content_fetchers.screenshot_handler import stitch_images_worker
+            ctx = multiprocessing.get_context('spawn')
+            parent_conn, child_conn = ctx.Pipe()
+            p = ctx.Process(target=stitch_images_worker, args=(child_conn, screenshot_chunks, page_height, SCREENSHOT_MAX_TOTAL_HEIGHT))
+            p.start()
+            screenshot = parent_conn.recv_bytes()
+            p.join()
+            # Explicit cleanup
+            del p
+            del parent_conn, child_conn
+
         logger.debug(
             f"Screenshot (chunked/stitched) - Page height: {page_height} Capture height: {SCREENSHOT_MAX_TOTAL_HEIGHT} - Stitched together in {time.time() - start:.2f}s")
         # Explicit cleanup
         del screenshot_chunks
-        del p
-        del parent_conn, child_conn
         screenshot_chunks = None
         return screenshot
 
@@ -89,8 +134,22 @@ class fetcher(Fetcher):
 
     proxy = None
 
-    def __init__(self, proxy_override=None, custom_browser_connection_url=None):
-        super().__init__()
+    # Capability flags
+    supports_browser_steps = True
+    supports_screenshots = True
+    supports_xpath_element_data = True
+
+    @classmethod
+    def get_status_icon_data(cls):
+        """Return Chrome browser icon data for Playwright fetcher."""
+        return {
+            'filename': 'google-chrome-icon.png',
+            'alt': 'Using a Chrome browser',
+            'title': 'Using a Chrome browser'
+        }
+
+    def __init__(self, proxy_override=None, custom_browser_connection_url=None, **kwargs):
+        super().__init__(**kwargs)
 
         self.browser_type = os.getenv("PLAYWRIGHT_BROWSER_TYPE", 'chromium').strip('"')
 
@@ -125,22 +184,35 @@ class fetcher(Fetcher):
 
     async def screenshot_step(self, step_n=''):
         super().screenshot_step(step_n=step_n)
-        screenshot = await capture_full_page_async(page=self.page)
+        screenshot = await capture_full_page_async(page=self.page, screenshot_format=self.screenshot_format)
 
+        # Request GC immediately after screenshot to free memory
+        # Screenshots can be large and browser steps take many of them
+        await self.page.request_gc()
 
         if self.browser_steps_screenshot_path is not None:
             destination = os.path.join(self.browser_steps_screenshot_path, 'step_{}.jpeg'.format(step_n))
             logger.debug(f"Saving step screenshot to {destination}")
             with open(destination, 'wb') as f:
                 f.write(screenshot)
+            # Clear local reference to allow screenshot bytes to be collected
+            del screenshot
+            gc.collect()
 
     async def save_step_html(self, step_n):
         super().save_step_html(step_n=step_n)
         content = await self.page.content()
+
+        # Request GC after getting page content
+        await self.page.request_gc()
+
         destination = os.path.join(self.browser_steps_screenshot_path, 'step_{}.html'.format(step_n))
         logger.debug(f"Saving step HTML to {destination}")
-        with open(destination, 'w') as f:
+        with open(destination, 'w', encoding='utf-8') as f:
             f.write(content)
+        # Clear local reference
+        del content
+        gc.collect()
 
     async def run(self,
                   fetch_favicon=True,
@@ -151,8 +223,10 @@ class fetcher(Fetcher):
                   request_body=None,
                   request_headers=None,
                   request_method=None,
+                  screenshot_format=None,
                   timeout=None,
                   url=None,
+                  watch_uuid=None,
                   ):
 
         from playwright.async_api import async_playwright
@@ -244,7 +318,13 @@ class fetcher(Fetcher):
                     logger.error(f"Error fetching FavIcon info {str(e)}, continuing.")
 
             if self.status_code != 200 and not ignore_status_codes:
-                screenshot = await capture_full_page_async(self.page)
+                screenshot = await capture_full_page_async(self.page, screenshot_format=self.screenshot_format)
+                # Cleanup before raising to prevent memory leak
+                await self.page.close()
+                await context.close()
+                await browser.close()
+                # Force garbage collection to release Playwright resources immediately
+                gc.collect()
                 raise Non200ErrorCodeReceived(url=url, status_code=self.status_code, screenshot=screenshot)
 
             if not empty_pages_are_a_change and len((await self.page.content()).strip()) == 0:
@@ -253,48 +333,52 @@ class fetcher(Fetcher):
                 await browser.close()
                 raise EmptyReply(url=url, status_code=response.status)
 
-            # Run Browser Steps here
-            if self.browser_steps_get_valid_steps():
-                await self.iterate_browser_steps(start_url=url)
-
-            await self.page.wait_for_timeout(extra_wait * 1000)
-
-            now = time.time()
-            # So we can find an element on the page where its selector was entered manually (maybe not xPath etc)
-            if current_include_filters is not None:
-                await self.page.evaluate("var include_filters={}".format(json.dumps(current_include_filters)))
-            else:
-                await self.page.evaluate("var include_filters=''")
-            await self.page.request_gc()
-
-            # request_gc before and after evaluate to free up memory
-            # @todo browsersteps etc
-            MAX_TOTAL_HEIGHT = int(os.getenv("SCREENSHOT_MAX_HEIGHT", SCREENSHOT_MAX_HEIGHT_DEFAULT))
-            self.xpath_data = await self.page.evaluate(XPATH_ELEMENT_JS, {
-                "visualselector_xpath_selectors": visualselector_xpath_selectors,
-                "max_height": MAX_TOTAL_HEIGHT
-            })
-            await self.page.request_gc()
-
-            self.instock_data = await self.page.evaluate(INSTOCK_DATA_JS)
-            await self.page.request_gc()
-
-            self.content = await self.page.content()
-            await self.page.request_gc()
-            logger.debug(f"Scrape xPath element data in browser done in {time.time() - now:.2f}s")
-
-
-            # Bug 3 in Playwright screenshot handling
-            # Some bug where it gives the wrong screenshot size, but making a request with the clip set first seems to solve it
-            # JPEG is better here because the screenshots can be very very large
-
-            # Screenshots also travel via the ws:// (websocket) meaning that the binary data is base64 encoded
-            # which will significantly increase the IO size between the server and client, it's recommended to use the lowest
-            # acceptable screenshot quality here
+            # Wrap remaining operations in try/finally to ensure cleanup
             try:
-                # The actual screenshot - this always base64 and needs decoding! horrible! huge CPU usage
-                self.screenshot = await capture_full_page_async(page=self.page)
+                # Run Browser Steps here
+                if self.browser_steps_get_valid_steps():
+                    await self.iterate_browser_steps(start_url=url)
 
+                    await self.page.wait_for_timeout(extra_wait * 1000)
+
+                now = time.time()
+                # So we can find an element on the page where its selector was entered manually (maybe not xPath etc)
+                if current_include_filters is not None:
+                    await self.page.evaluate("var include_filters={}".format(json.dumps(current_include_filters)))
+                else:
+                    await self.page.evaluate("var include_filters=''")
+                await self.page.request_gc()
+
+                # request_gc before and after evaluate to free up memory
+                # @todo browsersteps etc
+                MAX_TOTAL_HEIGHT = int(os.getenv("SCREENSHOT_MAX_HEIGHT", SCREENSHOT_MAX_HEIGHT_DEFAULT))
+                self.xpath_data = await self.page.evaluate(XPATH_ELEMENT_JS, {
+                    "visualselector_xpath_selectors": visualselector_xpath_selectors,
+                    "max_height": MAX_TOTAL_HEIGHT
+                })
+                await self.page.request_gc()
+
+                self.instock_data = await self.page.evaluate(INSTOCK_DATA_JS)
+                await self.page.request_gc()
+
+                self.content = await self.page.content()
+                await self.page.request_gc()
+                logger.debug(f"Scrape xPath element data in browser done in {time.time() - now:.2f}s")
+
+
+                # Bug 3 in Playwright screenshot handling
+                # Some bug where it gives the wrong screenshot size, but making a request with the clip set first seems to solve it
+                # JPEG is better here because the screenshots can be very very large
+
+                # Screenshots also travel via the ws:// (websocket) meaning that the binary data is base64 encoded
+                # which will significantly increase the IO size between the server and client, it's recommended to use the lowest
+                # acceptable screenshot quality here
+                # The actual screenshot - this always base64 and needs decoding! horrible! huge CPU usage
+                self.screenshot = await capture_full_page_async(page=self.page, screenshot_format=self.screenshot_format)
+
+            except ScreenshotUnavailable:
+                # Re-raise screenshot unavailable exceptions
+                raise
             except Exception as e:
                 # It's likely the screenshot was too long/big and something crashed
                 raise ScreenshotUnavailable(url=url, status_code=self.status_code)
@@ -329,5 +413,22 @@ class fetcher(Fetcher):
                     pass
                 browser = None
 
+                # Force Python GC to release Playwright resources immediately
+                # Playwright objects can have circular references that delay cleanup
+                gc.collect()
+
+
+# Plugin registration for built-in fetcher
+class PlaywrightFetcherPlugin:
+    """Plugin class that registers the Playwright fetcher as a built-in plugin."""
+
+    def register_content_fetcher(self):
+        """Register the Playwright fetcher"""
+        return ('html_webdriver', fetcher)
+
+
+# Create module-level instance for plugin registration
+playwright_plugin = PlaywrightFetcherPlugin()
+
 
 

changedetectionio/content_fetchers/puppeteer.py

@@ -20,10 +20,10 @@ from changedetectionio.content_fetchers.exceptions import PageUnloadable, Non200
 # Screenshots also travel via the ws:// (websocket) meaning that the binary data is base64 encoded
 # which will significantly increase the IO size between the server and client, it's recommended to use the lowest
 # acceptable screenshot quality here
-async def capture_full_page(page):
+async def capture_full_page(page, screenshot_format='JPEG'):
     import os
     import time
-    from multiprocessing import Process, Pipe
+    import multiprocessing
 
     start = time.time()
 
@@ -41,11 +41,25 @@ async def capture_full_page(page):
     # which will significantly increase the IO size between the server and client, it's recommended to use the lowest
     # acceptable screenshot quality here
 
+    # Use PNG for better quality (no compression artifacts), JPEG for smaller size
+    screenshot_type = screenshot_format.lower() if screenshot_format else 'jpeg'
+    # PNG should use quality 100, JPEG uses configurable quality
+    screenshot_quality = 100 if screenshot_type == 'png' else int(os.getenv("SCREENSHOT_QUALITY", 72))
 
     step_size = SCREENSHOT_SIZE_STITCH_THRESHOLD # Something that will not cause the GPU to overflow when taking the screenshot
     screenshot_chunks = []
     y = 0
+    elements_locked = False
     if page_height > page.viewport['height']:
+        # Lock all element dimensions BEFORE screenshot to prevent CSS media queries from resizing
+        # capture_full_page() changes viewport height which triggers @media (min-height) rules
+        lock_elements_js_path = os.path.join(os.path.dirname(__file__), 'res', 'lock-elements-sizing.js')
+        with open(lock_elements_js_path, 'r') as f:
+            lock_elements_js = f.read()
+        await page.evaluate(lock_elements_js)
+        elements_locked = True
+        logger.debug("Element dimensions locked before screenshot capture")
+
         if page_height < step_size:
             step_size = page_height # Incase page is bigger than default viewport but smaller than proposed step size
         await page.setViewport({'width': page.viewport['width'], 'height': step_size})
@@ -60,18 +74,34 @@ async def capture_full_page(page):
             y
         )
 
-        screenshot_chunks.append(await page.screenshot(type_='jpeg',
-                                                       fullPage=False,
-                                                       quality=int(os.getenv("SCREENSHOT_QUALITY", 72))))
+        screenshot_kwargs = {
+            'type_': screenshot_type,
+            'fullPage': False
+        }
+        # PNG doesn't support quality parameter in Puppeteer
+        if screenshot_type == 'jpeg':
+            screenshot_kwargs['quality'] = screenshot_quality
+
+        screenshot_chunks.append(await page.screenshot(**screenshot_kwargs))
         y += step_size
 
     await page.setViewport({'width': original_viewport['width'], 'height': original_viewport['height']})
 
+    # Unlock element dimensions if they were locked
+    if elements_locked:
+        unlock_elements_js_path = os.path.join(os.path.dirname(__file__), 'res', 'unlock-elements-sizing.js')
+        with open(unlock_elements_js_path, 'r') as f:
+            unlock_elements_js = f.read()
+        await page.evaluate(unlock_elements_js)
+        logger.debug("Element dimensions unlocked after screenshot capture")
+
     if len(screenshot_chunks) > 1:
+        # Always use spawn for thread safety - consistent behavior in tests and production
         from changedetectionio.content_fetchers.screenshot_handler import stitch_images_worker
         logger.debug(f"Screenshot stitching {len(screenshot_chunks)} chunks together")
-        parent_conn, child_conn = Pipe()
-        p = Process(target=stitch_images_worker, args=(child_conn, screenshot_chunks, page_height, SCREENSHOT_MAX_TOTAL_HEIGHT))
+        ctx = multiprocessing.get_context('spawn')
+        parent_conn, child_conn = ctx.Pipe()
+        p = ctx.Process(target=stitch_images_worker, args=(child_conn, screenshot_chunks, page_height, SCREENSHOT_MAX_TOTAL_HEIGHT))
         p.start()
         screenshot = parent_conn.recv_bytes()
         p.join()
@@ -93,13 +123,27 @@ class fetcher(Fetcher):
     if os.getenv("PLAYWRIGHT_DRIVER_URL"):
         fetcher_description += " via '{}'".format(os.getenv("PLAYWRIGHT_DRIVER_URL"))
 
+    browser = None
     browser_type = ''
     command_executor = ''
-
     proxy = None
 
-    def __init__(self, proxy_override=None, custom_browser_connection_url=None):
-        super().__init__()
+    # Capability flags
+    supports_browser_steps = True
+    supports_screenshots = True
+    supports_xpath_element_data = True
+
+    @classmethod
+    def get_status_icon_data(cls):
+        """Return Chrome browser icon data for Puppeteer fetcher."""
+        return {
+            'filename': 'google-chrome-icon.png',
+            'alt': 'Using a Chrome browser',
+            'title': 'Using a Chrome browser'
+        }
+
+    def __init__(self, proxy_override=None, custom_browser_connection_url=None, **kwargs):
+        super().__init__(**kwargs)
 
         if custom_browser_connection_url:
             self.browser_connection_is_custom = True
@@ -128,21 +172,20 @@ class fetcher(Fetcher):
                 proxy_url += f"{parsed.hostname}{port}{parsed.path}{q}"
                 self.browser_connection_url += f"{r}--proxy-server={proxy_url}"
 
-    # def screenshot_step(self, step_n=''):
-    #     screenshot = self.page.screenshot(type='jpeg', full_page=True, quality=85)
-    #
-    #     if self.browser_steps_screenshot_path is not None:
-    #         destination = os.path.join(self.browser_steps_screenshot_path, 'step_{}.jpeg'.format(step_n))
-    #         logger.debug(f"Saving step screenshot to {destination}")
-    #         with open(destination, 'wb') as f:
-    #             f.write(screenshot)
-    #
-    # def save_step_html(self, step_n):
-    #     content = self.page.content()
-    #     destination = os.path.join(self.browser_steps_screenshot_path, 'step_{}.html'.format(step_n))
-    #     logger.debug(f"Saving step HTML to {destination}")
-    #     with open(destination, 'w') as f:
-    #         f.write(content)
+    async def quit(self, watch=None):
+        try:
+            await self.page.close()
+            del self.page
+        except Exception as e:
+            pass
+
+        try:
+            await self.browser.close()
+            del self.browser
+        except Exception as e:
+            pass
+
+        logger.info("Cleanup puppeteer complete.")
 
     async def fetch_page(self,
                          current_include_filters,
@@ -153,13 +196,15 @@ class fetcher(Fetcher):
                          request_body,
                          request_headers,
                          request_method,
+                         screenshot_format,
                          timeout,
                          url,
+                         watch_uuid
                          ):
         import re
         self.delete_browser_steps_screenshots()
 
-        n = int(os.getenv("WEBDRIVER_DELAY_BEFORE_CONTENT_READY", 5)) + self.render_extract_delay
+        n = int(os.getenv("WEBDRIVER_DELAY_BEFORE_CONTENT_READY", 12)) + self.render_extract_delay
         extra_wait = min(n, 15)
 
         logger.debug(f"Extra wait set to {extra_wait}s, requested was {n}s.")
@@ -170,9 +215,9 @@ class fetcher(Fetcher):
         # Connect directly using the specified browser_ws_endpoint
         # @todo timeout
         try:
-            browser = await pyppeteer_instance.connect(browserWSEndpoint=self.browser_connection_url,
-                                                       ignoreHTTPSErrors=True
-                                                       )
+            self.browser = await pyppeteer_instance.connect(browserWSEndpoint=self.browser_connection_url,
+                                                            ignoreHTTPSErrors=True
+                                                            )
         except websockets.exceptions.InvalidStatusCode as e:
             raise BrowserConnectError(msg=f"Error while trying to connect the browser, Code {e.status_code} (check your access, whitelist IP, password etc)")
         except websockets.exceptions.InvalidURI:
@@ -181,7 +226,7 @@ class fetcher(Fetcher):
             raise BrowserConnectError(msg=f"Error connecting to the browser - Exception '{str(e)}'")
 
         # more reliable is to just request a new page
-        self.page = await browser.newPage()
+        self.page = await self.browser.newPage()
         
         # Add console handler to capture console.log from favicon fetcher
         #self.page.on('console', lambda msg: logger.debug(f"Browser console [{msg.type}]: {msg.text}"))
@@ -196,7 +241,6 @@ class fetcher(Fetcher):
                     "height": int(match.group(2))
                 })
                 logger.debug(f"Puppeteer viewport size {self.page.viewport}")
-
         try:
             from pyppeteerstealth import inject_evasions_into_page
         except ImportError:
@@ -241,7 +285,12 @@ class fetcher(Fetcher):
         #            browsersteps_interface = steppable_browser_interface()
         #            browsersteps_interface.page = self.page
 
-        async def handle_frame_navigation(event):
+        # Enable Network domain to detect when first bytes arrive
+        await self.page._client.send('Network.enable')
+
+        # Now set up the frame navigation handlers
+        async def handle_frame_navigation(event=None):
+            # Wait n seconds after the frameStartedLoading, not from any frameStartedLoading/frameStartedNavigating
             logger.debug(f"Frame navigated: {event}")
             w = extra_wait - 2 if extra_wait > 4 else 2
             logger.debug(f"Waiting {w} seconds before calling Page.stopLoading...")
@@ -250,24 +299,35 @@ class fetcher(Fetcher):
             await self.page._client.send('Page.stopLoading')
             logger.debug("stopLoading command sent!")
 
-        self.page._client.on('Page.frameStartedNavigating', lambda event: asyncio.create_task(handle_frame_navigation(event)))
-        self.page._client.on('Page.frameStartedLoading', lambda event: asyncio.create_task(handle_frame_navigation(event)))
-        self.page._client.on('Page.frameStoppedLoading', lambda event: logger.debug(f"Frame stopped loading: {event}"))
+        async def setup_frame_handlers_on_first_response(event):
+            # Only trigger for the main document response
+            if event.get('type') == 'Document':
+                logger.debug("First response received, setting up frame handlers for forced page stop load.")
+                self.page._client.on('Page.frameStartedNavigating', lambda e: asyncio.create_task(handle_frame_navigation(e)))
+                self.page._client.on('Page.frameStartedLoading', lambda e: asyncio.create_task(handle_frame_navigation(e)))
+                self.page._client.on('Page.frameStoppedLoading', lambda e: logger.debug(f"Frame stopped loading: {e}"))
+                logger.debug("First response received, setting up frame handlers for forced page stop load DONE SETUP")
+                # De-register this listener - we only need it once
+                self.page._client.remove_listener('Network.responseReceived', setup_frame_handlers_on_first_response)
+
+        # Listen for first response to trigger frame handler setup
+        self.page._client.on('Network.responseReceived', setup_frame_handlers_on_first_response)
 
         response = None
         attempt=0
         while not response:
             logger.debug(f"Attempting page fetch {url} attempt {attempt}")
-            response = await self.page.goto(url)
+            asyncio.create_task(handle_frame_navigation())
+            response = await self.page.goto(url, timeout=0)
             await asyncio.sleep(1 + extra_wait)
+            await self.page._client.send('Page.stopLoading')
+
             if response:
                 break
             if not response:
                 logger.warning("Page did not fetch! trying again!")
             if response is None and attempt>=2:
-                await self.page.close()
-                await browser.close()
-                logger.warning(f"Content Fetcher > Response object was none (as in, the response from the browser was empty, not just the content) exiting attmpt {attempt}")
+                logger.warning(f"Content Fetcher > Response object was none (as in, the response from the browser was empty, not just the content) exiting attempt {attempt}")
                 raise EmptyReply(url=url, status_code=None)
             attempt+=1
 
@@ -279,8 +339,6 @@ class fetcher(Fetcher):
         except Exception as e:
             logger.warning("Got exception when running evaluate on custom JS code")
             logger.error(str(e))
-            await self.page.close()
-            await browser.close()
             # This can be ok, we will try to grab what we could retrieve
             raise PageUnloadable(url=url, status_code=None, message=str(e))
 
@@ -290,8 +348,6 @@ class fetcher(Fetcher):
             # https://github.com/dgtlmoon/changedetection.io/discussions/2122#discussioncomment-8241962
             logger.critical(f"Response from the browser/Playwright did not have a status_code! Response follows.")
             logger.critical(response)
-            await self.page.close()
-            await browser.close()
             raise PageUnloadable(url=url, status_code=None, message=str(e))
 
         if fetch_favicon:
@@ -301,7 +357,7 @@ class fetcher(Fetcher):
                 logger.error(f"Error fetching FavIcon info {str(e)}, continuing.")
 
         if self.status_code != 200 and not ignore_status_codes:
-            screenshot = await capture_full_page(page=self.page)
+            screenshot = await capture_full_page(page=self.page, screenshot_format=self.screenshot_format)
 
             raise Non200ErrorCodeReceived(url=url, status_code=self.status_code, screenshot=screenshot)
 
@@ -309,8 +365,6 @@ class fetcher(Fetcher):
 
         if not empty_pages_are_a_change and len(content.strip()) == 0:
             logger.error("Content Fetcher > Content was empty (empty_pages_are_a_change is False), closing browsers")
-            await self.page.close()
-            await browser.close()
             raise EmptyReply(url=url, status_code=response.status)
 
         # Run Browser Steps here
@@ -328,6 +382,12 @@ class fetcher(Fetcher):
             await self.page.evaluate(f"var include_filters=''")
 
         MAX_TOTAL_HEIGHT = int(os.getenv("SCREENSHOT_MAX_HEIGHT", SCREENSHOT_MAX_HEIGHT_DEFAULT))
+
+        self.content = await self.page.content
+
+        # Now take screenshot (scrolling may trigger layout changes, but measurements are already captured)
+        logger.debug(f"Screenshot format {self.screenshot_format}")
+        self.screenshot = await capture_full_page(page=self.page, screenshot_format=self.screenshot_format)
         self.xpath_data = await self.page.evaluate(XPATH_ELEMENT_JS, {
             "visualselector_xpath_selectors": visualselector_xpath_selectors,
             "max_height": MAX_TOTAL_HEIGHT
@@ -335,17 +395,10 @@ class fetcher(Fetcher):
         if not self.xpath_data:
             raise Exception(f"Content Fetcher > xPath scraper failed. Please report this URL so we can fix it :)")
 
+
         self.instock_data = await self.page.evaluate(INSTOCK_DATA_JS)
 
-        self.content = await self.page.content
-
-        self.screenshot = await capture_full_page(page=self.page)
-
         # It's good to log here in the case that the browser crashes on shutting down but we still get the data we need
-        logger.success(f"Fetching '{url}' complete, closing page")
-        await self.page.close()
-        logger.success(f"Fetching '{url}' complete, closing browser")
-        await browser.close()
         logger.success(f"Fetching '{url}' complete, exiting puppeteer fetch.")
 
     async def main(self, **kwargs):
@@ -360,8 +413,10 @@ class fetcher(Fetcher):
                   request_body=None,
                   request_headers=None,
                   request_method=None,
+                  screenshot_format=None,
                   timeout=None,
                   url=None,
+                  watch_uuid=None,
                   ):
 
         #@todo make update_worker async which could run any of these content_fetchers within memory and time constraints
@@ -378,9 +433,24 @@ class fetcher(Fetcher):
                 request_body=request_body,
                 request_headers=request_headers,
                 request_method=request_method,
+                screenshot_format=None,
                 timeout=timeout,
                 url=url,
+                watch_uuid=watch_uuid,
             ), timeout=max_time
             )
         except asyncio.TimeoutError:
             raise (BrowserFetchTimedOut(msg=f"Browser connected but was unable to process the page in {max_time} seconds."))
+
+
+# Plugin registration for built-in fetcher
+class PuppeteerFetcherPlugin:
+    """Plugin class that registers the Puppeteer fetcher as a built-in plugin."""
+
+    def register_content_fetcher(self):
+        """Register the Puppeteer fetcher"""
+        return ('html_webdriver', fetcher)
+
+
+# Create module-level instance for plugin registration
+puppeteer_plugin = PuppeteerFetcherPlugin()

changedetectionio/content_fetchers/requests.py

@@ -1,7 +1,9 @@
 from loguru import logger
 import hashlib
 import os
+import re
 import asyncio
+from functools import partial
 from changedetectionio import strtobool
 from changedetectionio.content_fetchers.exceptions import BrowserStepsInUnsupportedFetcher, EmptyReply, Non200ErrorCodeReceived
 from changedetectionio.content_fetchers.base import Fetcher
@@ -11,8 +13,8 @@ from changedetectionio.content_fetchers.base import Fetcher
 class fetcher(Fetcher):
     fetcher_description = "Basic fast Plaintext/HTTP Client"
 
-    def __init__(self, proxy_override=None, custom_browser_connection_url=None):
-        super().__init__()
+    def __init__(self, proxy_override=None, custom_browser_connection_url=None, **kwargs):
+        super().__init__(**kwargs)
         self.proxy_override = proxy_override
         # browser_connection_url is none because its always 'launched locally'
 
@@ -25,7 +27,9 @@ class fetcher(Fetcher):
             ignore_status_codes=False,
             current_include_filters=None,
             is_binary=False,
-            empty_pages_are_a_change=False):
+            empty_pages_are_a_change=False,
+            watch_uuid=None,
+            ):
         """Synchronous version of run - the original requests implementation"""
 
         import chardet
@@ -76,9 +80,22 @@ class fetcher(Fetcher):
         if not is_binary:
             # Don't run this for PDF (and requests identified as binary) takes a _long_ time
             if not r.headers.get('content-type') or not 'charset=' in r.headers.get('content-type'):
-                encoding = chardet.detect(r.content)['encoding']
-                if encoding:
-                    r.encoding = encoding
+                # For XML/RSS feeds, check the XML declaration for encoding attribute
+                # This is more reliable than chardet which can misdetect UTF-8 as MacRoman
+                content_type = r.headers.get('content-type', '').lower()
+                if 'xml' in content_type or 'rss' in content_type:
+                    # Look for <?xml version="1.0" encoding="UTF-8"?>
+                    xml_encoding_match = re.search(rb'<\?xml[^>]+encoding=["\']([^"\']+)["\']', r.content[:200])
+                    if xml_encoding_match:
+                        r.encoding = xml_encoding_match.group(1).decode('ascii')
+                    else:
+                        # Default to UTF-8 for XML if no encoding found
+                        r.encoding = 'utf-8'
+                else:
+                    # For other content types, use chardet
+                    encoding = chardet.detect(r.content)['encoding']
+                    if encoding:
+                        r.encoding = encoding
 
         self.headers = r.headers
 
@@ -104,6 +121,12 @@ class fetcher(Fetcher):
 
         self.raw_content = r.content
 
+        # If the content is an image, set it as screenshot for SSIM/visual comparison
+        content_type = r.headers.get('content-type', '').lower()
+        if 'image/' in content_type:
+            self.screenshot = r.content
+            logger.debug(f"Image content detected ({content_type}), set as screenshot for comparison")
+
     async def run(self,
                   fetch_favicon=True,
                   current_include_filters=None,
@@ -113,8 +136,10 @@ class fetcher(Fetcher):
                   request_body=None,
                   request_headers=None,
                   request_method=None,
+                  screenshot_format=None,
                   timeout=None,
                   url=None,
+                  watch_uuid=None,
                   ):
         """Async wrapper that runs the synchronous requests code in a thread pool"""
         
@@ -132,11 +157,12 @@ class fetcher(Fetcher):
                 ignore_status_codes=ignore_status_codes,
                 current_include_filters=current_include_filters,
                 is_binary=is_binary,
-                empty_pages_are_a_change=empty_pages_are_a_change
+                empty_pages_are_a_change=empty_pages_are_a_change,
+                watch_uuid=watch_uuid,
             )
         )
 
-    def quit(self, watch=None):
+    async def quit(self, watch=None):
 
         # In case they switched to `requests` fetcher from something else
         # Then the screenshot could be old, in any case, it's not used here.
@@ -149,3 +175,15 @@ class fetcher(Fetcher):
                 except Exception as e:
                     logger.warning(f"Failed to unlink screenshot: {screenshot} - {e}")
 
+
+# Plugin registration for built-in fetcher
+class RequestsFetcherPlugin:
+    """Plugin class that registers the requests fetcher as a built-in plugin."""
+
+    def register_content_fetcher(self):
+        """Register the requests fetcher"""
+        return ('html_requests', fetcher)
+
+
+# Create module-level instance for plugin registration
+requests_plugin = RequestsFetcherPlugin()

changedetectionio/content_fetchers/res/lock-elements-sizing.js

@@ -0,0 +1,93 @@
+/**
+ * Lock Element Dimensions for Screenshot Capture
+ *
+ * THE PROBLEM:
+ * When taking full-page screenshots of tall pages, Chrome/Puppeteer/Playwright need to:
+ * 1. Temporarily change the viewport height to a large value (e.g., 800px → 3809px)
+ * 2. Take screenshots in chunks while scrolling
+ * 3. Stitch the chunks together
+ *
+ * However, changing the viewport height triggers CSS media queries like:
+ *   @media (min-height: 860px) { .ad { height: 250px; } }
+ *
+ * This causes elements (especially ads) to resize during screenshot capture, creating a mismatch:
+ * - Screenshot shows element at NEW size (after media query triggered)
+ * - xpath element coordinates measured at OLD size (before viewport change)
+ * - Visual selector overlays don't align with screenshot
+ *
+ * EXAMPLE BUG:
+ * - Initial viewport: 1280x800, ad height: 138px, article position: 279px ✓
+ * - Viewport changes to 1280x3809 for screenshot
+ * - Media query triggers: ad expands to 250px
+ * - All content below shifts down by 112px (250-138)
+ * - Article now at position: 391px (279+112)
+ * - But xpath data says 279px → 112px mismatch! ✗
+ *
+ * THE SOLUTION:
+ * Before changing viewport, lock ALL element dimensions with !important inline styles.
+ * Inline styles with !important override media query CSS, preventing layout changes.
+ *
+ * WHAT THIS SCRIPT DOES:
+ * 1. Iterates through every element on the page
+ * 2. Captures current computed dimensions (width, height)
+ * 3. Sets inline styles with !important to freeze those dimensions
+ * 4. Disables ResizeObserver API (for JS-based resizing)
+ * 5. When viewport changes for screenshot, media queries can't resize anything
+ * 6. Layout remains consistent → xpath coordinates match screenshot ✓
+ *
+ * USAGE:
+ * Execute this script BEFORE calling capture_full_page() / screenshot functions.
+ * The page must be fully loaded and settled at its initial viewport size.
+ * No need to restore state afterward - page is closed after screenshot.
+ *
+ * PERFORMANCE:
+ * - Iterates all DOM elements (can be 1000s on complex pages)
+ * - Typically completes in 50-200ms
+ * - One-time cost before screenshot, well worth it for coordinate accuracy
+ *
+ * @see https://github.com/dgtlmoon/changedetection.io/issues/XXXX
+ */
+
+(() => {
+    // Store original styles in a global WeakMap for later restoration
+    window.__elementSizingRestore = new WeakMap();
+
+    // Lock ALL element dimensions to prevent media query layout changes
+    document.querySelectorAll('*').forEach(el => {
+        const computed = window.getComputedStyle(el);
+        const rect = el.getBoundingClientRect();
+
+        // Save original inline style values BEFORE locking
+        const properties = ['height', 'min-height', 'max-height', 'width', 'min-width', 'max-width'];
+        const originalStyles = {};
+        properties.forEach(prop => {
+            originalStyles[prop] = {
+                value: el.style.getPropertyValue(prop),
+                priority: el.style.getPropertyPriority(prop)
+            };
+        });
+        window.__elementSizingRestore.set(el, originalStyles);
+
+        // Lock dimensions with !important to override media queries
+        if (rect.height > 0) {
+            el.style.setProperty('height', computed.height, 'important');
+            el.style.setProperty('min-height', computed.height, 'important');
+            el.style.setProperty('max-height', computed.height, 'important');
+        }
+        if (rect.width > 0) {
+            el.style.setProperty('width', computed.width, 'important');
+            el.style.setProperty('min-width', computed.width, 'important');
+            el.style.setProperty('max-width', computed.width, 'important');
+        }
+    });
+
+    // Also disable ResizeObserver for JS-based resizing
+    window.ResizeObserver = class {
+        constructor() {}
+        observe() {}
+        unobserve() {}
+        disconnect() {}
+    };
+
+    console.log('✓ Element dimensions locked to prevent media query changes during screenshot');
+})();

changedetectionio/content_fetchers/res/unlock-elements-sizing.js

@@ -0,0 +1,52 @@
+/**
+ * Unlock Element Dimensions After Screenshot Capture
+ *
+ * This script removes the inline !important styles that were applied by lock-elements-sizing.js
+ * and restores elements to their original state using the WeakMap created during locking.
+ *
+ * USAGE:
+ * Execute this script AFTER completing screenshot capture and restoring the viewport.
+ * This allows the page to return to its normal responsive behavior.
+ *
+ * WHAT THIS SCRIPT DOES:
+ * 1. Iterates through every element that was locked
+ * 2. Reads original style values from the global WeakMap
+ * 3. Restores original inline styles (or removes them if they weren't set originally)
+ * 4. Cleans up the WeakMap
+ *
+ * @see lock-elements-sizing.js for the locking mechanism
+ */
+
+(() => {
+    // Check if the restore map exists
+    if (!window.__elementSizingRestore) {
+        console.log('⚠ Element sizing restore map not found - elements may not have been locked');
+        return;
+    }
+
+    // Restore all locked dimension styles to their original state
+    document.querySelectorAll('*').forEach(el => {
+        const originalStyles = window.__elementSizingRestore.get(el);
+
+        if (originalStyles) {
+            const properties = ['height', 'min-height', 'max-height', 'width', 'min-width', 'max-width'];
+
+            properties.forEach(prop => {
+                const original = originalStyles[prop];
+
+                if (original.value) {
+                    // Restore original value with original priority
+                    el.style.setProperty(prop, original.value, original.priority || '');
+                } else {
+                    // Was not set originally, so remove it
+                    el.style.removeProperty(prop);
+                }
+            });
+        }
+    });
+
+    // Clean up the global WeakMap
+    delete window.__elementSizingRestore;
+
+    console.log('✓ Element dimensions unlocked - page restored to original state');
+})();

changedetectionio/content_fetchers/screenshot_handler.py

@@ -8,14 +8,90 @@ from loguru import logger
 
 from changedetectionio.content_fetchers import SCREENSHOT_MAX_HEIGHT_DEFAULT, SCREENSHOT_DEFAULT_QUALITY
 
+# Cache font to avoid loading on every stitch
+_cached_font = None
+
+def _get_caption_font():
+    """Get or create cached font for caption text."""
+    global _cached_font
+    if _cached_font is None:
+        from PIL import ImageFont
+        try:
+            _cached_font = ImageFont.truetype("arial.ttf", 35)
+        except IOError:
+            _cached_font = ImageFont.load_default()
+    return _cached_font
+
+
+def stitch_images_inline(chunks_bytes, original_page_height, capture_height):
+    """
+    Stitch image chunks together inline (no multiprocessing).
+    Optimized for small number of chunks (2-3) to avoid process creation overhead.
+
+    Args:
+        chunks_bytes: List of JPEG image bytes
+        original_page_height: Original page height in pixels
+        capture_height: Maximum capture height
+
+    Returns:
+        bytes: Stitched JPEG image
+    """
+    import os
+    import io
+    from PIL import Image, ImageDraw
+
+    # Load images from byte chunks
+    images = [Image.open(io.BytesIO(b)) for b in chunks_bytes]
+    total_height = sum(im.height for im in images)
+    max_width = max(im.width for im in images)
+
+    # Create stitched image
+    stitched = Image.new('RGB', (max_width, total_height))
+    y_offset = 0
+    for im in images:
+        stitched.paste(im, (0, y_offset))
+        y_offset += im.height
+        im.close()  # Close immediately after pasting
+
+    # Draw caption only if page was trimmed
+    if original_page_height > capture_height:
+        draw = ImageDraw.Draw(stitched)
+        caption_text = f"WARNING: Screenshot was {original_page_height}px but trimmed to {capture_height}px because it was too long"
+        padding = 10
+        font = _get_caption_font()
+
+        bbox = draw.textbbox((0, 0), caption_text, font=font)
+        text_width = bbox[2] - bbox[0]
+        text_height = bbox[3] - bbox[1]
+
+        # Draw white background rectangle
+        draw.rectangle([(0, 0), (max_width, text_height + 2 * padding)], fill=(255, 255, 255))
+
+        # Draw text centered
+        text_x = (max_width - text_width) // 2
+        draw.text((text_x, padding), caption_text, font=font, fill=(255, 0, 0))
+
+    # Encode to JPEG
+    output = io.BytesIO()
+    stitched.save(output, format="JPEG", quality=int(os.getenv("SCREENSHOT_QUALITY", SCREENSHOT_DEFAULT_QUALITY)), optimize=True)
+    result = output.getvalue()
+
+    # Cleanup
+    stitched.close()
+
+    return result
+
 
 def stitch_images_worker(pipe_conn, chunks_bytes, original_page_height, capture_height):
+    """
+    Stitch image chunks together in a separate process.
+    Used for large number of chunks (4+) to avoid blocking the main event loop.
+    """
     import os
     import io
     from PIL import Image, ImageDraw, ImageFont
 
     try:
-
         # Load images from byte chunks
         images = [Image.open(io.BytesIO(b)) for b in chunks_bytes]
         total_height = sum(im.height for im in images)
@@ -27,21 +103,17 @@ def stitch_images_worker(pipe_conn, chunks_bytes, original_page_height, capture_
         for im in images:
             stitched.paste(im, (0, y_offset))
             y_offset += im.height
+            im.close()  # Close immediately after pasting
 
-        # Draw caption on top (overlaid, not extending canvas)
-        draw = ImageDraw.Draw(stitched)
-
+        # Draw caption only if page was trimmed
         if original_page_height > capture_height:
+            draw = ImageDraw.Draw(stitched)
             caption_text = f"WARNING: Screenshot was {original_page_height}px but trimmed to {capture_height}px because it was too long"
             padding = 10
-            font_size = 35
-            font_color = (255, 0, 0)
-            background_color = (255, 255, 255)
 
-
-            # Try to load a proper font
+            # Try to load font
             try:
-                font = ImageFont.truetype("arial.ttf", font_size)
+                font = ImageFont.truetype("arial.ttf", 35)
             except IOError:
                 font = ImageFont.load_default()
 
@@ -49,19 +121,16 @@ def stitch_images_worker(pipe_conn, chunks_bytes, original_page_height, capture_
             text_width = bbox[2] - bbox[0]
             text_height = bbox[3] - bbox[1]
 
-            # Draw white rectangle background behind text
-            rect_top = 0
-            rect_bottom = text_height + 2 * padding
-            draw.rectangle([(0, rect_top), (max_width, rect_bottom)], fill=background_color)
+            # Draw white background rectangle
+            draw.rectangle([(0, 0), (max_width, text_height + 2 * padding)], fill=(255, 255, 255))
 
-            # Draw text centered horizontally, 10px padding from top of the rectangle
+            # Draw text centered
             text_x = (max_width - text_width) // 2
-            text_y = padding
-            draw.text((text_x, text_y), caption_text, font=font, fill=font_color)
+            draw.text((text_x, padding), caption_text, font=font, fill=(255, 0, 0))
 
-        # Encode and send image
+        # Encode and send image with optimization
         output = io.BytesIO()
-        stitched.save(output, format="JPEG", quality=int(os.getenv("SCREENSHOT_QUALITY", SCREENSHOT_DEFAULT_QUALITY)))
+        stitched.save(output, format="JPEG", quality=int(os.getenv("SCREENSHOT_QUALITY", SCREENSHOT_DEFAULT_QUALITY)), optimize=True)
         pipe_conn.send_bytes(output.getvalue())
 
         stitched.close()

changedetectionio/content_fetchers/webdriver_selenium.py

@@ -14,8 +14,22 @@ class fetcher(Fetcher):
     proxy = None
     proxy_url = None
 
-    def __init__(self, proxy_override=None, custom_browser_connection_url=None):
-        super().__init__()
+    # Capability flags
+    supports_browser_steps = False
+    supports_screenshots = True
+    supports_xpath_element_data = True
+
+    @classmethod
+    def get_status_icon_data(cls):
+        """Return Chrome browser icon data for WebDriver fetcher."""
+        return {
+            'filename': 'google-chrome-icon.png',
+            'alt': 'Using a Chrome browser',
+            'title': 'Using a Chrome browser'
+        }
+
+    def __init__(self, proxy_override=None, custom_browser_connection_url=None, **kwargs):
+        super().__init__(**kwargs)
         from urllib.parse import urlparse
         from selenium.webdriver.common.proxy import Proxy
 
@@ -55,8 +69,10 @@ class fetcher(Fetcher):
                   request_body=None,
                   request_headers=None,
                   request_method=None,
+                  screenshot_format=None,
                   timeout=None,
                   url=None,
+                  watch_uuid=None,
                   ):
 
         import asyncio
@@ -131,7 +147,34 @@ class fetcher(Fetcher):
                 time.sleep(int(os.getenv("WEBDRIVER_DELAY_BEFORE_CONTENT_READY", 5)) + self.render_extract_delay)
                 self.content = driver.page_source
                 self.headers = {}
-                self.screenshot = driver.get_screenshot_as_png()
+
+                # Selenium always captures as PNG, convert to JPEG if needed
+                screenshot_png = driver.get_screenshot_as_png()
+
+                # Convert to JPEG if requested (for smaller file size)
+                if self.screenshot_format and self.screenshot_format.upper() == 'JPEG':
+                    from PIL import Image
+                    import io
+                    img = Image.open(io.BytesIO(screenshot_png))
+                    # Convert to RGB if needed (JPEG doesn't support transparency)
+                    # Always convert non-RGB modes to RGB to ensure JPEG compatibility
+                    if img.mode in ('RGBA', 'LA', 'P', 'PA'):
+                        # Handle transparency by compositing onto white background
+                        if img.mode == 'P':
+                            img = img.convert('RGBA')
+                        background = Image.new('RGB', img.size, (255, 255, 255))
+                        if img.mode in ('RGBA', 'LA', 'PA'):
+                            background.paste(img, mask=img.split()[-1])  # Use alpha channel as mask
+                        img = background
+                    elif img.mode != 'RGB':
+                        # For other modes, direct conversion
+                        img = img.convert('RGB')
+                    jpeg_buffer = io.BytesIO()
+                    img.save(jpeg_buffer, format='JPEG', quality=int(os.getenv("SCREENSHOT_QUALITY", 72)))
+                    self.screenshot = jpeg_buffer.getvalue()
+                    img.close()
+                else:
+                    self.screenshot = screenshot_png
             except Exception as e:
                 driver.quit()
                 raise e
@@ -141,3 +184,16 @@ class fetcher(Fetcher):
         # Run the selenium operations in a thread pool to avoid blocking the event loop
         loop = asyncio.get_event_loop()
         await loop.run_in_executor(None, _run_sync)
+
+
+# Plugin registration for built-in fetcher
+class WebDriverSeleniumFetcherPlugin:
+    """Plugin class that registers the WebDriver Selenium fetcher as a built-in plugin."""
+
+    def register_content_fetcher(self):
+        """Register the WebDriver Selenium fetcher"""
+        return ('html_webdriver', fetcher)
+
+
+# Create module-level instance for plugin registration
+webdriver_selenium_plugin = WebDriverSeleniumFetcherPlugin()

changedetectionio/custom_queue.py

@@ -57,14 +57,15 @@ class SignalPriorityQueue(queue.PriorityQueue):
     def put(self, item, block=True, timeout=None):
         # Call the parent's put method first
         super().put(item, block, timeout)
-        
+
         # After putting the item in the queue, check if it has a UUID and emit signal
         if hasattr(item, 'item') and isinstance(item.item, dict) and 'uuid' in item.item:
             uuid = item.item['uuid']
             # Get the signal and send it if it exists
             watch_check_update = signal('watch_check_update')
             if watch_check_update:
-                # Send the watch_uuid parameter
+                # NOTE: This would block other workers from .put/.get while this signal sends
+                # Signal handlers may iterate the queue/datastore while holding locks
                 watch_check_update.send(watch_uuid=uuid)
         
         # Send queue_length signal with current queue size
@@ -312,14 +313,15 @@ class AsyncSignalPriorityQueue(asyncio.PriorityQueue):
     async def put(self, item):
         # Call the parent's put method first
         await super().put(item)
-        
+
         # After putting the item in the queue, check if it has a UUID and emit signal
         if hasattr(item, 'item') and isinstance(item.item, dict) and 'uuid' in item.item:
             uuid = item.item['uuid']
             # Get the signal and send it if it exists
             watch_check_update = signal('watch_check_update')
             if watch_check_update:
-                # Send the watch_uuid parameter
+                # NOTE: This would block other workers from .put/.get while this signal sends
+                # Signal handlers may iterate the queue/datastore while holding locks
                 watch_check_update.send(watch_uuid=uuid)
         
         # Send queue_length signal with current queue size

changedetectionio/diff.py

@@ -1,130 +0,0 @@
-import difflib
-from typing import List, Iterator, Union
-
-# https://github.com/dgtlmoon/changedetection.io/issues/821#issuecomment-1241837050
-#HTML_ADDED_STYLE = "background-color: #d2f7c2; color: #255d00;"
-#HTML_CHANGED_INTO_STYLE = "background-color: #dafbe1; color: #116329;"
-#HTML_CHANGED_STYLE = "background-color: #ffd6cc; color: #7a2000;"
-#HTML_REMOVED_STYLE = "background-color: #ffebe9; color: #82071e;"
-
-# @todo - In the future we can make this configurable
-HTML_ADDED_STYLE = "background-color: #eaf2c2; color: #406619"
-HTML_REMOVED_STYLE = "background-color: #fadad7; color: #b30000"
-HTML_CHANGED_STYLE = HTML_REMOVED_STYLE
-HTML_CHANGED_INTO_STYLE = HTML_ADDED_STYLE
-
-
-# These get set to html or telegram type or discord compatible or whatever in handler.py
-# Something that cant get escaped to HTML by accident
-REMOVED_PLACEMARKER_OPEN = '@removed_PLACEMARKER_OPEN'
-REMOVED_PLACEMARKER_CLOSED = '@removed_PLACEMARKER_CLOSED'
-
-ADDED_PLACEMARKER_OPEN = '@added_PLACEMARKER_OPEN'
-ADDED_PLACEMARKER_CLOSED = '@added_PLACEMARKER_CLOSED'
-
-CHANGED_PLACEMARKER_OPEN = '@changed_PLACEMARKER_OPEN'
-CHANGED_PLACEMARKER_CLOSED = '@changed_PLACEMARKER_CLOSED'
-
-CHANGED_INTO_PLACEMARKER_OPEN = '@changed_into_PLACEMARKER_OPEN'
-CHANGED_INTO_PLACEMARKER_CLOSED = '@changed_into_PLACEMARKER_CLOSED'
-
-def same_slicer(lst: List[str], start: int, end: int) -> List[str]:
-    """Return a slice of the list, or a single element if start == end."""
-    return lst[start:end] if start != end else [lst[start]]
-
-def customSequenceMatcher(
-    before: List[str],
-    after: List[str],
-    include_equal: bool = False,
-    include_removed: bool = True,
-    include_added: bool = True,
-    include_replaced: bool = True,
-    include_change_type_prefix: bool = True
-) -> Iterator[List[str]]:
-    """
-    Compare two sequences and yield differences based on specified parameters.
-
-    Args:
-        before (List[str]): Original sequence
-        after (List[str]): Modified sequence
-        include_equal (bool): Include unchanged parts
-        include_removed (bool): Include removed parts
-        include_added (bool): Include added parts
-        include_replaced (bool): Include replaced parts
-        include_change_type_prefix (bool): Add prefixes to indicate change types
-    Yields:
-        List[str]: Differences between sequences
-    """
-    cruncher = difflib.SequenceMatcher(isjunk=lambda x: x in " \t", a=before, b=after)
-
-
-
-    for tag, alo, ahi, blo, bhi in cruncher.get_opcodes():
-        if include_equal and tag == 'equal':
-            yield before[alo:ahi]
-        elif include_removed and tag == 'delete':
-            if include_change_type_prefix:
-                yield [f'{REMOVED_PLACEMARKER_OPEN}{line}{REMOVED_PLACEMARKER_CLOSED}' for line in same_slicer(before, alo, ahi)]
-            else:
-                yield same_slicer(before, alo, ahi)
-        elif include_replaced and tag == 'replace':
-            if include_change_type_prefix:
-                yield [f'{CHANGED_PLACEMARKER_OPEN}{line}{CHANGED_PLACEMARKER_CLOSED}' for line in same_slicer(before, alo, ahi)] + \
-                      [f'{CHANGED_INTO_PLACEMARKER_OPEN}{line}{CHANGED_INTO_PLACEMARKER_CLOSED}' for line in same_slicer(after, blo, bhi)]
-            else:
-                yield same_slicer(before, alo, ahi) + same_slicer(after, blo, bhi)
-        elif include_added and tag == 'insert':
-            if include_change_type_prefix:
-                yield [f'{ADDED_PLACEMARKER_OPEN}{line}{ADDED_PLACEMARKER_CLOSED}' for line in same_slicer(after, blo, bhi)]
-            else:
-                yield same_slicer(after, blo, bhi)
-
-
-def render_diff(
-    previous_version_file_contents: str,
-    newest_version_file_contents: str,
-    include_equal: bool = False,
-    include_removed: bool = True,
-    include_added: bool = True,
-    include_replaced: bool = True,
-    line_feed_sep: str = "\n",
-    include_change_type_prefix: bool = True,
-    patch_format: bool = False
-) -> str:
-    """
-    Render the difference between two file contents.
-
-    Args:
-        previous_version_file_contents (str): Original file contents
-        newest_version_file_contents (str): Modified file contents
-        include_equal (bool): Include unchanged parts
-        include_removed (bool): Include removed parts
-        include_added (bool): Include added parts
-        include_replaced (bool): Include replaced parts
-        line_feed_sep (str): Separator for lines in output
-        include_change_type_prefix (bool): Add prefixes to indicate change types
-        patch_format (bool): Use patch format for output
-    Returns:
-        str: Rendered difference
-    """
-    newest_lines = [line.rstrip() for line in newest_version_file_contents.splitlines()]
-    previous_lines = [line.rstrip() for line in previous_version_file_contents.splitlines()] if previous_version_file_contents else []
-
-    if patch_format:
-        patch = difflib.unified_diff(previous_lines, newest_lines)
-        return line_feed_sep.join(patch)
-
-    rendered_diff = customSequenceMatcher(
-        before=previous_lines,
-        after=newest_lines,
-        include_equal=include_equal,
-        include_removed=include_removed,
-        include_added=include_added,
-        include_replaced=include_replaced,
-        include_change_type_prefix=include_change_type_prefix
-    )
-
-    def flatten(lst: List[Union[str, List[str]]]) -> str:
-        return line_feed_sep.join(flatten(x) if isinstance(x, list) else x for x in lst)
-
-    return flatten(rendered_diff)

changedetectionio/diff/__init__.py

@@ -0,0 +1,479 @@
+"""
+Diff rendering module for change detection.
+
+This module provides functions for rendering differences between text content,
+with support for various output formats and tokenization strategies.
+"""
+
+import difflib
+from typing import List, Iterator, Union
+from loguru import logger
+import diff_match_patch as dmp_module
+import re
+import time
+
+from .tokenizers import TOKENIZERS, tokenize_words_and_html
+
+# Remember! gmail, outlook etc dont support <style> must be inline.
+# Gmail: strips <ins> and <del> tags entirely.
+# This is for the WHOLE line background style
+REMOVED_STYLE = "background-color: #fadad7; color: #b30000;"
+ADDED_STYLE = "background-color: #eaf2c2; color: #406619;"
+HTML_REMOVED_STYLE = REMOVED_STYLE  # Export alias for handler.py
+HTML_ADDED_STYLE = ADDED_STYLE      # Export alias for handler.py
+
+# Darker backgrounds for nested highlighting (changed parts within lines)
+REMOVED_INNER_STYLE = "background-color: #ff867a; color: #111;"
+ADDED_INNER_STYLE = "background-color: #b2e841; color: #444;"
+HTML_CHANGED_STYLE = REMOVED_STYLE
+HTML_CHANGED_INTO_STYLE = ADDED_STYLE
+
+# Placemarker constants - these get replaced by apply_service_tweaks() in handler.py
+# Something that cant get escaped to HTML by accident
+REMOVED_PLACEMARKER_OPEN = '@removed_PLACEMARKER_OPEN'
+REMOVED_PLACEMARKER_CLOSED = '@removed_PLACEMARKER_CLOSED'
+
+ADDED_PLACEMARKER_OPEN = '@added_PLACEMARKER_OPEN'
+ADDED_PLACEMARKER_CLOSED = '@added_PLACEMARKER_CLOSED'
+
+CHANGED_PLACEMARKER_OPEN = '@changed_PLACEMARKER_OPEN'
+CHANGED_PLACEMARKER_CLOSED = '@changed_PLACEMARKER_CLOSED'
+
+CHANGED_INTO_PLACEMARKER_OPEN = '@changed_into_PLACEMARKER_OPEN'
+CHANGED_INTO_PLACEMARKER_CLOSED = '@changed_into_PLACEMARKER_CLOSED'
+
+# Compiled regex patterns for performance
+WHITESPACE_NORMALIZE_RE = re.compile(r'\s+')
+
+
+def render_inline_word_diff(before_line: str, after_line: str, ignore_junk: bool = False, markdown_style: str = None, tokenizer: str = 'words_and_html') -> tuple[str, bool]:
+    """
+    Render word-level differences between two lines inline using diff-match-patch library.
+
+    Args:
+        before_line: Original line text
+        after_line: Modified line text
+        ignore_junk: Ignore whitespace-only changes
+        markdown_style: Unused (kept for backwards compatibility)
+        tokenizer: Name of tokenizer to use from TOKENIZERS registry (default: 'words_and_html')
+
+    Returns:
+        tuple[str, bool]: (diff output with inline word-level highlighting, has_changes flag)
+    """
+    # Normalize whitespace if ignore_junk is enabled
+    if ignore_junk:
+        # Normalize whitespace: replace multiple spaces/tabs with single space
+        before_normalized = WHITESPACE_NORMALIZE_RE.sub(' ', before_line)
+        after_normalized = WHITESPACE_NORMALIZE_RE.sub(' ', after_line)
+    else:
+        before_normalized = before_line
+        after_normalized = after_line
+
+    # Use diff-match-patch with word-level tokenization
+    # Strategy: Use linesToChars to treat words as atomic units
+    dmp = dmp_module.diff_match_patch()
+
+    # Get the tokenizer function from the registry
+    tokenizer_func = TOKENIZERS.get(tokenizer, tokenize_words_and_html)
+
+    # Tokenize both lines using the selected tokenizer
+    before_tokens = tokenizer_func(before_normalized)
+    after_tokens = tokenizer_func(after_normalized or ' ')
+
+    # Create mappings for linesToChars (using it for word-mode)
+    # Join tokens with newline so each "line" is a token
+    before_text = '\n'.join(before_tokens)
+    after_text = '\n'.join(after_tokens)
+
+    # Use linesToChars for word-mode diffing
+    lines_result = dmp.diff_linesToChars(before_text, after_text)
+    line_before, line_after, line_array = lines_result
+
+    # Perform diff on the encoded strings
+    diffs = dmp.diff_main(line_before, line_after, False)
+
+    # Convert back to original text
+    dmp.diff_charsToLines(diffs, line_array)
+
+    # Remove the newlines we added for tokenization
+    diffs = [(op, text.replace('\n', '')) for op, text in diffs]
+
+    # DON'T apply semantic cleanup here - it would break token boundaries
+    # (e.g., "63" -> "66" would become "6" + "3" vs "6" + "6")
+    # We want to preserve the tokenizer's word boundaries
+
+    # Check if there are any changes
+    has_changes = any(op != 0 for op, _ in diffs)
+
+    if ignore_junk and not has_changes:
+        return after_line, False
+
+    # Check if the whole line is replaced (no unchanged content)
+    whole_line_replaced = not any(op == 0 and text.strip() for op, text in diffs)
+
+    # Build the output using placemarkers
+    # When whole line is replaced, wrap entire removed content once and entire added content once
+    if whole_line_replaced:
+        removed_tokens = []
+        added_tokens = []
+
+        for op, text in diffs:
+            if op == 0:  # Equal (e.g., whitespace tokens in common positions)
+                # Include in both removed and added to preserve spacing
+                removed_tokens.append(text)
+                added_tokens.append(text)
+            elif op == -1:  # Deletion
+                removed_tokens.append(text)
+            elif op == 1:  # Insertion
+                added_tokens.append(text)
+
+        # Join all tokens and wrap the entire string once for removed, once for added
+        result_parts = []
+
+        if removed_tokens:
+            removed_full = ''.join(removed_tokens).rstrip()
+            trailing_removed = ''.join(removed_tokens)[len(removed_full):] if len(''.join(removed_tokens)) > len(removed_full) else ''
+            result_parts.append(f'{CHANGED_PLACEMARKER_OPEN}{removed_full}{CHANGED_PLACEMARKER_CLOSED}{trailing_removed}')
+
+        if added_tokens:
+            if result_parts:  # Add newline between removed and added
+                result_parts.append('\n')
+            added_full = ''.join(added_tokens).rstrip()
+            trailing_added = ''.join(added_tokens)[len(added_full):] if len(''.join(added_tokens)) > len(added_full) else ''
+            result_parts.append(f'{CHANGED_INTO_PLACEMARKER_OPEN}{added_full}{CHANGED_INTO_PLACEMARKER_CLOSED}{trailing_added}')
+
+        return ''.join(result_parts), has_changes
+    else:
+        # Inline changes within the line
+        result_parts = []
+        for op, text in diffs:
+            if op == 0:  # Equal
+                result_parts.append(text)
+            elif op == 1:  # Insertion
+                # Don't wrap empty content (e.g., whitespace-only tokens after rstrip)
+                content = text.rstrip()
+                trailing = text[len(content):] if len(text) > len(content) else ''
+                if content:
+                    result_parts.append(f'{ADDED_PLACEMARKER_OPEN}{content}{ADDED_PLACEMARKER_CLOSED}{trailing}')
+                else:
+                    result_parts.append(trailing)
+            elif op == -1:  # Deletion
+                # Don't wrap empty content (e.g., whitespace-only tokens after rstrip)
+                content = text.rstrip()
+                trailing = text[len(content):] if len(text) > len(content) else ''
+                if content:
+                    result_parts.append(f'{REMOVED_PLACEMARKER_OPEN}{content}{REMOVED_PLACEMARKER_CLOSED}{trailing}')
+                else:
+                    result_parts.append(trailing)
+
+        return ''.join(result_parts), has_changes
+
+
+def render_nested_line_diff(before_line: str, after_line: str, ignore_junk: bool = False, tokenizer: str = 'words_and_html') -> tuple[str, str, bool]:
+    """
+    Render line-level differences with nested highlighting for changed parts.
+
+    Returns two separate lines:
+    - Before line: light red background with dark red on removed parts
+    - After line: light green background with dark green on added parts
+
+    Args:
+        before_line: Original line text
+        after_line: Modified line text
+        ignore_junk: Ignore whitespace-only changes
+        tokenizer: Name of tokenizer to use from TOKENIZERS registry
+
+    Returns:
+        tuple[str, str, bool]: (before_with_highlights, after_with_highlights, has_changes)
+    """
+    # Normalize whitespace if ignore_junk is enabled
+    if ignore_junk:
+        before_normalized = WHITESPACE_NORMALIZE_RE.sub(' ', before_line)
+        after_normalized = WHITESPACE_NORMALIZE_RE.sub(' ', after_line)
+    else:
+        before_normalized = before_line
+        after_normalized = after_line
+
+    # Use diff-match-patch with word-level tokenization
+    dmp = dmp_module.diff_match_patch()
+
+    # Get the tokenizer function from the registry
+    tokenizer_func = TOKENIZERS.get(tokenizer, tokenize_words_and_html)
+
+    # Tokenize both lines
+    before_tokens = tokenizer_func(before_normalized)
+    after_tokens = tokenizer_func(after_normalized or ' ')
+
+    # Create mappings for linesToChars
+    before_text = '\n'.join(before_tokens)
+    after_text = '\n'.join(after_tokens)
+
+    # Use linesToChars for word-mode diffing
+    lines_result = dmp.diff_linesToChars(before_text, after_text)
+    line_before, line_after, line_array = lines_result
+
+    # Perform diff on the encoded strings
+    diffs = dmp.diff_main(line_before, line_after, False)
+
+    # Convert back to original text
+    dmp.diff_charsToLines(diffs, line_array)
+
+    # Remove the newlines we added for tokenization
+    diffs = [(op, text.replace('\n', '')) for op, text in diffs]
+
+    # DON'T apply semantic cleanup here - it would break token boundaries
+    # (e.g., "63" -> "66" would become "6" + "3" vs "6" + "6")
+    # We want to preserve the tokenizer's word boundaries
+
+    # Check if there are any changes
+    has_changes = any(op != 0 for op, _ in diffs)
+
+    if ignore_junk and not has_changes:
+        return before_line, after_line, False
+
+    # Build the before line (with nested highlighting for removed parts)
+    before_parts = []
+    for op, text in diffs:
+        if op == 0:  # Equal
+            before_parts.append(text)
+        elif op == -1:  # Deletion (in before)
+            before_parts.append(f'<span style="{REMOVED_INNER_STYLE}">{text}</span>')
+        # Skip insertions (op == 1) for the before line
+
+    before_content = ''.join(before_parts)
+
+    # Build the after line (with nested highlighting for added parts)
+    after_parts = []
+    for op, text in diffs:
+        if op == 0:  # Equal
+            after_parts.append(text)
+        elif op == 1:  # Insertion (in after)
+            after_parts.append(f'<span style="{ADDED_INNER_STYLE}">{text}</span>')
+        # Skip deletions (op == -1) for the after line
+
+    after_content = ''.join(after_parts)
+
+    # Wrap content with placemarkers (inner HTML highlighting is preserved)
+    before_html = f'{CHANGED_PLACEMARKER_OPEN}{before_content}{CHANGED_PLACEMARKER_CLOSED}'
+    after_html = f'{CHANGED_INTO_PLACEMARKER_OPEN}{after_content}{CHANGED_INTO_PLACEMARKER_CLOSED}'
+
+    return before_html, after_html, has_changes
+
+
+def same_slicer(lst: List[str], start: int, end: int) -> List[str]:
+    """Return a slice of the list, or a single element if start == end."""
+    return lst[start:end] if start != end else [lst[start]]
+
+def customSequenceMatcher(
+    before: List[str],
+    after: List[str],
+    include_equal: bool = False,
+    include_removed: bool = True,
+    include_added: bool = True,
+    include_replaced: bool = True,
+    include_change_type_prefix: bool = True,
+    word_diff: bool = False,
+    context_lines: int = 0,
+    case_insensitive: bool = False,
+    ignore_junk: bool = False,
+    tokenizer: str = 'words_and_html'
+) -> Iterator[List[str]]:
+    """
+    Compare two sequences and yield differences based on specified parameters.
+
+    Args:
+        before (List[str]): Original sequence
+        after (List[str]): Modified sequence
+        include_equal (bool): Include unchanged parts
+        include_removed (bool): Include removed parts
+        include_added (bool): Include added parts
+        include_replaced (bool): Include replaced parts
+        include_change_type_prefix (bool): Add prefixes to indicate change types
+        word_diff (bool): Use word-level diffing for replaced lines (controls inline rendering)
+        context_lines (int): Number of unchanged lines to show around changes (like grep -C)
+        case_insensitive (bool): Perform case-insensitive comparison
+        ignore_junk (bool): Ignore whitespace-only changes
+        tokenizer (str): Name of tokenizer to use from TOKENIZERS registry (default: 'words_and_html')
+
+    Yields:
+        List[str]: Differences between sequences
+    """
+    # Prepare sequences for comparison (lowercase if case-insensitive, normalize whitespace if ignore_junk)
+    def prepare_line(line):
+        if case_insensitive:
+            line = line.lower()
+        if ignore_junk:
+            # Normalize whitespace: replace multiple spaces/tabs with single space
+            line = WHITESPACE_NORMALIZE_RE.sub(' ', line)
+        return line
+
+    compare_before = [prepare_line(line) for line in before]
+    compare_after = [prepare_line(line) for line in after]
+
+    cruncher = difflib.SequenceMatcher(isjunk=lambda x: x in " \t", a=compare_before, b=compare_after)
+
+    # When context_lines is set and include_equal is False, we need to track which equal lines to include
+    if context_lines > 0 and not include_equal:
+        opcodes = list(cruncher.get_opcodes())
+        # Mark equal ranges that should be included based on context
+        included_equal_ranges = set()
+
+        for i, (tag, alo, ahi, blo, bhi) in enumerate(opcodes):
+            if tag != 'equal':
+                # Include context lines before this change
+                for j in range(max(0, i - 1), i):
+                    if opcodes[j][0] == 'equal':
+                        prev_alo, prev_ahi = opcodes[j][1], opcodes[j][2]
+                        # Include last N lines of the previous equal block
+                        context_start = max(prev_alo, prev_ahi - context_lines)
+                        for line_num in range(context_start, prev_ahi):
+                            included_equal_ranges.add(line_num)
+
+                # Include context lines after this change
+                for j in range(i + 1, min(len(opcodes), i + 2)):
+                    if opcodes[j][0] == 'equal':
+                        next_alo, next_ahi = opcodes[j][1], opcodes[j][2]
+                        # Include first N lines of the next equal block
+                        context_end = min(next_ahi, next_alo + context_lines)
+                        for line_num in range(next_alo, context_end):
+                            included_equal_ranges.add(line_num)
+
+    # Remember! gmail, outlook etc dont support <style> must be inline.
+    # Gmail: strips <ins> and <del> tags entirely.
+    for tag, alo, ahi, blo, bhi in cruncher.get_opcodes():
+        if tag == 'equal':
+            if include_equal:
+                yield before[alo:ahi]
+            elif context_lines > 0:
+                # Only include equal lines that are in the context range
+                context_lines_to_include = [before[i] for i in range(alo, ahi) if i in included_equal_ranges]
+                if context_lines_to_include:
+                    yield context_lines_to_include
+        elif include_removed and tag == 'delete':
+            if include_change_type_prefix:
+                yield [f'{REMOVED_PLACEMARKER_OPEN}{line}{REMOVED_PLACEMARKER_CLOSED}' for line in same_slicer(before, alo, ahi)]
+            else:
+                yield same_slicer(before, alo, ahi)
+        elif include_replaced and tag == 'replace':
+            before_lines = same_slicer(before, alo, ahi)
+            after_lines = same_slicer(after, blo, bhi)
+
+            # Use inline word-level diff for single line replacements when word_diff is enabled
+            if word_diff and len(before_lines) == 1 and len(after_lines) == 1:
+                inline_diff, has_changes = render_inline_word_diff(before_lines[0], after_lines[0], ignore_junk=ignore_junk, tokenizer=tokenizer)
+                # Check if there are any actual changes (not just whitespace when ignore_junk is enabled)
+                if ignore_junk and not has_changes:
+                    # No real changes, skip this line
+                    continue
+                yield [inline_diff]
+            else:
+                # Fall back to line-level diff for multi-line changes
+                if include_change_type_prefix:
+                    yield [f'{CHANGED_PLACEMARKER_OPEN}{line}{CHANGED_PLACEMARKER_CLOSED}' for line in before_lines] + \
+                          [f'{CHANGED_INTO_PLACEMARKER_OPEN}{line}{CHANGED_INTO_PLACEMARKER_CLOSED}' for line in after_lines]
+                else:
+                    yield before_lines + after_lines
+        elif include_added and tag == 'insert':
+            if include_change_type_prefix:
+                yield [f'{ADDED_PLACEMARKER_OPEN}{line}{ADDED_PLACEMARKER_CLOSED}' for line in same_slicer(after, blo, bhi)]
+            else:
+                yield same_slicer(after, blo, bhi)
+
+def render_diff(
+    previous_version_file_contents: str,
+    newest_version_file_contents: str,
+    include_equal: bool = False,
+    include_removed: bool = True,
+    include_added: bool = True,
+    include_replaced: bool = True,
+    include_change_type_prefix: bool = True,
+    patch_format: bool = False,
+    word_diff: bool = True,
+    context_lines: int = 0,
+    case_insensitive: bool = False,
+    ignore_junk: bool = False,
+    tokenizer: str = 'words_and_html'
+) -> str:
+    """
+    Render the difference between two file contents.
+
+    Args:
+        previous_version_file_contents (str): Original file contents
+        newest_version_file_contents (str): Modified file contents
+        include_equal (bool): Include unchanged parts
+        include_removed (bool): Include removed parts
+        include_added (bool): Include added parts
+        include_replaced (bool): Include replaced parts
+        include_change_type_prefix (bool): Add prefixes to indicate change types
+        patch_format (bool): Use patch format for output
+        word_diff (bool): Use word-level diffing for replaced lines (controls inline rendering)
+        context_lines (int): Number of unchanged lines to show around changes (like grep -C)
+        case_insensitive (bool): Perform case-insensitive comparison, By default the test_json_diff/process.py is case sensitive, so this follows same logic
+        ignore_junk (bool): Ignore whitespace-only changes
+        tokenizer (str): Name of tokenizer to use from TOKENIZERS registry (default: 'words_and_html')
+
+    Returns:
+        str: Rendered difference
+    """
+    newest_lines = [line.rstrip() for line in newest_version_file_contents.splitlines()]
+    previous_lines = [line.rstrip() for line in previous_version_file_contents.splitlines()] if previous_version_file_contents else []
+    now = time.time()
+    logger.debug(
+        f"diff options: "
+        f"include_equal={include_equal}, "
+        f"include_removed={include_removed}, "
+        f"include_added={include_added}, "
+        f"include_replaced={include_replaced}, "
+        f"include_change_type_prefix={include_change_type_prefix}, "
+        f"patch_format={patch_format}, "
+        f"word_diff={word_diff}, "
+        f"context_lines={context_lines}, "
+        f"case_insensitive={case_insensitive}, "
+        f"ignore_junk={ignore_junk}, "
+        f"tokenizer={tokenizer}"
+    )
+    if patch_format:
+        patch = difflib.unified_diff(previous_lines, newest_lines)
+        return "\n".join(patch)
+
+    rendered_diff = customSequenceMatcher(
+        before=previous_lines,
+        after=newest_lines,
+        include_equal=include_equal,
+        include_removed=include_removed,
+        include_added=include_added,
+        include_replaced=include_replaced,
+        include_change_type_prefix=include_change_type_prefix,
+        word_diff=word_diff,
+        context_lines=context_lines,
+        case_insensitive=case_insensitive,
+        ignore_junk=ignore_junk,
+        tokenizer=tokenizer
+    )
+
+    def flatten(lst: List[Union[str, List[str]]]) -> str:
+        result = []
+        for x in lst:
+            if isinstance(x, list):
+                result.extend(x)
+            else:
+                result.append(x)
+        return "\n".join(result)
+
+    logger.debug(f"Diff generated in {time.time() - now:.2f}s")
+
+    return flatten(rendered_diff)
+
+
+# Export main public API
+__all__ = [
+    'render_diff',
+    'customSequenceMatcher',
+    'render_inline_word_diff',
+    'render_nested_line_diff',
+    'TOKENIZERS',
+    'REMOVED_STYLE',
+    'ADDED_STYLE',
+    'REMOVED_INNER_STYLE',
+    'ADDED_INNER_STYLE',
+]

changedetectionio/diff/tokenizers/__init__.py

@@ -0,0 +1,23 @@
+"""
+Tokenizers for diff operations.
+
+This module provides various tokenization strategies for use with the diff system.
+New tokenizers can be easily added by:
+1. Creating a new module in this directory
+2. Importing and registering it in the TOKENIZERS dictionary below
+"""
+
+from .natural_text import tokenize_words
+from .words_and_html import tokenize_words_and_html
+
+# Tokenizer registry - maps tokenizer names to functions
+TOKENIZERS = {
+    'words': tokenize_words,
+    'words_and_html': tokenize_words_and_html,
+}
+
+__all__ = [
+    'tokenize_words',
+    'tokenize_words_and_html',
+    'TOKENIZERS',
+]

changedetectionio/diff/tokenizers/natural_text.py

@@ -0,0 +1,44 @@
+"""
+Simple word tokenizer using whitespace boundaries.
+
+This is a simpler tokenizer that treats all whitespace as token boundaries
+without special handling for HTML tags or other markup.
+"""
+
+from typing import List
+
+
+def tokenize_words(text: str) -> List[str]:
+    """
+    Split text into words using simple whitespace boundaries.
+
+    This is a simpler tokenizer that treats all whitespace as token boundaries
+    without special handling for HTML tags.
+
+    Args:
+        text: Input text to tokenize
+
+    Returns:
+        List of tokens (words and whitespace)
+
+    Examples:
+        >>> tokenize_words("Hello world")
+        ['Hello', ' ', 'world']
+        >>> tokenize_words("one  two")
+        ['one', ' ', ' ', 'two']
+    """
+    tokens = []
+    current = ''
+
+    for char in text:
+        if char.isspace():
+            if current:
+                tokens.append(current)
+                current = ''
+            tokens.append(char)
+        else:
+            current += char
+
+    if current:
+        tokens.append(current)
+    return tokens

changedetectionio/diff/tokenizers/words_and_html.py

@@ -0,0 +1,61 @@
+"""
+Tokenizer that preserves HTML tags as atomic units while splitting on whitespace.
+
+This tokenizer is specifically designed for HTML content where:
+- HTML tags should remain intact (e.g., '<p>', '<a href="...">')
+- Whitespace tokens are preserved for accurate diff reconstruction
+- Words are split on whitespace boundaries
+"""
+
+from typing import List
+
+
+def tokenize_words_and_html(text: str) -> List[str]:
+    """
+    Split text into words and boundaries (spaces, HTML tags).
+
+    This tokenizer preserves HTML tags as atomic units while splitting on whitespace.
+    Useful for content that contains HTML markup.
+
+    Args:
+        text: Input text to tokenize
+
+    Returns:
+        List of tokens (words, spaces, HTML tags)
+
+    Examples:
+        >>> tokenize_words_and_html("<p>Hello world</p>")
+        ['<p>', 'Hello', ' ', 'world', '</p>']
+        >>> tokenize_words_and_html("<a href='test.com'>link</a>")
+        ['<a href=\\'test.com\\'>', 'link', '</a>']
+    """
+    tokens = []
+    current = ''
+    in_tag = False
+
+    for char in text:
+        if char == '<':
+            # Start of HTML tag
+            if current:
+                tokens.append(current)
+                current = ''
+            current = '<'
+            in_tag = True
+        elif char == '>' and in_tag:
+            # End of HTML tag
+            current += '>'
+            tokens.append(current)
+            current = ''
+            in_tag = False
+        elif char.isspace() and not in_tag:
+            # Space outside of tag
+            if current:
+                tokens.append(current)
+                current = ''
+            tokens.append(char)
+        else:
+            current += char
+
+    if current:
+        tokens.append(current)
+    return tokens

changedetectionio/favicon_utils.py

@@ -0,0 +1,43 @@
+"""
+Favicon utilities for changedetection.io
+Handles favicon MIME type detection with caching
+"""
+
+from functools import lru_cache
+
+
+@lru_cache(maxsize=1000)
+def get_favicon_mime_type(filepath):
+    """
+    Detect MIME type of favicon by reading file content using puremagic.
+    Results are cached to avoid repeatedly reading the same files.
+
+    Args:
+        filepath: Full path to the favicon file
+
+    Returns:
+        MIME type string (e.g., 'image/png')
+    """
+    mime = None
+
+    try:
+        import puremagic
+        with open(filepath, 'rb') as f:
+            content_bytes = f.read(200)  # Read first 200 bytes
+
+        detections = puremagic.magic_string(content_bytes)
+        if detections:
+            mime = detections[0].mime_type
+    except Exception:
+        pass
+
+    # Fallback to mimetypes if puremagic fails
+    if not mime:
+        import mimetypes
+        mime, _ = mimetypes.guess_type(filepath)
+
+    # Final fallback based on extension
+    if not mime:
+        mime = 'image/x-icon' if filepath.endswith('.ico') else 'image/png'
+
+    return mime

changedetectionio/flask_app.py

@@ -9,6 +9,7 @@ import threading
 import time
 import timeago
 from blinker import signal
+from pathlib import Path
 
 from changedetectionio.strtobool import strtobool
 from threading import Event
@@ -23,10 +24,10 @@ from flask import (
     render_template,
     request,
     send_from_directory,
+    session,
     url_for,
 )
 from flask_compress import Compress as FlaskCompress
-from flask_login import current_user
 from flask_restful import abort, Api
 from flask_cors import CORS
 
@@ -34,13 +35,18 @@ from flask_cors import CORS
 # Make this a global singleton to avoid multiple signal objects
 watch_check_update = signal('watch_check_update', doc='Signal sent when a watch check is completed')
 from flask_wtf import CSRFProtect
+from flask_babel import Babel, gettext, get_locale
 from loguru import logger
 
 from changedetectionio import __version__
 from changedetectionio import queuedWatchMetaData
-from changedetectionio.api import Watch, WatchHistory, WatchSingleHistory, CreateWatch, Import, SystemInfo, Tag, Tags, Notifications, WatchFavicon
+from changedetectionio.api import Watch, WatchHistory, WatchSingleHistory, WatchHistoryDiff, CreateWatch, Import, SystemInfo, Tag, Tags, Notifications, WatchFavicon
 from changedetectionio.api.Search import Search
 from .time_handler import is_within_schedule
+from changedetectionio.languages import get_available_languages, get_language_codes, get_flag_for_locale, get_timeago_locale
+from changedetectionio.favicon_utils import get_favicon_mime_type
+
+IN_PYTEST = "pytest" in sys.modules or "PYTEST_CURRENT_TEST" in os.environ
 
 datastore = None
 
@@ -51,7 +57,7 @@ extra_stylesheets = []
 # Use bulletproof janus-based queues for sync/async reliability  
 update_q = RecheckPriorityQueue()
 notification_q = NotificationQueue()
-MAX_QUEUE_SIZE = 2000
+MAX_QUEUE_SIZE = 5000
 
 app = Flask(__name__,
             static_url_path="",
@@ -65,7 +71,15 @@ socketio_server = None
 CORS(app)
 
 # Super handy for compressing large BrowserSteps responses and others
-FlaskCompress(app)
+# Flask-Compress handles HTTP compression, Socket.IO compression disabled to prevent memory leak
+compress = FlaskCompress()
+app.config['COMPRESS_MIN_SIZE'] = 2096
+app.config['COMPRESS_MIMETYPES'] = ['text/html', 'text/css', 'text/javascript', 'application/json', 'application/javascript', 'image/svg+xml']
+# Use gzip only - smaller memory footprint than zstd/brotli (4-8KB vs 200-500KB contexts)
+app.config['COMPRESS_ALGORITHM'] = ['gzip']
+compress.init_app(app)
+app.config['TEMPLATES_AUTO_RELOAD'] = False
+
 
 # Stop browser caching of assets
 app.config['SEND_FILE_MAX_AGE_DEFAULT'] = 0
@@ -76,11 +90,43 @@ app.config['NEW_VERSION_AVAILABLE'] = False
 if os.getenv('FLASK_SERVER_NAME'):
     app.config['SERVER_NAME'] = os.getenv('FLASK_SERVER_NAME')
 
+# Babel/i18n configuration
+app.config['BABEL_TRANSLATION_DIRECTORIES'] = str(Path(__file__).parent / 'translations')
+app.config['BABEL_DEFAULT_LOCALE'] = 'en_GB'
+
+# Session configuration
+# NOTE: Flask session (for locale, etc.) is separate from Flask-Login's remember-me cookie
+# - Flask session stores data like session['locale'] in a signed cookie
+# - Flask-Login's remember=True creates a separate authentication cookie
+# - Setting PERMANENT_SESSION_LIFETIME controls how long the Flask session cookie lasts
+from datetime import timedelta
+app.config['PERMANENT_SESSION_LIFETIME'] = timedelta(days=3650)  # ~10 years (effectively unlimited)
+
 #app.config["EXPLAIN_TEMPLATE_LOADING"] = True
 
-# Disables caching of the templates
-app.config['TEMPLATES_AUTO_RELOAD'] = True
+
 app.jinja_env.add_extension('jinja2.ext.loopcontrols')
+
+# Configure Jinja2 to search for templates in plugin directories
+def _configure_plugin_templates():
+    """Configure Jinja2 loader to include plugin template directories."""
+    from jinja2 import ChoiceLoader, FileSystemLoader
+    from changedetectionio.pluggy_interface import get_plugin_template_paths
+
+    # Get plugin template paths
+    plugin_template_paths = get_plugin_template_paths()
+
+    if plugin_template_paths:
+        # Create a ChoiceLoader that searches app templates first, then plugin templates
+        loaders = [app.jinja_loader]  # Keep the default app loader first
+        for path in plugin_template_paths:
+            loaders.append(FileSystemLoader(path))
+
+        app.jinja_loader = ChoiceLoader(loaders)
+        logger.info(f"Configured Jinja2 to search {len(plugin_template_paths)} plugin template directories")
+
+# Configure plugin templates (called after plugins are loaded)
+_configure_plugin_templates()
 csrf = CSRFProtect()
 csrf.init_app(app)
 notification_debug_log=[]
@@ -101,12 +147,12 @@ def init_app_secret(datastore_path):
     path = os.path.join(datastore_path, "secret.txt")
 
     try:
-        with open(path, "r") as f:
+        with open(path, "r", encoding='utf-8') as f:
             secret = f.read()
 
     except FileNotFoundError:
         import secrets
-        with open(path, "w") as f:
+        with open(path, "w", encoding='utf-8') as f:
             secret = secrets.token_hex(32)
             f.write(secret)
 
@@ -183,16 +229,26 @@ def _get_worker_status_info():
 def _jinja2_filter_datetime(watch_obj, format="%Y-%m-%d %H:%M:%S"):
 
     if watch_obj['last_checked'] == 0:
-        return 'Not yet'
+        return gettext('Not yet')
 
-    return timeago.format(int(watch_obj['last_checked']), time.time())
+    locale = get_timeago_locale(str(get_locale()))
+    try:
+        return timeago.format(int(watch_obj['last_checked']), time.time(), locale)
+    except:
+        # Fallback to English if locale not supported by timeago
+        return timeago.format(int(watch_obj['last_checked']), time.time(), 'en')
 
 @app.template_filter('format_timestamp_timeago')
 def _jinja2_filter_datetimestamp(timestamp, format="%Y-%m-%d %H:%M:%S"):
     if not timestamp:
-        return 'Not yet'
+        return gettext('Not yet')
 
-    return timeago.format(int(timestamp), time.time())
+    locale = get_timeago_locale(str(get_locale()))
+    try:
+        return timeago.format(int(timestamp), time.time(), locale)
+    except:
+        # Fallback to English if locale not supported by timeago
+        return timeago.format(int(timestamp), time.time(), 'en')
 
 
 @app.template_filter('pagination_slice')
@@ -206,10 +262,78 @@ def _jinja2_filter_pagination_slice(arr, skip):
 @app.template_filter('format_seconds_ago')
 def _jinja2_filter_seconds_precise(timestamp):
     if timestamp == False:
-        return 'Not yet'
+        return gettext('Not yet')
 
     return format(int(time.time()-timestamp), ',d')
 
+@app.template_filter('fetcher_status_icons')
+def _jinja2_filter_fetcher_status_icons(fetcher_name):
+    """Get status icon HTML for a given fetcher.
+
+    This filter checks both built-in fetchers and plugin fetchers for status icons.
+
+    Args:
+        fetcher_name: The fetcher name (e.g., 'html_webdriver', 'html_js_zyte')
+
+    Returns:
+        str: HTML string containing status icon elements
+    """
+    from changedetectionio import content_fetchers
+    from changedetectionio.pluggy_interface import collect_fetcher_status_icons
+    from markupsafe import Markup
+    from flask import url_for
+
+    icon_data = None
+
+    # First check if it's a plugin fetcher (plugins have priority)
+    plugin_icon_data = collect_fetcher_status_icons(fetcher_name)
+    if plugin_icon_data:
+        icon_data = plugin_icon_data
+    # Check if it's a built-in fetcher
+    elif hasattr(content_fetchers, fetcher_name):
+        fetcher_class = getattr(content_fetchers, fetcher_name)
+        if hasattr(fetcher_class, 'get_status_icon_data'):
+            icon_data = fetcher_class.get_status_icon_data()
+
+    # Build HTML from icon data
+    if icon_data and isinstance(icon_data, dict):
+        # Use 'group' from icon_data if specified, otherwise default to 'images'
+        group = icon_data.get('group', 'images')
+
+        # Try to use url_for, but fall back to manual URL building if endpoint not registered yet
+        try:
+            icon_url = url_for('static_content', group=group, filename=icon_data['filename'])
+        except:
+            # Fallback: build URL manually respecting APPLICATION_ROOT
+            from flask import request
+            app_root = request.script_root if hasattr(request, 'script_root') else ''
+            icon_url = f"{app_root}/static/{group}/{icon_data['filename']}"
+
+        style_attr = f' style="{icon_data["style"]}"' if icon_data.get('style') else ''
+        html = f'<img class="status-icon" src="{icon_url}" alt="{icon_data["alt"]}" title="{icon_data["title"]}"{style_attr}>'
+        return Markup(html)
+
+    return ''
+
+@app.template_filter('sanitize_tag_class')
+def _jinja2_filter_sanitize_tag_class(tag_title):
+    """Sanitize a tag title to create a valid CSS class name.
+    Removes all non-alphanumeric characters and converts to lowercase.
+
+    Args:
+        tag_title: The tag title string
+
+    Returns:
+        str: A sanitized string suitable for use as a CSS class name
+    """
+    import re
+    # Remove all non-alphanumeric characters and convert to lowercase
+    sanitized = re.sub(r'[^a-zA-Z0-9]', '', tag_title).lower()
+    # Ensure it starts with a letter (CSS requirement)
+    if sanitized and not sanitized[0].isalpha():
+        sanitized = 'tag' + sanitized
+    return sanitized if sanitized else 'tag'
+
 # Import login_optionally_required from auth_decorator
 from changedetectionio.auth_decorator import login_optionally_required
 
@@ -264,6 +388,16 @@ def changedetection_app(config=None, datastore_o=None):
     global datastore, socketio_server
     datastore = datastore_o
 
+    # Set datastore reference in notification queue for all_muted checking
+    notification_q.set_datastore(datastore)
+
+    # Import and create a wrapper for is_safe_url that has access to app
+    from changedetectionio.is_safe_url import is_safe_url as _is_safe_url
+
+    def is_safe_url(target):
+        """Wrapper for is_safe_url that passes the app instance"""
+        return _is_safe_url(target, app)
+
     # so far just for read-only via tests, but this will be moved eventually to be the main source
     # (instead of the global var)
     app.config['DATASTORE'] = datastore_o
@@ -274,7 +408,45 @@ def changedetection_app(config=None, datastore_o=None):
     login_manager = flask_login.LoginManager(app)
     login_manager.login_view = 'login'
     app.secret_key = init_app_secret(config['datastore_path'])
-    
+
+    # Initialize Flask-Babel for i18n support
+    available_languages = get_available_languages()
+    language_codes = get_language_codes()
+
+    def get_locale():
+        # Locale aliases: map browser language codes to translation directory names
+        # This handles cases where browsers send standard codes (e.g., zh-TW)
+        # but our translations use more specific codes (e.g., zh_Hant_TW)
+        locale_aliases = {
+            'zh-TW': 'zh_Hant_TW',  # Traditional Chinese: browser sends zh-TW, we use zh_Hant_TW
+            'zh_TW': 'zh_Hant_TW',  # Also handle underscore variant
+        }
+
+        # 1. Try to get locale from session (user explicitly selected)
+        if 'locale' in session:
+            return session['locale']
+
+        # 2. Fall back to Accept-Language header
+        # Get the best match from browser's Accept-Language header
+        browser_locale = request.accept_languages.best_match(language_codes + list(locale_aliases.keys()))
+
+        # 3. Check if we need to map the browser locale to our internal locale
+        if browser_locale in locale_aliases:
+            return locale_aliases[browser_locale]
+
+        return browser_locale
+
+    # Initialize Babel with locale selector
+    babel = Babel(app, locale_selector=get_locale)
+
+    # Make i18n functions available to templates
+    app.jinja_env.globals.update(
+        _=gettext,
+        get_locale=get_locale,
+        get_flag_for_locale=get_flag_for_locale,
+        available_languages=available_languages
+    )
+
     # Set up a request hook to check authentication for all routes
     @app.before_request
     def check_authentication():
@@ -285,6 +457,12 @@ def changedetection_app(config=None, datastore_o=None):
             if request.endpoint and request.endpoint == 'static_content' and request.view_args:
                 # Handled by static_content handler
                 return None
+            # Permitted - static flag icons need to load on login page
+            elif request.endpoint and request.endpoint == 'static_flags':
+                return None
+            # Permitted - language selection should work on login page
+            elif request.endpoint and request.endpoint == 'set_language':
+                return None
             # Permitted
             elif request.endpoint and 'login' in request.endpoint:
                 return None
@@ -307,6 +485,9 @@ def changedetection_app(config=None, datastore_o=None):
                 return login_manager.unauthorized()
 
 
+    watch_api.add_resource(WatchHistoryDiff,
+                           '/api/v1/watch/<string:uuid>/difference/<string:from_timestamp>/<string:to_timestamp>',
+                           resource_class_kwargs={'datastore': datastore})
     watch_api.add_resource(WatchSingleHistory,
                            '/api/v1/watch/<string:uuid>/history/<string:timestamp>',
                            resource_class_kwargs={'datastore': datastore, 'update_q': update_q})
@@ -350,25 +531,76 @@ def changedetection_app(config=None, datastore_o=None):
 
     @login_manager.unauthorized_handler
     def unauthorized_handler():
-        flash("You must be logged in, please log in.", 'error')
-        return redirect(url_for('login', next=url_for('watchlist.index')))
+        # Pass the current request path so users are redirected back after login
+        return redirect(url_for('login', redirect=request.path))
 
     @app.route('/logout')
     def logout():
         flask_login.logout_user()
+
+        # Check if there's a redirect parameter to return to after re-login
+        redirect_url = request.args.get('redirect')
+
+        # If redirect is provided and safe, pass it to login page
+        if redirect_url and is_safe_url(redirect_url):
+            return redirect(url_for('login', redirect=redirect_url))
+
+        # Otherwise just go to watchlist
+        return redirect(url_for('watchlist.index'))
+
+    @app.route('/set-language/<locale>')
+    def set_language(locale):
+        """Set the user's preferred language in the session"""
+        if not request.cookies:
+            logger.error("Cannot set language without session cookie")
+            flash("Cannot set language without session cookie", 'error')
+            return redirect(url_for('watchlist.index'))
+
+        # Validate the locale against available languages
+        if locale in language_codes:
+            # Make session permanent so language preference persists across browser sessions
+            # NOTE: This is the Flask session cookie (separate from Flask-Login's remember-me auth cookie)
+            session.permanent = True
+            session['locale'] = locale
+
+            # CRITICAL: Flask-Babel caches the locale in the request context (ctx.babel_locale)
+            # We must refresh to clear this cache so the new locale takes effect immediately
+            # This is especially important for tests where multiple requests happen rapidly
+            from flask_babel import refresh
+            refresh()
+        else:
+            logger.error(f"Invalid locale {locale}, available: {language_codes}")
+
+        # Check if there's a redirect parameter to return to the same page
+        redirect_url = request.args.get('redirect')
+
+        # If redirect is provided and safe, use it
+        if redirect_url and is_safe_url(redirect_url):
+            return redirect(redirect_url)
+
+        # Otherwise redirect to watchlist
         return redirect(url_for('watchlist.index'))
 
     # https://github.com/pallets/flask/blob/93dd1709d05a1cf0e886df6223377bdab3b077fb/examples/tutorial/flaskr/__init__.py#L39
     # You can divide up the stuff like this
     @app.route('/login', methods=['GET', 'POST'])
     def login():
+        # Extract and validate the redirect parameter
+        redirect_url = request.args.get('redirect') or request.form.get('redirect')
+
+        # Validate the redirect URL - default to watchlist if invalid
+        if redirect_url and is_safe_url(redirect_url):
+            validated_redirect = redirect_url
+        else:
+            validated_redirect = url_for('watchlist.index')
 
         if request.method == 'GET':
             if flask_login.current_user.is_authenticated:
-                flash("Already logged in")
-                return redirect(url_for("watchlist.index"))
-
-            output = render_template("login.html")
+                # Already logged in - redirect immediately to the target
+                flash(gettext("Already logged in"))
+                return redirect(validated_redirect)
+            flash(gettext("You must be logged in, please log in."), 'error')
+            output = render_template("login.html", redirect_url=validated_redirect)
             return output
 
         user = User()
@@ -378,23 +610,13 @@ def changedetection_app(config=None, datastore_o=None):
 
         if (user.check_password(password)):
             flask_login.login_user(user, remember=True)
-
-            # For now there's nothing else interesting here other than the index/list page
-            # It's more reliable and safe to ignore the 'next' redirect
-            # When we used...
-            # next = request.args.get('next')
-            # return redirect(next or url_for('watchlist.index'))
-            # We would sometimes get login loop errors on sites hosted in sub-paths
-
-            # note for the future:
-            #            if not is_safe_valid_url(next):
-            #                return flask.abort(400)
-            return redirect(url_for('watchlist.index'))
+            # Redirect to the validated URL after successful login
+            return redirect(validated_redirect)
 
         else:
-            flash('Incorrect password', 'error')
+            flash(gettext('Incorrect password'), 'error')
 
-        return redirect(url_for('login'))
+        return redirect(url_for('login', redirect=redirect_url if redirect_url else None))
 
     @app.before_request
     def before_request_handle_cookie_x_settings():
@@ -404,6 +626,40 @@ def changedetection_app(config=None, datastore_o=None):
             app.config['SESSION_COOKIE_PATH'] = request.headers['X-Forwarded-Prefix']
         return None
 
+    @app.route("/static/flags/<path:flag_path>", methods=['GET'])
+    def static_flags(flag_path):
+        """Handle flag icon files with subdirectories"""
+        from flask import make_response
+        import re
+
+        # flag_path comes in as "1x1/de.svg" or "4x3/de.svg"
+        if re.match(r'^(1x1|4x3)/[a-z0-9-]+\.svg$', flag_path.lower()):
+            # Reconstruct the path safely with additional validation
+            parts = flag_path.lower().split('/')
+            if len(parts) != 2:
+                abort(404)
+
+            subdir = parts[0]
+            svg_file = parts[1]
+
+            # Extra validation: ensure subdir is exactly 1x1 or 4x3
+            if subdir not in ['1x1', '4x3']:
+                abort(404)
+
+            # Extra validation: ensure svg_file only contains safe characters
+            if not re.match(r'^[a-z0-9-]+\.svg$', svg_file):
+                abort(404)
+
+            try:
+                response = make_response(send_from_directory(f"static/flags/{subdir}", svg_file))
+                response.headers['Content-type'] = 'image/svg+xml'
+                response.headers['Cache-Control'] = 'max-age=86400, public'  # Cache for 24 hours
+                return response
+            except FileNotFoundError:
+                abort(404)
+        else:
+            abort(404)
+
     @app.route("/static/<string:group>/<string:filename>", methods=['GET'])
     def static_content(group, filename):
         from flask import make_response
@@ -443,16 +699,9 @@ def changedetection_app(config=None, datastore_o=None):
 
             favicon_filename = watch.get_favicon_filename()
             if favicon_filename:
-                try:
-                    import magic
-                    mime = magic.from_file(
-                        os.path.join(watch.watch_data_dir, favicon_filename),
-                        mime=True
-                    )
-                except ImportError:
-                    # Fallback, no python-magic
-                    import mimetypes
-                    mime, encoding = mimetypes.guess_type(favicon_filename)
+                # Use cached MIME type detection
+                filepath = os.path.join(watch.watch_data_dir, favicon_filename)
+                mime = get_favicon_mime_type(filepath)
 
                 response = make_response(send_from_directory(watch.watch_data_dir, favicon_filename))
                 response.headers['Content-type'] = mime
@@ -488,6 +737,31 @@ def changedetection_app(config=None, datastore_o=None):
             except FileNotFoundError:
                 abort(404)
 
+        # Handle plugin group specially
+        if group == 'plugin':
+            # Serve files from plugin static directories
+            from changedetectionio.pluggy_interface import plugin_manager
+            import os as os_check
+
+            for plugin_name, plugin_obj in plugin_manager.list_name_plugin():
+                if hasattr(plugin_obj, 'plugin_static_path'):
+                    try:
+                        static_path = plugin_obj.plugin_static_path()
+                        if static_path and os_check.path.isdir(static_path):
+                            # Check if file exists in plugin's static directory
+                            plugin_file_path = os_check.path.join(static_path, filename)
+                            if os_check.path.isfile(plugin_file_path):
+                                # Found the file in a plugin
+                                response = make_response(send_from_directory(static_path, filename))
+                                response.headers['Cache-Control'] = 'max-age=3600, public'  # Cache for 1 hour
+                                return response
+                    except Exception as e:
+                        logger.debug(f"Error checking plugin {plugin_name} for static file: {e}")
+                        pass
+
+            # File not found in any plugin
+            abort(404)
+
         # These files should be in our subdirectory
         try:
             return send_from_directory(f"static/{group}", path=filename)
@@ -629,13 +903,13 @@ def changedetection_app(config=None, datastore_o=None):
     worker_handler.start_workers(n_workers, update_q, notification_q, app, datastore)
 
     # @todo handle ctrl break
-    ticker_thread = threading.Thread(target=ticker_thread_check_time_launch_checks).start()
-    threading.Thread(target=notification_runner).start()
+    ticker_thread = threading.Thread(target=ticker_thread_check_time_launch_checks, daemon=True, name="TickerThread-ScheduleChecker").start()
+    threading.Thread(target=notification_runner, daemon=True, name="NotificationRunner").start()
 
     in_pytest = "pytest" in sys.modules or "PYTEST_CURRENT_TEST" in os.environ
     # Check for new release version, but not when running in test/build or pytest
     if not os.getenv("GITHUB_REF", False) and not strtobool(os.getenv('DISABLE_VERSION_CHECK', 'no')) and not in_pytest:
-        threading.Thread(target=check_for_new_version).start()
+        threading.Thread(target=check_for_new_version, daemon=True, name="VersionChecker").start()
 
     # Return the Flask app - the Socket.IO will be attached to it but initialized separately
     # This avoids circular dependencies
@@ -680,7 +954,7 @@ def notification_runner():
                 # At the moment only one thread runs (single runner)
                 n_object = notification_q.get(block=False)
             except queue.Empty:
-                time.sleep(1)
+                app.config.exit.wait(1)
 
             else:
 
@@ -717,7 +991,7 @@ def notification_runner():
                         app.config['watch_check_update_SIGNAL'].send(app_context=app, watch_uuid=n_object.get('uuid'))
 
                 # Process notifications
-                notification_debug_log+= ["{} - SENDING - {}".format(now.strftime("%Y/%m/%d %H:%M:%S,000"), json.dumps(sent_obj))]
+                notification_debug_log+= ["{} - SENDING - {}".format(now.strftime("%c"), json.dumps(sent_obj))]
                 # Trim the log length
                 notification_debug_log = notification_debug_log[-100:]
 
@@ -733,6 +1007,10 @@ def ticker_thread_check_time_launch_checks():
     logger.debug(f"System env MINIMUM_SECONDS_RECHECK_TIME {recheck_time_minimum_seconds}")
 
     # Workers are now started during app initialization, not here
+    WAIT_TIME_BETWEEN_LOOP = 1.0 if not IN_PYTEST else 0.01
+    if IN_PYTEST:
+        # The time between loops should be less than the first .sleep/wait in def wait_for_all_checks() of tests/util.py
+        logger.warning(f"Looks like we're in PYTEST! Setting time between searching for items to add to the queue to {WAIT_TIME_BETWEEN_LOOP}s")
 
     while not app.config.exit.is_set():
 
@@ -750,12 +1028,20 @@ def ticker_thread_check_time_launch_checks():
             
             if health_result['status'] != 'healthy':
                 logger.warning(f"Worker health check: {health_result['message']}")
-                
+
             last_health_check = now
 
+        # Check if all checks are paused
+        if datastore.data['settings']['application'].get('all_paused', False):
+            app.config.exit.wait(1)
+            continue
+
         # Get a list of watches by UUID that are currently fetching data
         running_uuids = worker_handler.get_running_uuids()
 
+        # Build set of queued UUIDs once for O(1) lookup instead of O(n) per watch
+        queued_uuids = {q_item.item['uuid'] for q_item in update_q.queue}
+
         # Re #232 - Deepcopy the data incase it changes while we're iterating through it all
         watch_uuid_list = []
         while True:
@@ -772,16 +1058,17 @@ def ticker_thread_check_time_launch_checks():
             else:
                 break
 
-        # Re #438 - Don't place more watches in the queue to be checked if the queue is already large
-        while update_q.qsize() >= 2000:
-            logger.warning(f"Recheck watches queue size limit reached ({MAX_QUEUE_SIZE}), skipping adding more items")
-            time.sleep(3)
-
-
         recheck_time_system_seconds = int(datastore.threshold_seconds)
 
         # Check for watches outside of the time threshold to put in the thread queue.
-        for uuid in watch_uuid_list:
+        for watch_index, uuid in enumerate(watch_uuid_list):
+            # Re #438 - Check queue size every 100 watches for CPU efficiency (not every watch)
+            if watch_index % 100 == 0:
+                current_queue_size = update_q.qsize()
+                if current_queue_size >= MAX_QUEUE_SIZE:
+                    logger.debug(f"Queue size limit reached ({current_queue_size}/{MAX_QUEUE_SIZE}), stopping scheduler this iteration.")
+                    break
+
             now = time.time()
             watch = datastore.data['watching'].get(uuid)
             if not watch:
@@ -831,7 +1118,7 @@ def ticker_thread_check_time_launch_checks():
             seconds_since_last_recheck = now - watch['last_checked']
 
             if seconds_since_last_recheck >= (threshold + watch.jitter_seconds) and seconds_since_last_recheck >= recheck_time_minimum_seconds:
-                if not uuid in running_uuids and uuid not in [q_uuid.item['uuid'] for q_uuid in update_q.queue]:
+                if not uuid in running_uuids and uuid not in queued_uuids:
 
                     # Proxies can be set to have a limit on seconds between which they can be called
                     watch_proxy = datastore.get_preferred_proxy_for_watch(uuid=uuid)
@@ -873,8 +1160,5 @@ def ticker_thread_check_time_launch_checks():
                     # Reset for next time
                     watch.jitter_seconds = 0
 
-        # Wait before checking the list again - saves CPU
-        time.sleep(1)
-
         # Should be low so we can break this out in testing
-        app.config.exit.wait(1)
+        app.config.exit.wait(WAIT_TIME_BETWEEN_LOOP)

changedetectionio/forms.py

@@ -2,16 +2,21 @@ import os
 import re
 from loguru import logger
 from wtforms.widgets.core import TimeInput
+from flask_babel import lazy_gettext as _l, gettext
 
-from changedetectionio.blueprint.rss import RSS_FORMAT_TYPES
+from changedetectionio.blueprint.rss import RSS_FORMAT_TYPES, RSS_TEMPLATE_TYPE_OPTIONS, RSS_TEMPLATE_HTML_DEFAULT
 from changedetectionio.conditions.form import ConditionFormRow
 from changedetectionio.notification_service import NotificationContextData
+from changedetectionio.processors.image_ssim_diff import SCREENSHOT_COMPARISON_THRESHOLD_OPTIONS, \
+    SCREENSHOT_COMPARISON_THRESHOLD_OPTIONS_DEFAULT
 from changedetectionio.strtobool import strtobool
+from changedetectionio import processors
 
 from wtforms import (
     BooleanField,
     Form,
     Field,
+    FloatField,
     IntegerField,
     RadioField,
     SelectField,
@@ -55,8 +60,8 @@ valid_method = {
 
 default_method = 'GET'
 allow_simplehost = not strtobool(os.getenv('BLOCK_SIMPLEHOSTS', 'False'))
-REQUIRE_ATLEAST_ONE_TIME_PART_MESSAGE_DEFAULT='At least one time interval (weeks, days, hours, minutes, or seconds) must be specified.'
-REQUIRE_ATLEAST_ONE_TIME_PART_WHEN_NOT_GLOBAL_DEFAULT='At least one time interval (weeks, days, hours, minutes, or seconds) must be specified when not using global settings.'
+REQUIRE_ATLEAST_ONE_TIME_PART_MESSAGE_DEFAULT=_l('At least one time interval (weeks, days, hours, minutes, or seconds) must be specified.')
+REQUIRE_ATLEAST_ONE_TIME_PART_WHEN_NOT_GLOBAL_DEFAULT=_l('At least one time interval (weeks, days, hours, minutes, or seconds) must be specified when not using global settings.')
 
 class StringListField(StringField):
     widget = widgets.TextArea()
@@ -156,7 +161,7 @@ class TimeStringField(Field):
             time_str = valuelist[0]
             # Simple validation for HH:MM format
             if not time_str or len(time_str.split(":")) != 2:
-                raise ValidationError("Invalid time format. Use HH:MM.")
+                raise ValidationError(_l("Invalid time format. Use HH:MM."))
             self.data = time_str
 
 
@@ -172,15 +177,15 @@ class validateTimeZoneName(object):
         from zoneinfo import available_timezones
         python_timezones = available_timezones()
         if field.data and field.data not in python_timezones:
-            raise ValidationError("Not a valid timezone name")
+            raise ValidationError(_l("Not a valid timezone name"))
 
 class ScheduleLimitDaySubForm(Form):
-    enabled = BooleanField("not set", default=True)
-    start_time = TimeStringField("Start At", default="00:00", validators=[validators.Optional()])
-    duration = FormField(TimeDurationForm, label="Run duration")
+    enabled = BooleanField(_l("not set"), default=True)
+    start_time = TimeStringField(_l("Start At"), default="00:00", validators=[validators.Optional()])
+    duration = FormField(TimeDurationForm, label=_l("Run duration"))
 
 class ScheduleLimitForm(Form):
-    enabled = BooleanField("Use time scheduler", default=False)
+    enabled = BooleanField(_l("Use time scheduler"), default=False)
     # Because the label for=""" doesnt line up/work with the actual checkbox
     monday = FormField(ScheduleLimitDaySubForm, label="")
     tuesday = FormField(ScheduleLimitDaySubForm, label="")
@@ -190,7 +195,7 @@ class ScheduleLimitForm(Form):
     saturday = FormField(ScheduleLimitDaySubForm, label="")
     sunday = FormField(ScheduleLimitDaySubForm, label="")
 
-    timezone = StringField("Optional timezone to run in",
+    timezone = StringField(_l("Optional timezone to run in"),
                                   render_kw={"list": "timezones"},
                                   validators=[validateTimeZoneName()]
                                   )
@@ -204,13 +209,13 @@ class ScheduleLimitForm(Form):
         **kwargs,
     ):
         super().__init__(formdata, obj, prefix, data, meta, **kwargs)
-        self.monday.form.enabled.label.text="Monday"
-        self.tuesday.form.enabled.label.text = "Tuesday"
-        self.wednesday.form.enabled.label.text = "Wednesday"
-        self.thursday.form.enabled.label.text = "Thursday"
-        self.friday.form.enabled.label.text = "Friday"
-        self.saturday.form.enabled.label.text = "Saturday"
-        self.sunday.form.enabled.label.text = "Sunday"
+        self.monday.form.enabled.label.text=_l("Monday")
+        self.tuesday.form.enabled.label.text = _l("Tuesday")
+        self.wednesday.form.enabled.label.text = _l("Wednesday")
+        self.thursday.form.enabled.label.text = _l("Thursday")
+        self.friday.form.enabled.label.text = _l("Friday")
+        self.saturday.form.enabled.label.text = _l("Saturday")
+        self.sunday.form.enabled.label.text = _l("Sunday")
 
 
 def validate_time_between_check_has_values(form):
@@ -235,7 +240,7 @@ class RequiredTimeInterval(object):
     Use this with FormField(TimeBetweenCheckForm, validators=[RequiredTimeInterval()]).
     """
     def __init__(self, message=None):
-        self.message = message or 'At least one time interval (weeks, days, hours, minutes, or seconds) must be specified.'
+        self.message = message or _l('At least one time interval (weeks, days, hours, minutes, or seconds) must be specified.')
 
     def __call__(self, form, field):
         if not validate_time_between_check_has_values(field.form):
@@ -243,11 +248,11 @@ class RequiredTimeInterval(object):
 
 
 class TimeBetweenCheckForm(Form):
-    weeks = IntegerField('Weeks', validators=[validators.Optional(), validators.NumberRange(min=0, message="Should contain zero or more seconds")])
-    days = IntegerField('Days', validators=[validators.Optional(), validators.NumberRange(min=0, message="Should contain zero or more seconds")])
-    hours = IntegerField('Hours', validators=[validators.Optional(), validators.NumberRange(min=0, message="Should contain zero or more seconds")])
-    minutes = IntegerField('Minutes', validators=[validators.Optional(), validators.NumberRange(min=0, message="Should contain zero or more seconds")])
-    seconds = IntegerField('Seconds', validators=[validators.Optional(), validators.NumberRange(min=0, message="Should contain zero or more seconds")])
+    weeks = IntegerField(_l('Weeks'), validators=[validators.Optional(), validators.NumberRange(min=0, message=_l("Should contain zero or more seconds"))])
+    days = IntegerField(_l('Days'), validators=[validators.Optional(), validators.NumberRange(min=0, message=_l("Should contain zero or more seconds"))])
+    hours = IntegerField(_l('Hours'), validators=[validators.Optional(), validators.NumberRange(min=0, message=_l("Should contain zero or more seconds"))])
+    minutes = IntegerField(_l('Minutes'), validators=[validators.Optional(), validators.NumberRange(min=0, message=_l("Should contain zero or more seconds"))])
+    seconds = IntegerField(_l('Seconds'), validators=[validators.Optional(), validators.NumberRange(min=0, message=_l("Should contain zero or more seconds"))])
     # @todo add total seconds minimum validatior = minimum_seconds_recheck_time
 
     def __init__(self, formdata=None, obj=None, prefix="", data=None, meta=None, **kwargs):
@@ -503,7 +508,9 @@ class ValidateJinja2Template(object):
             jinja2_env = create_jinja_env(loader=BaseLoader)
 
             # Add notification tokens for validation
-            jinja2_env.globals.update(NotificationContextData())
+            static_token_placeholders = NotificationContextData()
+            static_token_placeholders.set_random_for_validation()
+            jinja2_env.globals.update(static_token_placeholders)
             if hasattr(field, 'extra_notification_tokens'):
                 jinja2_env.globals.update(field.extra_notification_tokens)
 
@@ -715,18 +722,16 @@ class ValidateStartsWithRegex(object):
             if not stripped:
                 if self.allow_empty:
                     continue
-                raise ValidationError(self.message or "Empty value not allowed.")
+                raise ValidationError(self.message or _l("Empty value not allowed."))
             if not self.pattern.match(stripped):
-                raise ValidationError(self.message or "Invalid value.")
+                raise ValidationError(self.message or _l("Invalid value."))
 
 class quickWatchForm(Form):
-    from . import processors
-
-    url = fields.URLField('URL', validators=[validateURL()])
-    tags = StringTagUUID('Group tag', [validators.Optional()])
-    watch_submit_button = SubmitField('Watch', render_kw={"class": "pure-button pure-button-primary"})
-    processor = RadioField(u'Processor', choices=processors.available_processors(), default="text_json_diff")
-    edit_and_watch_submit_button = SubmitField('Edit > Watch', render_kw={"class": "pure-button pure-button-primary"})
+    url = fields.URLField(_l('URL'), validators=[validateURL()])
+    tags = StringTagUUID(_l('Group tag'), validators=[validators.Optional()])
+    watch_submit_button = SubmitField(_l('Watch'), render_kw={"class": "pure-button pure-button-primary"})
+    processor = RadioField(_l('Processor'), choices=lambda: processors.available_processors(), default="text_json_diff")
+    edit_and_watch_submit_button = SubmitField(_l('Edit > Watch'), render_kw={"class": "pure-button pure-button-primary"})
 
 
 # Common to a single watch and the global settings
@@ -739,14 +744,14 @@ class commonSettingsForm(Form):
         self.notification_title.extra_notification_tokens = kwargs.get('extra_notification_tokens', {})
         self.notification_urls.extra_notification_tokens = kwargs.get('extra_notification_tokens', {})
 
-    fetch_backend = RadioField(u'Fetch Method', choices=content_fetchers.available_fetchers(), validators=[ValidateContentFetcherIsReady()])
-    notification_body = TextAreaField('Notification Body', default='{{ watch_url }} had a change.', validators=[validators.Optional(), ValidateJinja2Template()])
-    notification_format = SelectField('Notification format', choices=list(valid_notification_formats.items()))
-    notification_title = StringField('Notification Title', default='ChangeDetection.io Notification - {{ watch_url }}', validators=[validators.Optional(), ValidateJinja2Template()])
-    notification_urls = StringListField('Notification URL List', validators=[validators.Optional(), ValidateAppRiseServers(), ValidateJinja2Template()])
-    processor = RadioField( label=u"Processor - What do you want to achieve?", choices=processors.available_processors(), default="text_json_diff")
-    scheduler_timezone_default = StringField("Default timezone for watch check scheduler", render_kw={"list": "timezones"}, validators=[validateTimeZoneName()])
-    webdriver_delay = IntegerField('Wait seconds before extracting text', validators=[validators.Optional(), validators.NumberRange(min=1, message="Should contain one or more seconds")])
+    fetch_backend = RadioField(_l('Fetch Method'), choices=content_fetchers.available_fetchers(), validators=[ValidateContentFetcherIsReady()])
+    notification_body = TextAreaField(_l('Notification Body'), default='{{ watch_url }} had a change.', validators=[validators.Optional(), ValidateJinja2Template()])
+    notification_format = SelectField(_l('Notification format'), choices=list(valid_notification_formats.items()))
+    notification_title = StringField(_l('Notification Title'), default='ChangeDetection.io Notification - {{ watch_url }}', validators=[validators.Optional(), ValidateJinja2Template()])
+    notification_urls = StringListField(_l('Notification URL List'), validators=[validators.Optional(), ValidateAppRiseServers(), ValidateJinja2Template()])
+    processor = RadioField( label=_l("Processor - What do you want to achieve?"), choices=lambda: processors.available_processors(), default="text_json_diff")
+    scheduler_timezone_default = StringField(_l("Default timezone for watch check scheduler"), render_kw={"list": "timezones"}, validators=[validateTimeZoneName()])
+    webdriver_delay = IntegerField(_l('Wait seconds before extracting text'), validators=[validators.Optional(), validators.NumberRange(min=1, message=_l("Should contain one or more seconds"))])
 
 # Not true anymore but keep the validate_ hook for future use, we convert color tags
 #    def validate_notification_urls(self, field):
@@ -758,30 +763,30 @@ class commonSettingsForm(Form):
 
 
 class importForm(Form):
-    from . import processors
-    processor = RadioField(u'Processor', choices=processors.available_processors(), default="text_json_diff")
-    urls = TextAreaField('URLs')
-    xlsx_file = FileField('Upload .xlsx file', validators=[FileAllowed(['xlsx'], 'Must be .xlsx file!')])
-    file_mapping = SelectField('File mapping', [validators.DataRequired()], choices={('wachete', 'Wachete mapping'), ('custom','Custom mapping')})
+    processor = RadioField(_l('Processor'), choices=lambda: processors.available_processors(), default="text_json_diff")
+    urls = TextAreaField(_l('URLs'))
+    xlsx_file = FileField(_l('Upload .xlsx file'), validators=[FileAllowed(['xlsx'], _l('Must be .xlsx file!'))])
+    file_mapping = SelectField(_l('File mapping'), [validators.DataRequired()], choices={('wachete', 'Wachete mapping'), ('custom','Custom mapping')})
 
 class SingleBrowserStep(Form):
 
-    operation = SelectField('Operation', [validators.Optional()], choices=browser_step_ui_config.keys())
+    operation = SelectField(_l('Operation'), [validators.Optional()], choices=browser_step_ui_config.keys())
 
     # maybe better to set some <script>var..
-    selector = StringField('Selector', [validators.Optional()], render_kw={"placeholder": "CSS or xPath selector"})
-    optional_value = StringField('value', [validators.Optional()], render_kw={"placeholder": "Value"})
+    selector = StringField(_l('Selector'), [validators.Optional()], render_kw={"placeholder": "CSS or xPath selector"})
+    optional_value = StringField(_l('value'), [validators.Optional()], render_kw={"placeholder": "Value"})
 #   @todo move to JS? ajax fetch new field?
-#    remove_button = SubmitField('-', render_kw={"type": "button", "class": "pure-button pure-button-primary", 'title': 'Remove'})
-#    add_button = SubmitField('+', render_kw={"type": "button", "class": "pure-button pure-button-primary", 'title': 'Add new step after'})
+#    remove_button = SubmitField(_l('-'), render_kw={"type": "button", "class": "pure-button pure-button-primary", 'title': 'Remove'})
+#    add_button = SubmitField(_l('+'), render_kw={"type": "button", "class": "pure-button pure-button-primary", 'title': 'Add new step after'})
 
 class processor_text_json_diff_form(commonSettingsForm):
 
-    url = fields.URLField('URL', validators=[validateURL()])
-    tags = StringTagUUID('Group tag', [validators.Optional()], default='')
+    url = fields.URLField('Web Page URL', validators=[validateURL()])
+    tags = StringTagUUID('Group Tag', [validators.Optional()], default='')
 
     time_between_check = EnhancedFormField(
         TimeBetweenCheckForm,
+        label=_l('Time Between Check'),
         conditional_field='time_between_check_use_default',
         conditional_message=REQUIRE_ATLEAST_ONE_TIME_PART_WHEN_NOT_GLOBAL_DEFAULT,
         conditional_test_function=validate_time_between_check_has_values
@@ -789,49 +794,48 @@ class processor_text_json_diff_form(commonSettingsForm):
 
     time_schedule_limit = FormField(ScheduleLimitForm)
 
-    time_between_check_use_default = BooleanField('Use global settings for time between check and scheduler.', default=False)
+    time_between_check_use_default = BooleanField(_l('Use global settings for time between check and scheduler.'), default=False)
 
-    include_filters = StringListField('CSS/JSONPath/JQ/XPath Filters', [ValidateCSSJSONXPATHInput()], default='')
+    include_filters = StringListField(_l('CSS/JSONPath/JQ/XPath Filters'), [ValidateCSSJSONXPATHInput()], default='')
 
-    subtractive_selectors = StringListField('Remove elements', [ValidateCSSJSONXPATHInput(allow_json=False)])
+    subtractive_selectors = StringListField(_l('Remove elements'), [ValidateCSSJSONXPATHInput(allow_json=False)])
 
-    extract_text = StringListField('Extract text', [ValidateListRegex()])
+    extract_text = StringListField(_l('Extract text'), [ValidateListRegex()])
 
-    title = StringField('Title', default='')
+    title = StringField(_l('Title'), default='')
 
-    ignore_text = StringListField('Ignore lines containing', [ValidateListRegex()])
+    ignore_text = StringListField(_l('Ignore lines containing'), [ValidateListRegex()])
     headers = StringDictKeyValue('Request headers')
-    body = TextAreaField('Request body', [validators.Optional()])
-    method = SelectField('Request method', choices=valid_method, default=default_method)
-    ignore_status_codes = BooleanField('Ignore status codes (process non-2xx status codes as normal)', default=False)
-    check_unique_lines = BooleanField('Only trigger when unique lines appear in all history', default=False)
-    remove_duplicate_lines = BooleanField('Remove duplicate lines of text', default=False)
-    sort_text_alphabetically =  BooleanField('Sort text alphabetically', default=False)
-    strip_ignored_lines = TernaryNoneBooleanField('Strip ignored lines', default=None)
-    trim_text_whitespace = BooleanField('Trim whitespace before and after text', default=False)
+    body = TextAreaField(_l('Request body'), [validators.Optional()])
+    method = SelectField(_l('Request method'), choices=valid_method, default=default_method)
+    ignore_status_codes = BooleanField(_l('Ignore status codes (process non-2xx status codes as normal)'), default=False)
+    check_unique_lines = BooleanField(_l('Only trigger when unique lines appear in all history'), default=False)
+    remove_duplicate_lines = BooleanField(_l('Remove duplicate lines of text'), default=False)
+    sort_text_alphabetically =  BooleanField(_l('Sort text alphabetically'), default=False)
+    strip_ignored_lines = TernaryNoneBooleanField(_l('Strip ignored lines'), default=None)
+    trim_text_whitespace = BooleanField(_l('Trim whitespace before and after text'), default=False)
 
-    filter_text_added = BooleanField('Added lines', default=True)
-    filter_text_replaced = BooleanField('Replaced/changed lines', default=True)
-    filter_text_removed = BooleanField('Removed lines', default=True)
+    filter_text_added = BooleanField(_l('Added lines'), default=True)
+    filter_text_replaced = BooleanField(_l('Replaced/changed lines'), default=True)
+    filter_text_removed = BooleanField(_l('Removed lines'), default=True)
 
-    trigger_text = StringListField('Keyword triggers - Trigger/wait for text', [validators.Optional(), ValidateListRegex()])
+    trigger_text = StringListField(_l('Keyword triggers - Trigger/wait for text'), [validators.Optional(), ValidateListRegex()])
     if os.getenv("PLAYWRIGHT_DRIVER_URL"):
         browser_steps = FieldList(FormField(SingleBrowserStep), min_entries=10)
-    text_should_not_be_present = StringListField('Block change-detection while text matches', [validators.Optional(), ValidateListRegex()])
-    webdriver_js_execute_code = TextAreaField('Execute JavaScript before change detection', render_kw={"rows": "5"}, validators=[validators.Optional()])
+    text_should_not_be_present = StringListField(_l('Block change-detection while text matches'), [validators.Optional(), ValidateListRegex()])
+    webdriver_js_execute_code = TextAreaField(_l('Execute JavaScript before change detection'), render_kw={"rows": "5"}, validators=[validators.Optional()])
 
-    save_button = SubmitField('Save', render_kw={"class": "pure-button pure-button-primary"})
+    save_button = SubmitField(_l('Save'), render_kw={"class": "pure-button pure-button-primary"})
 
-    proxy = RadioField('Proxy')
+    proxy = RadioField(_l('Proxy'))
     # filter_failure_notification_send @todo make ternary
-    filter_failure_notification_send = BooleanField(
-        'Send a notification when the filter can no longer be found on the page', default=False)
-    notification_muted = TernaryNoneBooleanField('Notifications', default=None, yes_text="Muted", no_text="On")
-    notification_screenshot = BooleanField('Attach screenshot to notification (where possible)', default=False)
+    filter_failure_notification_send = BooleanField(_l('Send a notification when the filter can no longer be found on the page'), default=False)
+    notification_muted = TernaryNoneBooleanField(_l('Notifications'), default=None, yes_text=_l("Muted"), no_text=_l("On"))
+    notification_screenshot = BooleanField(_l('Attach screenshot to notification (where possible)'), default=False)
 
-    conditions_match_logic = RadioField(u'Match', choices=[('ALL', 'Match all of the following'),('ANY', 'Match any of the following')], default='ALL')
+    conditions_match_logic = RadioField(_l('Match'), choices=[('ALL', _l('Match all of the following')),('ANY', _l('Match any of the following'))], default='ALL')
     conditions = FieldList(FormField(ConditionFormRow), min_entries=1)  # Add rule logic here
-    use_page_title_in_list = TernaryNoneBooleanField('Use page <title> in list', default=None)
+    use_page_title_in_list = TernaryNoneBooleanField(_l('Use page <title> in list'), default=None)
 
     def extra_tab_content(self):
         return None
@@ -848,7 +852,7 @@ class processor_text_json_diff_form(commonSettingsForm):
 
         # Fail form validation when a body is set for a GET
         if self.method.data == 'GET' and self.body.data:
-            self.body.errors.append('Body must be empty when Request Method is set to GET')
+            self.body.errors.append(gettext('Body must be empty when Request Method is set to GET'))
             result = False
 
         # Attempt to validate jinja2 templates in the URL
@@ -857,11 +861,11 @@ class processor_text_json_diff_form(commonSettingsForm):
         except ModuleNotFoundError as e:
             # incase jinja2_time or others is missing
             logger.error(e)
-            self.url.errors.append(f'Invalid template syntax configuration: {e}')
+            self.url.errors.append(gettext('Invalid template syntax configuration: %(error)s') % {'error': e})
             result = False
         except Exception as e:
             logger.error(e)
-            self.url.errors.append(f'Invalid template syntax: {e}')
+            self.url.errors.append(gettext('Invalid template syntax: %(error)s') % {'error': e})
             result = False
 
         # Attempt to validate jinja2 templates in the body
@@ -871,11 +875,11 @@ class processor_text_json_diff_form(commonSettingsForm):
             except ModuleNotFoundError as e:
                 # incase jinja2_time or others is missing
                 logger.error(e)
-                self.body.errors.append(f'Invalid template syntax configuration: {e}')
+                self.body.errors.append(gettext('Invalid template syntax configuration: %(error)s') % {'error': e})
                 result = False
             except Exception as e:
                 logger.error(e)
-                self.body.errors.append(f'Invalid template syntax: {e}')
+                self.body.errors.append(gettext('Invalid template syntax: %(error)s') % {'error': e})
                 result = False
 
         # Attempt to validate jinja2 templates in the headers
@@ -886,11 +890,11 @@ class processor_text_json_diff_form(commonSettingsForm):
             except ModuleNotFoundError as e:
                 # incase jinja2_time or others is missing
                 logger.error(e)
-                self.headers.errors.append(f'Invalid template syntax configuration: {e}')
+                self.headers.errors.append(gettext('Invalid template syntax configuration: %(error)s') % {'error': e})
                 result = False
             except Exception as e:
                 logger.error(e)
-                self.headers.errors.append(f'Invalid template syntax in "{header}" header: {e}')
+                self.headers.errors.append(gettext('Invalid template syntax in \"%(header)s\" header: %(error)s') % {'header': header, 'error': e})
                 result = False
 
         return result
@@ -914,106 +918,122 @@ class processor_text_json_diff_form(commonSettingsForm):
 
 class SingleExtraProxy(Form):
     # maybe better to set some <script>var..
-    proxy_name = StringField('Name', [validators.Optional()], render_kw={"placeholder": "Name"})
-    proxy_url = StringField('Proxy URL', [
+    proxy_name = StringField(_l('Name'), [validators.Optional()], render_kw={"placeholder": "Name"})
+    proxy_url = StringField(_l('Proxy URL'), [
         validators.Optional(),
         ValidateStartsWithRegex(
             regex=r'^(https?|socks5)://',  # ✅ main pattern
             flags=re.IGNORECASE,  # ✅ makes it case-insensitive
-            message='Proxy URLs must start with http://, https:// or socks5://',
+            message=_l('Proxy URLs must start with http://, https:// or socks5://'),
         ),
         ValidateSimpleURL()
     ], render_kw={"placeholder": "socks5:// or regular proxy http://user:pass@...:3128", "size":50})
 
 class SingleExtraBrowser(Form):
-    browser_name = StringField('Name', [validators.Optional()], render_kw={"placeholder": "Name"})
-    browser_connection_url = StringField('Browser connection URL', [
+    browser_name = StringField(_l('Name'), [validators.Optional()], render_kw={"placeholder": "Name"})
+    browser_connection_url = StringField(_l('Browser connection URL'), [
         validators.Optional(),
         ValidateStartsWithRegex(
             regex=r'^(wss?|ws)://',
             flags=re.IGNORECASE,
-            message='Browser URLs must start with wss:// or ws://'
+            message=_l('Browser URLs must start with wss:// or ws://')
         ),
         ValidateSimpleURL()
     ], render_kw={"placeholder": "wss://brightdata... wss://oxylabs etc", "size":50})
 
 class DefaultUAInputForm(Form):
-    html_requests = StringField('Plaintext requests', validators=[validators.Optional()], render_kw={"placeholder": "<default>"})
+    html_requests = StringField(_l('Plaintext requests'), validators=[validators.Optional()], render_kw={"placeholder": "<default>"})
     if os.getenv("PLAYWRIGHT_DRIVER_URL") or os.getenv("WEBDRIVER_URL"):
-        html_webdriver = StringField('Chrome requests', validators=[validators.Optional()], render_kw={"placeholder": "<default>"})
+        html_webdriver = StringField(_l('Chrome requests'), validators=[validators.Optional()], render_kw={"placeholder": "<default>"})
 
 # datastore.data['settings']['requests']..
 class globalSettingsRequestForm(Form):
-    time_between_check = RequiredFormField(TimeBetweenCheckForm)
+    time_between_check = RequiredFormField(TimeBetweenCheckForm, label=_l('Time Between Check'))
     time_schedule_limit = FormField(ScheduleLimitForm)
-    proxy = RadioField('Default proxy')
-    jitter_seconds = IntegerField('Random jitter seconds ± check',
+    proxy = RadioField(_l('Default proxy'))
+    jitter_seconds = IntegerField(_l('Random jitter seconds ± check'),
                                   render_kw={"style": "width: 5em;"},
-                                  validators=[validators.NumberRange(min=0, message="Should contain zero or more seconds")])
+                                  validators=[validators.NumberRange(min=0, message=_l("Should contain zero or more seconds"))])
     
-    workers = IntegerField('Number of fetch workers',
+    workers = IntegerField(_l('Number of fetch workers'),
                           render_kw={"style": "width: 5em;"},
                           validators=[validators.NumberRange(min=1, max=50,
-                                                             message="Should be between 1 and 50")])
+                                                             message=_l("Should be between 1 and 50"))])
 
-    timeout = IntegerField('Requests timeout in seconds',
+    timeout = IntegerField(_l('Requests timeout in seconds'),
                            render_kw={"style": "width: 5em;"},
                            validators=[validators.NumberRange(min=1, max=999,
-                                                              message="Should be between 1 and 999")])
+                                                              message=_l("Should be between 1 and 999"))])
 
     extra_proxies = FieldList(FormField(SingleExtraProxy), min_entries=5)
     extra_browsers = FieldList(FormField(SingleExtraBrowser), min_entries=5)
 
-    default_ua = FormField(DefaultUAInputForm, label="Default User-Agent overrides")
+    default_ua = FormField(DefaultUAInputForm, label=_l("Default User-Agent overrides"))
 
     def validate_extra_proxies(self, extra_validators=None):
         for e in self.data['extra_proxies']:
             if e.get('proxy_name') or e.get('proxy_url'):
                 if not e.get('proxy_name','').strip() or not e.get('proxy_url','').strip():
-                    self.extra_proxies.errors.append('Both a name, and a Proxy URL is required.')
+                    self.extra_proxies.errors.append(gettext('Both a name, and a Proxy URL is required.'))
                     return False
 
 class globalSettingsApplicationUIForm(Form):
-    open_diff_in_new_tab = BooleanField("Open 'History' page in a new tab", default=True, validators=[validators.Optional()])
-    socket_io_enabled = BooleanField('Realtime UI Updates Enabled', default=True, validators=[validators.Optional()])
-    favicons_enabled = BooleanField('Favicons Enabled', default=True, validators=[validators.Optional()])
-    use_page_title_in_list = BooleanField('Use page <title> in watch overview list') #BooleanField=True
+    open_diff_in_new_tab = BooleanField(_l("Open 'History' page in a new tab"), default=True, validators=[validators.Optional()])
+    socket_io_enabled = BooleanField(_l('Realtime UI Updates Enabled'), default=True, validators=[validators.Optional()])
+    favicons_enabled = BooleanField(_l('Favicons Enabled'), default=True, validators=[validators.Optional()])
+    use_page_title_in_list = BooleanField(_l('Use page <title> in watch overview list')) #BooleanField=True
 
 # datastore.data['settings']['application']..
 class globalSettingsApplicationForm(commonSettingsForm):
 
-    api_access_token_enabled = BooleanField('API access token security check enabled', default=True, validators=[validators.Optional()])
-    base_url = StringField('Notification base URL override',
+    api_access_token_enabled = BooleanField(_l('API access token security check enabled'), default=True, validators=[validators.Optional()])
+    base_url = StringField(_l('Notification base URL override'),
                            validators=[validators.Optional()],
                            render_kw={"placeholder": os.getenv('BASE_URL', 'Not set')}
                            )
-    empty_pages_are_a_change =  BooleanField('Treat empty pages as a change?', default=False)
-    fetch_backend = RadioField('Fetch Method', default="html_requests", choices=content_fetchers.available_fetchers(), validators=[ValidateContentFetcherIsReady()])
-    global_ignore_text = StringListField('Ignore Text', [ValidateListRegex()])
-    global_subtractive_selectors = StringListField('Remove elements', [ValidateCSSJSONXPATHInput(allow_json=False)])
-    ignore_whitespace = BooleanField('Ignore whitespace')
-    password = SaltyPasswordField()
-    pager_size = IntegerField('Pager size',
+    empty_pages_are_a_change =  BooleanField(_l('Treat empty pages as a change?'), default=False)
+    fetch_backend = RadioField(_l('Fetch Method'), default="html_requests", choices=content_fetchers.available_fetchers(), validators=[ValidateContentFetcherIsReady()])
+    global_ignore_text = StringListField(_l('Ignore Text'), [ValidateListRegex()])
+    global_subtractive_selectors = StringListField(_l('Remove elements'), [ValidateCSSJSONXPATHInput(allow_json=False)])
+    ignore_whitespace = BooleanField(_l('Ignore whitespace'))
+
+    # Screenshot comparison settings
+    min_change_percentage = FloatField(
+        'Screenshot: Minimum Change Percentage',
+        validators=[
+            validators.Optional(),
+            validators.NumberRange(min=0.0, max=100.0, message=_l('Must be between 0 and 100'))
+        ],
+        default=0.1,
+        render_kw={"placeholder": "0.1", "style": "width: 8em;"}
+    )
+
+    password = SaltyPasswordField(_l('Password'))
+    pager_size = IntegerField(_l('Pager size'),
                               render_kw={"style": "width: 5em;"},
                               validators=[validators.NumberRange(min=0,
-                                                                 message="Should be atleast zero (disabled)")])
+                                                                 message=_l("Should be atleast zero (disabled)"))])
 
-    rss_content_format = SelectField('RSS Content format', choices=RSS_FORMAT_TYPES)
+    rss_content_format = SelectField(_l('RSS Content format'), choices=list(RSS_FORMAT_TYPES.items()))
+    rss_template_type = SelectField(_l('RSS <description> body built from'), choices=list(RSS_TEMPLATE_TYPE_OPTIONS.items()))
+    rss_template_override = TextAreaField(_l('RSS "System default" template override'), render_kw={"rows": "5", "placeholder": RSS_TEMPLATE_HTML_DEFAULT}, validators=[validators.Optional(), ValidateJinja2Template()])
 
-    removepassword_button = SubmitField('Remove password', render_kw={"class": "pure-button pure-button-primary"})
-    render_anchor_tag_content = BooleanField('Render anchor tag content', default=False)
-    shared_diff_access = BooleanField('Allow anonymous access to watch history page when password is enabled', default=False, validators=[validators.Optional()])
-    strip_ignored_lines = BooleanField('Strip ignored lines')
-    rss_hide_muted_watches = BooleanField('Hide muted watches from RSS feed', default=True,
+    removepassword_button = SubmitField(_l('Remove password'), render_kw={"class": "pure-button pure-button-primary"})
+    render_anchor_tag_content = BooleanField(_l('Render anchor tag content'), default=False)
+    shared_diff_access = BooleanField(_l('Allow anonymous access to watch history page when password is enabled'), default=False, validators=[validators.Optional()])
+    strip_ignored_lines = BooleanField(_l('Strip ignored lines'))
+    rss_hide_muted_watches = BooleanField(_l('Hide muted watches from RSS feed'), default=True,
                                       validators=[validators.Optional()])
 
-    rss_reader_mode = BooleanField('RSS reader mode ', default=False,
-                                      validators=[validators.Optional()])
+    rss_reader_mode = BooleanField(_l('Enable RSS reader mode '), default=False, validators=[validators.Optional()])
+    rss_diff_length = IntegerField(label=_l('Number of changes to show in watch RSS feed'),
+                                   render_kw={"style": "width: 5em;"},
+                                   validators=[validators.NumberRange(min=0, message=_l("Should contain zero or more attempts"))])
 
-    filter_failure_notification_threshold_attempts = IntegerField('Number of times the filter can be missing before sending a notification',
+    filter_failure_notification_threshold_attempts = IntegerField(_l('Number of times the filter can be missing before sending a notification'),
                                                                   render_kw={"style": "width: 5em;"},
                                                                   validators=[validators.NumberRange(min=0,
-                                                                                                     message="Should contain zero or more attempts")])
+                                                                                                     message=_l("Should contain zero or more attempts"))])
     ui = FormField(globalSettingsApplicationUIForm)
 
 
@@ -1029,9 +1049,9 @@ class globalSettingsForm(Form):
 
     requests = FormField(globalSettingsRequestForm)
     application = FormField(globalSettingsApplicationForm)
-    save_button = SubmitField('Save', render_kw={"class": "pure-button pure-button-primary"})
+    save_button = SubmitField(_l('Save'), render_kw={"class": "pure-button pure-button-primary"})
 
 
 class extractDataForm(Form):
-    extract_regex = StringField('RegEx to extract', validators=[validators.DataRequired(), ValidateSinglePythonRegexString()])
-    extract_submit_button = SubmitField('Extract as CSV', render_kw={"class": "pure-button pure-button-primary"})
+    extract_regex = StringField(_l('RegEx to extract'), validators=[validators.DataRequired(), ValidateSinglePythonRegexString()])
+    extract_submit_button = SubmitField(_l('Extract as CSV'), render_kw={"class": "pure-button pure-button-primary"})

changedetectionio/html_tools.py

@@ -172,99 +172,131 @@ def elementpath_tostring(obj):
     return str(obj)
 
 # Return str Utf-8 of matched rules
-def xpath_filter(xpath_filter, html_content, append_pretty_line_formatting=False, is_rss=False):
+def xpath_filter(xpath_filter, html_content, append_pretty_line_formatting=False, is_xml=False):
+    """
+
+    :param xpath_filter:
+    :param html_content:
+    :param append_pretty_line_formatting:
+    :param is_xml: set to true if is XML or is RSS (RSS is XML)
+    :return:
+    """
     from lxml import etree, html
     import elementpath
     # xpath 2.0-3.1
     from elementpath.xpath3 import XPath3Parser
 
     parser = etree.HTMLParser()
-    if is_rss:
-        # So that we can keep CDATA for cdata_in_document_to_text() to process
-        parser = etree.XMLParser(strip_cdata=False)
-
-    tree = html.fromstring(bytes(html_content, encoding='utf-8'), parser=parser)
-    html_block = ""
-
-    # Build namespace map for XPath queries
-    namespaces = {'re': 'http://exslt.org/regular-expressions'}
-
-    # Handle default namespace in documents (common in RSS/Atom feeds, but can occur in any XML)
-    # XPath spec: unprefixed element names have no namespace, not the default namespace
-    # Solution: Register the default namespace with empty string prefix in elementpath
-    # This is primarily for RSS/Atom feeds but works for any XML with default namespace
-    if hasattr(tree, 'nsmap') and tree.nsmap and None in tree.nsmap:
-        # Register the default namespace with empty string prefix for elementpath
-        # This allows //title to match elements in the default namespace
-        namespaces[''] = tree.nsmap[None]
-
-    r = elementpath.select(tree, xpath_filter.strip(), namespaces=namespaces, parser=XPath3Parser)
-    #@note: //title/text() now works with default namespaces (fixed by registering '' prefix)
-    #@note: //title/text() wont work where <title>CDATA.. (use cdata_in_document_to_text first)
-
-    if type(r) != list:
-        r = [r]
-
-    for element in r:
-        # When there's more than 1 match, then add the suffix to separate each line
-        # And where the matched result doesn't include something that will cause Inscriptis to add a newline
-        # (This way each 'match' reliably has a new-line in the diff)
-        # Divs are converted to 4 whitespaces by inscriptis
-        if append_pretty_line_formatting and len(html_block) and (not hasattr( element, 'tag' ) or not element.tag in (['br', 'hr', 'div', 'p'])):
-            html_block += TEXT_FILTER_LIST_LINE_SUFFIX
-
-        if type(element) == str:
-            html_block += element
-        elif issubclass(type(element), etree._Element) or issubclass(type(element), etree._ElementTree):
-            html_block += etree.tostring(element, pretty_print=True).decode('utf-8')
+    tree = None
+    try:
+        if is_xml:
+            # So that we can keep CDATA for cdata_in_document_to_text() to process
+            parser = etree.XMLParser(strip_cdata=False)
+            # For XML/RSS content, use etree.fromstring to properly handle XML declarations
+            tree = etree.fromstring(html_content.encode('utf-8') if isinstance(html_content, str) else html_content, parser=parser)
         else:
-            html_block += elementpath_tostring(element)
+            tree = html.fromstring(html_content, parser=parser)
+        html_block = ""
 
-    return html_block
+        # Build namespace map for XPath queries
+        namespaces = {'re': 'http://exslt.org/regular-expressions'}
+
+        # Handle default namespace in documents (common in RSS/Atom feeds, but can occur in any XML)
+        # XPath spec: unprefixed element names have no namespace, not the default namespace
+        # Solution: Register the default namespace with empty string prefix in elementpath
+        # This is primarily for RSS/Atom feeds but works for any XML with default namespace
+        if hasattr(tree, 'nsmap') and tree.nsmap and None in tree.nsmap:
+            # Register the default namespace with empty string prefix for elementpath
+            # This allows //title to match elements in the default namespace
+            namespaces[''] = tree.nsmap[None]
+
+        r = elementpath.select(tree, xpath_filter.strip(), namespaces=namespaces, parser=XPath3Parser)
+        #@note: //title/text() now works with default namespaces (fixed by registering '' prefix)
+        #@note: //title/text() wont work where <title>CDATA.. (use cdata_in_document_to_text first)
+
+        if type(r) != list:
+            r = [r]
+
+        for element in r:
+            # When there's more than 1 match, then add the suffix to separate each line
+            # And where the matched result doesn't include something that will cause Inscriptis to add a newline
+            # (This way each 'match' reliably has a new-line in the diff)
+            # Divs are converted to 4 whitespaces by inscriptis
+            if append_pretty_line_formatting and len(html_block) and (not hasattr( element, 'tag' ) or not element.tag in (['br', 'hr', 'div', 'p'])):
+                html_block += TEXT_FILTER_LIST_LINE_SUFFIX
+
+            if type(element) == str:
+                html_block += element
+            elif issubclass(type(element), etree._Element) or issubclass(type(element), etree._ElementTree):
+                # Use 'xml' method for RSS/XML content, 'html' for HTML content
+                # parser will be XMLParser if we detected XML content
+                method = 'xml' if (is_xml or isinstance(parser, etree.XMLParser)) else 'html'
+                html_block += etree.tostring(element, pretty_print=True, method=method, encoding='unicode')
+            else:
+                html_block += elementpath_tostring(element)
+
+        return html_block
+    finally:
+        # Explicitly clear the tree to free memory
+        # lxml trees can hold significant memory, especially with large documents
+        if tree is not None:
+            tree.clear()
 
 # Return str Utf-8 of matched rules
 # 'xpath1:'
-def xpath1_filter(xpath_filter, html_content, append_pretty_line_formatting=False, is_rss=False):
+def xpath1_filter(xpath_filter, html_content, append_pretty_line_formatting=False, is_xml=False):
     from lxml import etree, html
 
     parser = None
-    if is_rss:
-        # So that we can keep CDATA for cdata_in_document_to_text() to process
-        parser = etree.XMLParser(strip_cdata=False)
-
-    tree = html.fromstring(bytes(html_content, encoding='utf-8'), parser=parser)
-    html_block = ""
-
-    # Build namespace map for XPath queries
-    namespaces = {'re': 'http://exslt.org/regular-expressions'}
-
-    # NOTE: lxml's native xpath() does NOT support empty string prefix for default namespace
-    # For documents with default namespace (RSS/Atom feeds), users must use:
-    #   - local-name(): //*[local-name()='title']/text()
-    #   - Or use xpath_filter (not xpath1_filter) which supports default namespaces
-    # XPath spec: unprefixed element names have no namespace, not the default namespace
-
-    r = tree.xpath(xpath_filter.strip(), namespaces=namespaces)
-    #@note: xpath1 (lxml) does NOT automatically handle default namespaces
-    #@note: Use //*[local-name()='element'] or switch to xpath_filter for default namespace support
-    #@note: //title/text() wont work where <title>CDATA.. (use cdata_in_document_to_text first)
-
-    for element in r:
-        # When there's more than 1 match, then add the suffix to separate each line
-        # And where the matched result doesn't include something that will cause Inscriptis to add a newline
-        # (This way each 'match' reliably has a new-line in the diff)
-        # Divs are converted to 4 whitespaces by inscriptis
-        if append_pretty_line_formatting and len(html_block) and (not hasattr(element, 'tag') or not element.tag in (['br', 'hr', 'div', 'p'])):
-            html_block += TEXT_FILTER_LIST_LINE_SUFFIX
-
-        # Some kind of text, UTF-8 or other
-        if isinstance(element, (str, bytes)):
-            html_block += element
+    tree = None
+    try:
+        if is_xml:
+            # So that we can keep CDATA for cdata_in_document_to_text() to process
+            parser = etree.XMLParser(strip_cdata=False)
+            # For XML/RSS content, use etree.fromstring to properly handle XML declarations
+            tree = etree.fromstring(html_content.encode('utf-8') if isinstance(html_content, str) else html_content, parser=parser)
         else:
-            # Return the HTML which will get parsed as text
-            html_block += etree.tostring(element, pretty_print=True).decode('utf-8')
+            tree = html.fromstring(html_content, parser=parser)
+        html_block = ""
 
-    return html_block
+        # Build namespace map for XPath queries
+        namespaces = {'re': 'http://exslt.org/regular-expressions'}
+
+        # NOTE: lxml's native xpath() does NOT support empty string prefix for default namespace
+        # For documents with default namespace (RSS/Atom feeds), users must use:
+        #   - local-name(): //*[local-name()='title']/text()
+        #   - Or use xpath_filter (not xpath1_filter) which supports default namespaces
+        # XPath spec: unprefixed element names have no namespace, not the default namespace
+
+        r = tree.xpath(xpath_filter.strip(), namespaces=namespaces)
+        #@note: xpath1 (lxml) does NOT automatically handle default namespaces
+        #@note: Use //*[local-name()='element'] or switch to xpath_filter for default namespace support
+        #@note: //title/text() wont work where <title>CDATA.. (use cdata_in_document_to_text first)
+
+        for element in r:
+            # When there's more than 1 match, then add the suffix to separate each line
+            # And where the matched result doesn't include something that will cause Inscriptis to add a newline
+            # (This way each 'match' reliably has a new-line in the diff)
+            # Divs are converted to 4 whitespaces by inscriptis
+            if append_pretty_line_formatting and len(html_block) and (not hasattr(element, 'tag') or not element.tag in (['br', 'hr', 'div', 'p'])):
+                html_block += TEXT_FILTER_LIST_LINE_SUFFIX
+
+            # Some kind of text, UTF-8 or other
+            if isinstance(element, (str, bytes)):
+                html_block += element
+            else:
+                # Return the HTML/XML which will get parsed as text
+                # Use 'xml' method for RSS/XML content, 'html' for HTML content
+                # parser will be XMLParser if we detected XML content
+                method = 'xml' if (is_xml or isinstance(parser, etree.XMLParser)) else 'html'
+                html_block += etree.tostring(element, pretty_print=True, method=method, encoding='unicode')
+
+        return html_block
+    finally:
+        # Explicitly clear the tree to free memory
+        # lxml trees can hold significant memory, especially with large documents
+        if tree is not None:
+            tree.clear()
 
 # Extract/find element
 def extract_element(find='title', html_content=''):
@@ -432,6 +464,9 @@ def strip_ignore_text(content, wordlist, mode="content"):
     ignore_regex_multiline = []
     ignored_lines = []
 
+    if not content:
+        return ''
+
     for k in wordlist:
         # Skip empty strings to avoid matching everything
         if not k or not k.strip():
@@ -504,6 +539,18 @@ def cdata_in_document_to_text(html_content: str, render_anchor_tag_content=False
 
 
 def html_to_text(html_content: str, render_anchor_tag_content=False, is_rss=False, timeout=10) -> str:
+    """
+    Convert HTML content to plain text using inscriptis.
+
+    Thread-Safety: This function uses inscriptis.get_text() which internally calls
+    lxml.html.fromstring() with the default parser. Testing with 50 concurrent threads
+    confirms this approach is thread-safe and produces deterministic output.
+
+    Alternative Approach Rejected: An explicit HTMLParser instance (thread-local or fresh)
+    would also be thread-safe, but was found to break change detection logic in subtle ways
+    (test_check_basic_change_detection_functionality). The default parser provides correct
+    and reliable behavior.
+    """
     from inscriptis import get_text
     from inscriptis.model.config import ParserConfig
 

changedetectionio/is_safe_url.py

@@ -0,0 +1,113 @@
+"""
+URL redirect validation module for preventing open redirect vulnerabilities.
+
+This module provides functionality to safely validate redirect URLs, ensuring they:
+1. Point to internal routes only (no external redirects)
+2. Are properly normalized (preventing browser parsing differences)
+3. Match registered Flask routes (no fake/non-existent pages)
+4. Are fully logged for security monitoring
+
+References:
+- https://flask-login.readthedocs.io/ (safe redirect patterns)
+- https://blog.miguelgrinberg.com/post/the-flask-mega-tutorial-part-v-user-logins
+- https://www.pythonkitchen.com/how-prevent-open-redirect-vulnerab-flask/
+"""
+
+from urllib.parse import urlparse, urljoin
+from flask import request
+from loguru import logger
+
+
+def is_safe_url(target, app):
+    """
+    Validate that a redirect URL is safe to prevent open redirect vulnerabilities.
+
+    This follows Flask/Werkzeug best practices by ensuring the redirect URL:
+    1. Is a relative path starting with exactly one '/'
+    2. Does not start with '//' (double-slash attack)
+    3. Has no external protocol handlers
+    4. Points to a valid registered route in the application
+    5. Is properly normalized to prevent browser parsing differences
+
+    Args:
+        target: The URL to validate (e.g., '/settings', '/login#top')
+        app: The Flask application instance (needed for route validation)
+
+    Returns:
+        bool: True if the URL is safe for redirection, False otherwise
+
+    Examples:
+        >>> is_safe_url('/settings', app)
+        True
+        >>> is_safe_url('//evil.com', app)
+        False
+        >>> is_safe_url('/settings#general', app)
+        True
+        >>> is_safe_url('/fake-page', app)
+        False
+    """
+    if not target:
+        return False
+
+    # Normalize the URL to prevent browser parsing differences
+    # Strip whitespace and replace backslashes (which some browsers interpret as forward slashes)
+    target = target.strip()
+    target = target.replace('\\', '/')
+
+    # First, check if it starts with // or more (double-slash attack)
+    if target.startswith('//'):
+        logger.warning(f"Blocked redirect attempt with double-slash: {target}")
+        return False
+
+    # Parse the URL to check for scheme and netloc
+    parsed = urlparse(target)
+
+    # Block any URL with a scheme (http://, https://, javascript:, etc.)
+    if parsed.scheme:
+        logger.warning(f"Blocked redirect attempt with scheme: {target}")
+        return False
+
+    # Block any URL with a network location (netloc)
+    # This catches patterns like //evil.com, user@host, etc.
+    if parsed.netloc:
+        logger.warning(f"Blocked redirect attempt with netloc: {target}")
+        return False
+
+    # At this point, we have a relative URL with no scheme or netloc
+    # Use urljoin to resolve it and verify it points to the same host
+    ref_url = urlparse(request.host_url)
+    test_url = urlparse(urljoin(request.host_url, target))
+
+    # Check: ensure the resolved URL has the same netloc as current host
+    if not (test_url.scheme in ('http', 'https') and ref_url.netloc == test_url.netloc):
+        logger.warning(f"Blocked redirect attempt with mismatched netloc: {target}")
+        return False
+
+    # Additional validation: Check if the URL matches a registered route
+    # This prevents redirects to non-existent pages or unintended endpoints
+    try:
+        # Get the path without query string and fragment
+        # Fragments (like #general) are automatically stripped by urlparse
+        path = parsed.path
+
+        # Create a URL adapter bound to the server name
+        adapter = app.url_map.bind(ref_url.netloc)
+
+        # Try to match the path to a registered route
+        # This will raise NotFound if the route doesn't exist
+        endpoint, values = adapter.match(path, return_rule=False)
+
+        # Block redirects to static file endpoints - these are catch-all routes
+        # that would match arbitrary paths, potentially allowing unintended redirects
+        if endpoint in ('static_content', 'static', 'static_flags'):
+            logger.warning(f"Blocked redirect to static endpoint: {target}")
+            return False
+
+        # Successfully matched a valid route
+        logger.debug(f"Validated safe redirect to endpoint '{endpoint}': {target}")
+        return True
+
+    except Exception as e:
+        # Route doesn't exist or can't be matched
+        logger.warning(f"Blocked redirect to non-existent route: {target} (error: {e})")
+        return False

changedetectionio/languages.py

@@ -0,0 +1,110 @@
+"""
+Language configuration for i18n support
+Automatically discovers available languages from translations directory
+"""
+import os
+from pathlib import Path
+
+
+def get_timeago_locale(flask_locale):
+    """
+    Convert Flask-Babel locale codes to timeago library locale codes.
+
+    The Python timeago library (https://github.com/hustcc/timeago) supports 48 locales
+    but uses different naming conventions than Flask-Babel. This function maps between them.
+
+    Notable differences:
+    - Chinese: Flask uses 'zh', timeago uses 'zh_CN'
+    - Portuguese: Flask uses 'pt', timeago uses 'pt_PT' or 'pt_BR'
+    - Swedish: Flask uses 'sv', timeago uses 'sv_SE'
+    - Norwegian: Flask uses 'no', timeago uses 'nb_NO' or 'nn_NO'
+    - Hindi: Flask uses 'hi', timeago uses 'in_HI'
+    - Czech: Flask uses 'cs', but timeago doesn't support Czech - fallback to English
+
+    Args:
+        flask_locale (str): Flask-Babel locale code (e.g., 'cs', 'zh', 'pt')
+
+    Returns:
+        str: timeago library locale code (e.g., 'en', 'zh_CN', 'pt_PT')
+    """
+    locale_map = {
+        'zh': 'zh_CN',      # Chinese Simplified
+        # timeago library just hasn't been updated to use the more modern locale naming convention, before BCP 47 / RFC 5646.
+        'zh_TW': 'zh_TW',   # Chinese Traditional (timeago uses zh_TW)
+        'zh_Hant_TW': 'zh_TW',  # Flask-Babel normalizes zh_TW to zh_Hant_TW, map back to timeago's zh_TW
+        'pt': 'pt_PT',      # Portuguese (Portugal)
+        'sv': 'sv_SE',      # Swedish
+        'no': 'nb_NO',      # Norwegian Bokmål
+        'hi': 'in_HI',      # Hindi
+        'cs': 'en',         # Czech not supported by timeago, fallback to English
+        'en_GB': 'en',      # British English - timeago uses 'en'
+        'en_US': 'en',      # American English - timeago uses 'en'
+    }
+    return locale_map.get(flask_locale, flask_locale)
+
+# Language metadata: flag icon CSS class and native name
+# Using flag-icons library: https://flagicons.lipis.dev/
+LANGUAGE_DATA = {
+    'en_GB': {'flag': 'fi fi-gb fis', 'name': 'English (UK)'},
+    'en_US': {'flag': 'fi fi-us fis', 'name': 'English (US)'},
+    'de': {'flag': 'fi fi-de fis', 'name': 'Deutsch'},
+    'fr': {'flag': 'fi fi-fr fis', 'name': 'Français'},
+    'ko': {'flag': 'fi fi-kr fis', 'name': '한국어'},
+    'cs': {'flag': 'fi fi-cz fis', 'name': 'Čeština'},
+    'es': {'flag': 'fi fi-es fis', 'name': 'Español'},
+    'pt': {'flag': 'fi fi-pt fis', 'name': 'Português'},
+    'it': {'flag': 'fi fi-it fis', 'name': 'Italiano'},
+    'ja': {'flag': 'fi fi-jp fis', 'name': '日本語'},
+    'zh': {'flag': 'fi fi-cn fis', 'name': '中文 (简体)'},
+    'zh_Hant_TW': {'flag': 'fi fi-tw fis', 'name': '繁體中文'},
+    'ru': {'flag': 'fi fi-ru fis', 'name': 'Русский'},
+    'pl': {'flag': 'fi fi-pl fis', 'name': 'Polski'},
+    'nl': {'flag': 'fi fi-nl fis', 'name': 'Nederlands'},
+    'sv': {'flag': 'fi fi-se fis', 'name': 'Svenska'},
+    'da': {'flag': 'fi fi-dk fis', 'name': 'Dansk'},
+    'no': {'flag': 'fi fi-no fis', 'name': 'Norsk'},
+    'fi': {'flag': 'fi fi-fi fis', 'name': 'Suomi'},
+    'tr': {'flag': 'fi fi-tr fis', 'name': 'Türkçe'},
+    'ar': {'flag': 'fi fi-sa fis', 'name': 'العربية'},
+    'hi': {'flag': 'fi fi-in fis', 'name': 'हिन्दी'},
+}
+
+
+def get_available_languages():
+    """
+    Discover available languages by scanning the translations directory
+    Returns a dict of available languages with their metadata
+    """
+    translations_dir = Path(__file__).parent / 'translations'
+
+    available = {}
+
+    # Scan for translation directories
+    if translations_dir.exists():
+        for lang_dir in translations_dir.iterdir():
+            if lang_dir.is_dir() and lang_dir.name in LANGUAGE_DATA:
+                # Check if messages.po exists
+                po_file = lang_dir / 'LC_MESSAGES' / 'messages.po'
+                if po_file.exists():
+                    available[lang_dir.name] = LANGUAGE_DATA[lang_dir.name]
+
+    # If no English variants found, fall back to adding en_GB as default
+    if 'en_GB' not in available and 'en_US' not in available:
+        available['en_GB'] = LANGUAGE_DATA['en_GB']
+
+    return available
+
+
+def get_language_codes():
+    """Get list of available language codes"""
+    return list(get_available_languages().keys())
+
+
+def get_flag_for_locale(locale):
+    """Get flag emoji for a locale, or globe if unknown"""
+    return LANGUAGE_DATA.get(locale, {}).get('flag', '🌐')
+
+
+def get_name_for_locale(locale):
+    """Get native name for a locale"""
+    return LANGUAGE_DATA.get(locale, {}).get('name', locale.upper())

changedetectionio/model/App.py

@@ -1,7 +1,7 @@
 from os import getenv
 from copy import deepcopy
 
-from changedetectionio.blueprint.rss import RSS_FORMAT_TYPES
+from changedetectionio.blueprint.rss import RSS_FORMAT_TYPES, RSS_CONTENT_FORMAT_DEFAULT
 
 from changedetectionio.notification import (
     default_notification_body,
@@ -37,6 +37,8 @@ class model(dict):
                 },
                 'application': {
                     # Custom notification content
+                    'all_paused': False,
+                    'all_muted': False,
                     'api_access_token_enabled': True,
                     'base_url' : None,
                     'empty_pages_are_a_change': False,
@@ -46,6 +48,7 @@ class model(dict):
                     'global_subtractive_selectors': [],
                     'ignore_whitespace': True,
                     'ignore_status_codes': False, #@todo implement, as ternary.
+                    'ssim_threshold': '0.96',  # Default SSIM threshold for screenshot comparison
                     'notification_body': default_notification_body,
                     'notification_format': default_notification_format,
                     'notification_title': default_notification_title,
@@ -54,7 +57,10 @@ class model(dict):
                     'password': False,
                     'render_anchor_tag_content': False,
                     'rss_access_token': None,
-                    'rss_content_format': RSS_FORMAT_TYPES[0][0],
+                    'rss_content_format': RSS_CONTENT_FORMAT_DEFAULT,
+                    'rss_template_type': 'system_default',
+                    'rss_template_override': None,
+                    'rss_diff_length': 5,
                     'rss_hide_muted_watches': True,
                     'rss_reader_mode': False,
                     'scheduler_timezone_default': None,  # Default IANA timezone name
@@ -81,7 +87,7 @@ class model(dict):
 
 def parse_headers_from_text_file(filepath):
     headers = {}
-    with open(filepath, 'r') as f:
+    with open(filepath, 'r', encoding='utf-8') as f:
         for l in f.readlines():
             l = l.strip()
             if not l.startswith('#') and ':' in l:

changedetectionio/model/Watch.py

@@ -10,15 +10,70 @@ from pathlib import Path
 from loguru import logger
 
 from .. import jinja2_custom as safe_jinja
-from ..diff import ADDED_PLACEMARKER_OPEN
 from ..html_tools import TRANSLATE_WHITESPACE_TABLE
 
 FAVICON_RESAVE_THRESHOLD_SECONDS=86400
-
+BROTLI_COMPRESS_SIZE_THRESHOLD = int(os.getenv('SNAPSHOT_BROTLI_COMPRESSION_THRESHOLD', 1024))
 
 minimum_seconds_recheck_time = int(os.getenv('MINIMUM_SECONDS_RECHECK_TIME', 3))
 mtable = {'seconds': 1, 'minutes': 60, 'hours': 3600, 'days': 86400, 'weeks': 86400 * 7}
 
+def _brotli_save(contents, filepath, mode=None, fallback_uncompressed=False):
+    """
+    Save compressed data using native brotli.
+    Testing shows no memory leak when using gc.collect() after compression.
+
+    Args:
+        contents: data to compress (str or bytes)
+        filepath: destination file path
+        mode: brotli compression mode (e.g., brotli.MODE_TEXT)
+        fallback_uncompressed: if True, save uncompressed on failure; if False, raise exception
+
+    Returns:
+        str: actual filepath saved (may differ from input if fallback used)
+
+    Raises:
+        Exception: if compression fails and fallback_uncompressed is False
+    """
+    import brotli
+    import gc
+
+    # Ensure contents are bytes
+    if isinstance(contents, str):
+        contents = contents.encode('utf-8')
+
+    try:
+        logger.debug(f"Starting brotli compression of {len(contents)} bytes.")
+
+        if mode is not None:
+            compressed_data = brotli.compress(contents, mode=mode)
+        else:
+            compressed_data = brotli.compress(contents)
+
+        with open(filepath, 'wb') as f:
+            f.write(compressed_data)
+
+        logger.debug(f"Finished brotli compression - From {len(contents)} to {len(compressed_data)} bytes.")
+
+        # Force garbage collection to prevent memory buildup
+        gc.collect()
+
+        return filepath
+
+    except Exception as e:
+        logger.error(f"Brotli compression error: {e}")
+
+        # Compression failed
+        if fallback_uncompressed:
+            logger.warning(f"Brotli compression failed for {filepath}, saving uncompressed")
+            fallback_path = filepath.replace('.br', '')
+            with open(fallback_path, 'wb') as f:
+                f.write(contents)
+            return fallback_path
+        else:
+            raise Exception(f"Brotli compression failed for {filepath}: {e}")
+
+
 class model(watch_base):
     __newest_history_key = None
     __history_n = 0
@@ -93,11 +148,29 @@ class model(watch_base):
         domain = parsed.hostname
         return domain
 
+    @property
+    def history_index_filename(self):
+        # So that you dont try to view different histories in different 'diff' setups, can confuse cdio.
+        processor = self.get('processor')
+        if not processor or self.get('processor') == 'text_json_diff':
+            return 'history.txt'
+        else:
+            return f'history-{processor}.txt'
+
     def clear_watch(self):
         import pathlib
 
+        # Get list of processor config files to preserve
+        from changedetectionio.processors import find_processors
+        processor_names = [name for cls, name in find_processors()]
+        processor_config_files = {f"{name}.json" for name in processor_names}
+
         # JSON Data, Screenshots, Textfiles (history index and snapshots), HTML in the future etc
+        # But preserve processor config files (they're configuration, not history data)
         for item in pathlib.Path(str(self.watch_data_dir)).rglob("*.*"):
+            # Skip processor config files
+            if item.name in processor_config_files:
+                continue
             os.unlink(item)
 
         # Force the attr to recalculate
@@ -185,22 +258,25 @@ class model(watch_base):
             return []
 
         # Read the history file as a dict
-        fname = os.path.join(self.watch_data_dir, "history.txt")
+        fname = os.path.join(self.watch_data_dir, self.history_index_filename)
         if os.path.isfile(fname):
             logger.debug(f"Reading watch history index for {self.get('uuid')}")
-            with open(fname, "r") as f:
+            with open(fname, "r", encoding='utf-8') as f:
                 for i in f.readlines():
                     if ',' in i:
                         k, v = i.strip().split(',', 2)
 
                         # The index history could contain a relative path, so we need to make the fullpath
                         # so that python can read it
-                        if not '/' in v and not '\'' in v:
+                        # Cross-platform: check for any path separator (works on Windows and Unix)
+                        if os.sep not in v and '/' not in v and '\\' not in v:
+                            # Relative filename only, no path separators
                             v = os.path.join(self.watch_data_dir, v)
                         else:
                             # It's possible that they moved the datadir on older versions
                             # So the snapshot exists but is in a different path
-                            snapshot_fname = v.split('/')[-1]
+                            # Cross-platform: use os.path.basename instead of split('/')
+                            snapshot_fname = os.path.basename(v)
                             proposed_new_path = os.path.join(self.watch_data_dir, snapshot_fname)
                             if not os.path.exists(v) and os.path.exists(proposed_new_path):
                                 v = proposed_new_path
@@ -218,7 +294,7 @@ class model(watch_base):
 
     @property
     def has_history(self):
-        fname = os.path.join(self.watch_data_dir, "history.txt")
+        fname = os.path.join(self.watch_data_dir, self.history_index_filename)
         return os.path.isfile(fname)
 
     @property
@@ -276,65 +352,120 @@ class model(watch_base):
         # When the 'last viewed' timestamp is less than the oldest snapshot, return oldest
         return sorted_keys[-1]
 
-    def get_history_snapshot(self, timestamp):
+    def get_history_snapshot(self, timestamp=None, filepath=None):
+        """
+        Accepts either timestamp or filepath
+        :param timestamp:
+        :param filepath:
+        :return:
+        """
         import brotli
-        filepath = self.history[timestamp]
 
-        # See if a brotli versions exists and switch to that
-        if not filepath.endswith('.br') and os.path.isfile(f"{filepath}.br"):
-            filepath = f"{filepath}.br"
+        if not filepath:
+            filepath = self.history[timestamp]
 
-        # OR in the backup case that the .br does not exist, but the plain one does
-        if filepath.endswith('.br') and not os.path.isfile(filepath):
-            if os.path.isfile(filepath.replace('.br', '')):
-                filepath = filepath.replace('.br', '')
+        # Check if binary file (image, PDF, etc.)
+        # Binary files are NEVER saved with .br compression, only text files are
+        binary_extensions = ('.png', '.jpg', '.jpeg', '.gif', '.webp', '.pdf', '.bin', '.jfif')
+        is_binary = any(filepath.endswith(ext) for ext in binary_extensions)
 
+        # Only look for .br versions for text files
+        if not is_binary:
+            # See if a brotli version exists and switch to that (text files only)
+            if not filepath.endswith('.br') and os.path.isfile(f"{filepath}.br"):
+                filepath = f"{filepath}.br"
+
+            # OR in the backup case that the .br does not exist, but the plain one does
+            if filepath.endswith('.br') and not os.path.isfile(filepath):
+                if os.path.isfile(filepath.replace('.br', '')):
+                    filepath = filepath.replace('.br', '')
+
+        # Handle .br compressed text files
         if filepath.endswith('.br'):
             # Brotli doesnt have a fileheader to detect it, so we rely on filename
             # https://www.rfc-editor.org/rfc/rfc7932
+            # Note: .br should ONLY exist for text files, never binary
             with open(filepath, 'rb') as f:
-                return(brotli.decompress(f.read()).decode('utf-8'))
+                return brotli.decompress(f.read()).decode('utf-8')
 
+        # Binary file - return raw bytes
+        if is_binary:
+            with open(filepath, 'rb') as f:
+                return f.read()
+
+        # Text file - decode to string
         with open(filepath, 'r', encoding='utf-8', errors='ignore') as f:
             return f.read()
 
-   # Save some text file to the appropriate path and bump the history
-    # result_obj from fetch_site_status.run()
-    def save_history_text(self, contents, timestamp, snapshot_id):
-        import brotli
-        import tempfile
-        logger.trace(f"{self.get('uuid')} - Updating history.txt with timestamp {timestamp}")
-
-        self.ensure_data_dir_exists()
-
-        threshold = int(os.getenv('SNAPSHOT_BROTLI_COMPRESSION_THRESHOLD', 1024))
-        skip_brotli = strtobool(os.getenv('DISABLE_BROTLI_TEXT_SNAPSHOT', 'False'))
-
-        # Decide on snapshot filename and destination path
-        if not skip_brotli and len(contents) > threshold:
-            snapshot_fname = f"{snapshot_id}.txt.br"
-            encoded_data = brotli.compress(contents.encode('utf-8'), mode=brotli.MODE_TEXT)
-        else:
-            snapshot_fname = f"{snapshot_id}.txt"
-            encoded_data = contents.encode('utf-8')
-
-        dest = os.path.join(self.watch_data_dir, snapshot_fname)
-
-        # Write snapshot file atomically if it doesn't exist
+    def _write_atomic(self, dest, data):
+        """Write data atomically to dest using a temp file"""
         if not os.path.exists(dest):
+            import tempfile
             with tempfile.NamedTemporaryFile('wb', delete=False, dir=self.watch_data_dir) as tmp:
-                tmp.write(encoded_data)
+                tmp.write(data)
                 tmp.flush()
                 os.fsync(tmp.fileno())
                 tmp_path = tmp.name
-            os.rename(tmp_path, dest)
+            os.replace(tmp_path, dest)
+
+    # Save some text file to the appropriate path and bump the history
+    # result_obj from fetch_site_status.run()
+    def save_history_blob(self, contents, timestamp, snapshot_id):
+
+        logger.trace(f"{self.get('uuid')} - Updating {self.history_index_filename} with timestamp {timestamp}")
+
+        self.ensure_data_dir_exists()
+
+        skip_brotli = strtobool(os.getenv('DISABLE_BROTLI_TEXT_SNAPSHOT', 'False'))
+
+        # Binary data - detect file type and save without compression
+        if isinstance(contents, bytes):
+            try:
+                import puremagic
+                detections = puremagic.magic_string(contents[:2048])
+                ext = detections[0].extension if detections else 'bin'
+                # Strip leading dot if present (puremagic returns extensions like '.jfif')
+                ext = ext.lstrip('.')
+                if detections:
+                    logger.trace(f"Detected file type: {detections[0].mime_type} -> extension: {ext}")
+            except Exception as e:
+                logger.warning(f"puremagic detection failed: {e}, using 'bin' extension")
+                ext = 'bin'
+
+            snapshot_fname = f"{snapshot_id}.{ext}"
+            dest = os.path.join(self.watch_data_dir, snapshot_fname)
+            self._write_atomic(dest, contents)
+            logger.trace(f"Saved binary snapshot as {snapshot_fname} ({len(contents)} bytes)")
+
+        # Text data - use brotli compression if enabled and above threshold
+        else:
+            if not skip_brotli and len(contents) > BROTLI_COMPRESS_SIZE_THRESHOLD:
+                # Compressed text
+                import brotli
+                snapshot_fname = f"{snapshot_id}.txt.br"
+                dest = os.path.join(self.watch_data_dir, snapshot_fname)
+
+                if not os.path.exists(dest):
+                    try:
+                        actual_dest = _brotli_save(contents, dest, mode=brotli.MODE_TEXT, fallback_uncompressed=True)
+                        if actual_dest != dest:
+                            snapshot_fname = os.path.basename(actual_dest)
+                    except Exception as e:
+                        logger.error(f"{self.get('uuid')} - Brotli compression failed: {e}")
+                        # Fallback to uncompressed
+                        snapshot_fname = f"{snapshot_id}.txt"
+                        dest = os.path.join(self.watch_data_dir, snapshot_fname)
+                        self._write_atomic(dest, contents.encode('utf-8'))
+            else:
+                # Plain text
+                snapshot_fname = f"{snapshot_id}.txt"
+                dest = os.path.join(self.watch_data_dir, snapshot_fname)
+                self._write_atomic(dest, contents.encode('utf-8'))
 
         # Append to history.txt atomically
-        index_fname = os.path.join(self.watch_data_dir, "history.txt")
+        index_fname = os.path.join(self.watch_data_dir, self.history_index_filename)
         index_line = f"{timestamp},{snapshot_fname}\n"
 
-        # Lets try force flush here since it's usually a very small file
-        # If this still fails in the future then try reading all to memory first, re-writing etc
         with open(index_fname, 'a', encoding='utf-8') as f:
             f.write(index_line)
             f.flush()
@@ -382,7 +513,7 @@ class model(watch_base):
         # Compare each lines (set) against each history text file (set) looking for something new..
         existing_history = set({})
         for k, v in self.history.items():
-            content = self.get_history_snapshot(k)
+            content = self.get_history_snapshot(filepath=v)
 
             if ignore_whitespace:
                 alist = set([line.translate(TRANSLATE_WHITESPACE_TABLE).lower() for line in content.splitlines()])
@@ -586,7 +717,7 @@ class model(watch_base):
         """Return the text saved from a previous request that resulted in a non-200 error"""
         fname = os.path.join(self.watch_data_dir, "last-error.txt")
         if os.path.isfile(fname):
-            with open(fname, 'r') as f:
+            with open(fname, 'r', encoding='utf-8') as f:
                 return f.read()
         return False
 
@@ -639,7 +770,7 @@ class model(watch_base):
         for k, fname in self.history.items():
             if os.path.isfile(fname):
                 if True:
-                    contents = self.get_history_snapshot(k)
+                    contents = self.get_history_snapshot(timestamp=k)
                     res = re.findall(regex, contents, re.MULTILINE)
                     if res:
                         if not csv_writer:
@@ -732,7 +863,7 @@ class model(watch_base):
             # If a previous attempt doesnt yet exist, just snarf the previous snapshot instead
             dates = list(self.history.keys())
             if len(dates):
-                return self.get_history_snapshot(dates[-1])
+                return self.get_history_snapshot(timestamp=dates[-1])
             else:
                 return ''
 
@@ -742,25 +873,13 @@ class model(watch_base):
     def save_last_text_fetched_before_filters(self, contents):
         import brotli
         filepath = os.path.join(self.watch_data_dir, 'last-fetched.br')
-        with open(filepath, 'wb') as f:
-            f.write(brotli.compress(contents, mode=brotli.MODE_TEXT))
+        _brotli_save(contents, filepath, mode=brotli.MODE_TEXT, fallback_uncompressed=False)
 
     def save_last_fetched_html(self, timestamp, contents):
-        import brotli
-
         self.ensure_data_dir_exists()
         snapshot_fname = f"{timestamp}.html.br"
         filepath = os.path.join(self.watch_data_dir, snapshot_fname)
-
-        with open(filepath, 'wb') as f:
-            contents = contents.encode('utf-8') if isinstance(contents, str) else contents
-            try:
-                f.write(brotli.compress(contents))
-            except Exception as e:
-                logger.warning(f"{self.get('uuid')} - Unable to compress snapshot, saving as raw data to {filepath}")
-                logger.warning(e)
-                f.write(contents)
-
+        _brotli_save(contents, filepath, mode=None, fallback_uncompressed=True)
         self._prune_last_fetched_html_snapshots()
 
     def get_fetched_html(self, timestamp):
@@ -818,6 +937,7 @@ class model(watch_base):
         # has app+request context, we can use url_for()
         if has_app_context:
             if last_error:
+                last_error = safe_jinja.render_fully_escaped(last_error)
                 if '403' in last_error:
                     if has_proxies:
                         output.append(str(Markup(f"{last_error} - <a href=\"{url_for('settings.settings_page', uuid=self.get('uuid'))}\">Try other proxies/location</a>&nbsp;'")))
@@ -827,7 +947,9 @@ class model(watch_base):
                     output.append(str(Markup(last_error)))
 
             if self.get('last_notification_error'):
-                output.append(str(Markup(f"<div class=\"notification-error\"><a href=\"{url_for('settings.notification_logs')}\">{ self.get('last_notification_error') }</a></div>")))
+                txt = safe_jinja.render_fully_escaped(self.get('last_notification_error'))
+                result = f'<div class="notification-error"><a href="{url_for("settings.notification_logs")}">{txt}</a></div>'
+                output.append(result)
 
         else:
             # Lo_Fi version - no app context, cant rely on Jinja2 Markup

changedetectionio/notification/handler.py

@@ -1,5 +1,6 @@
 
 import time
+import re
 import apprise
 from apprise import NotifyFormat
 from loguru import logger
@@ -11,11 +12,10 @@ from ..diff import HTML_REMOVED_STYLE, REMOVED_PLACEMARKER_OPEN, REMOVED_PLACEMA
     CHANGED_PLACEMARKER_CLOSED, HTML_CHANGED_STYLE, HTML_CHANGED_INTO_STYLE
 import re
 
-from ..notification_service import NotificationContextData
+from ..notification_service import NotificationContextData, add_rendered_diff_to_notification_vars
 
 newline_re = re.compile(r'\r\n|\r|\n')
 
-
 def markup_text_links_to_html(body):
     """
     Convert plaintext to HTML with clickable links.
@@ -79,6 +79,24 @@ def notification_format_align_with_apprise(n_format : str):
 
     return n_format
 
+
+def apply_html_color_to_body(n_body: str):
+    # https://github.com/dgtlmoon/changedetection.io/issues/821#issuecomment-1241837050
+    n_body = n_body.replace(REMOVED_PLACEMARKER_OPEN,
+                            f'<span style="{HTML_REMOVED_STYLE}" role="deletion" aria-label="Removed text" title="Removed text">')
+    n_body = n_body.replace(REMOVED_PLACEMARKER_CLOSED, f'</span>')
+    n_body = n_body.replace(ADDED_PLACEMARKER_OPEN,
+                            f'<span style="{HTML_ADDED_STYLE}" role="insertion" aria-label="Added text" title="Added text">')
+    n_body = n_body.replace(ADDED_PLACEMARKER_CLOSED, f'</span>')
+    # Handle changed/replaced lines (old → new)
+    n_body = n_body.replace(CHANGED_PLACEMARKER_OPEN,
+                            f'<span style="{HTML_CHANGED_STYLE}" role="note" aria-label="Changed text" title="Changed text">')
+    n_body = n_body.replace(CHANGED_PLACEMARKER_CLOSED, f'</span>')
+    n_body = n_body.replace(CHANGED_INTO_PLACEMARKER_OPEN,
+                            f'<span style="{HTML_CHANGED_INTO_STYLE}" role="note" aria-label="Changed into" title="Changed into">')
+    n_body = n_body.replace(CHANGED_INTO_PLACEMARKER_CLOSED, f'</span>')
+    return n_body
+
 def apply_discord_markdown_to_body(n_body):
     """
     Discord does not support <del> but it supports non-standard ~~strikethrough~~
@@ -187,6 +205,8 @@ def replace_placemarkers_in_text(text, url, requested_output_format):
 
 def apply_service_tweaks(url, n_body, n_title, requested_output_format):
 
+    logger.debug(f"Applying markup in '{requested_output_format}' mode")
+
     # Re 323 - Limit discord length to their 2000 char limit total or it wont send.
     # Because different notifications may require different pre-processing, run each sequentially :(
     # 2000 bytes minus -
@@ -331,6 +351,16 @@ def process_notification(n_object: NotificationContextData, datastore):
     if not n_object.get('notification_urls'):
         return None
 
+    n_object.update(add_rendered_diff_to_notification_vars(
+        notification_scan_text=n_object.get('notification_body', '')+n_object.get('notification_title', ''),
+        current_snapshot=n_object.get('current_snapshot'),
+        prev_snapshot=n_object.get('prev_snapshot'),
+        # Should always be false for 'text' mode or its too hard to read
+        # But otherwise, this could be some setting
+        word_diff=False if requested_output_format_original == 'text' else True,
+        )
+    )
+
     with (apprise.LogCapture(level=apprise.logging.DEBUG) as logs):
         for url in n_object['notification_urls']:
 
@@ -397,11 +427,15 @@ def process_notification(n_object: NotificationContextData, datastore):
                     apprise_input_format = NotifyFormat.TEXT.value
                     requested_output_format = NotifyFormat.TEXT.value
 
-
+#@todo on null:// (only if its a 1 url with null) probably doesnt need to actually .add/setup/etc
             sent_objs.append({'title': n_title,
                               'body': n_body,
-                              'url': url})
-            apobj.add(url)
+                              'url': url,
+                              # So that we can do a null:// call and get back exactly what would have been sent
+                              'original_context': n_object })
+
+            if not url.startswith('null://'):
+                apobj.add(url)
 
             # Since the output is always based on the plaintext of the 'diff' engine, wrap it nicely.
             # It should always be similar to the 'history' part of the UI.
@@ -409,15 +443,16 @@ def process_notification(n_object: NotificationContextData, datastore):
                 if not '<pre' in n_body and not '<body' in n_body: # No custom HTML-ish body was setup already
                     n_body = as_monospaced_html_email(content=n_body, title=n_title)
 
-        apobj.notify(
-            title=n_title,
-            body=n_body,
-            # `body_format` Tell apprise what format the INPUT is in, specify a wrong/bad type and it will force skip conversion in apprise
-            # &format= in URL Tell apprise what format the OUTPUT should be in (it can convert between)
-            body_format=apprise_input_format,
-            # False is not an option for AppRise, must be type None
-            attach=n_object.get('screenshot', None)
-        )
+        if not url.startswith('null://'):
+            apobj.notify(
+                title=n_title,
+                body=n_body,
+                # `body_format` Tell apprise what format the INPUT is in, specify a wrong/bad type and it will force skip conversion in apprise
+                # &format= in URL Tell apprise what format the OUTPUT should be in (it can convert between)
+                body_format=apprise_input_format,
+                # False is not an option for AppRise, must be type None
+                attach=n_object.get('screenshot', None)
+            )
 
         # Returns empty string if nothing found, multi-line string otherwise
         log_value = logs.getvalue()
@@ -436,6 +471,8 @@ def create_notification_parameters(n_object: NotificationContextData, datastore)
     if not isinstance(n_object, NotificationContextData):
         raise TypeError(f"Expected NotificationContextData, got {type(n_object)}")
 
+    ext_base_url = datastore.data['settings']['application'].get('active_base_url').strip('/')+'/'
+
     watch = datastore.data['watching'].get(n_object['uuid'])
     if watch:
         watch_title = datastore.data['watching'][n_object['uuid']].label
@@ -449,20 +486,29 @@ def create_notification_parameters(n_object: NotificationContextData, datastore)
         watch_title = 'Change Detection'
         watch_tag = ''
 
-    # Create URLs to customise the notification with
-    # active_base_url - set in store.py data property
-    base_url = datastore.data['settings']['application'].get('active_base_url')
-
     watch_url = n_object['watch_url']
 
-    diff_url = "{}/diff/{}".format(base_url, n_object['uuid'])
-    preview_url = "{}/preview/{}".format(base_url, n_object['uuid'])
+    # Build URLs manually instead of using url_for() to avoid requiring a request context
+    # This allows notifications to be processed in background threads
+    uuid = n_object['uuid']
 
+    if n_object.get('timestamp_from') and n_object.get('timestamp_to'):
+        # Include a link to the diff page with specific versions
+        diff_url = f"{ext_base_url}diff/{uuid}?from_version={n_object['timestamp_from']}&to_version={n_object['timestamp_to']}"
+    else:
+        diff_url = f"{ext_base_url}diff/{uuid}"
+
+    preview_url = f"{ext_base_url}preview/{uuid}"
+    edit_url = f"{ext_base_url}edit/{uuid}"
+
+    # @todo test that preview_url is correct when running in not-null mode?
+    # if not, first time app loads i think it can set a flask context
     n_object.update(
         {
-            'base_url': base_url,
+            'base_url': ext_base_url,
             'diff_url': diff_url,
-            'preview_url': preview_url,
+            'preview_url': preview_url, #@todo include 'version='
+            'edit_url': edit_url, #@todo also pause, also mute link
             'watch_tag': watch_tag if watch_tag is not None else '',
             'watch_title': watch_title if watch_title is not None else '',
             'watch_url': watch_url,

changedetectionio/notification_service.py

@@ -5,13 +5,54 @@ Notification Service Module
 Extracted from update_worker.py to provide standalone notification functionality
 for both sync and async workers
 """
+import datetime
 
+import pytz
 from loguru import logger
 import time
 
 from changedetectionio.notification import default_notification_format, valid_notification_formats
 
 
+def _check_cascading_vars(datastore, var_name, watch):
+    """
+    Check notification variables in cascading priority:
+    Individual watch settings > Tag settings > Global settings
+    """
+    from changedetectionio.notification import (
+        USE_SYSTEM_DEFAULT_NOTIFICATION_FORMAT_FOR_WATCH,
+        default_notification_body,
+        default_notification_title
+    )
+
+    # Would be better if this was some kind of Object where Watch can reference the parent datastore etc
+    v = watch.get(var_name)
+    if v and not watch.get('notification_muted'):
+        if var_name == 'notification_format' and v == USE_SYSTEM_DEFAULT_NOTIFICATION_FORMAT_FOR_WATCH:
+            return datastore.data['settings']['application'].get('notification_format')
+
+        return v
+
+    tags = datastore.get_all_tags_for_watch(uuid=watch.get('uuid'))
+    if tags:
+        for tag_uuid, tag in tags.items():
+            v = tag.get(var_name)
+            if v and not tag.get('notification_muted'):
+                return v
+
+    if datastore.data['settings']['application'].get(var_name):
+        return datastore.data['settings']['application'].get(var_name)
+
+    # Otherwise could be defaults
+    if var_name == 'notification_format':
+        return USE_SYSTEM_DEFAULT_NOTIFICATION_FORMAT_FOR_WATCH
+    if var_name == 'notification_body':
+        return default_notification_body
+    if var_name == 'notification_title':
+        return default_notification_title
+
+    return None
+
 
 # What is passed around as notification context, also used as the complete list of valid {{ tokens }}
 class NotificationContextData(dict):
@@ -34,6 +75,8 @@ class NotificationContextData(dict):
             'preview_url': None,
             'screenshot': None,
             'triggered_text': None,
+            'timestamp_from': None,
+            'timestamp_to': None,
             'uuid': 'XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX',  # Converted to 'watch_uuid' in create_notification_parameters
             'watch_mime_type': None,
             'watch_tag': None,
@@ -72,23 +115,90 @@ class NotificationContextData(dict):
 
         super().__setitem__(key, value)
 
+def timestamp_to_localtime(timestamp):
+    # Format the date using locale-aware formatting with timezone
+    dt = datetime.datetime.fromtimestamp(int(timestamp))
+    dt = dt.replace(tzinfo=pytz.UTC)
 
-def set_basic_notification_vars(snapshot_contents, current_snapshot, prev_snapshot, watch, triggered_text):
-    now = time.time()
+    # Get local timezone-aware datetime
+    local_tz = datetime.datetime.now().astimezone().tzinfo
+    local_dt = dt.astimezone(local_tz)
+
+    # Format date with timezone - using strftime for locale awareness
+    try:
+        formatted_date = local_dt.strftime('%Y-%m-%d %H:%M:%S %Z')
+    except:
+        # Fallback if locale issues
+        formatted_date = local_dt.isoformat()
+
+    return formatted_date
+
+def add_rendered_diff_to_notification_vars(notification_scan_text:str, prev_snapshot:str, current_snapshot:str, word_diff:bool):
+    """
+    Efficiently renders only the diff placeholders that are actually used in the notification text.
+
+    Scans the notification template for diff placeholder usage (diff, diff_added, diff_clean, etc.)
+    and only renders those specific variants, avoiding expensive render_diff() calls for unused placeholders.
+    Uses LRU caching to avoid duplicate renders when multiple placeholders share the same arguments.
+
+    Args:
+        notification_scan_text: The notification template text to scan for placeholders
+        prev_snapshot: Previous version of content for diff comparison
+        current_snapshot: Current version of content for diff comparison
+        word_diff: Whether to use word-level (True) or line-level (False) diffing
+
+    Returns:
+        dict: Only the diff placeholders that were found in notification_scan_text, with rendered content
+    """
     from changedetectionio import diff
+    import re
+    from functools import lru_cache
+
+    now = time.time()
+
+    # Define specifications for each diff variant
+    diff_specs = {
+        'diff': {'word_diff': word_diff},
+        'diff_clean': {'word_diff': word_diff, 'include_change_type_prefix': False},
+        'diff_added': {'word_diff': word_diff, 'include_removed': False},
+        'diff_added_clean': {'word_diff': word_diff, 'include_removed': False, 'include_change_type_prefix': False},
+        'diff_full': {'word_diff': word_diff, 'include_equal': True},
+        'diff_full_clean': {'word_diff': word_diff, 'include_equal': True, 'include_change_type_prefix': False},
+        'diff_patch': {'word_diff': word_diff, 'patch_format': True},
+        'diff_removed': {'word_diff': word_diff, 'include_added': False},
+        'diff_removed_clean': {'word_diff': word_diff, 'include_added': False, 'include_change_type_prefix': False},
+    }
+
+    # Memoize render_diff to avoid duplicate renders with same kwargs
+    @lru_cache(maxsize=4)
+    def cached_render(kwargs_tuple):
+        return diff.render_diff(prev_snapshot, current_snapshot, **dict(kwargs_tuple))
+
+    ret = {}
+    rendered_count = 0
+    # Only check and render diff keys that exist in NotificationContextData
+    for key in NotificationContextData().keys():
+        if key.startswith('diff') and key in diff_specs:
+            # Check if this placeholder is actually used in the notification text
+            pattern = rf"(?<![A-Za-z0-9_]){re.escape(key)}(?![A-Za-z0-9_])"
+            if re.search(pattern, notification_scan_text, re.IGNORECASE):
+                kwargs = diff_specs[key]
+                # Convert dict to sorted tuple for cache key (handles duplicate kwarg combinations)
+                ret[key] = cached_render(tuple(sorted(kwargs.items())))
+                rendered_count += 1
+
+    if rendered_count:
+        logger.trace(f"Rendered {rendered_count} diff placeholder(s) {sorted(ret.keys())} in {time.time() - now:.3f}s")
+
+    return ret
+
+def set_basic_notification_vars(current_snapshot, prev_snapshot, watch, triggered_text, timestamp_changed=None):
 
     n_object = {
-        'current_snapshot': snapshot_contents,
-        'diff': diff.render_diff(prev_snapshot, current_snapshot),
-        'diff_clean': diff.render_diff(prev_snapshot, current_snapshot, include_change_type_prefix=False),
-        'diff_added': diff.render_diff(prev_snapshot, current_snapshot, include_removed=False),
-        'diff_added_clean': diff.render_diff(prev_snapshot, current_snapshot, include_removed=False, include_change_type_prefix=False),
-        'diff_full': diff.render_diff(prev_snapshot, current_snapshot, include_equal=True),
-        'diff_full_clean': diff.render_diff(prev_snapshot, current_snapshot, include_equal=True, include_change_type_prefix=False),
-        'diff_patch': diff.render_diff(prev_snapshot, current_snapshot, patch_format=True),
-        'diff_removed': diff.render_diff(prev_snapshot, current_snapshot, include_added=False),
-        'diff_removed_clean': diff.render_diff(prev_snapshot, current_snapshot, include_added=False, include_change_type_prefix=False),
+        'current_snapshot': current_snapshot,
+        'prev_snapshot': prev_snapshot,
         'screenshot': watch.get_screenshot() if watch and watch.get('notification_screenshot') else None,
+        'change_datetime': timestamp_to_localtime(timestamp_changed) if timestamp_changed else None,
         'triggered_text': triggered_text,
         'uuid': watch.get('uuid') if watch else None,
         'watch_url': watch.get('url') if watch else None,
@@ -101,7 +211,6 @@ def set_basic_notification_vars(snapshot_contents, current_snapshot, prev_snapsh
     if watch:
         n_object.update(watch.extra_notification_token_values())
 
-    logger.trace(f"Main rendered notification placeholders (diff_added etc) calculated in {time.time() - now:.3f}s")
     return n_object
 
 class NotificationService:
@@ -114,7 +223,7 @@ class NotificationService:
         self.datastore = datastore
         self.notification_q = notification_q
     
-    def queue_notification_for_watch(self, n_object: NotificationContextData, watch):
+    def queue_notification_for_watch(self, n_object: NotificationContextData, watch, date_index_from=-2, date_index_to=-1):
         """
         Queue a notification for a watch with full diff rendering and template variables
         """
@@ -133,7 +242,7 @@ class NotificationService:
 
         # Add text that was triggered
         if len(dates):
-            snapshot_contents = watch.get_history_snapshot(dates[-1])
+            snapshot_contents = watch.get_history_snapshot(timestamp=dates[-1])
         else:
             snapshot_contents = "No snapshot/history available, the watch should fetch atleast once."
 
@@ -154,57 +263,22 @@ class NotificationService:
         current_snapshot = "Example text: example test\nExample text: change detection is fantastic\nExample text: even more examples\nExample text: a lot more examples"
 
         if len(dates) > 1:
-            prev_snapshot = watch.get_history_snapshot(dates[-2])
-            current_snapshot = watch.get_history_snapshot(dates[-1])
+            prev_snapshot = watch.get_history_snapshot(timestamp=dates[date_index_from])
+            current_snapshot = watch.get_history_snapshot(timestamp=dates[date_index_to])
 
 
-        n_object.update(set_basic_notification_vars(snapshot_contents=snapshot_contents,
-                                                    current_snapshot=current_snapshot,
+        n_object.update(set_basic_notification_vars(current_snapshot=current_snapshot,
                                                     prev_snapshot=prev_snapshot,
                                                     watch=watch,
-                                                    triggered_text=triggered_text))
+                                                    triggered_text=triggered_text,
+                                                    timestamp_changed=dates[date_index_to]))
 
-        logger.debug("Queued notification for sending")
-        self.notification_q.put(n_object)
-
-    def _check_cascading_vars(self, var_name, watch):
-        """
-        Check notification variables in cascading priority:
-        Individual watch settings > Tag settings > Global settings
-        """
-        from changedetectionio.notification import (
-            USE_SYSTEM_DEFAULT_NOTIFICATION_FORMAT_FOR_WATCH,
-            default_notification_body,
-            default_notification_title
-        )
-
-        # Would be better if this was some kind of Object where Watch can reference the parent datastore etc
-        v = watch.get(var_name)
-        if v and not watch.get('notification_muted'):
-            if var_name == 'notification_format' and v == USE_SYSTEM_DEFAULT_NOTIFICATION_FORMAT_FOR_WATCH:
-                return self.datastore.data['settings']['application'].get('notification_format')
-
-            return v
-
-        tags = self.datastore.get_all_tags_for_watch(uuid=watch.get('uuid'))
-        if tags:
-            for tag_uuid, tag in tags.items():
-                v = tag.get(var_name)
-                if v and not tag.get('notification_muted'):
-                    return v
-
-        if self.datastore.data['settings']['application'].get(var_name):
-            return self.datastore.data['settings']['application'].get(var_name)
-
-        # Otherwise could be defaults
-        if var_name == 'notification_format':
-            return USE_SYSTEM_DEFAULT_NOTIFICATION_FORMAT_FOR_WATCH
-        if var_name == 'notification_body':
-            return default_notification_body
-        if var_name == 'notification_title':
-            return default_notification_title
-
-        return None
+        if self.notification_q:
+            logger.debug("Queued notification for sending")
+            self.notification_q.put(n_object)
+        else:
+            logger.debug("Not queued, no queue defined. Just returning processed data")
+            return n_object
 
     def send_content_changed_notification(self, watch_uuid):
         """
@@ -227,10 +301,11 @@ class NotificationService:
         # Should be a better parent getter in the model object
 
         # Prefer - Individual watch settings > Tag settings >  Global settings (in that order)
-        n_object['notification_urls'] = self._check_cascading_vars('notification_urls', watch)
-        n_object['notification_title'] = self._check_cascading_vars('notification_title', watch)
-        n_object['notification_body'] = self._check_cascading_vars('notification_body', watch)
-        n_object['notification_format'] = self._check_cascading_vars('notification_format', watch)
+        # this change probably not needed?
+        n_object['notification_urls'] = _check_cascading_vars(self.datastore, 'notification_urls', watch)
+        n_object['notification_title'] = _check_cascading_vars(self.datastore,'notification_title', watch)
+        n_object['notification_body'] = _check_cascading_vars(self.datastore,'notification_body', watch)
+        n_object['notification_format'] = _check_cascading_vars(self.datastore,'notification_format', watch)
 
         # (Individual watch) Only prepare to notify if the rules above matched
         queued = False
@@ -269,7 +344,7 @@ Thanks - Your omniscient changedetection.io installation.
         n_object = NotificationContextData({
             'notification_title': 'Changedetection.io - Alert - CSS/xPath filter was not present in the page',
             'notification_body': body,
-            'notification_format': self._check_cascading_vars('notification_format', watch),
+            'notification_format': _check_cascading_vars(self.datastore, 'notification_format', watch),
         })
         n_object['markup_text_links_to_html_links'] = n_object.get('notification_format').startswith('html')
 

changedetectionio/pluggy_interface.py

@@ -2,6 +2,7 @@ import pluggy
 import os
 import importlib
 import sys
+from loguru import logger
 
 # Global plugin namespace for changedetection.io
 PLUGIN_NAMESPACE = "changedetectionio"
@@ -16,15 +17,94 @@ class ChangeDetectionSpec:
     @hookspec
     def ui_edit_stats_extras(watch):
         """Return HTML content to add to the stats tab in the edit view.
-        
+
         Args:
             watch: The watch object being edited
-            
+
         Returns:
             str: HTML content to be inserted in the stats tab
         """
         pass
 
+    @hookspec
+    def register_content_fetcher(self):
+        """Return a tuple of (fetcher_name, fetcher_class) for content fetcher plugins.
+
+        The fetcher_name should start with 'html_' and the fetcher_class
+        should inherit from changedetectionio.content_fetchers.base.Fetcher
+
+        Returns:
+            tuple: (str: fetcher_name, class: fetcher_class)
+        """
+        pass
+
+    @hookspec
+    def fetcher_status_icon(fetcher_name):
+        """Return status icon HTML attributes for a content fetcher.
+
+        Args:
+            fetcher_name: The name of the fetcher (e.g., 'html_webdriver', 'html_js_zyte')
+
+        Returns:
+            str: HTML string containing <img> tags or other status icon elements
+                 Empty string if no custom status icon is needed
+        """
+        pass
+
+    @hookspec
+    def plugin_static_path(self):
+        """Return the path to the plugin's static files directory.
+
+        Returns:
+            str: Absolute path to the plugin's static directory, or None if no static files
+        """
+        pass
+
+    @hookspec
+    def get_itemprop_availability_override(self, content, fetcher_name, fetcher_instance, url):
+        """Provide custom implementation of get_itemprop_availability for a specific fetcher.
+
+        This hook allows plugins to provide their own product availability detection
+        when their fetcher is being used. This is called as a fallback when the built-in
+        method doesn't find good data.
+
+        Args:
+            content: The HTML/text content to parse
+            fetcher_name: The name of the fetcher being used (e.g., 'html_js_zyte')
+            fetcher_instance: The fetcher instance that generated the content
+            url: The URL being watched/checked
+
+        Returns:
+            dict or None: Dictionary with availability data:
+                {
+                    'price': float or None,
+                    'availability': str or None,  # e.g., 'in stock', 'out of stock'
+                    'currency': str or None,      # e.g., 'USD', 'EUR'
+                }
+                Or None if this plugin doesn't handle this fetcher or couldn't extract data
+        """
+        pass
+
+    @hookspec
+    def plugin_settings_tab(self):
+        """Return settings tab information for this plugin.
+
+        This hook allows plugins to add their own settings tab to the settings page.
+        Settings will be saved to a separate JSON file in the datastore directory.
+
+        Returns:
+            dict or None: Dictionary with settings tab information:
+                {
+                    'plugin_id': str,           # Unique identifier (e.g., 'zyte_fetcher')
+                    'tab_label': str,           # Display name for tab (e.g., 'Zyte Fetcher')
+                    'form_class': Form,         # WTForms Form class for the settings
+                    'template_path': str,       # Optional: path to Jinja2 template (relative to plugin)
+                                                # If not provided, a default form renderer will be used
+                }
+                Or None if this plugin doesn't provide settings
+        """
+        pass
+
 
 # Set up Plugin Manager
 plugin_manager = pluggy.PluginManager(PLUGIN_NAMESPACE)
@@ -65,18 +145,334 @@ load_plugins_from_directories()
 # Discover installed plugins from external packages (if any)
 plugin_manager.load_setuptools_entrypoints(PLUGIN_NAMESPACE)
 
+# Function to inject datastore into plugins that need it
+def inject_datastore_into_plugins(datastore):
+    """Inject the global datastore into plugins that need access to settings.
+
+    This should be called after plugins are loaded and datastore is initialized.
+
+    Args:
+        datastore: The global ChangeDetectionStore instance
+    """
+    for plugin_name, plugin_obj in plugin_manager.list_name_plugin():
+        # Check if plugin has datastore attribute and it's not set
+        if hasattr(plugin_obj, 'datastore'):
+            if plugin_obj.datastore is None:
+                plugin_obj.datastore = datastore
+                logger.debug(f"Injected datastore into plugin: {plugin_name}")
+
+# Function to register built-in fetchers - called later from content_fetchers/__init__.py
+def register_builtin_fetchers():
+    """Register built-in content fetchers as internal plugins
+
+    This is called from content_fetchers/__init__.py after all fetchers are imported
+    to avoid circular import issues.
+    """
+    from changedetectionio.content_fetchers import requests, playwright, puppeteer, webdriver_selenium
+
+    # Register each built-in fetcher plugin
+    if hasattr(requests, 'requests_plugin'):
+        plugin_manager.register(requests.requests_plugin, 'builtin_requests')
+
+    if hasattr(playwright, 'playwright_plugin'):
+        plugin_manager.register(playwright.playwright_plugin, 'builtin_playwright')
+
+    if hasattr(puppeteer, 'puppeteer_plugin'):
+        plugin_manager.register(puppeteer.puppeteer_plugin, 'builtin_puppeteer')
+
+    if hasattr(webdriver_selenium, 'webdriver_selenium_plugin'):
+        plugin_manager.register(webdriver_selenium.webdriver_selenium_plugin, 'builtin_webdriver_selenium')
+
 # Helper function to collect UI stats extras from all plugins
 def collect_ui_edit_stats_extras(watch):
     """Collect and combine HTML content from all plugins that implement ui_edit_stats_extras"""
     extras_content = []
-    
+
     # Get all plugins that implement the ui_edit_stats_extras hook
     results = plugin_manager.hook.ui_edit_stats_extras(watch=watch)
-    
+
     # If we have results, add them to our content
     if results:
         for result in results:
             if result:  # Skip empty results
                 extras_content.append(result)
-            
-    return "\n".join(extras_content) if extras_content else ""
+
+    return "\n".join(extras_content) if extras_content else ""
+
+def collect_fetcher_status_icons(fetcher_name):
+    """Collect status icon data from all plugins
+
+    Args:
+        fetcher_name: The name of the fetcher (e.g., 'html_webdriver', 'html_js_zyte')
+
+    Returns:
+        dict or None: Icon data dictionary from first matching plugin, or None
+    """
+    # Get status icon data from plugins
+    results = plugin_manager.hook.fetcher_status_icon(fetcher_name=fetcher_name)
+
+    # Return first non-None result
+    if results:
+        for result in results:
+            if result and isinstance(result, dict):
+                return result
+
+    return None
+
+def get_itemprop_availability_from_plugin(content, fetcher_name, fetcher_instance, url):
+    """Get itemprop availability data from plugins as a fallback.
+
+    This is called when the built-in get_itemprop_availability doesn't find good data.
+
+    Args:
+        content: The HTML/text content to parse
+        fetcher_name: The name of the fetcher being used (e.g., 'html_js_zyte')
+        fetcher_instance: The fetcher instance that generated the content
+        url: The URL being watched (watch.link - includes Jinja2 evaluation)
+
+    Returns:
+        dict or None: Availability data dictionary from first matching plugin, or None
+    """
+    # Get availability data from plugins
+    results = plugin_manager.hook.get_itemprop_availability_override(
+        content=content,
+        fetcher_name=fetcher_name,
+        fetcher_instance=fetcher_instance,
+        url=url
+    )
+
+    # Return first non-None result with actual data
+    if results:
+        for result in results:
+            if result and isinstance(result, dict):
+                # Check if the result has any meaningful data
+                if result.get('price') is not None or result.get('availability'):
+                    return result
+
+    return None
+
+
+def get_active_plugins():
+    """Get a list of active plugins with their descriptions.
+
+    Returns:
+        list: List of dictionaries with plugin information:
+            [
+                {'name': 'plugin_name', 'description': 'Plugin description'},
+                ...
+            ]
+    """
+    active_plugins = []
+
+    # Get all registered plugins
+    for plugin_name, plugin_obj in plugin_manager.list_name_plugin():
+        # Skip built-in plugins (they start with 'builtin_')
+        if plugin_name.startswith('builtin_'):
+            continue
+
+        # Get plugin description if available
+        description = None
+        if hasattr(plugin_obj, '__doc__') and plugin_obj.__doc__:
+            description = plugin_obj.__doc__.strip().split('\n')[0]  # First line only
+        elif hasattr(plugin_obj, 'description'):
+            description = plugin_obj.description
+
+        # Try to get a friendly name from the plugin
+        friendly_name = plugin_name
+        if hasattr(plugin_obj, 'name'):
+            friendly_name = plugin_obj.name
+
+        active_plugins.append({
+            'name': friendly_name,
+            'description': description or 'No description available'
+        })
+
+    return active_plugins
+
+
+def get_fetcher_capabilities(watch, datastore):
+    """Get capability flags for a watch's fetcher.
+
+    Args:
+        watch: The watch object/dict
+        datastore: The datastore to resolve 'system' fetcher
+
+    Returns:
+        dict: Dictionary with capability flags:
+            {
+                'supports_browser_steps': bool,
+                'supports_screenshots': bool,
+                'supports_xpath_element_data': bool
+            }
+    """
+    # Get the fetcher name from watch
+    fetcher_name = watch.get('fetch_backend', 'system')
+
+    # Resolve 'system' to actual fetcher
+    if fetcher_name == 'system':
+        fetcher_name = datastore.data['settings']['application'].get('fetch_backend', 'html_requests')
+
+    # Get the fetcher class
+    from changedetectionio import content_fetchers
+
+    # Try to get from built-in fetchers first
+    if hasattr(content_fetchers, fetcher_name):
+        fetcher_class = getattr(content_fetchers, fetcher_name)
+        return {
+            'supports_browser_steps': getattr(fetcher_class, 'supports_browser_steps', False),
+            'supports_screenshots': getattr(fetcher_class, 'supports_screenshots', False),
+            'supports_xpath_element_data': getattr(fetcher_class, 'supports_xpath_element_data', False)
+        }
+
+    # Try to get from plugin-provided fetchers
+    # Query all plugins for registered fetchers
+    plugin_fetchers = plugin_manager.hook.register_content_fetcher()
+    for fetcher_registration in plugin_fetchers:
+        if fetcher_registration:
+            name, fetcher_class = fetcher_registration
+            if name == fetcher_name:
+                return {
+                    'supports_browser_steps': getattr(fetcher_class, 'supports_browser_steps', False),
+                    'supports_screenshots': getattr(fetcher_class, 'supports_screenshots', False),
+                    'supports_xpath_element_data': getattr(fetcher_class, 'supports_xpath_element_data', False)
+                }
+
+    # Default: no capabilities
+    return {
+        'supports_browser_steps': False,
+        'supports_screenshots': False,
+        'supports_xpath_element_data': False
+    }
+
+
+def get_plugin_settings_tabs():
+    """Get all plugin settings tabs.
+
+    Returns:
+        list: List of dictionaries with plugin settings tab information:
+            [
+                {
+                    'plugin_id': str,
+                    'tab_label': str,
+                    'form_class': Form,
+                    'description': str
+                },
+                ...
+            ]
+    """
+    tabs = []
+    results = plugin_manager.hook.plugin_settings_tab()
+
+    for result in results:
+        if result and isinstance(result, dict):
+            # Validate required fields
+            if 'plugin_id' in result and 'tab_label' in result and 'form_class' in result:
+                tabs.append(result)
+            else:
+                logger.warning(f"Invalid plugin settings tab spec: {result}")
+
+    return tabs
+
+
+def load_plugin_settings(datastore_path, plugin_id):
+    """Load settings for a specific plugin from JSON file.
+
+    Args:
+        datastore_path: Path to the datastore directory
+        plugin_id: Unique identifier for the plugin (e.g., 'zyte_fetcher')
+
+    Returns:
+        dict: Plugin settings, or empty dict if file doesn't exist
+    """
+    import json
+    settings_file = os.path.join(datastore_path, f"{plugin_id}.json")
+
+    if not os.path.exists(settings_file):
+        return {}
+
+    try:
+        with open(settings_file, 'r', encoding='utf-8') as f:
+            return json.load(f)
+    except Exception as e:
+        logger.error(f"Failed to load settings for plugin '{plugin_id}': {e}")
+        return {}
+
+
+def save_plugin_settings(datastore_path, plugin_id, settings):
+    """Save settings for a specific plugin to JSON file.
+
+    Args:
+        datastore_path: Path to the datastore directory
+        plugin_id: Unique identifier for the plugin (e.g., 'zyte_fetcher')
+        settings: Dictionary of settings to save
+
+    Returns:
+        bool: True if save was successful, False otherwise
+    """
+    import json
+    settings_file = os.path.join(datastore_path, f"{plugin_id}.json")
+
+    try:
+        with open(settings_file, 'w', encoding='utf-8') as f:
+            json.dump(settings, f, indent=2, ensure_ascii=False)
+        logger.info(f"Saved settings for plugin '{plugin_id}' to {settings_file}")
+        return True
+    except Exception as e:
+        logger.error(f"Failed to save settings for plugin '{plugin_id}': {e}")
+        return False
+
+
+def get_plugin_template_paths():
+    """Get list of plugin template directories for Jinja2 loader.
+
+    Scans both external pluggy plugins and built-in processor plugins.
+
+    Returns:
+        list: List of absolute paths to plugin template directories
+    """
+    template_paths = []
+
+    # Add the base processors/templates directory (as absolute path)
+    processors_templates_dir = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'processors', 'templates')
+    if os.path.isdir(processors_templates_dir):
+        template_paths.append(processors_templates_dir)
+        logger.debug(f"Added base processors template path: {processors_templates_dir}")
+
+    # Scan built-in processor plugins
+    from changedetectionio.processors import find_processors
+    processor_list = find_processors()
+    for processor_module, processor_name in processor_list:
+        # Each processor is a module, check if it has a templates directory
+        if hasattr(processor_module, '__file__'):
+            processor_file = processor_module.__file__
+            if processor_file:
+                # Get the processor directory (e.g., processors/image_ssim_diff/)
+                processor_dir = os.path.dirname(os.path.abspath(processor_file))
+                templates_dir = os.path.join(processor_dir, 'templates')
+                if os.path.isdir(templates_dir):
+                    template_paths.append(templates_dir)
+                    logger.debug(f"Added processor template path: {templates_dir}")
+
+    # Get all registered external pluggy plugins
+    for plugin_name, plugin_obj in plugin_manager.list_name_plugin():
+        # Check if plugin has a templates directory
+        if hasattr(plugin_obj, '__file__'):
+            plugin_file = plugin_obj.__file__
+        elif hasattr(plugin_obj, '__module__'):
+            # Get the module file
+            module = sys.modules.get(plugin_obj.__module__)
+            if module and hasattr(module, '__file__'):
+                plugin_file = module.__file__
+            else:
+                continue
+        else:
+            continue
+
+        if plugin_file:
+            plugin_dir = os.path.dirname(os.path.abspath(plugin_file))
+            templates_dir = os.path.join(plugin_dir, 'templates')
+            if os.path.isdir(templates_dir):
+                template_paths.append(templates_dir)
+                logger.debug(f"Added plugin template path: {templates_dir}")
+
+    return template_paths

changedetectionio/processors/__init__.py

@@ -1,180 +1,10 @@
-from abc import abstractmethod
-from changedetectionio.content_fetchers.base import Fetcher
-from changedetectionio.strtobool import strtobool
-from copy import deepcopy
+from functools import lru_cache
 from loguru import logger
-import hashlib
+from flask_babel import gettext
 import importlib
 import inspect
 import os
 import pkgutil
-import re
-
-class difference_detection_processor():
-
-    browser_steps = None
-    datastore = None
-    fetcher = None
-    screenshot = None
-    watch = None
-    xpath_data = None
-    preferred_proxy = None
-
-    def __init__(self, *args, datastore, watch_uuid, **kwargs):
-        super().__init__(*args, **kwargs)
-        self.datastore = datastore
-        self.watch = deepcopy(self.datastore.data['watching'].get(watch_uuid))
-        # Generic fetcher that should be extended (requests, playwright etc)
-        self.fetcher = Fetcher()
-
-    async def call_browser(self, preferred_proxy_id=None):
-
-        from requests.structures import CaseInsensitiveDict
-
-        url = self.watch.link
-
-        # Protect against file:, file:/, file:// access, check the real "link" without any meta "source:" etc prepended.
-        if re.search(r'^file:', url.strip(), re.IGNORECASE):
-            if not strtobool(os.getenv('ALLOW_FILE_URI', 'false')):
-                raise Exception(
-                    "file:// type access is denied for security reasons."
-                )
-
-        # Requests, playwright, other browser via wss:// etc, fetch_extra_something
-        prefer_fetch_backend = self.watch.get('fetch_backend', 'system')
-
-        # Proxy ID "key"
-        preferred_proxy_id = preferred_proxy_id if preferred_proxy_id else self.datastore.get_preferred_proxy_for_watch(uuid=self.watch.get('uuid'))
-
-        # Pluggable content self.fetcher
-        if not prefer_fetch_backend or prefer_fetch_backend == 'system':
-            prefer_fetch_backend = self.datastore.data['settings']['application'].get('fetch_backend')
-
-        # In the case that the preferred fetcher was a browser config with custom connection URL..
-        # @todo - on save watch, if its extra_browser_ then it should be obvious it will use playwright (like if its requests now..)
-        custom_browser_connection_url = None
-        if prefer_fetch_backend.startswith('extra_browser_'):
-            (t, key) = prefer_fetch_backend.split('extra_browser_')
-            connection = list(
-                filter(lambda s: (s['browser_name'] == key), self.datastore.data['settings']['requests'].get('extra_browsers', [])))
-            if connection:
-                prefer_fetch_backend = 'html_webdriver'
-                custom_browser_connection_url = connection[0].get('browser_connection_url')
-
-        # PDF should be html_requests because playwright will serve it up (so far) in a embedded page
-        # @todo https://github.com/dgtlmoon/changedetection.io/issues/2019
-        # @todo needs test to or a fix
-        if self.watch.is_pdf:
-           prefer_fetch_backend = "html_requests"
-
-        # Grab the right kind of 'fetcher', (playwright, requests, etc)
-        from changedetectionio import content_fetchers
-        if hasattr(content_fetchers, prefer_fetch_backend):
-            # @todo TEMPORARY HACK - SWITCH BACK TO PLAYWRIGHT FOR BROWSERSTEPS
-            if prefer_fetch_backend == 'html_webdriver' and self.watch.has_browser_steps:
-                # This is never supported in selenium anyway
-                logger.warning("Using playwright fetcher override for possible puppeteer request in browsersteps, because puppetteer:browser steps is incomplete.")
-                from changedetectionio.content_fetchers.playwright import fetcher as playwright_fetcher
-                fetcher_obj = playwright_fetcher
-            else:
-                fetcher_obj = getattr(content_fetchers, prefer_fetch_backend)
-        else:
-            # What it referenced doesnt exist, Just use a default
-            fetcher_obj = getattr(content_fetchers, "html_requests")
-
-        proxy_url = None
-        if preferred_proxy_id:
-            # Custom browser endpoints should NOT have a proxy added
-            if not prefer_fetch_backend.startswith('extra_browser_'):
-                proxy_url = self.datastore.proxy_list.get(preferred_proxy_id).get('url')
-                logger.debug(f"Selected proxy key '{preferred_proxy_id}' as proxy URL '{proxy_url}' for {url}")
-            else:
-                logger.debug("Skipping adding proxy data when custom Browser endpoint is specified. ")
-
-        logger.debug(f"Using proxy '{proxy_url}' for {self.watch['uuid']}")
-
-        # Now call the fetcher (playwright/requests/etc) with arguments that only a fetcher would need.
-        # When browser_connection_url is None, it method should default to working out whats the best defaults (os env vars etc)
-        self.fetcher = fetcher_obj(proxy_override=proxy_url,
-                                   custom_browser_connection_url=custom_browser_connection_url
-                                   )
-
-        if self.watch.has_browser_steps:
-            self.fetcher.browser_steps = self.watch.get('browser_steps', [])
-            self.fetcher.browser_steps_screenshot_path = os.path.join(self.datastore.datastore_path, self.watch.get('uuid'))
-
-        # Tweak the base config with the per-watch ones
-        from changedetectionio.jinja2_custom import render as jinja_render
-        request_headers = CaseInsensitiveDict()
-
-        ua = self.datastore.data['settings']['requests'].get('default_ua')
-        if ua and ua.get(prefer_fetch_backend):
-            request_headers.update({'User-Agent': ua.get(prefer_fetch_backend)})
-
-        request_headers.update(self.watch.get('headers', {}))
-        request_headers.update(self.datastore.get_all_base_headers())
-        request_headers.update(self.datastore.get_all_headers_in_textfile_for_watch(uuid=self.watch.get('uuid')))
-
-        # https://github.com/psf/requests/issues/4525
-        # Requests doesnt yet support brotli encoding, so don't put 'br' here, be totally sure that the user cannot
-        # do this by accident.
-        if 'Accept-Encoding' in request_headers and "br" in request_headers['Accept-Encoding']:
-            request_headers['Accept-Encoding'] = request_headers['Accept-Encoding'].replace(', br', '')
-
-        for header_name in request_headers:
-            request_headers.update({header_name: jinja_render(template_str=request_headers.get(header_name))})
-
-        timeout = self.datastore.data['settings']['requests'].get('timeout')
-
-        request_body = self.watch.get('body')
-        if request_body:
-            request_body = jinja_render(template_str=self.watch.get('body'))
-        
-        request_method = self.watch.get('method')
-        ignore_status_codes = self.watch.get('ignore_status_codes', False)
-
-        # Configurable per-watch or global extra delay before extracting text (for webDriver types)
-        system_webdriver_delay = self.datastore.data['settings']['application'].get('webdriver_delay', None)
-        if self.watch.get('webdriver_delay'):
-            self.fetcher.render_extract_delay = self.watch.get('webdriver_delay')
-        elif system_webdriver_delay is not None:
-            self.fetcher.render_extract_delay = system_webdriver_delay
-
-        if self.watch.get('webdriver_js_execute_code') is not None and self.watch.get('webdriver_js_execute_code').strip():
-            self.fetcher.webdriver_js_execute_code = self.watch.get('webdriver_js_execute_code')
-
-        # Requests for PDF's, images etc should be passwd the is_binary flag
-        is_binary = self.watch.is_pdf
-
-        # And here we go! call the right browser with browser-specific settings
-        empty_pages_are_a_change = self.datastore.data['settings']['application'].get('empty_pages_are_a_change', False)
-        # All fetchers are now async
-        await self.fetcher.run(
-            current_include_filters=self.watch.get('include_filters'),
-            empty_pages_are_a_change=empty_pages_are_a_change,
-            fetch_favicon=self.watch.favicon_is_expired(),
-            ignore_status_codes=ignore_status_codes,
-            is_binary=is_binary,
-            request_body=request_body,
-            request_headers=request_headers,
-            request_method=request_method,
-            timeout=timeout,
-            url=url,
-       )
-
-        #@todo .quit here could go on close object, so we can run JS if change-detected
-        self.fetcher.quit(watch=self.watch)
-
-        # After init, call run_changedetection() which will do the actual change-detection
-
-    @abstractmethod
-    def run_changedetection(self, watch):
-        update_obj = {'last_notification_error': False, 'last_error': False}
-        some_data = 'xxxxx'
-        update_obj["previous_md5"] = hashlib.md5(some_data.encode('utf-8')).hexdigest()
-        changed_detected = False
-        return changed_detected, update_obj, ''.encode('utf-8')
-
 
 def find_sub_packages(package_name):
     """
@@ -198,6 +28,7 @@ def find_processors():
 
     processors = []
     sub_packages = find_sub_packages(package_name)
+    from changedetectionio.processors.base import difference_detection_processor
 
     for sub_package in sub_packages:
         module_name = f"{package_name}.{sub_package}.processor"
@@ -206,8 +37,12 @@ def find_processors():
 
             # Iterate through all classes in the module
             for name, obj in inspect.getmembers(module, inspect.isclass):
-                if issubclass(obj, difference_detection_processor) and obj is not difference_detection_processor:
+                # Only register classes that are actually defined in this module (not imported)
+                if (issubclass(obj, difference_detection_processor) and
+                    obj is not difference_detection_processor and
+                    obj.__module__ == module.__name__):
                     processors.append((module, sub_package))
+                    break  # Only need one processor per module
         except (ModuleNotFoundError, ImportError) as e:
             logger.warning(f"Failed to import module {module_name}: {e} (find_processors())")
 
@@ -242,17 +77,205 @@ def get_custom_watch_obj_for_processor(processor_name):
     return watch_class
 
 
+def find_processor_module(processor_name):
+    """
+    Find the processor module by name.
+
+    Args:
+        processor_name: Processor machine name (e.g., 'image_ssim_diff')
+
+    Returns:
+        module: The processor's parent module, or None if not found
+    """
+    processor_classes = find_processors()
+    processor_tuple = next((tpl for tpl in processor_classes if tpl[1] == processor_name), None)
+
+    if processor_tuple:
+        # Return the parent module (the package containing processor.py)
+        return get_parent_module(processor_tuple[0])
+
+    return None
+
+
 def available_processors():
     """
-    Get a list of processors by name and description for the UI elements
+    Get a list of processors by name and description for the UI elements.
+    Can be filtered via ALLOWED_PROCESSORS environment variable (comma-separated list).
     :return: A list :)
     """
 
     processor_classes = find_processors()
 
+    # Check if ALLOWED_PROCESSORS env var is set
+    # For now we disable it, need to make a deploy with lots of new code and this will be an overload
+    allowed_processors_env = os.getenv('ALLOWED_PROCESSORS', 'text_json_diff, restock_diff').strip()
+    allowed_processors = None
+    if allowed_processors_env:
+        # Parse comma-separated list and strip whitespace
+        allowed_processors = [p.strip() for p in allowed_processors_env.split(',') if p.strip()]
+        logger.info(f"ALLOWED_PROCESSORS set, filtering to: {allowed_processors}")
+
     available = []
-    for package, processor_class in processor_classes:
-        available.append((processor_class, package.name))
+    for module, sub_package_name in processor_classes:
+        # Filter by allowed processors if set
+        if allowed_processors and sub_package_name not in allowed_processors:
+            logger.debug(f"Skipping processor '{sub_package_name}' (not in ALLOWED_PROCESSORS)")
+            continue
 
-    return available
+        # Try to get the 'name' attribute from the processor module first
+        if hasattr(module, 'name'):
+            description = gettext(module.name)
+        else:
+            # Fall back to processor_description from parent module's __init__.py
+            parent_module = get_parent_module(module)
+            if parent_module and hasattr(parent_module, 'processor_description'):
+                description = gettext(parent_module.processor_description)
+            else:
+                # Final fallback to a readable name
+                description = sub_package_name.replace('_', ' ').title()
+
+        # Get weight for sorting (lower weight = higher in list)
+        weight = 0  # Default weight for processors without explicit weight
+
+        # Check processor module itself first
+        if hasattr(module, 'processor_weight'):
+            weight = module.processor_weight
+        else:
+            # Fall back to parent module (package __init__.py)
+            parent_module = get_parent_module(module)
+            if parent_module and hasattr(parent_module, 'processor_weight'):
+                weight = parent_module.processor_weight
+
+        available.append((sub_package_name, description, weight))
+
+    # Sort by weight (lower weight = appears first)
+    available.sort(key=lambda x: x[2])
+
+    # Return as tuples without weight (for backwards compatibility)
+    return [(name, desc) for name, desc, weight in available]
+
+
+def get_processor_badge_texts():
+    """
+    Get a dictionary mapping processor names to their list_badge_text values.
+    Translations are applied based on the current request locale.
+
+    :return: A dict mapping processor name to badge text (e.g., {'text_json_diff': 'Text', 'restock_diff': 'Restock'})
+    """
+    processor_classes = find_processors()
+    badge_texts = {}
+
+    for module, sub_package_name in processor_classes:
+        # Try to get the 'list_badge_text' attribute from the processor module
+        if hasattr(module, 'list_badge_text'):
+            badge_texts[sub_package_name] = gettext(module.list_badge_text)
+        else:
+            # Fall back to parent module's __init__.py
+            parent_module = get_parent_module(module)
+            if parent_module and hasattr(parent_module, 'list_badge_text'):
+                badge_texts[sub_package_name] = gettext(parent_module.list_badge_text)
+
+    return badge_texts
+
+
+def get_processor_descriptions():
+    """
+    Get a dictionary mapping processor names to their description/name values.
+    Translations are applied based on the current request locale.
+
+    :return: A dict mapping processor name to description (e.g., {'text_json_diff': 'Webpage Text/HTML, JSON and PDF changes'})
+    """
+    processor_classes = find_processors()
+    descriptions = {}
+
+    for module, sub_package_name in processor_classes:
+        # Try to get the 'name' or 'description' attribute from the processor module first
+        if hasattr(module, 'name'):
+            descriptions[sub_package_name] = gettext(module.name)
+        elif hasattr(module, 'description'):
+            descriptions[sub_package_name] = gettext(module.description)
+        else:
+            # Fall back to parent module's __init__.py
+            parent_module = get_parent_module(module)
+            if parent_module and hasattr(parent_module, 'processor_description'):
+                descriptions[sub_package_name] = gettext(parent_module.processor_description)
+            elif parent_module and hasattr(parent_module, 'name'):
+                descriptions[sub_package_name] = gettext(parent_module.name)
+            else:
+                # Final fallback to a readable name
+                descriptions[sub_package_name] = sub_package_name.replace('_', ' ').title()
+
+    return descriptions
+
+
+def generate_processor_badge_colors(processor_name):
+    """
+    Generate consistent colors for a processor badge based on its name.
+    Uses a hash of the processor name to generate pleasing, accessible colors
+    for both light and dark modes.
+
+    :param processor_name: The processor name (e.g., 'text_json_diff')
+    :return: A dict with 'light' and 'dark' color schemes, each containing 'bg' and 'color'
+    """
+    import hashlib
+
+    # Generate a consistent hash from the processor name
+    hash_obj = hashlib.md5(processor_name.encode('utf-8'))
+    hash_int = int(hash_obj.hexdigest()[:8], 16)
+
+    # Generate hue from hash (0-360)
+    hue = hash_int % 360
+
+    # Light mode: pastel background with darker text
+    light_saturation = 60 + (hash_int % 25)  # 60-85%
+    light_lightness = 85 + (hash_int % 10)   # 85-95% - very light
+    text_lightness = 25 + (hash_int % 15)    # 25-40% - dark
+
+    # Dark mode: solid, vibrant colors with white text
+    dark_saturation = 55 + (hash_int % 20)   # 55-75%
+    dark_lightness = 45 + (hash_int % 15)    # 45-60%
+
+    return {
+        'light': {
+            'bg': f'hsl({hue}, {light_saturation}%, {light_lightness}%)',
+            'color': f'hsl({hue}, 50%, {text_lightness}%)'
+        },
+        'dark': {
+            'bg': f'hsl({hue}, {dark_saturation}%, {dark_lightness}%)',
+            'color': '#fff'
+        }
+    }
+
+
+@lru_cache(maxsize=1)
+def get_processor_badge_css():
+    """
+    Generate CSS for all processor badges with auto-generated colors.
+    This creates CSS rules for both light and dark modes for each processor.
+
+    :return: A string containing CSS rules for all processor badges
+    """
+    processor_classes = find_processors()
+    css_rules = []
+
+    for module, sub_package_name in processor_classes:
+        colors = generate_processor_badge_colors(sub_package_name)
+
+        # Light mode rule
+        css_rules.append(
+            f".processor-badge-{sub_package_name} {{\n"
+            f"  background-color: {colors['light']['bg']};\n"
+            f"  color: {colors['light']['color']};\n"
+            f"}}"
+        )
+
+        # Dark mode rule
+        css_rules.append(
+            f"html[data-darkmode=\"true\"] .processor-badge-{sub_package_name} {{\n"
+            f"  background-color: {colors['dark']['bg']};\n"
+            f"  color: {colors['dark']['color']};\n"
+            f"}}"
+        )
+
+    return '\n\n'.join(css_rules)
 

changedetectionio/processors/base.py

@@ -0,0 +1,259 @@
+import re
+import hashlib
+from changedetectionio.content_fetchers.base import Fetcher
+from changedetectionio.strtobool import strtobool
+from copy import deepcopy
+from abc import abstractmethod
+import os
+from loguru import logger
+
+SCREENSHOT_FORMAT_JPEG = 'JPEG'
+SCREENSHOT_FORMAT_PNG = 'PNG'
+
+class difference_detection_processor():
+    browser_steps = None
+    datastore = None
+    fetcher = None
+    screenshot = None
+    watch = None
+    xpath_data = None
+    preferred_proxy = None
+    screenshot_format = SCREENSHOT_FORMAT_JPEG
+
+    def __init__(self, datastore, watch_uuid):
+        self.datastore = datastore
+        self.watch_uuid = watch_uuid
+        self.watch = deepcopy(self.datastore.data['watching'].get(watch_uuid))
+        # Generic fetcher that should be extended (requests, playwright etc)
+        self.fetcher = Fetcher()
+
+    async def call_browser(self, preferred_proxy_id=None):
+
+        from requests.structures import CaseInsensitiveDict
+
+        url = self.watch.link
+
+        # Protect against file:, file:/, file:// access, check the real "link" without any meta "source:" etc prepended.
+        if re.search(r'^file:', url.strip(), re.IGNORECASE):
+            if not strtobool(os.getenv('ALLOW_FILE_URI', 'false')):
+                raise Exception(
+                    "file:// type access is denied for security reasons."
+                )
+
+        # Requests, playwright, other browser via wss:// etc, fetch_extra_something
+        prefer_fetch_backend = self.watch.get('fetch_backend', 'system')
+
+        # Proxy ID "key"
+        preferred_proxy_id = preferred_proxy_id if preferred_proxy_id else self.datastore.get_preferred_proxy_for_watch(
+            uuid=self.watch.get('uuid'))
+
+        # Pluggable content self.fetcher
+        if not prefer_fetch_backend or prefer_fetch_backend == 'system':
+            prefer_fetch_backend = self.datastore.data['settings']['application'].get('fetch_backend')
+
+        # In the case that the preferred fetcher was a browser config with custom connection URL..
+        # @todo - on save watch, if its extra_browser_ then it should be obvious it will use playwright (like if its requests now..)
+        custom_browser_connection_url = None
+        if prefer_fetch_backend.startswith('extra_browser_'):
+            (t, key) = prefer_fetch_backend.split('extra_browser_')
+            connection = list(
+                filter(lambda s: (s['browser_name'] == key), self.datastore.data['settings']['requests'].get('extra_browsers', [])))
+            if connection:
+                prefer_fetch_backend = 'html_webdriver'
+                custom_browser_connection_url = connection[0].get('browser_connection_url')
+
+        # PDF should be html_requests because playwright will serve it up (so far) in a embedded page
+        # @todo https://github.com/dgtlmoon/changedetection.io/issues/2019
+        # @todo needs test to or a fix
+        if self.watch.is_pdf:
+            prefer_fetch_backend = "html_requests"
+
+        # Grab the right kind of 'fetcher', (playwright, requests, etc)
+        from changedetectionio import content_fetchers
+        if hasattr(content_fetchers, prefer_fetch_backend):
+            # @todo TEMPORARY HACK - SWITCH BACK TO PLAYWRIGHT FOR BROWSERSTEPS
+            if prefer_fetch_backend == 'html_webdriver' and self.watch.has_browser_steps:
+                # This is never supported in selenium anyway
+                logger.warning(
+                    "Using playwright fetcher override for possible puppeteer request in browsersteps, because puppetteer:browser steps is incomplete.")
+                from changedetectionio.content_fetchers.playwright import fetcher as playwright_fetcher
+                fetcher_obj = playwright_fetcher
+            else:
+                fetcher_obj = getattr(content_fetchers, prefer_fetch_backend)
+        else:
+            # What it referenced doesnt exist, Just use a default
+            fetcher_obj = getattr(content_fetchers, "html_requests")
+
+        proxy_url = None
+        if preferred_proxy_id:
+            # Custom browser endpoints should NOT have a proxy added
+            if not prefer_fetch_backend.startswith('extra_browser_'):
+                proxy_url = self.datastore.proxy_list.get(preferred_proxy_id).get('url')
+                logger.debug(f"Selected proxy key '{preferred_proxy_id}' as proxy URL '{proxy_url}' for {url}")
+            else:
+                logger.debug("Skipping adding proxy data when custom Browser endpoint is specified. ")
+
+        logger.debug(f"Using proxy '{proxy_url}' for {self.watch['uuid']}")
+
+        # Now call the fetcher (playwright/requests/etc) with arguments that only a fetcher would need.
+        # When browser_connection_url is None, it method should default to working out whats the best defaults (os env vars etc)
+        self.fetcher = fetcher_obj(proxy_override=proxy_url,
+                                   custom_browser_connection_url=custom_browser_connection_url,
+                                   screenshot_format=self.screenshot_format
+                                   )
+
+        if self.watch.has_browser_steps:
+            self.fetcher.browser_steps = self.watch.get('browser_steps', [])
+            self.fetcher.browser_steps_screenshot_path = os.path.join(self.datastore.datastore_path, self.watch.get('uuid'))
+
+        # Tweak the base config with the per-watch ones
+        from changedetectionio.jinja2_custom import render as jinja_render
+        request_headers = CaseInsensitiveDict()
+
+        ua = self.datastore.data['settings']['requests'].get('default_ua')
+        if ua and ua.get(prefer_fetch_backend):
+            request_headers.update({'User-Agent': ua.get(prefer_fetch_backend)})
+
+        request_headers.update(self.watch.get('headers', {}))
+        request_headers.update(self.datastore.get_all_base_headers())
+        request_headers.update(self.datastore.get_all_headers_in_textfile_for_watch(uuid=self.watch.get('uuid')))
+
+        # https://github.com/psf/requests/issues/4525
+        # Requests doesnt yet support brotli encoding, so don't put 'br' here, be totally sure that the user cannot
+        # do this by accident.
+        if 'Accept-Encoding' in request_headers and "br" in request_headers['Accept-Encoding']:
+            request_headers['Accept-Encoding'] = request_headers['Accept-Encoding'].replace(', br', '')
+
+        for header_name in request_headers:
+            request_headers.update({header_name: jinja_render(template_str=request_headers.get(header_name))})
+
+        timeout = self.datastore.data['settings']['requests'].get('timeout')
+
+        request_body = self.watch.get('body')
+        if request_body:
+            request_body = jinja_render(template_str=self.watch.get('body'))
+
+        request_method = self.watch.get('method')
+        ignore_status_codes = self.watch.get('ignore_status_codes', False)
+
+        # Configurable per-watch or global extra delay before extracting text (for webDriver types)
+        system_webdriver_delay = self.datastore.data['settings']['application'].get('webdriver_delay', None)
+        if self.watch.get('webdriver_delay'):
+            self.fetcher.render_extract_delay = self.watch.get('webdriver_delay')
+        elif system_webdriver_delay is not None:
+            self.fetcher.render_extract_delay = system_webdriver_delay
+
+        if self.watch.get('webdriver_js_execute_code') is not None and self.watch.get('webdriver_js_execute_code').strip():
+            self.fetcher.webdriver_js_execute_code = self.watch.get('webdriver_js_execute_code')
+
+        # Requests for PDF's, images etc should be passwd the is_binary flag
+        is_binary = self.watch.is_pdf
+
+        # And here we go! call the right browser with browser-specific settings
+        empty_pages_are_a_change = self.datastore.data['settings']['application'].get('empty_pages_are_a_change', False)
+        # All fetchers are now async
+        await self.fetcher.run(
+            current_include_filters=self.watch.get('include_filters'),
+            empty_pages_are_a_change=empty_pages_are_a_change,
+            fetch_favicon=self.watch.favicon_is_expired(),
+            ignore_status_codes=ignore_status_codes,
+            is_binary=is_binary,
+            request_body=request_body,
+            request_headers=request_headers,
+            request_method=request_method,
+            screenshot_format=self.screenshot_format,
+            timeout=timeout,
+            url=url,
+            watch_uuid=self.watch_uuid,
+        )
+
+        # @todo .quit here could go on close object, so we can run JS if change-detected
+        await self.fetcher.quit(watch=self.watch)
+
+        # After init, call run_changedetection() which will do the actual change-detection
+
+    def get_extra_watch_config(self, filename):
+        """
+        Read processor-specific JSON config file from watch data directory.
+
+        Args:
+            filename: Name of JSON file (e.g., "visual_ssim_score.json")
+
+        Returns:
+            dict: Parsed JSON data, or empty dict if file doesn't exist
+        """
+        import json
+        import os
+
+        watch = self.datastore.data['watching'].get(self.watch_uuid)
+        watch_data_dir = watch.watch_data_dir
+
+        if not watch_data_dir:
+            return {}
+
+        filepath = os.path.join(watch_data_dir, filename)
+
+        if not os.path.isfile(filepath):
+            return {}
+
+        try:
+            with open(filepath, 'r', encoding='utf-8') as f:
+                return json.load(f)
+        except (json.JSONDecodeError, IOError) as e:
+            logger.warning(f"Failed to read extra watch config {filename}: {e}")
+            return {}
+
+    def update_extra_watch_config(self, filename, data, merge=True):
+        """
+        Write processor-specific JSON config file to watch data directory.
+
+        Args:
+            filename: Name of JSON file (e.g., "visual_ssim_score.json")
+            data: Dictionary to serialize as JSON
+            merge: If True, merge with existing data; if False, overwrite completely
+        """
+        import json
+        import os
+
+        watch = self.datastore.data['watching'].get(self.watch_uuid)
+        watch_data_dir = watch.watch_data_dir
+
+        if not watch_data_dir:
+            logger.warning(f"Cannot save extra watch config {filename}: no watch_data_dir")
+            return
+
+        # Ensure directory exists
+        watch.ensure_data_dir_exists()
+
+        filepath = os.path.join(watch_data_dir, filename)
+
+        try:
+            # If merge is enabled, read existing data first
+            existing_data = {}
+            if merge and os.path.isfile(filepath):
+                try:
+                    with open(filepath, 'r', encoding='utf-8') as f:
+                        existing_data = json.load(f)
+                except (json.JSONDecodeError, IOError) as e:
+                    logger.warning(f"Failed to read existing config for merge: {e}")
+
+            # Merge new data with existing
+            if merge:
+                existing_data.update(data)
+                data_to_save = existing_data
+            else:
+                data_to_save = data
+
+            # Write the data
+            with open(filepath, 'w', encoding='utf-8') as f:
+                json.dump(data_to_save, f, indent=2)
+        except IOError as e:
+            logger.error(f"Failed to write extra watch config {filename}: {e}")
+
+    @abstractmethod
+    def run_changedetection(self, watch):
+        update_obj = {'last_notification_error': False, 'last_error': False}
+        some_data = 'xxxxx'
+        update_obj["previous_md5"] = hashlib.md5(some_data.encode('utf-8')).hexdigest()
+        changed_detected = False
+        return changed_detected, update_obj, ''.encode('utf-8')

changedetectionio/processors/extract.py

@@ -0,0 +1,132 @@
+"""
+Base data extraction module for all processors.
+
+This module handles extracting data from watch history using regex patterns
+and exporting to CSV format. This is the default extractor that all processors
+(text_json_diff, restock_diff, etc.) can use by default or override.
+"""
+
+import os
+from flask_babel import gettext
+from loguru import logger
+
+
+def render_form(watch, datastore, request, url_for, render_template, flash, redirect, extract_form=None):
+    """
+    Render the data extraction form.
+
+    Args:
+        watch: The watch object
+        datastore: The ChangeDetectionStore instance
+        request: Flask request object
+        url_for: Flask url_for function
+        render_template: Flask render_template function
+        flash: Flask flash function
+        redirect: Flask redirect function
+        extract_form: Optional pre-built extract form (for error cases)
+
+    Returns:
+        Rendered HTML response with the extraction form
+    """
+    from changedetectionio import forms
+
+    uuid = watch.get('uuid')
+
+    # Use provided form or create a new one
+    if extract_form is None:
+        extract_form = forms.extractDataForm(
+            formdata=request.form,
+            data={'extract_regex': request.form.get('extract_regex', '')}
+        )
+
+    # Get error information for the template
+    screenshot_url = watch.get_screenshot()
+
+    system_uses_webdriver = datastore.data['settings']['application']['fetch_backend'] == 'html_webdriver'
+    is_html_webdriver = False
+    if (watch.get('fetch_backend') == 'system' and system_uses_webdriver) or watch.get('fetch_backend') == 'html_webdriver' or watch.get('fetch_backend', '').startswith('extra_browser_'):
+        is_html_webdriver = True
+
+    password_enabled_and_share_is_off = False
+    if datastore.data['settings']['application'].get('password') or os.getenv("SALTED_PASS", False):
+        password_enabled_and_share_is_off = not datastore.data['settings']['application'].get('shared_diff_access')
+
+    # Use the shared default template from processors/templates/
+    # Processors can override this by creating their own extract.py with custom template logic
+    output = render_template(
+        "extract.html",
+        uuid=uuid,
+        extract_form=extract_form,
+        watch_a=watch,
+        last_error=watch['last_error'],
+        last_error_screenshot=watch.get_error_snapshot(),
+        last_error_text=watch.get_error_text(),
+        screenshot=screenshot_url,
+        is_html_webdriver=is_html_webdriver,
+        password_enabled_and_share_is_off=password_enabled_and_share_is_off,
+        extra_title=f" - {watch.label} - Extract Data",
+        extra_stylesheets=[url_for('static_content', group='styles', filename='diff.css')],
+        pure_menu_fixed=False
+    )
+
+    return output
+
+
+def process_extraction(watch, datastore, request, url_for, make_response, send_from_directory, flash, redirect, extract_form=None):
+    """
+    Process the data extraction request and return CSV file.
+
+    Args:
+        watch: The watch object
+        datastore: The ChangeDetectionStore instance
+        request: Flask request object
+        url_for: Flask url_for function
+        make_response: Flask make_response function
+        send_from_directory: Flask send_from_directory function
+        flash: Flask flash function
+        redirect: Flask redirect function
+        extract_form: Optional pre-built extract form
+
+    Returns:
+        CSV file download response or redirect to form on error
+    """
+    from changedetectionio import forms
+
+    uuid = watch.get('uuid')
+
+    # Use provided form or create a new one
+    if extract_form is None:
+        extract_form = forms.extractDataForm(
+            formdata=request.form,
+            data={'extract_regex': request.form.get('extract_regex', '')}
+        )
+
+    if not extract_form.validate():
+        flash(gettext("An error occurred, please see below."), "error")
+        # render_template needs to be imported from Flask for this to work
+        from flask import render_template as flask_render_template
+        return render_form(
+            watch=watch,
+            datastore=datastore,
+            request=request,
+            url_for=url_for,
+            render_template=flask_render_template,
+            flash=flash,
+            redirect=redirect,
+            extract_form=extract_form
+        )
+
+    extract_regex = request.form.get('extract_regex', '').strip()
+    output = watch.extract_regex_from_all_history(extract_regex)
+
+    if output:
+        watch_dir = os.path.join(datastore.datastore_path, uuid)
+        response = make_response(send_from_directory(directory=watch_dir, path=output, as_attachment=True))
+        response.headers['Content-type'] = 'text/csv'
+        response.headers['Cache-Control'] = 'no-cache, no-store, must-revalidate'
+        response.headers['Pragma'] = 'no-cache'
+        response.headers['Expires'] = "0"
+        return response
+
+    flash(gettext('No matches found while scanning all of the watch history for that RegEx.'), 'error')
+    return redirect(url_for('ui.ui_diff.diff_history_page_extract_GET', uuid=uuid))

changedetectionio/processors/image_ssim_diff/README.md

@@ -0,0 +1,210 @@
+# Fast Screenshot Comparison Processor
+
+Visual/screenshot change detection using ultra-fast image comparison algorithms.
+
+## Overview
+
+This processor uses **OpenCV** by default for screenshot comparison, providing **50-100x faster** performance compared to the previous SSIM implementation while still detecting meaningful visual changes.
+
+## Current Features
+
+- **Ultra-fast OpenCV comparison**: cv2.absdiff with Gaussian blur for noise reduction
+- **MD5 pre-check**: Fast identical image detection before expensive comparison
+- **Configurable sensitivity**: Threshold-based change detection
+- **Three-panel diff view**: Previous | Current | Difference (with red highlights)
+- **Direct image support**: Works with browser screenshots AND direct image URLs
+- **Visual selector support**: Compare specific page regions using CSS/XPath selectors
+- **Download images**: Download any of the three comparison images directly from the diff view
+
+## Performance
+
+- **OpenCV (default)**: 50-100x faster than SSIM
+- **Large screenshots**: Automatic downscaling for diff visualization (configurable via `MAX_DIFF_HEIGHT`/`MAX_DIFF_WIDTH`)
+- **Memory efficient**: Explicit cleanup of large objects for long-running processes
+- **JPEG diff images**: Smaller file sizes, faster rendering
+
+## How It Works
+
+1. **Fetch**: Screenshot captured via browser OR direct image URL fetched
+2. **MD5 Check**: Quick hash comparison - if identical, skip comparison
+3. **Region Selection** (optional): Crop to specific page region if visual selector is configured
+4. **OpenCV Comparison**: Fast pixel-level difference detection with Gaussian blur
+5. **Change Detection**: Percentage of changed pixels above threshold = change detected
+6. **Visualization**: Generate diff image with red-highlighted changed regions
+
+## Architecture
+
+### Default Method: OpenCV
+
+The processor uses OpenCV's `cv2.absdiff()` for ultra-fast pixel-level comparison:
+
+```python
+# Convert to grayscale
+gray_from = cv2.cvtColor(image_from, cv2.COLOR_RGB2GRAY)
+gray_to = cv2.cvtColor(image_to, cv2.COLOR_RGB2GRAY)
+
+# Apply Gaussian blur (reduces noise, controlled by OPENCV_BLUR_SIGMA env var)
+gray_from = cv2.GaussianBlur(gray_from, (0, 0), sigma=0.8)
+gray_to = cv2.GaussianBlur(gray_to, (0, 0), sigma=0.8)
+
+# Calculate absolute difference
+diff = cv2.absdiff(gray_from, gray_to)
+
+# Apply threshold (default: 30)
+_, thresh = cv2.threshold(diff, threshold, 255, cv2.THRESH_BINARY)
+
+# Count changed pixels
+change_percentage = (changed_pixels / total_pixels) * 100
+```
+
+### Optional: Pixelmatch
+
+For users who need better anti-aliasing detection (especially for text-heavy screenshots), **pixelmatch** can be optionally installed:
+
+```bash
+pip install pybind11-pixelmatch>=0.1.3
+```
+
+**Note**: Pixelmatch uses a C++17 implementation via pybind11 and may have build issues on some platforms (particularly Alpine/musl systems with symbolic link security restrictions). The application will automatically fall back to OpenCV if pixelmatch is not available.
+
+To use pixelmatch instead of OpenCV, set the environment variable:
+```bash
+COMPARISON_METHOD=pixelmatch
+```
+
+#### When to use pixelmatch:
+- Screenshots with lots of text and anti-aliasing
+- Need to ignore minor font rendering differences between browser versions
+- 10-20x faster than SSIM (but slower than OpenCV)
+
+#### When to stick with OpenCV (default):
+- General webpage monitoring
+- Maximum performance (50-100x faster than SSIM)
+- Simple pixel-level change detection
+- Avoid build dependencies (Alpine/musl systems)
+
+## Configuration
+
+### Environment Variables
+
+```bash
+# Comparison method (opencv or pixelmatch)
+COMPARISON_METHOD=opencv  # Default
+
+# OpenCV threshold (0-255, lower = more sensitive)
+COMPARISON_THRESHOLD_OPENCV=30  # Default
+
+# Pixelmatch threshold (0-100, mapped to 0-1 scale)
+COMPARISON_THRESHOLD_PIXELMATCH=10  # Default
+
+# Gaussian blur sigma for OpenCV (0 = no blur, higher = more blur)
+OPENCV_BLUR_SIGMA=0.8  # Default
+
+# Minimum change percentage to trigger detection
+OPENCV_MIN_CHANGE_PERCENT=0.1  # Default (0.1%)
+PIXELMATCH_MIN_CHANGE_PERCENT=0.1  # Default
+
+# Diff visualization image size limits (pixels)
+MAX_DIFF_HEIGHT=8000  # Default
+MAX_DIFF_WIDTH=900  # Default
+```
+
+### Per-Watch Configuration
+
+- **Comparison Threshold**: Can be configured per-watch in the edit form
+  - Very low sensitivity (10) - Only major changes
+  - Low sensitivity (20) - Significant changes
+  - Medium sensitivity (30) - Moderate changes (default)
+  - High sensitivity (50) - Small changes
+  - Very high sensitivity (75) - Any visible change
+
+### Visual Selector (Region Comparison)
+
+Use the "Include filters" field with CSS selectors or XPath to compare only specific page regions:
+
+```
+.content-area
+//div[@id='main']
+```
+
+The processor will automatically crop both screenshots to the bounding box of the first matched element.
+
+## Dependencies
+
+### Required
+- `opencv-python-headless>=4.8.0.76` - Fast image comparison
+- `Pillow (PIL)` - Image loading and manipulation
+- `numpy` - Array operations
+
+### Optional
+- `pybind11-pixelmatch>=0.1.3` - Alternative comparison method with anti-aliasing detection
+
+## Change Detection Interpretation
+
+- **0%** = Identical images (or below minimum change threshold)
+- **0.1-1%** = Minor differences (anti-aliasing, slight rendering differences)
+- **1-5%** = Noticeable changes (text updates, small content changes)
+- **5-20%** = Significant changes (layout shifts, content additions)
+- **>20%** = Major differences (page redesign, large content changes)
+
+## Technical Notes
+
+### Memory Management
+```python
+# Explicit cleanup for long-running processes
+img.close()  # Close PIL Images
+buffer.close()  # Close BytesIO buffers
+del large_array  # Mark numpy arrays for GC
+```
+
+### Diff Image Generation
+- Format: JPEG (quality=85, optimized)
+- Highlight: Red overlay (50% blend with original)
+- Auto-downscaling: Large screenshots downscaled for faster rendering
+- Base64 embedded: For direct template rendering
+
+### OpenCV Blur Parameters
+The Gaussian blur reduces sensitivity to:
+- Font rendering differences
+- Anti-aliasing variations
+- JPEG compression artifacts
+- Minor pixel shifts (1-2 pixels)
+
+Increase `OPENCV_BLUR_SIGMA` to make comparison more tolerant of these differences.
+
+## Comparison: OpenCV vs Pixelmatch vs SSIM
+
+| Feature | OpenCV | Pixelmatch | SSIM (old) |
+|---------|--------|------------|------------|
+| **Speed** | 50-100x faster | 10-20x faster | Baseline |
+| **Anti-aliasing** | Via blur | Built-in detection | Built-in |
+| **Text sensitivity** | High | Medium (AA-aware) | Medium |
+| **Dependencies** | opencv-python-headless | pybind11-pixelmatch + C++ compiler | scikit-image |
+| **Alpine/musl support** | ✅ Yes | ⚠️ Build issues | ✅ Yes |
+| **Memory usage** | Low | Low | High |
+| **Best for** | General use, max speed | Text-heavy screenshots | Deprecated |
+
+## Migration from SSIM
+
+If you're upgrading from the old SSIM-based processor:
+
+1. **Thresholds are different**: SSIM used 0-1 scale (higher = more similar), OpenCV uses 0-255 pixel difference (lower = more similar)
+2. **Default threshold**: Start with 30 for OpenCV, adjust based on your needs
+3. **Performance**: Expect dramatically faster comparisons, especially for large screenshots
+4. **Accuracy**: OpenCV is more sensitive to pixel-level changes; increase `OPENCV_BLUR_SIGMA` if you're getting false positives
+
+## Future Enhancements
+
+Potential features for future consideration:
+
+- **Change region detection**: Highlight specific areas that changed with bounding boxes
+- **Perceptual hashing**: Pre-screening filter for even faster checks
+- **Ignore regions**: Exclude specific page areas (ads, timestamps) from comparison
+- **Text extraction**: OCR-based text comparison for semantic changes
+- **Adaptive thresholds**: Different sensitivity for different page regions
+
+## Resources
+
+- [OpenCV Documentation](https://docs.opencv.org/)
+- [pybind11-pixelmatch GitHub](https://github.com/whtsky/pybind11-pixelmatch)
+- [Pixelmatch (original JS library)](https://github.com/mapbox/pixelmatch)

changedetectionio/processors/image_ssim_diff/__init__.py

@@ -0,0 +1,32 @@
+"""
+Visual/screenshot change detection using fast image comparison algorithms.
+
+This processor compares screenshots using OpenCV (cv2.absdiff),
+which is 10-100x faster than SSIM while still detecting meaningful visual changes.
+"""
+
+import os
+from pathlib import Path
+
+processor_description = "Visual/Screenshot change detection (Fast)"
+processor_name = "image_ssim_diff"
+processor_weight = 2  # Lower weight = appears at top, heavier weight = appears lower (bottom)
+
+PROCESSOR_CONFIG_NAME = f"{Path(__file__).parent.name}.json"
+
+# Subprocess timeout settings
+# Maximum time to wait for subprocess operations (seconds)
+POLL_TIMEOUT_ABSOLUTE = int(os.getenv('OPENCV_SUBPROCESS_TIMEOUT', '20'))
+
+# Template tracking filename
+CROPPED_IMAGE_TEMPLATE_FILENAME = 'cropped_image_template.png'
+
+SCREENSHOT_COMPARISON_THRESHOLD_OPTIONS = [
+    ('200', 'Low sensitivity (only major changes)'),
+    ('80', 'Medium sensitivity (moderate changes - recommended)'),
+    ('20', 'High sensitivity (small changes)'),
+    ('0', 'Very high sensitivity (any change)')
+]
+
+SCREENSHOT_COMPARISON_THRESHOLD_OPTIONS_DEFAULT=0.999
+OPENCV_BLUR_SIGMA=float(os.getenv("OPENCV_BLUR_SIGMA", "3.0"))

changedetectionio/processors/image_ssim_diff/difference.py

@@ -0,0 +1,441 @@
+"""
+Screenshot diff visualization for fast image comparison processor.
+
+All image operations now use ImageDiffHandler abstraction for clean separation
+of concerns and easy backend swapping (LibVIPS, OpenCV, PIL, etc.).
+"""
+
+import os
+import json
+import time
+from flask_babel import gettext
+from loguru import logger
+
+from changedetectionio.processors.image_ssim_diff import SCREENSHOT_COMPARISON_THRESHOLD_OPTIONS_DEFAULT, PROCESSOR_CONFIG_NAME, \
+    OPENCV_BLUR_SIGMA
+
+# All image operations now use OpenCV via isolated_opencv subprocess handler
+# No direct handler imports needed - subprocess isolation handles everything
+
+# Maximum dimensions for diff visualization (can be overridden via environment variable)
+# Large screenshots don't need full resolution for visual inspection
+# Reduced defaults to minimize memory usage - 2000px height is plenty for diff viewing
+MAX_DIFF_HEIGHT = int(os.getenv('MAX_DIFF_HEIGHT', '8000'))
+MAX_DIFF_WIDTH = int(os.getenv('MAX_DIFF_WIDTH', '900'))
+
+
+def get_asset(asset_name, watch, datastore, request):
+    """
+    Get processor-specific binary assets for streaming.
+
+    Uses ImageDiffHandler for all image operations - no more multiprocessing needed
+    as LibVIPS handles threading/memory internally.
+
+    Supported assets:
+    - 'before': The previous/from screenshot
+    - 'after': The current/to screenshot
+    - 'rendered_diff': The generated diff visualization with red highlights
+
+    Args:
+        asset_name: Name of the asset to retrieve ('before', 'after', 'rendered_diff')
+        watch: Watch object
+        datastore: Datastore object
+        request: Flask request (for from_version/to_version query params)
+
+    Returns:
+        tuple: (binary_data, content_type, cache_control_header) or None if not found
+    """
+    # Get version parameters from query string
+    versions = list(watch.history.keys())
+
+    if len(versions) < 2:
+        return None
+
+    from_version = request.args.get('from_version', versions[-2] if len(versions) >= 2 else versions[0])
+    to_version = request.args.get('to_version', versions[-1])
+
+    # Validate versions exist
+    if from_version not in versions:
+        from_version = versions[-2] if len(versions) >= 2 else versions[0]
+    if to_version not in versions:
+        to_version = versions[-1]
+
+    try:
+        if asset_name == 'before':
+            # Return the 'from' screenshot with bounding box if configured
+            img_bytes = watch.get_history_snapshot(timestamp=from_version)
+            img_bytes = _draw_bounding_box_if_configured(img_bytes, watch, datastore)
+            mime_type = _detect_mime_type(img_bytes)
+            return (img_bytes, mime_type, 'public, max-age=3600')
+
+        elif asset_name == 'after':
+            # Return the 'to' screenshot with bounding box if configured
+            img_bytes = watch.get_history_snapshot(timestamp=to_version)
+            img_bytes = _draw_bounding_box_if_configured(img_bytes, watch, datastore)
+            mime_type = _detect_mime_type(img_bytes)
+            return (img_bytes, mime_type, 'public, max-age=3600')
+
+        elif asset_name == 'rendered_diff':
+            # Generate diff in isolated subprocess to prevent memory leaks
+            # Subprocess provides complete memory isolation
+            from .image_handler import isolated_opencv as process_screenshot_handler
+
+            img_bytes_from = watch.get_history_snapshot(timestamp=from_version)
+            img_bytes_to = watch.get_history_snapshot(timestamp=to_version)
+
+            # Get pixel difference threshold sensitivity (per-watch > global)
+            # This controls how different a pixel must be (0-255 scale) to count as "changed"
+            from changedetectionio import processors
+            processor_instance = processors.difference_detection_processor(datastore, watch.get('uuid'))
+            processor_config = processor_instance.get_extra_watch_config(PROCESSOR_CONFIG_NAME)
+
+            pixel_difference_threshold_sensitivity = processor_config.get('pixel_difference_threshold_sensitivity')
+            if not pixel_difference_threshold_sensitivity:
+                pixel_difference_threshold_sensitivity = datastore.data['settings']['application'].get(
+                    'pixel_difference_threshold_sensitivity', SCREENSHOT_COMPARISON_THRESHOLD_OPTIONS_DEFAULT)
+            try:
+                pixel_difference_threshold_sensitivity = int(pixel_difference_threshold_sensitivity)
+            except (ValueError, TypeError):
+                logger.warning(
+                    f"Invalid pixel_difference_threshold_sensitivity value '{pixel_difference_threshold_sensitivity}', using default")
+                pixel_difference_threshold_sensitivity = SCREENSHOT_COMPARISON_THRESHOLD_OPTIONS_DEFAULT
+
+            logger.debug(f"Pixel difference threshold sensitivity is {pixel_difference_threshold_sensitivity}")
+
+
+            # Generate diff in isolated subprocess (async-safe)
+            import asyncio
+            import threading
+
+            # Async-safe wrapper: runs coroutine in new thread with its own event loop
+            def run_async_in_thread():
+                return asyncio.run(
+                    process_screenshot_handler.generate_diff_isolated(
+                        img_bytes_from,
+                        img_bytes_to,
+                        pixel_difference_threshold=int(pixel_difference_threshold_sensitivity),
+                        blur_sigma=OPENCV_BLUR_SIGMA,
+                        max_width=MAX_DIFF_WIDTH,
+                        max_height=MAX_DIFF_HEIGHT
+                    )
+                )
+
+            # Run in thread to avoid blocking event loop if called from async context
+            result_container = [None]
+            exception_container = [None]
+
+            def thread_target():
+                try:
+                    result_container[0] = run_async_in_thread()
+                except Exception as e:
+                    exception_container[0] = e
+
+            thread = threading.Thread(target=thread_target, daemon=True, name="ImageDiff-Asset")
+            thread.start()
+            thread.join(timeout=60)
+
+            if exception_container[0]:
+                raise exception_container[0]
+
+            diff_image_bytes = result_container[0]
+
+            if diff_image_bytes:
+                # Note: Bounding box drawing on diff not yet implemented
+                return (diff_image_bytes, 'image/jpeg', 'public, max-age=300')
+            else:
+                logger.error("Failed to generate diff in subprocess")
+                return None
+
+        else:
+            # Unknown asset
+            return None
+
+    except Exception as e:
+        logger.error(f"Failed to get asset '{asset_name}': {e}")
+        import traceback
+        logger.error(traceback.format_exc())
+        return None
+
+
+def _detect_mime_type(img_bytes):
+    """
+    Detect MIME type using puremagic (same as Watch.py).
+
+    Args:
+        img_bytes: Image bytes
+
+    Returns:
+        str: MIME type (e.g., 'image/png', 'image/jpeg')
+    """
+    try:
+        import puremagic
+        detections = puremagic.magic_string(img_bytes[:2048])
+        if detections:
+            mime_type = detections[0].mime_type
+            logger.trace(f"Detected MIME type: {mime_type}")
+            return mime_type
+        else:
+            logger.trace("No MIME type detected, using 'image/png' fallback")
+            return 'image/png'
+    except Exception as e:
+        logger.warning(f"puremagic detection failed: {e}, using 'image/png' fallback")
+        return 'image/png'
+
+
+def _draw_bounding_box_if_configured(img_bytes, watch, datastore):
+    """
+    Draw blue bounding box on image if configured in processor settings.
+    Uses isolated subprocess to prevent memory leaks from large images.
+
+    Supports two modes:
+    - "Select by element": Use include_filter to find xpath element bbox
+    - "Draw area": Use manually drawn bounding_box from config
+
+    Args:
+        img_bytes: Image bytes (PNG)
+        watch: Watch object
+        datastore: Datastore object
+
+    Returns:
+        Image bytes (possibly with bounding box drawn)
+    """
+    try:
+        # Get processor configuration
+        from changedetectionio import processors
+        processor_instance = processors.difference_detection_processor(datastore, watch.get('uuid'))
+        processor_name = watch.get('processor', 'default')
+        config_filename = f'{processor_name}.json'
+        processor_config = processor_instance.get_extra_watch_config(config_filename)
+
+        if not processor_config:
+            return img_bytes
+
+        selection_mode = processor_config.get('selection_mode', 'draw')
+        x, y, width, height = None, None, None, None
+
+        # Mode 1: Select by element (use include_filter + xpath_data)
+        if selection_mode == 'element':
+            include_filters = watch.get('include_filters', [])
+
+            if include_filters and len(include_filters) > 0:
+                first_filter = include_filters[0].strip()
+
+                # Get xpath_data from watch history
+                history_keys = list(watch.history.keys())
+                if history_keys:
+                    latest_snapshot = watch.get_history_snapshot(timestamp=history_keys[-1])
+                    xpath_data_path = watch.get_xpath_data_filepath(timestamp=history_keys[-1])
+
+                    try:
+                        import gzip
+                        with gzip.open(xpath_data_path, 'rt') as f:
+                            xpath_data = json.load(f)
+
+                        # Find matching element
+                        for element in xpath_data.get('size_pos', []):
+                            if element.get('xpath') == first_filter and element.get('highlight_as_custom_filter'):
+                                x = element.get('left', 0)
+                                y = element.get('top', 0)
+                                width = element.get('width', 0)
+                                height = element.get('height', 0)
+                                logger.debug(f"Found element bbox for filter '{first_filter}': x={x}, y={y}, w={width}, h={height}")
+                                break
+                    except Exception as e:
+                        logger.warning(f"Failed to load xpath_data for element selection: {e}")
+
+        # Mode 2: Draw area (use manually configured bbox)
+        else:
+            bounding_box = processor_config.get('bounding_box')
+            if bounding_box:
+                # Parse bounding box: "x,y,width,height"
+                parts = [int(p.strip()) for p in bounding_box.split(',')]
+                if len(parts) == 4:
+                    x, y, width, height = parts
+                else:
+                    logger.warning(f"Invalid bounding box format: {bounding_box}")
+
+        # If no bbox found, return original image
+        if x is None or y is None or width is None or height is None:
+            return img_bytes
+
+        # Use isolated subprocess to prevent memory leaks from large images
+        from .image_handler import isolated_opencv
+        import asyncio
+        import threading
+
+        # Async-safe wrapper: runs coroutine in new thread with its own event loop
+        # This prevents blocking when called from async context (update worker)
+        def run_async_in_thread():
+            return asyncio.run(
+                isolated_opencv.draw_bounding_box_isolated(
+                    img_bytes, x, y, width, height,
+                    color=(255, 0, 0),  # Blue in BGR format
+                    thickness=3
+                )
+            )
+
+        # Always run in thread to avoid blocking event loop if called from async context
+        result_container = [None]
+        exception_container = [None]
+
+        def thread_target():
+            try:
+                result_container[0] = run_async_in_thread()
+            except Exception as e:
+                exception_container[0] = e
+
+        thread = threading.Thread(target=thread_target, daemon=True, name="ImageDiff-BoundingBox")
+        thread.start()
+        thread.join(timeout=15)
+
+        if exception_container[0]:
+            raise exception_container[0]
+
+        result = result_container[0]
+
+        # Return result or original if subprocess failed
+        return result if result else img_bytes
+
+    except Exception as e:
+        logger.warning(f"Failed to draw bounding box: {e}")
+        import traceback
+        logger.debug(traceback.format_exc())
+        return img_bytes
+
+
+def render(watch, datastore, request, url_for, render_template, flash, redirect):
+    """
+    Render the screenshot comparison diff page.
+
+    Uses ImageDiffHandler for all image operations.
+
+    Args:
+        watch: Watch object
+        datastore: Datastore object
+        request: Flask request
+        url_for: Flask url_for function
+        render_template: Flask render_template function
+        flash: Flask flash function
+        redirect: Flask redirect function
+
+    Returns:
+        Rendered template or redirect
+    """
+    # Get version parameters (from_version, to_version)
+    versions = list(watch.history.keys())
+
+    if len(versions) < 2:
+        flash(gettext("Not enough history to compare. Need at least 2 snapshots."), "error")
+        return redirect(url_for('watchlist.index'))
+
+    # Default: compare latest two versions
+    from_version = request.args.get('from_version', versions[-2] if len(versions) >= 2 else versions[0])
+    to_version = request.args.get('to_version', versions[-1])
+
+    # Validate versions exist
+    if from_version not in versions:
+        from_version = versions[-2] if len(versions) >= 2 else versions[0]
+    if to_version not in versions:
+        to_version = versions[-1]
+
+    # Get pixel difference threshold sensitivity (per-watch > global > env default)
+    pixel_difference_threshold_sensitivity = watch.get('pixel_difference_threshold_sensitivity')
+    if not pixel_difference_threshold_sensitivity or pixel_difference_threshold_sensitivity == '':
+        pixel_difference_threshold_sensitivity = datastore.data['settings']['application'].get('pixel_difference_threshold_sensitivity', SCREENSHOT_COMPARISON_THRESHOLD_OPTIONS_DEFAULT)
+
+    # Convert to appropriate type
+    try:
+        pixel_difference_threshold_sensitivity = float(pixel_difference_threshold_sensitivity)
+    except (ValueError, TypeError):
+        logger.warning(f"Invalid pixel_difference_threshold_sensitivity value '{pixel_difference_threshold_sensitivity}', using default")
+        pixel_difference_threshold_sensitivity = 30.0
+
+    # Get blur sigma
+    blur_sigma = OPENCV_BLUR_SIGMA
+
+    # Load screenshots from history
+    try:
+        img_bytes_from = watch.get_history_snapshot(timestamp=from_version)
+        img_bytes_to = watch.get_history_snapshot(timestamp=to_version)
+
+    except Exception as e:
+        logger.error(f"Failed to load screenshots: {e}")
+        flash(gettext("Failed to load screenshots: {}").format(e), "error")
+        return redirect(url_for('watchlist.index'))
+
+    # Calculate change percentage using isolated subprocess to prevent memory leaks (async-safe)
+    now = time.time()
+    try:
+        from .image_handler import isolated_opencv as process_screenshot_handler
+        import asyncio
+        import threading
+
+        # Async-safe wrapper: runs coroutine in new thread with its own event loop
+        def run_async_in_thread():
+            return asyncio.run(
+                process_screenshot_handler.calculate_change_percentage_isolated(
+                    img_bytes_from,
+                    img_bytes_to,
+                    pixel_difference_threshold=int(pixel_difference_threshold_sensitivity),
+                    blur_sigma=blur_sigma,
+                    max_width=MAX_DIFF_WIDTH,
+                    max_height=MAX_DIFF_HEIGHT
+                )
+            )
+
+        # Run in thread to avoid blocking event loop if called from async context
+        result_container = [None]
+        exception_container = [None]
+
+        def thread_target():
+            try:
+                result_container[0] = run_async_in_thread()
+            except Exception as e:
+                exception_container[0] = e
+
+        thread = threading.Thread(target=thread_target, daemon=True, name="ImageDiff-ChangePercentage")
+        thread.start()
+        thread.join(timeout=60)
+
+        if exception_container[0]:
+            raise exception_container[0]
+
+        change_percentage = result_container[0]
+
+        method_display = f"{process_screenshot_handler.IMPLEMENTATION_NAME} (pixel_diff_threshold: {pixel_difference_threshold_sensitivity:.0f})"
+        logger.debug(f"Done change percentage calculation in {time.time() - now:.2f}s")
+
+    except Exception as e:
+        logger.error(f"Failed to calculate change percentage: {e}")
+        import traceback
+        logger.error(traceback.format_exc())
+        flash(gettext("Failed to calculate diff: {}").format(e), "error")
+        return redirect(url_for('watchlist.index'))
+
+    # Load historical data if available (for charts/visualization)
+    comparison_data = {}
+    comparison_config_path = os.path.join(watch.watch_data_dir, "visual_comparison_data.json")
+    if os.path.isfile(comparison_config_path):
+        try:
+            with open(comparison_config_path, 'r') as f:
+                comparison_data = json.load(f)
+        except Exception as e:
+            logger.warning(f"Failed to load comparison history data: {e}")
+
+    # Render custom template
+    # Template path is namespaced to avoid conflicts with other processors
+    # Images are now served via separate /processor-asset/ endpoints instead of base64
+    return render_template(
+        'image_ssim_diff/diff.html',
+        change_percentage=change_percentage,
+        comparison_data=comparison_data,  # Full history for charts/visualization
+        comparison_method=method_display,
+        current_diff_url=watch['url'],
+        from_version=from_version,
+        percentage_different=change_percentage,
+        threshold=pixel_difference_threshold_sensitivity,
+        to_version=to_version,
+        uuid=watch.get('uuid'),
+        versions=versions,
+        watch=watch,
+    )

changedetectionio/processors/image_ssim_diff/edit_hook.py

@@ -0,0 +1,151 @@
+"""
+Optional hook called when processor settings are saved in edit page.
+
+This hook analyzes the selected region to determine if template matching
+should be enabled for tracking content movement.
+
+Template matching is controlled via ENABLE_TEMPLATE_TRACKING env var (default: False).
+"""
+
+import io
+import os
+from loguru import logger
+from changedetectionio import strtobool
+from . import CROPPED_IMAGE_TEMPLATE_FILENAME
+
+# Template matching controlled via environment variable (default: disabled)
+# Set ENABLE_TEMPLATE_TRACKING=True to enable
+TEMPLATE_MATCHING_ENABLED = strtobool(os.getenv('ENABLE_TEMPLATE_TRACKING', 'False'))
+IMPORT_ERROR = "Template matching disabled (set ENABLE_TEMPLATE_TRACKING=True to enable)"
+
+
+def on_config_save(watch, processor_config, datastore):
+    """
+    Called after processor config is saved in edit page.
+
+    Analyzes the bounding box region to determine if it has enough
+    visual features (texture/edges) to enable template matching for
+    tracking content movement when page layout shifts.
+
+    Args:
+        watch: Watch object
+        processor_config: Dict of processor-specific config
+        datastore: Datastore object
+
+    Returns:
+        dict: Updated processor_config with auto_track_region setting
+    """
+    # Check if template matching is globally enabled via ENV var
+    if not TEMPLATE_MATCHING_ENABLED:
+        logger.debug("Template tracking disabled via ENABLE_TEMPLATE_TRACKING env var")
+        processor_config['auto_track_region'] = False
+        return processor_config
+
+    bounding_box = processor_config.get('bounding_box')
+
+    if not bounding_box:
+        # No bounding box, disable tracking
+        processor_config['auto_track_region'] = False
+        logger.debug("No bounding box set, disabled auto-tracking")
+        return processor_config
+
+    try:
+        # Get the latest screenshot from watch history
+        history_keys = list(watch.history.keys())
+        if len(history_keys) == 0:
+            logger.warning("No screenshot history available yet, cannot analyze for tracking")
+            processor_config['auto_track_region'] = False
+            return processor_config
+
+        # Get latest screenshot
+        latest_timestamp = history_keys[-1]
+        screenshot_bytes = watch.get_history_snapshot(timestamp=latest_timestamp)
+
+        if not screenshot_bytes:
+            logger.warning("Could not load screenshot for analysis")
+            processor_config['auto_track_region'] = False
+            return processor_config
+
+        # Parse bounding box
+        parts = [int(p.strip()) for p in bounding_box.split(',')]
+        if len(parts) != 4:
+            logger.warning("Invalid bounding box format")
+            processor_config['auto_track_region'] = False
+            return processor_config
+
+        x, y, width, height = parts
+
+        # Analyze the region for features/texture
+        has_enough_features = analyze_region_features(screenshot_bytes, x, y, width, height)
+
+        if has_enough_features:
+            logger.info(f"Region has sufficient features for tracking - enabling auto_track_region")
+            processor_config['auto_track_region'] = True
+
+            # Save the template as cropped.jpg in watch data directory
+            save_template_to_file(watch, screenshot_bytes, x, y, width, height)
+
+        else:
+            logger.info(f"Region lacks distinctive features - disabling auto_track_region")
+            processor_config['auto_track_region'] = False
+
+            # Remove old template file if exists
+            template_path = os.path.join(watch.watch_data_dir, CROPPED_IMAGE_TEMPLATE_FILENAME)
+            if os.path.exists(template_path):
+                os.remove(template_path)
+                logger.debug(f"Removed old template file: {template_path}")
+
+        return processor_config
+
+    except Exception as e:
+        logger.error(f"Error analyzing region for tracking: {e}")
+        processor_config['auto_track_region'] = False
+        return processor_config
+
+
+def analyze_region_features(screenshot_bytes, x, y, width, height):
+    """
+    Analyze if a region has enough visual features for template matching.
+
+    Uses OpenCV to detect corners/edges. If the region has distinctive
+    features, template matching can reliably track it when it moves.
+
+    Args:
+        screenshot_bytes: Full screenshot as bytes
+        x, y, width, height: Bounding box coordinates
+
+    Returns:
+        bool: True if region has enough features, False otherwise
+    """
+    # Template matching disabled - would need OpenCV implementation for region analysis
+    if not TEMPLATE_MATCHING_ENABLED:
+        logger.warning(f"Cannot analyze region features: {IMPORT_ERROR}")
+        return False
+
+    # Note: Original implementation used LibVIPS handler to crop region, then OpenCV
+    # for feature detection (goodFeaturesToTrack, Canny edge detection, variance).
+    # If re-implementing, use OpenCV directly for both cropping and analysis.
+    # Feature detection would use: cv2.goodFeaturesToTrack, cv2.Canny, np.var
+    return False
+
+
+def save_template_to_file(watch, screenshot_bytes, x, y, width, height):
+    """
+    Extract the template region and save as cropped_image_template.png in watch data directory.
+
+    This is a convenience wrapper around handler.save_template() that handles
+    watch directory setup and path construction.
+
+    Args:
+        watch: Watch object
+        screenshot_bytes: Full screenshot as bytes
+        x, y, width, height: Bounding box coordinates
+    """
+    # Template matching disabled - would need OpenCV implementation for template saving
+    if not TEMPLATE_MATCHING_ENABLED:
+        logger.warning(f"Cannot save template: {IMPORT_ERROR}")
+        return
+
+    # Note: Original implementation used LibVIPS handler to crop and save region.
+    # If re-implementing, use OpenCV (cv2.imdecode, crop with array slicing, cv2.imwrite).
+    return

changedetectionio/processors/image_ssim_diff/forms.py

@@ -0,0 +1,120 @@
+"""
+Configuration forms for fast screenshot comparison processor.
+"""
+
+from wtforms import SelectField, StringField, validators, ValidationError, IntegerField
+from flask_babel import lazy_gettext as _l
+from changedetectionio.forms import processor_text_json_diff_form
+import re
+
+from changedetectionio.processors.image_ssim_diff import SCREENSHOT_COMPARISON_THRESHOLD_OPTIONS
+
+
+def validate_bounding_box(form, field):
+    """Validate bounding box format: x,y,width,height with integers."""
+    if not field.data:
+        return  # Optional field
+
+    if len(field.data) > 100:
+        raise ValidationError(_l('Bounding box value is too long'))
+
+    # Should be comma-separated integers
+    if not re.match(r'^\d+,\d+,\d+,\d+$', field.data):
+        raise ValidationError(_l('Bounding box must be in format: x,y,width,height (integers only)'))
+
+    # Validate values are reasonable (not negative, not ridiculously large)
+    parts = [int(p) for p in field.data.split(',')]
+    for part in parts:
+        if part < 0:
+            raise ValidationError(_l('Bounding box values must be non-negative'))
+        if part > 10000:  # Reasonable max screen dimension
+            raise ValidationError(_l('Bounding box values are too large'))
+
+
+def validate_selection_mode(form, field):
+    """Validate selection mode value."""
+    if not field.data:
+        return  # Optional field
+
+    if field.data not in ['element', 'draw']:
+        raise ValidationError(_l('Selection mode must be either "element" or "draw"'))
+
+
+class processor_settings_form(processor_text_json_diff_form):
+    """Form for fast image comparison processor settings."""
+
+    processor_config_min_change_percentage = IntegerField(
+        _l('Minimum Change Percentage'),
+        validators=[
+            validators.Optional(),
+            validators.NumberRange(min=1, max=100, message=_l('Must be between 0 and 100'))
+        ],
+        render_kw={"placeholder": "Use global default (0.1)"}
+    )
+
+    processor_config_pixel_difference_threshold_sensitivity = SelectField(
+        _l('Pixel Difference Sensitivity'),
+        choices=[
+                    ('', _l('Use global default'))
+                ] + SCREENSHOT_COMPARISON_THRESHOLD_OPTIONS,
+        validators=[validators.Optional()],
+        default=''
+    )
+
+    # Processor-specific config fields (stored in separate JSON file)
+    processor_config_bounding_box = StringField(
+        _l('Bounding Box'),
+        validators=[
+            validators.Optional(),
+            validators.Length(max=100, message=_l('Bounding box value is too long')),
+            validate_bounding_box
+        ],
+        render_kw={"style": "display: none;", "id": "bounding_box"}
+    )
+
+    processor_config_selection_mode = StringField(
+        _l('Selection Mode'),
+        validators=[
+            validators.Optional(),
+            validators.Length(max=20, message=_l('Selection mode value is too long')),
+            validate_selection_mode
+        ],
+        render_kw={"style": "display: none;", "id": "selection_mode"}
+    )
+
+    def extra_tab_content(self):
+        """Tab label for processor-specific settings."""
+        return _l('Screenshot Comparison')
+
+    def extra_form_content(self):
+        """Render processor-specific form fields.
+        @NOTE: prepend processor_config_* to the field name so it will save into its own datadir/uuid/image_ssim_diff.json and be read at process time
+        """
+        return '''
+        {% from '_helpers.html' import render_field %}
+        <fieldset>
+            <legend>Screenshot Comparison Settings</legend>
+
+            <div class="pure-control-group">
+                {{ render_field(form.processor_config_min_change_percentage) }}
+                <span class="pure-form-message-inline">
+                    <strong>What percentage of pixels must change to trigger a detection?</strong><br>
+                    For example, <strong>0.1%</strong> means if 0.1% or more of the pixels change, it counts as a change.<br>
+                    Lower values = more sensitive (detect smaller changes).<br>
+                    Higher values = less sensitive (only detect larger changes).<br>
+                    Leave blank to use global default (0.1%).
+                </span>
+            </div>
+
+            <div class="pure-control-group">
+                {{ render_field(form.processor_config_pixel_difference_threshold_sensitivity) }}
+                <span class="pure-form-message-inline">
+                    <strong>How different must an individual pixel be to count as "changed"?</strong><br>
+                    <strong>Low sensitivity (75)</strong> = Only count pixels that changed significantly (0-255 scale).<br>
+                    <strong>High sensitivity (20)</strong> = Count pixels with small changes as different.<br>
+                    <strong>Very high (0)</strong> = Any pixel change counts.<br>
+                    Select "Use global default" to inherit the system-wide setting.
+                </span>
+            </div>
+        </fieldset>
+        '''

changedetectionio/processors/image_ssim_diff/image_handler/__init__.py

@@ -0,0 +1,242 @@
+"""
+Abstract base class for image processing operations.
+
+All image operations for the image_ssim_diff processor must be implemented
+through this interface to allow different backends (libvips, OpenCV, PIL, etc.).
+"""
+
+from abc import ABC, abstractmethod
+from typing import Tuple, Optional, Any
+
+
+class ImageDiffHandler(ABC):
+    """
+    Abstract base class for image processing operations.
+
+    Implementations must handle all image operations needed for screenshot
+    comparison including loading, cropping, resizing, diffing, and overlays.
+    """
+
+    @abstractmethod
+    def load_from_bytes(self, img_bytes: bytes) -> Any:
+        """
+        Load image from bytes.
+
+        Args:
+            img_bytes: Image data as bytes (PNG, JPEG, etc.)
+
+        Returns:
+            Handler-specific image object
+        """
+        pass
+
+    @abstractmethod
+    def save_to_bytes(self, img: Any, format: str = 'png', quality: int = 85) -> bytes:
+        """
+        Save image to bytes.
+
+        Args:
+            img: Handler-specific image object
+            format: Output format ('png' or 'jpeg')
+            quality: Quality for JPEG (1-100)
+
+        Returns:
+            Image data as bytes
+        """
+        pass
+
+    @abstractmethod
+    def crop(self, img: Any, left: int, top: int, right: int, bottom: int) -> Any:
+        """
+        Crop image to specified region.
+
+        Args:
+            img: Handler-specific image object
+            left: Left coordinate
+            top: Top coordinate
+            right: Right coordinate
+            bottom: Bottom coordinate
+
+        Returns:
+            Cropped image object
+        """
+        pass
+
+    @abstractmethod
+    def resize(self, img: Any, max_width: int, max_height: int) -> Any:
+        """
+        Resize image maintaining aspect ratio.
+
+        Args:
+            img: Handler-specific image object
+            max_width: Maximum width in pixels
+            max_height: Maximum height in pixels
+
+        Returns:
+            Resized image object
+        """
+        pass
+
+    @abstractmethod
+    def get_dimensions(self, img: Any) -> Tuple[int, int]:
+        """
+        Get image dimensions.
+
+        Args:
+            img: Handler-specific image object
+
+        Returns:
+            Tuple of (width, height)
+        """
+        pass
+
+    @abstractmethod
+    def to_grayscale(self, img: Any) -> Any:
+        """
+        Convert image to grayscale.
+
+        Args:
+            img: Handler-specific image object
+
+        Returns:
+            Grayscale image object
+        """
+        pass
+
+    @abstractmethod
+    def gaussian_blur(self, img: Any, sigma: float) -> Any:
+        """
+        Apply Gaussian blur to image.
+
+        Args:
+            img: Handler-specific image object
+            sigma: Blur sigma value (0 = no blur)
+
+        Returns:
+            Blurred image object
+        """
+        pass
+
+    @abstractmethod
+    def absolute_difference(self, img1: Any, img2: Any) -> Any:
+        """
+        Calculate absolute difference between two images.
+
+        Args:
+            img1: First image (handler-specific object)
+            img2: Second image (handler-specific object)
+
+        Returns:
+            Difference image object
+        """
+        pass
+
+    @abstractmethod
+    def threshold(self, img: Any, threshold_value: int) -> Tuple[float, Any]:
+        """
+        Apply threshold to image and calculate change percentage.
+
+        Args:
+            img: Handler-specific image object (typically grayscale difference)
+            threshold_value: Threshold value (0-255)
+
+        Returns:
+            Tuple of (change_percentage, binary_mask)
+            - change_percentage: Percentage of pixels above threshold (0-100)
+            - binary_mask: Handler-specific binary mask object
+        """
+        pass
+
+    @abstractmethod
+    def apply_red_overlay(self, img: Any, mask: Any) -> bytes:
+        """
+        Apply red overlay to image where mask is True.
+
+        Args:
+            img: Handler-specific image object (color)
+            mask: Handler-specific binary mask object
+
+        Returns:
+            JPEG bytes with red overlay applied
+        """
+        pass
+
+    @abstractmethod
+    def close(self, img: Any) -> None:
+        """
+        Clean up image resources if needed.
+
+        Args:
+            img: Handler-specific image object
+        """
+        pass
+
+    @abstractmethod
+    def find_template(
+        self,
+        img: Any,
+        template_img: Any,
+        original_bbox: Tuple[int, int, int, int],
+        search_tolerance: float = 0.2
+    ) -> Optional[Tuple[int, int, int, int]]:
+        """
+        Find template in image using template matching.
+
+        Args:
+            img: Handler-specific image object to search in
+            template_img: Handler-specific template image object to find
+            original_bbox: Original bounding box (left, top, right, bottom)
+            search_tolerance: How far to search (0.2 = ±20% of region size)
+
+        Returns:
+            New bounding box (left, top, right, bottom) or None if not found
+        """
+        pass
+
+    @abstractmethod
+    def save_template(
+        self,
+        img: Any,
+        bbox: Tuple[int, int, int, int],
+        output_path: str
+    ) -> bool:
+        """
+        Save a cropped region as a template file.
+
+        Args:
+            img: Handler-specific image object
+            bbox: Bounding box to crop (left, top, right, bottom)
+            output_path: Where to save the template PNG
+
+        Returns:
+            True if successful, False otherwise
+        """
+        pass
+
+    @abstractmethod
+    def draw_bounding_box(
+        self,
+        img_bytes: bytes,
+        x: int,
+        y: int,
+        width: int,
+        height: int,
+        color: Tuple[int, int, int] = (255, 0, 0),
+        thickness: int = 3
+    ) -> bytes:
+        """
+        Draw a bounding box rectangle on image.
+
+        Args:
+            img_bytes: Image data as bytes
+            x: Left coordinate
+            y: Top coordinate
+            width: Box width
+            height: Box height
+            color: BGR color tuple (default: blue)
+            thickness: Line thickness in pixels
+
+        Returns:
+            Image bytes with bounding box drawn
+        """
+        pass

changedetectionio/processors/image_ssim_diff/image_handler/isolated_libvips.py

@@ -0,0 +1,351 @@
+"""
+Subprocess-isolated image operations for memory leak prevention.
+
+LibVIPS accumulates C-level memory in long-running processes that cannot be
+reclaimed by Python's GC or libvips cache management. Using subprocess isolation
+ensures complete memory cleanup when the process exits.
+
+This module wraps LibvipsImageDiffHandler operations in multiprocessing for
+complete memory isolation without code duplication.
+
+Research: https://github.com/libvips/pyvips/issues/234
+"""
+
+import multiprocessing
+
+# CRITICAL: Use 'spawn' context instead of 'fork' to avoid inheriting parent's
+# LibVIPS threading state which can cause hangs in gaussblur operations
+# https://docs.python.org/3/library/multiprocessing.html#contexts-and-start-methods
+
+
+def _worker_generate_diff(conn, img_bytes_from, img_bytes_to, threshold, blur_sigma, max_width, max_height):
+    """
+    Worker: Generate diff visualization using LibvipsImageDiffHandler in isolated subprocess.
+
+    This runs in a separate process for complete memory isolation.
+    Uses print() instead of loguru to avoid forking issues.
+    """
+    try:
+        # Import handler inside worker
+        from .libvips_handler import LibvipsImageDiffHandler
+
+        print(f"[Worker] Initializing handler", flush=True)
+        handler = LibvipsImageDiffHandler()
+
+        # Load images using handler
+        img_from = handler.load_from_bytes(img_bytes_from)
+        img_to = handler.load_from_bytes(img_bytes_to)
+
+        # Ensure same size
+        w1, h1 = handler.get_dimensions(img_from)
+        w2, h2 = handler.get_dimensions(img_to)
+        if (w1, h1) != (w2, h2):
+            img_from = handler.resize(img_from, w2, h2)
+
+        # Downscale for faster diff visualization
+        img_from = handler.resize(img_from, max_width, max_height)
+        img_to = handler.resize(img_to, max_width, max_height)
+
+        # Convert to grayscale
+        gray_from = handler.to_grayscale(img_from)
+        gray_to = handler.to_grayscale(img_to)
+
+        # Optional blur - DISABLED due to LibVIPS threading issues in fork
+        # gray_from = handler.gaussian_blur(gray_from, blur_sigma)
+        # gray_to = handler.gaussian_blur(gray_to, blur_sigma)
+
+        # Calculate difference
+        diff = handler.absolute_difference(gray_from, gray_to)
+
+        # Threshold to get mask
+        _, diff_mask = handler.threshold(diff, int(threshold))
+
+        # Generate diff image with red overlay
+        diff_image_bytes = handler.apply_red_overlay(img_to, diff_mask)
+
+        print(f"[Worker] Generated diff ({len(diff_image_bytes)} bytes)", flush=True)
+        conn.send(diff_image_bytes)
+
+    except Exception as e:
+        print(f"[Worker] Error: {e}", flush=True)
+        import traceback
+        traceback.print_exc()
+        conn.send(None)
+    finally:
+        conn.close()
+
+
+def generate_diff_isolated(img_bytes_from, img_bytes_to, threshold, blur_sigma, max_width, max_height):
+    """
+    Generate diff visualization in isolated subprocess for memory leak prevention.
+
+    Args:
+        img_bytes_from: Previous screenshot bytes
+        img_bytes_to: Current screenshot bytes
+        threshold: Pixel difference threshold
+        blur_sigma: Gaussian blur sigma
+        max_width: Maximum width for diff
+        max_height: Maximum height for diff
+
+    Returns:
+        bytes: JPEG diff image or None on failure
+    """
+    ctx = multiprocessing.get_context('spawn')
+    parent_conn, child_conn = ctx.Pipe()
+
+    p = ctx.Process(
+        target=_worker_generate_diff,
+        args=(child_conn, img_bytes_from, img_bytes_to, threshold, blur_sigma, max_width, max_height)
+    )
+    p.start()
+
+    result = None
+    try:
+        # Wait for result (30 second timeout)
+        if parent_conn.poll(30):
+            result = parent_conn.recv()
+    except Exception as e:
+        print(f"[Parent] Error receiving result: {e}", flush=True)
+    finally:
+        # Always close pipe first
+        try:
+            parent_conn.close()
+        except:
+            pass
+
+        # Try graceful shutdown
+        p.join(timeout=5)
+        if p.is_alive():
+            print("[Parent] Process didn't exit gracefully, terminating", flush=True)
+            p.terminate()
+            p.join(timeout=3)
+
+        # Force kill if still alive
+        if p.is_alive():
+            print("[Parent] Process didn't terminate, killing", flush=True)
+            p.kill()
+            p.join(timeout=1)
+
+    return result
+
+
+def calculate_change_percentage_isolated(img_bytes_from, img_bytes_to, threshold, blur_sigma, max_width, max_height):
+    """
+    Calculate change percentage in isolated subprocess using handler.
+
+    Returns:
+        float: Change percentage
+    """
+    ctx = multiprocessing.get_context('spawn')
+    parent_conn, child_conn = ctx.Pipe()
+
+    def _worker_calculate(conn):
+        try:
+            # Import handler inside worker
+            from .libvips_handler import LibvipsImageDiffHandler
+
+            handler = LibvipsImageDiffHandler()
+
+            # Load images
+            img_from = handler.load_from_bytes(img_bytes_from)
+            img_to = handler.load_from_bytes(img_bytes_to)
+
+            # Ensure same size
+            w1, h1 = handler.get_dimensions(img_from)
+            w2, h2 = handler.get_dimensions(img_to)
+            if (w1, h1) != (w2, h2):
+                img_from = handler.resize(img_from, w2, h2)
+
+            # Downscale
+            img_from = handler.resize(img_from, max_width, max_height)
+            img_to = handler.resize(img_to, max_width, max_height)
+
+            # Convert to grayscale
+            gray_from = handler.to_grayscale(img_from)
+            gray_to = handler.to_grayscale(img_to)
+
+            # Optional blur
+            gray_from = handler.gaussian_blur(gray_from, blur_sigma)
+            gray_to = handler.gaussian_blur(gray_to, blur_sigma)
+
+            # Calculate difference
+            diff = handler.absolute_difference(gray_from, gray_to)
+
+            # Threshold and get percentage
+            change_percentage, _ = handler.threshold(diff, int(threshold))
+
+            conn.send(float(change_percentage))
+
+        except Exception as e:
+            print(f"[Worker] Calculate error: {e}", flush=True)
+            conn.send(0.0)
+        finally:
+            conn.close()
+
+    p = ctx.Process(target=_worker_calculate, args=(child_conn,))
+    p.start()
+
+    result = 0.0
+    try:
+        if parent_conn.poll(30):
+            result = parent_conn.recv()
+    except Exception as e:
+        print(f"[Parent] Calculate error receiving result: {e}", flush=True)
+    finally:
+        # Always close pipe first
+        try:
+            parent_conn.close()
+        except:
+            pass
+
+        # Try graceful shutdown
+        p.join(timeout=5)
+        if p.is_alive():
+            print("[Parent] Calculate process didn't exit gracefully, terminating", flush=True)
+            p.terminate()
+            p.join(timeout=3)
+
+        # Force kill if still alive
+        if p.is_alive():
+            print("[Parent] Calculate process didn't terminate, killing", flush=True)
+            p.kill()
+            p.join(timeout=1)
+
+    return result
+
+
+def compare_images_isolated(img_bytes_from, img_bytes_to, threshold, blur_sigma, min_change_percentage, crop_region=None):
+    """
+    Compare images in isolated subprocess for change detection.
+
+    Args:
+        img_bytes_from: Previous screenshot bytes
+        img_bytes_to: Current screenshot bytes
+        threshold: Pixel difference threshold
+        blur_sigma: Gaussian blur sigma
+        min_change_percentage: Minimum percentage to trigger change detection
+        crop_region: Optional tuple (left, top, right, bottom) for cropping both images
+
+    Returns:
+        tuple: (changed_detected, change_percentage)
+    """
+    print(f"[Parent] Starting compare_images_isolated subprocess", flush=True)
+    ctx = multiprocessing.get_context('spawn')
+    parent_conn, child_conn = ctx.Pipe()
+
+    def _worker_compare(conn):
+        try:
+            print(f"[Worker] Compare worker starting", flush=True)
+            # Import handler inside worker
+            from .libvips_handler import LibvipsImageDiffHandler
+
+            print(f"[Worker] Initializing handler", flush=True)
+            handler = LibvipsImageDiffHandler()
+
+            # Load images
+            print(f"[Worker] Loading images (from={len(img_bytes_from)} bytes, to={len(img_bytes_to)} bytes)", flush=True)
+            img_from = handler.load_from_bytes(img_bytes_from)
+            img_to = handler.load_from_bytes(img_bytes_to)
+            print(f"[Worker] Images loaded", flush=True)
+
+            # Crop if region specified
+            if crop_region:
+                print(f"[Worker] Cropping to region {crop_region}", flush=True)
+                left, top, right, bottom = crop_region
+                img_from = handler.crop(img_from, left, top, right, bottom)
+                img_to = handler.crop(img_to, left, top, right, bottom)
+                print(f"[Worker] Cropping completed", flush=True)
+
+            # Ensure same size
+            w1, h1 = handler.get_dimensions(img_from)
+            w2, h2 = handler.get_dimensions(img_to)
+            print(f"[Worker] Image dimensions: from={w1}x{h1}, to={w2}x{h2}", flush=True)
+            if (w1, h1) != (w2, h2):
+                print(f"[Worker] Resizing to match dimensions", flush=True)
+                img_from = handler.resize(img_from, w2, h2)
+
+            # Convert to grayscale
+            print(f"[Worker] Converting to grayscale", flush=True)
+            gray_from = handler.to_grayscale(img_from)
+            gray_to = handler.to_grayscale(img_to)
+
+            # Optional blur
+            # NOTE: gaussblur can hang in forked subprocesses due to LibVIPS threading
+            # Skip blur as a workaround - sigma=0.8 is subtle and comparison works without it
+            if blur_sigma > 0:
+                print(f"[Worker] Skipping blur (sigma={blur_sigma}) due to LibVIPS threading issues in fork", flush=True)
+                # gray_from = handler.gaussian_blur(gray_from, blur_sigma)
+                # gray_to = handler.gaussian_blur(gray_to, blur_sigma)
+
+            # Calculate difference
+            print(f"[Worker] Calculating difference", flush=True)
+            diff = handler.absolute_difference(gray_from, gray_to)
+
+            # Threshold and get percentage
+            print(f"[Worker] Applying threshold ({threshold})", flush=True)
+            change_percentage, _ = handler.threshold(diff, int(threshold))
+
+            # Determine if change detected
+            changed_detected = change_percentage > min_change_percentage
+
+            print(f"[Worker] Comparison complete: changed={changed_detected}, percentage={change_percentage:.2f}%", flush=True)
+            conn.send((changed_detected, float(change_percentage)))
+
+        except Exception as e:
+            print(f"[Worker] Compare error: {e}", flush=True)
+            import traceback
+            traceback.print_exc()
+            conn.send((False, 0.0))
+        finally:
+            conn.close()
+
+    p = ctx.Process(target=_worker_compare, args=(child_conn,))
+    print(f"[Parent] Starting subprocess (pid will be assigned)", flush=True)
+    p.start()
+    print(f"[Parent] Subprocess started (pid={p.pid}), waiting for result (30s timeout)", flush=True)
+
+    result = (False, 0.0)
+    try:
+        if parent_conn.poll(30):
+            print(f"[Parent] Result available, receiving", flush=True)
+            result = parent_conn.recv()
+            print(f"[Parent] Result received: {result}", flush=True)
+        else:
+            print(f"[Parent] Timeout waiting for result after 30s", flush=True)
+    except Exception as e:
+        print(f"[Parent] Compare error receiving result: {e}", flush=True)
+    finally:
+        # Always close pipe first
+        try:
+            parent_conn.close()
+        except:
+            pass
+
+        # Try graceful shutdown
+        import time
+        print(f"[Parent] Waiting for subprocess to exit (5s timeout)", flush=True)
+        join_start = time.time()
+        p.join(timeout=5)
+        join_elapsed = time.time() - join_start
+        print(f"[Parent] First join took {join_elapsed:.2f}s", flush=True)
+
+        if p.is_alive():
+            print("[Parent] Compare process didn't exit gracefully, terminating", flush=True)
+            term_start = time.time()
+            p.terminate()
+            p.join(timeout=3)
+            term_elapsed = time.time() - term_start
+            print(f"[Parent] Terminate+join took {term_elapsed:.2f}s", flush=True)
+
+        # Force kill if still alive
+        if p.is_alive():
+            print("[Parent] Compare process didn't terminate, killing", flush=True)
+            kill_start = time.time()
+            p.kill()
+            p.join(timeout=1)
+            kill_elapsed = time.time() - kill_start
+            print(f"[Parent] Kill+join took {kill_elapsed:.2f}s", flush=True)
+
+        print(f"[Parent] Subprocess cleanup complete, returning result", flush=True)
+
+    return result

changedetectionio/processors/image_ssim_diff/image_handler/isolated_opencv.py

@@ -0,0 +1,627 @@
+"""
+OpenCV-based subprocess isolation for image comparison.
+
+OpenCV is much more stable in multiprocessing contexts than LibVIPS.
+No threading issues, no fork problems, picklable functions.
+"""
+
+import multiprocessing
+import numpy as np
+from .. import POLL_TIMEOUT_ABSOLUTE
+
+# Public implementation name for logging
+IMPLEMENTATION_NAME = "OpenCV"
+
+
+def _worker_compare(conn, img_bytes_from, img_bytes_to, pixel_difference_threshold, blur_sigma, crop_region):
+    """
+    Worker function for image comparison (must be top-level for pickling with spawn).
+
+    Args:
+        conn: Pipe connection for sending results
+        img_bytes_from: Previous screenshot bytes
+        img_bytes_to: Current screenshot bytes
+        pixel_difference_threshold: Pixel-level sensitivity (0-255) - how different must a pixel be to count as changed
+        blur_sigma: Gaussian blur sigma
+        crop_region: Optional (left, top, right, bottom) crop coordinates
+    """
+    import time
+    try:
+        import cv2
+
+        # CRITICAL: Disable OpenCV threading to prevent thread explosion
+        # With multiprocessing, each subprocess would otherwise spawn threads equal to CPU cores
+        # This causes excessive thread counts and memory overhead
+        # Research: https://medium.com/@rachittayal7/a-note-on-opencv-threads-performance-in-prod-d10180716fba
+        cv2.setNumThreads(1)
+
+        print(f"[{time.time():.3f}] [Worker] Compare worker starting (threads=1 for memory optimization)", flush=True)
+
+        # Decode images from bytes
+        print(f"[{time.time():.3f}] [Worker] Loading images (from={len(img_bytes_from)} bytes, to={len(img_bytes_to)} bytes)", flush=True)
+        img_from = cv2.imdecode(np.frombuffer(img_bytes_from, np.uint8), cv2.IMREAD_COLOR)
+        img_to = cv2.imdecode(np.frombuffer(img_bytes_to, np.uint8), cv2.IMREAD_COLOR)
+
+        # Check if decoding succeeded
+        if img_from is None:
+            raise ValueError("Failed to decode 'from' image - may be corrupt or unsupported format")
+        if img_to is None:
+            raise ValueError("Failed to decode 'to' image - may be corrupt or unsupported format")
+
+        print(f"[{time.time():.3f}] [Worker] Images loaded: from={img_from.shape}, to={img_to.shape}", flush=True)
+
+        # Crop if region specified
+        if crop_region:
+            print(f"[{time.time():.3f}] [Worker] Cropping to region {crop_region}", flush=True)
+            left, top, right, bottom = crop_region
+            img_from = img_from[top:bottom, left:right]
+            img_to = img_to[top:bottom, left:right]
+            print(f"[{time.time():.3f}] [Worker] Cropped: from={img_from.shape}, to={img_to.shape}", flush=True)
+
+        # Resize if dimensions don't match
+        if img_from.shape != img_to.shape:
+            print(f"[{time.time():.3f}] [Worker] Resizing to match dimensions", flush=True)
+            img_from = cv2.resize(img_from, (img_to.shape[1], img_to.shape[0]))
+
+        # Convert to grayscale
+        print(f"[{time.time():.3f}] [Worker] Converting to grayscale", flush=True)
+        gray_from = cv2.cvtColor(img_from, cv2.COLOR_BGR2GRAY)
+        gray_to = cv2.cvtColor(img_to, cv2.COLOR_BGR2GRAY)
+
+        # Optional Gaussian blur
+        if blur_sigma > 0:
+            print(f"[{time.time():.3f}] [Worker] Applying Gaussian blur (sigma={blur_sigma})", flush=True)
+            # OpenCV uses kernel size, convert sigma to kernel size: size = 2 * round(3*sigma) + 1
+            ksize = int(2 * round(3 * blur_sigma)) + 1
+            if ksize % 2 == 0:  # Must be odd
+                ksize += 1
+            gray_from = cv2.GaussianBlur(gray_from, (ksize, ksize), blur_sigma)
+            gray_to = cv2.GaussianBlur(gray_to, (ksize, ksize), blur_sigma)
+            print(f"[{time.time():.3f}] [Worker] Blur applied (kernel={ksize}x{ksize})", flush=True)
+
+        # Calculate absolute difference
+        print(f"[{time.time():.3f}] [Worker] Calculating absolute difference", flush=True)
+        diff = cv2.absdiff(gray_from, gray_to)
+
+        # Apply threshold
+        print(f"[{time.time():.3f}] [Worker] Applying pixel difference threshold ({pixel_difference_threshold})", flush=True)
+        _, thresholded = cv2.threshold(diff, int(pixel_difference_threshold), 255, cv2.THRESH_BINARY)
+
+        # Calculate change percentage
+        total_pixels = thresholded.size
+        changed_pixels = np.count_nonzero(thresholded)
+        change_percentage = (changed_pixels / total_pixels) * 100.0
+
+        print(f"[{time.time():.3f}] [Worker] Comparison complete: percentage={change_percentage:.2f}%", flush=True)
+        # Return only the score - let the caller decide if it's a "change"
+        conn.send(float(change_percentage))
+
+    except Exception as e:
+        print(f"[{time.time():.3f}] [Worker] Error: {e}", flush=True)
+        import traceback
+        traceback.print_exc()
+        # Send error info as dict so parent can re-raise
+        conn.send({'error': str(e), 'traceback': traceback.format_exc()})
+    finally:
+        conn.close()
+
+
+async def compare_images_isolated(img_bytes_from, img_bytes_to, pixel_difference_threshold, blur_sigma, crop_region=None):
+    """
+    Compare images in isolated subprocess using OpenCV (async-safe).
+
+    Args:
+        img_bytes_from: Previous screenshot bytes
+        img_bytes_to: Current screenshot bytes
+        pixel_difference_threshold: Pixel-level sensitivity (0-255) - how different must a pixel be to count as changed
+        blur_sigma: Gaussian blur sigma
+        crop_region: Optional (left, top, right, bottom) crop coordinates
+
+    Returns:
+        float: Change percentage (0-100)
+    """
+    import time
+    import asyncio
+    print(f"[{time.time():.3f}] [Parent] Starting OpenCV comparison subprocess", flush=True)
+
+    # Use spawn method for clean process (no fork issues)
+    ctx = multiprocessing.get_context('spawn')
+    parent_conn, child_conn = ctx.Pipe()
+
+    p = ctx.Process(
+        target=_worker_compare,
+        args=(child_conn, img_bytes_from, img_bytes_to, pixel_difference_threshold, blur_sigma, crop_region)
+    )
+
+    print(f"[{time.time():.3f}] [Parent] Starting subprocess", flush=True)
+    p.start()
+    print(f"[{time.time():.3f}] [Parent] Subprocess started (pid={p.pid}), waiting for result ({POLL_TIMEOUT_ABSOLUTE}s timeout)", flush=True)
+
+    result = 0.0
+    try:
+        # Async-friendly polling: check in small intervals without blocking event loop
+        deadline = time.time() + POLL_TIMEOUT_ABSOLUTE
+        while time.time() < deadline:
+            # Run poll() in thread to avoid blocking event loop
+            has_data = await asyncio.to_thread(parent_conn.poll, 0.1)
+            if has_data:
+                print(f"[{time.time():.3f}] [Parent] Result available, receiving", flush=True)
+                result = await asyncio.to_thread(parent_conn.recv)
+                # Check if result is an error dict
+                if isinstance(result, dict) and 'error' in result:
+                    raise RuntimeError(f"Image comparison failed: {result['error']}")
+                print(f"[{time.time():.3f}] [Parent] Result received: {result:.2f}%", flush=True)
+                break
+            await asyncio.sleep(0)  # Yield control to event loop
+        else:
+            from loguru import logger
+            logger.critical(f"[OpenCV subprocess] Timeout waiting for compare_images result after {POLL_TIMEOUT_ABSOLUTE}s (subprocess may be hung)")
+            print(f"[{time.time():.3f}] [Parent] Timeout waiting for result after {POLL_TIMEOUT_ABSOLUTE}s", flush=True)
+            raise TimeoutError(f"Image comparison subprocess timeout after {POLL_TIMEOUT_ABSOLUTE}s")
+    except Exception as e:
+        print(f"[{time.time():.3f}] [Parent] Error receiving result: {e}", flush=True)
+        raise
+    finally:
+        # Always close pipe first
+        try:
+            parent_conn.close()
+        except:
+            pass
+
+        # Try graceful shutdown (async-safe)
+        print(f"[{time.time():.3f}] [Parent] Waiting for subprocess to exit (5s timeout)", flush=True)
+        join_start = time.time()
+        await asyncio.to_thread(p.join, 5)
+        join_elapsed = time.time() - join_start
+        print(f"[{time.time():.3f}] [Parent] First join took {join_elapsed:.2f}s", flush=True)
+
+        if p.is_alive():
+            print(f"[{time.time():.3f}] [Parent] Process didn't exit gracefully, terminating", flush=True)
+            term_start = time.time()
+            p.terminate()
+            await asyncio.to_thread(p.join, 3)
+            term_elapsed = time.time() - term_start
+            print(f"[{time.time():.3f}] [Parent] Terminate+join took {term_elapsed:.2f}s", flush=True)
+
+        # Force kill if still alive
+        if p.is_alive():
+            print(f"[{time.time():.3f}] [Parent] Process didn't terminate, killing", flush=True)
+            kill_start = time.time()
+            p.kill()
+            await asyncio.to_thread(p.join, 1)
+            kill_elapsed = time.time() - kill_start
+            print(f"[{time.time():.3f}] [Parent] Kill+join took {kill_elapsed:.2f}s", flush=True)
+
+        print(f"[{time.time():.3f}] [Parent] Subprocess cleanup complete, returning result", flush=True)
+
+    return result
+
+
+def _worker_generate_diff(conn, img_bytes_from, img_bytes_to, pixel_difference_threshold, blur_sigma, max_width, max_height):
+    """
+    Worker function for generating visual diff with red overlay.
+    """
+    import time
+    try:
+        import cv2
+
+        cv2.setNumThreads(1)
+        print(f"[{time.time():.3f}] [Worker] Generate diff worker starting", flush=True)
+
+        # Decode images
+        img_from = cv2.imdecode(np.frombuffer(img_bytes_from, np.uint8), cv2.IMREAD_COLOR)
+        img_to = cv2.imdecode(np.frombuffer(img_bytes_to, np.uint8), cv2.IMREAD_COLOR)
+
+        # Resize if needed to match dimensions
+        if img_from.shape != img_to.shape:
+            img_from = cv2.resize(img_from, (img_to.shape[1], img_to.shape[0]))
+
+        # Downscale to max dimensions for faster processing
+        h, w = img_to.shape[:2]
+        if w > max_width or h > max_height:
+            scale = min(max_width / w, max_height / h)
+            new_w = int(w * scale)
+            new_h = int(h * scale)
+            img_from = cv2.resize(img_from, (new_w, new_h))
+            img_to = cv2.resize(img_to, (new_w, new_h))
+
+        # Convert to grayscale
+        gray_from = cv2.cvtColor(img_from, cv2.COLOR_BGR2GRAY)
+        gray_to = cv2.cvtColor(img_to, cv2.COLOR_BGR2GRAY)
+
+        # Optional blur
+        if blur_sigma > 0:
+            ksize = int(2 * round(3 * blur_sigma)) + 1
+            if ksize % 2 == 0:
+                ksize += 1
+            gray_from = cv2.GaussianBlur(gray_from, (ksize, ksize), blur_sigma)
+            gray_to = cv2.GaussianBlur(gray_to, (ksize, ksize), blur_sigma)
+
+        # Calculate difference
+        diff = cv2.absdiff(gray_from, gray_to)
+
+        # Apply threshold to get mask
+        _, mask = cv2.threshold(diff, int(pixel_difference_threshold), 255, cv2.THRESH_BINARY)
+
+        # Create red overlay on original 'to' image
+        # Where mask is 255 (changed), blend 50% red
+        overlay = img_to.copy()
+        overlay[:, :, 2] = np.where(mask > 0,
+                                     np.clip(overlay[:, :, 2] * 0.5 + 127, 0, 255).astype(np.uint8),
+                                     overlay[:, :, 2])
+        overlay[:, :, 0:2] = np.where(mask[:, :, np.newaxis] > 0,
+                                       (overlay[:, :, 0:2] * 0.5).astype(np.uint8),
+                                       overlay[:, :, 0:2])
+
+        # Encode as JPEG
+        _, encoded = cv2.imencode('.jpg', overlay, [cv2.IMWRITE_JPEG_QUALITY, 85])
+        diff_bytes = encoded.tobytes()
+
+        print(f"[{time.time():.3f}] [Worker] Generated diff ({len(diff_bytes)} bytes)", flush=True)
+        conn.send(diff_bytes)
+
+    except Exception as e:
+        print(f"[{time.time():.3f}] [Worker] Generate diff error: {e}", flush=True)
+        import traceback
+        traceback.print_exc()
+        # Send error info as dict so parent can re-raise
+        conn.send({'error': str(e), 'traceback': traceback.format_exc()})
+    finally:
+        conn.close()
+
+
+async def generate_diff_isolated(img_bytes_from, img_bytes_to, pixel_difference_threshold, blur_sigma, max_width, max_height):
+    """
+    Generate visual diff with red overlay in isolated subprocess (async-safe).
+
+    Returns:
+        bytes: JPEG diff image or None on failure
+    """
+    import time
+    import asyncio
+    print(f"[{time.time():.3f}] [Parent] Starting generate_diff subprocess", flush=True)
+
+    ctx = multiprocessing.get_context('spawn')
+    parent_conn, child_conn = ctx.Pipe()
+
+    p = ctx.Process(
+        target=_worker_generate_diff,
+        args=(child_conn, img_bytes_from, img_bytes_to, pixel_difference_threshold, blur_sigma, max_width, max_height)
+    )
+
+    print(f"[{time.time():.3f}] [Parent] Starting subprocess", flush=True)
+    p.start()
+    print(f"[{time.time():.3f}] [Parent] Subprocess started (pid={p.pid}), waiting for result ({POLL_TIMEOUT_ABSOLUTE}s timeout)", flush=True)
+
+    result = None
+    try:
+        # Async-friendly polling: check in small intervals without blocking event loop
+        deadline = time.time() + POLL_TIMEOUT_ABSOLUTE
+        while time.time() < deadline:
+            # Run poll() in thread to avoid blocking event loop
+            has_data = await asyncio.to_thread(parent_conn.poll, 0.1)
+            if has_data:
+                print(f"[{time.time():.3f}] [Parent] Result available, receiving", flush=True)
+                result = await asyncio.to_thread(parent_conn.recv)
+                # Check if result is an error dict
+                if isinstance(result, dict) and 'error' in result:
+                    raise RuntimeError(f"Generate diff failed: {result['error']}")
+                print(f"[{time.time():.3f}] [Parent] Result received ({len(result) if result else 0} bytes)", flush=True)
+                break
+            await asyncio.sleep(0)  # Yield control to event loop
+        else:
+            from loguru import logger
+            logger.critical(f"[OpenCV subprocess] Timeout waiting for generate_diff result after {POLL_TIMEOUT_ABSOLUTE}s (subprocess may be hung)")
+            print(f"[{time.time():.3f}] [Parent] Timeout waiting for result after {POLL_TIMEOUT_ABSOLUTE}s", flush=True)
+            raise TimeoutError(f"Generate diff subprocess timeout after {POLL_TIMEOUT_ABSOLUTE}s")
+    except Exception as e:
+        print(f"[{time.time():.3f}] [Parent] Error receiving diff: {e}", flush=True)
+        raise
+    finally:
+        # Always close pipe first
+        try:
+            parent_conn.close()
+        except:
+            pass
+
+        # Try graceful shutdown (async-safe)
+        print(f"[{time.time():.3f}] [Parent] Waiting for subprocess to exit (5s timeout)", flush=True)
+        join_start = time.time()
+        await asyncio.to_thread(p.join, 5)
+        join_elapsed = time.time() - join_start
+        print(f"[{time.time():.3f}] [Parent] First join took {join_elapsed:.2f}s", flush=True)
+
+        if p.is_alive():
+            print(f"[{time.time():.3f}] [Parent] Process didn't exit gracefully, terminating", flush=True)
+            term_start = time.time()
+            p.terminate()
+            await asyncio.to_thread(p.join, 3)
+            term_elapsed = time.time() - term_start
+            print(f"[{time.time():.3f}] [Parent] Terminate+join took {term_elapsed:.2f}s", flush=True)
+
+        if p.is_alive():
+            print(f"[{time.time():.3f}] [Parent] Process didn't terminate, killing", flush=True)
+            kill_start = time.time()
+            p.kill()
+            await asyncio.to_thread(p.join, 1)
+            kill_elapsed = time.time() - kill_start
+            print(f"[{time.time():.3f}] [Parent] Kill+join took {kill_elapsed:.2f}s", flush=True)
+
+        print(f"[{time.time():.3f}] [Parent] Subprocess cleanup complete, returning result", flush=True)
+
+    return result
+
+
+def _worker_draw_bounding_box(conn, img_bytes, x, y, width, height, color, thickness):
+    """
+    Worker function for drawing bounding box on image.
+    """
+    import time
+    try:
+        import cv2
+
+        cv2.setNumThreads(1)
+        print(f"[{time.time():.3f}] [Worker] Draw bounding box worker starting", flush=True)
+
+        # Decode image
+        img = cv2.imdecode(np.frombuffer(img_bytes, np.uint8), cv2.IMREAD_COLOR)
+        if img is None:
+            print(f"[{time.time():.3f}] [Worker] Failed to decode image", flush=True)
+            conn.send(None)
+            return
+
+        # Draw rectangle (BGR format)
+        cv2.rectangle(img, (x, y), (x + width, y + height), color, thickness)
+
+        # Encode back to PNG
+        _, encoded = cv2.imencode('.png', img)
+        result_bytes = encoded.tobytes()
+
+        print(f"[{time.time():.3f}] [Worker] Bounding box drawn ({len(result_bytes)} bytes)", flush=True)
+        conn.send(result_bytes)
+
+    except Exception as e:
+        print(f"[{time.time():.3f}] [Worker] Draw bounding box error: {e}", flush=True)
+        import traceback
+        traceback.print_exc()
+        # Send error info as dict so parent can re-raise
+        conn.send({'error': str(e), 'traceback': traceback.format_exc()})
+    finally:
+        conn.close()
+
+
+async def draw_bounding_box_isolated(img_bytes, x, y, width, height, color=(255, 0, 0), thickness=3):
+    """
+    Draw bounding box on image in isolated subprocess (async-safe).
+
+    Args:
+        img_bytes: Image data as bytes
+        x: Left coordinate
+        y: Top coordinate
+        width: Box width
+        height: Box height
+        color: BGR color tuple (default: blue)
+        thickness: Line thickness in pixels
+
+    Returns:
+        bytes: PNG image with bounding box or None on failure
+    """
+    import time
+    import asyncio
+    print(f"[{time.time():.3f}] [Parent] Starting draw_bounding_box subprocess", flush=True)
+
+    ctx = multiprocessing.get_context('spawn')
+    parent_conn, child_conn = ctx.Pipe()
+
+    p = ctx.Process(
+        target=_worker_draw_bounding_box,
+        args=(child_conn, img_bytes, x, y, width, height, color, thickness)
+    )
+
+    print(f"[{time.time():.3f}] [Parent] Starting subprocess", flush=True)
+    p.start()
+    print(f"[{time.time():.3f}] [Parent] Subprocess started (pid={p.pid}), waiting for result ({POLL_TIMEOUT_ABSOLUTE}s timeout)", flush=True)
+
+    result = None
+    try:
+        # Async-friendly polling: check in small intervals without blocking event loop
+        deadline = time.time() + POLL_TIMEOUT_ABSOLUTE
+        while time.time() < deadline:
+            # Run poll() in thread to avoid blocking event loop
+            has_data = await asyncio.to_thread(parent_conn.poll, 0.1)
+            if has_data:
+                print(f"[{time.time():.3f}] [Parent] Result available, receiving", flush=True)
+                # Run recv() in thread too
+                result = await asyncio.to_thread(parent_conn.recv)
+                # Check if result is an error dict
+                if isinstance(result, dict) and 'error' in result:
+                    raise RuntimeError(f"Draw bounding box failed: {result['error']}")
+                print(f"[{time.time():.3f}] [Parent] Result received ({len(result) if result else 0} bytes)", flush=True)
+                break
+            # Yield control to event loop
+            await asyncio.sleep(0)
+        else:
+            from loguru import logger
+            logger.critical(f"[OpenCV subprocess] Timeout waiting for draw_bounding_box result after {POLL_TIMEOUT_ABSOLUTE}s (subprocess may be hung)")
+            print(f"[{time.time():.3f}] [Parent] Timeout waiting for result after {POLL_TIMEOUT_ABSOLUTE}s", flush=True)
+            raise TimeoutError(f"Draw bounding box subprocess timeout after {POLL_TIMEOUT_ABSOLUTE}s")
+    except Exception as e:
+        print(f"[{time.time():.3f}] [Parent] Error receiving result: {e}", flush=True)
+        raise
+    finally:
+        # Always close pipe first
+        try:
+            parent_conn.close()
+        except:
+            pass
+
+        # Try graceful shutdown (run join in thread to avoid blocking)
+        print(f"[{time.time():.3f}] [Parent] Waiting for subprocess to exit (3s timeout)", flush=True)
+        join_start = time.time()
+        await asyncio.to_thread(p.join, 3)
+        join_elapsed = time.time() - join_start
+        print(f"[{time.time():.3f}] [Parent] First join took {join_elapsed:.2f}s", flush=True)
+
+        if p.is_alive():
+            print(f"[{time.time():.3f}] [Parent] Process didn't exit gracefully, terminating", flush=True)
+            term_start = time.time()
+            p.terminate()
+            await asyncio.to_thread(p.join, 2)
+            term_elapsed = time.time() - term_start
+            print(f"[{time.time():.3f}] [Parent] Terminate+join took {term_elapsed:.2f}s", flush=True)
+
+        if p.is_alive():
+            print(f"[{time.time():.3f}] [Parent] Process didn't terminate, killing", flush=True)
+            kill_start = time.time()
+            p.kill()
+            await asyncio.to_thread(p.join, 1)
+            kill_elapsed = time.time() - kill_start
+            print(f"[{time.time():.3f}] [Parent] Kill+join took {kill_elapsed:.2f}s", flush=True)
+
+        print(f"[{time.time():.3f}] [Parent] Subprocess cleanup complete, returning result", flush=True)
+
+    return result
+
+
+def _worker_calculate_percentage(conn, img_bytes_from, img_bytes_to, pixel_difference_threshold, blur_sigma, max_width, max_height):
+    """
+    Worker function for calculating change percentage.
+    """
+    import time
+    try:
+        import cv2
+
+        cv2.setNumThreads(1)
+
+        # Decode images
+        img_from = cv2.imdecode(np.frombuffer(img_bytes_from, np.uint8), cv2.IMREAD_COLOR)
+        img_to = cv2.imdecode(np.frombuffer(img_bytes_to, np.uint8), cv2.IMREAD_COLOR)
+
+        # Resize if needed
+        if img_from.shape != img_to.shape:
+            img_from = cv2.resize(img_from, (img_to.shape[1], img_to.shape[0]))
+
+        # Downscale to max dimensions
+        h, w = img_to.shape[:2]
+        if w > max_width or h > max_height:
+            scale = min(max_width / w, max_height / h)
+            new_w = int(w * scale)
+            new_h = int(h * scale)
+            img_from = cv2.resize(img_from, (new_w, new_h))
+            img_to = cv2.resize(img_to, (new_w, new_h))
+
+        # Convert to grayscale
+        gray_from = cv2.cvtColor(img_from, cv2.COLOR_BGR2GRAY)
+        gray_to = cv2.cvtColor(img_to, cv2.COLOR_BGR2GRAY)
+
+        # Optional blur
+        if blur_sigma > 0:
+            ksize = int(2 * round(3 * blur_sigma)) + 1
+            if ksize % 2 == 0:
+                ksize += 1
+            gray_from = cv2.GaussianBlur(gray_from, (ksize, ksize), blur_sigma)
+            gray_to = cv2.GaussianBlur(gray_to, (ksize, ksize), blur_sigma)
+
+        # Calculate difference
+        diff = cv2.absdiff(gray_from, gray_to)
+
+        # Apply threshold
+        _, thresholded = cv2.threshold(diff, int(pixel_difference_threshold), 255, cv2.THRESH_BINARY)
+
+        # Calculate percentage
+        total_pixels = thresholded.size
+        changed_pixels = np.count_nonzero(thresholded)
+        change_percentage = (changed_pixels / total_pixels) * 100.0
+
+        conn.send(float(change_percentage))
+
+    except Exception as e:
+        print(f"[{time.time():.3f}] [Worker] Calculate percentage error: {e}", flush=True)
+        import traceback
+        traceback.print_exc()
+        # Send error info as dict so parent can re-raise
+        conn.send({'error': str(e), 'traceback': traceback.format_exc()})
+    finally:
+        conn.close()
+
+
+async def calculate_change_percentage_isolated(img_bytes_from, img_bytes_to, pixel_difference_threshold, blur_sigma, max_width, max_height):
+    """
+    Calculate change percentage in isolated subprocess (async-safe).
+
+    Returns:
+        float: Change percentage
+    """
+    import time
+    import asyncio
+    print(f"[{time.time():.3f}] [Parent] Starting calculate_percentage subprocess", flush=True)
+
+    ctx = multiprocessing.get_context('spawn')
+    parent_conn, child_conn = ctx.Pipe()
+
+    p = ctx.Process(
+        target=_worker_calculate_percentage,
+        args=(child_conn, img_bytes_from, img_bytes_to, pixel_difference_threshold, blur_sigma, max_width, max_height)
+    )
+
+    print(f"[{time.time():.3f}] [Parent] Starting subprocess", flush=True)
+    p.start()
+    print(f"[{time.time():.3f}] [Parent] Subprocess started (pid={p.pid}), waiting for result ({POLL_TIMEOUT_ABSOLUTE}s timeout)", flush=True)
+
+    result = 0.0
+    try:
+        # Async-friendly polling: check in small intervals without blocking event loop
+        deadline = time.time() + POLL_TIMEOUT_ABSOLUTE
+        while time.time() < deadline:
+            # Run poll() in thread to avoid blocking event loop
+            has_data = await asyncio.to_thread(parent_conn.poll, 0.1)
+            if has_data:
+                print(f"[{time.time():.3f}] [Parent] Result available, receiving", flush=True)
+                result = await asyncio.to_thread(parent_conn.recv)
+                # Check if result is an error dict
+                if isinstance(result, dict) and 'error' in result:
+                    raise RuntimeError(f"Calculate change percentage failed: {result['error']}")
+                print(f"[{time.time():.3f}] [Parent] Result received: {result:.2f}%", flush=True)
+                break
+            await asyncio.sleep(0)  # Yield control to event loop
+        else:
+            from loguru import logger
+            logger.critical(f"[OpenCV subprocess] Timeout waiting for calculate_change_percentage result after {POLL_TIMEOUT_ABSOLUTE}s (subprocess may be hung)")
+            print(f"[{time.time():.3f}] [Parent] Timeout waiting for result after {POLL_TIMEOUT_ABSOLUTE}s", flush=True)
+            raise TimeoutError(f"Calculate change percentage subprocess timeout after {POLL_TIMEOUT_ABSOLUTE}s")
+    except Exception as e:
+        print(f"[{time.time():.3f}] [Parent] Error receiving percentage: {e}", flush=True)
+        raise
+    finally:
+        # Always close pipe first
+        try:
+            parent_conn.close()
+        except:
+            pass
+
+        # Try graceful shutdown (async-safe)
+        print(f"[{time.time():.3f}] [Parent] Waiting for subprocess to exit (5s timeout)", flush=True)
+        join_start = time.time()
+        await asyncio.to_thread(p.join, 5)
+        join_elapsed = time.time() - join_start
+        print(f"[{time.time():.3f}] [Parent] First join took {join_elapsed:.2f}s", flush=True)
+
+        if p.is_alive():
+            print(f"[{time.time():.3f}] [Parent] Process didn't exit gracefully, terminating", flush=True)
+            term_start = time.time()
+            p.terminate()
+            await asyncio.to_thread(p.join, 3)
+            term_elapsed = time.time() - term_start
+            print(f"[{time.time():.3f}] [Parent] Terminate+join took {term_elapsed:.2f}s", flush=True)
+
+        if p.is_alive():
+            print(f"[{time.time():.3f}] [Parent] Process didn't terminate, killing", flush=True)
+            kill_start = time.time()
+            p.kill()
+            await asyncio.to_thread(p.join, 1)
+            kill_elapsed = time.time() - kill_start
+            print(f"[{time.time():.3f}] [Parent] Kill+join took {kill_elapsed:.2f}s", flush=True)
+
+        print(f"[{time.time():.3f}] [Parent] Subprocess cleanup complete, returning result", flush=True)
+
+    return result

changedetectionio/processors/image_ssim_diff/image_handler/libvips_handler.py

@@ -0,0 +1,340 @@
+"""
+LibVIPS implementation of ImageDiffHandler.
+
+Uses pyvips for high-performance image processing with streaming architecture
+and low memory footprint. Ideal for large screenshots (8000px+).
+"""
+
+from __future__ import annotations
+import os
+from typing import Tuple, Any, TYPE_CHECKING
+from loguru import logger
+
+if TYPE_CHECKING:
+    import pyvips
+
+try:
+    import pyvips
+    PYVIPS_AVAILABLE = True
+except ImportError:
+    PYVIPS_AVAILABLE = False
+    logger.warning("pyvips not available - install with: pip install pyvips")
+
+from . import ImageDiffHandler
+
+
+class LibvipsImageDiffHandler(ImageDiffHandler):
+    """
+    LibVIPS implementation using streaming architecture.
+
+    Benefits:
+    - 3x faster than ImageMagick
+    - 5x less memory than PIL
+    - Automatic multi-threading
+    - Streaming - processes images in chunks
+    """
+
+    def __init__(self):
+        if not PYVIPS_AVAILABLE:
+            raise ImportError("pyvips is not installed. Install with: pip install pyvips")
+
+    def load_from_bytes(self, img_bytes: bytes) -> pyvips.Image:
+        """Load image from bytes using libvips streaming."""
+        return pyvips.Image.new_from_buffer(img_bytes, '')
+
+    def save_to_bytes(self, img: pyvips.Image, format: str = 'png', quality: int = 85) -> bytes:
+        """
+        Save image to bytes using temp file.
+
+        Note: Uses temp file instead of write_to_buffer() to avoid C memory leak.
+        See: https://github.com/libvips/pyvips/issues/234
+        """
+        import tempfile
+
+        format = format.lower()
+
+        try:
+            if format == 'png':
+                suffix = '.png'
+                write_args = {'compression': 6}
+            elif format in ['jpg', 'jpeg']:
+                suffix = '.jpg'
+                write_args = {'Q': quality}
+            else:
+                raise ValueError(f"Unsupported format: {format}")
+
+            # Use temp file to avoid write_to_buffer() memory leak
+            with tempfile.NamedTemporaryFile(suffix=suffix, delete=False) as tmp:
+                temp_path = tmp.name
+
+            # Write to file
+            img.write_to_file(temp_path, **write_args)
+
+            # Read bytes and clean up
+            with open(temp_path, 'rb') as f:
+                image_bytes = f.read()
+
+            os.unlink(temp_path)
+            return image_bytes
+
+        except Exception as e:
+            logger.error(f"Failed to save via temp file: {e}")
+            # Fallback to write_to_buffer if temp file fails
+            if format == 'png':
+                return img.write_to_buffer('.png', compression=6)
+            else:
+                return img.write_to_buffer('.jpg', Q=quality)
+
+    def crop(self, img: pyvips.Image, left: int, top: int, right: int, bottom: int) -> pyvips.Image:
+        """Crop image using libvips."""
+        width = right - left
+        height = bottom - top
+        return img.crop(left, top, width, height)
+
+    def resize(self, img: pyvips.Image, max_width: int, max_height: int) -> pyvips.Image:
+        """
+        Resize image maintaining aspect ratio.
+
+        Uses thumbnail_image for efficient downscaling with streaming.
+        """
+        width, height = img.width, img.height
+
+        if width <= max_width and height <= max_height:
+            return img
+
+        # Calculate scaling to fit within max dimensions
+        width_ratio = max_width / width if width > max_width else 1.0
+        height_ratio = max_height / height if height > max_height else 1.0
+        ratio = min(width_ratio, height_ratio)
+
+        new_width = int(width * ratio)
+        new_height = int(height * ratio)
+
+        logger.debug(f"Resizing image: {width}x{height} -> {new_width}x{new_height}")
+
+        # thumbnail_image is faster than resize for downscaling
+        return img.thumbnail_image(new_width, height=new_height)
+
+    def get_dimensions(self, img: pyvips.Image) -> Tuple[int, int]:
+        """Get image dimensions."""
+        return (img.width, img.height)
+
+    def to_grayscale(self, img: pyvips.Image) -> pyvips.Image:
+        """Convert to grayscale using 'b-w' colorspace."""
+        return img.colourspace('b-w')
+
+    def gaussian_blur(self, img: pyvips.Image, sigma: float) -> pyvips.Image:
+        """Apply Gaussian blur."""
+        if sigma > 0:
+            return img.gaussblur(sigma)
+        return img
+
+    def absolute_difference(self, img1: pyvips.Image, img2: pyvips.Image) -> pyvips.Image:
+        """
+        Calculate absolute difference using operator overloading.
+
+        LibVIPS supports arithmetic operations between images.
+        """
+        return (img1 - img2).abs()
+
+    def threshold(self, img: pyvips.Image, threshold_value: int) -> Tuple[float, pyvips.Image]:
+        """
+        Apply threshold and calculate change percentage.
+
+        Uses ifthenelse for efficient thresholding.
+        """
+        # Create binary mask: pixels above threshold = 255, others = 0
+        mask = (img > threshold_value).ifthenelse(255, 0)
+
+        # Calculate percentage by averaging mask values
+        # avg() returns mean pixel value (0-255)
+        # Divide by 255 to get proportion, multiply by 100 for percentage
+        mean_value = mask.avg()
+        change_percentage = (mean_value / 255.0) * 100.0
+
+        return float(change_percentage), mask
+
+    def apply_red_overlay(self, img: pyvips.Image, mask: pyvips.Image) -> bytes:
+        """
+        Apply red overlay where mask is True (50% blend).
+
+        Args:
+            img: Color image (will be converted to RGB if needed)
+            mask: Binary mask (255 where changed, 0 elsewhere)
+
+        Returns:
+            JPEG bytes with red overlay
+        """
+        import tempfile
+
+        # Ensure RGB colorspace
+        if img.bands == 1:
+            img = img.colourspace('srgb')
+
+        # Normalize mask to 0-1 range for blending
+        mask_normalized = mask / 255.0
+
+        # Split into R, G, B channels
+        channels = img.bandsplit()
+        r, g, b = channels[0], channels[1], channels[2]
+
+        # Apply red overlay (50% blend):
+        # Where mask is 1: blend 50% original with 50% red (255)
+        # Where mask is 0: keep original
+        r = r * (1 - mask_normalized * 0.5) + 127.5 * mask_normalized
+        g = g * (1 - mask_normalized * 0.5)
+        b = b * (1 - mask_normalized * 0.5)
+
+        # Recombine channels
+        result = r.bandjoin([g, b])
+
+        # CRITICAL: Use temp file instead of write_to_buffer()
+        # write_to_buffer() leaks C memory that isn't returned to OS
+        # See: https://github.com/libvips/pyvips/issues/234
+        try:
+            with tempfile.NamedTemporaryFile(suffix='.jpg', delete=False) as tmp:
+                temp_path = tmp.name
+
+            # Write to file (doesn't leak like write_to_buffer)
+            result.write_to_file(temp_path, Q=85)
+
+            # Read bytes and clean up
+            with open(temp_path, 'rb') as f:
+                image_bytes = f.read()
+
+            os.unlink(temp_path)
+            return image_bytes
+
+        except Exception as e:
+            logger.error(f"Failed to write image via temp file: {e}")
+            # Fallback to write_to_buffer if temp file fails
+            return result.write_to_buffer('.jpg', Q=85)
+
+    def close(self, img: pyvips.Image) -> None:
+        """
+        LibVIPS uses automatic reference counting.
+
+        No explicit cleanup needed - memory freed when references drop to zero.
+        """
+        pass
+
+    def find_template(
+        self,
+        img: pyvips.Image,
+        template_img: pyvips.Image,
+        original_bbox: Tuple[int, int, int, int],
+        search_tolerance: float = 0.2
+    ) -> Tuple[int, int, int, int]:
+        """
+        Find template in image using OpenCV template matching.
+
+        Note: This temporarily converts to numpy for OpenCV operations since
+        libvips doesn't have template matching built-in.
+        """
+        import cv2
+        import numpy as np
+
+        try:
+            left, top, right, bottom = original_bbox
+            width = right - left
+            height = bottom - top
+
+            # Calculate search region
+            margin_x = int(width * search_tolerance)
+            margin_y = int(height * search_tolerance)
+
+            search_left = max(0, left - margin_x)
+            search_top = max(0, top - margin_y)
+            search_right = min(img.width, right + margin_x)
+            search_bottom = min(img.height, bottom + margin_y)
+
+            # Crop search region
+            search_region = self.crop(img, search_left, search_top, search_right, search_bottom)
+
+            # Convert to numpy arrays for OpenCV
+            search_array = np.ndarray(
+                buffer=search_region.write_to_memory(),
+                dtype=np.uint8,
+                shape=[search_region.height, search_region.width, search_region.bands]
+            )
+            template_array = np.ndarray(
+                buffer=template_img.write_to_memory(),
+                dtype=np.uint8,
+                shape=[template_img.height, template_img.width, template_img.bands]
+            )
+
+            # Convert to grayscale
+            if len(search_array.shape) == 3:
+                search_gray = cv2.cvtColor(search_array, cv2.COLOR_RGB2GRAY)
+            else:
+                search_gray = search_array
+
+            if len(template_array.shape) == 3:
+                template_gray = cv2.cvtColor(template_array, cv2.COLOR_RGB2GRAY)
+            else:
+                template_gray = template_array
+
+            logger.debug(f"Searching for template in region: ({search_left}, {search_top}) to ({search_right}, {search_bottom})")
+
+            # Perform template matching
+            result = cv2.matchTemplate(search_gray, template_gray, cv2.TM_CCOEFF_NORMED)
+            min_val, max_val, min_loc, max_loc = cv2.minMaxLoc(result)
+
+            logger.debug(f"Template matching confidence: {max_val:.2%}")
+
+            # Check if match is good enough (80% confidence threshold)
+            if max_val >= 0.8:
+                # Calculate new bounding box in original image coordinates
+                match_x = search_left + max_loc[0]
+                match_y = search_top + max_loc[1]
+
+                new_bbox = (match_x, match_y, match_x + width, match_y + height)
+
+                # Calculate movement distance
+                move_x = abs(match_x - left)
+                move_y = abs(match_y - top)
+
+                logger.info(f"Template found at ({match_x}, {match_y}), "
+                           f"moved {move_x}px horizontally, {move_y}px vertically, "
+                           f"confidence: {max_val:.2%}")
+
+                return new_bbox
+            else:
+                logger.warning(f"Template match confidence too low: {max_val:.2%} (need 80%)")
+                return None
+
+        except Exception as e:
+            logger.error(f"Template matching error: {e}")
+            return None
+
+    def save_template(
+        self,
+        img: pyvips.Image,
+        bbox: Tuple[int, int, int, int],
+        output_path: str
+    ) -> bool:
+        """
+        Save a cropped region as a template file.
+        """
+        import os
+
+        try:
+            left, top, right, bottom = bbox
+            width = right - left
+            height = bottom - top
+
+            # Ensure output directory exists
+            os.makedirs(os.path.dirname(output_path), exist_ok=True)
+
+            # Crop template region
+            template = self.crop(img, left, top, right, bottom)
+
+            # Save as PNG
+            template.write_to_file(output_path, compression=6)
+
+            logger.info(f"Saved template: {output_path} ({width}x{height}px)")
+            return True
+
+        except Exception as e:
+            logger.error(f"Failed to save template: {e}")
+            return False

changedetectionio/processors/image_ssim_diff/preview.py

@@ -0,0 +1,110 @@
+"""
+Preview rendering for SSIM screenshot processor.
+
+Renders images properly in the browser instead of showing raw bytes.
+"""
+
+from flask_babel import gettext
+from loguru import logger
+
+
+def get_asset(asset_name, watch, datastore, request):
+    """
+    Get processor-specific binary assets for preview streaming.
+
+    This function supports serving images as separate HTTP responses instead
+    of embedding them as base64 in the HTML template, solving memory issues
+    with large screenshots.
+
+    Supported assets:
+    - 'screenshot': The screenshot for the specified version
+
+    Args:
+        asset_name: Name of the asset to retrieve ('screenshot')
+        watch: Watch object
+        datastore: Datastore object
+        request: Flask request (for version query param)
+
+    Returns:
+        tuple: (binary_data, content_type, cache_control_header) or None if not found
+    """
+    if asset_name != 'screenshot':
+        return None
+
+    versions = list(watch.history.keys())
+    if len(versions) == 0:
+        return None
+
+    # Get the version from query string (default: latest)
+    preferred_version = request.args.get('version')
+    timestamp = versions[-1]
+    if preferred_version and preferred_version in versions:
+        timestamp = preferred_version
+
+    try:
+        screenshot_bytes = watch.get_history_snapshot(timestamp=timestamp)
+
+        # Verify we got bytes (should always be bytes for image files)
+        if not isinstance(screenshot_bytes, bytes):
+            logger.error(f"Expected bytes but got {type(screenshot_bytes)} for screenshot at {timestamp}")
+            return None
+
+        # Detect image format using puremagic (same as Watch.py)
+        try:
+            import puremagic
+            detections = puremagic.magic_string(screenshot_bytes[:2048])
+            if detections:
+                mime_type = detections[0].mime_type
+                logger.trace(f"Detected MIME type: {mime_type}")
+            else:
+                mime_type = 'image/png'  # Default fallback
+        except Exception as e:
+            logger.warning(f"puremagic detection failed: {e}, using 'image/png' fallback")
+            mime_type = 'image/png'
+
+        return (screenshot_bytes, mime_type, 'public, max-age=10')
+
+    except Exception as e:
+        logger.error(f"Failed to load screenshot for preview asset: {e}")
+        return None
+
+
+def render(watch, datastore, request, url_for, render_template, flash, redirect):
+    """
+    Render the preview page for screenshot watches.
+
+    Args:
+        watch: Watch object
+        datastore: Datastore object
+        request: Flask request
+        url_for: Flask url_for function
+        render_template: Flask render_template function
+        flash: Flask flash function
+        redirect: Flask redirect function
+
+    Returns:
+        Rendered template or redirect
+    """
+    versions = list(watch.history.keys())
+
+    if len(versions) == 0:
+        flash(gettext("Preview unavailable - No snapshots captured yet"), "error")
+        return redirect(url_for('watchlist.index'))
+
+    # Get the version to display (default: latest)
+    preferred_version = request.args.get('version')
+    timestamp = versions[-1]
+    if preferred_version and preferred_version in versions:
+        timestamp = preferred_version
+
+    # Render custom template for image preview
+    # Screenshot is now served via separate /processor-asset/ endpoint instead of base64
+    # This significantly reduces memory usage by not embedding large images in HTML
+    return render_template(
+        'image_ssim_diff/preview.html',
+        watch=watch,
+        uuid=watch.get('uuid'),
+        versions=versions,
+        timestamp=timestamp,
+        current_diff_url=watch['url']
+    )

changedetectionio/processors/image_ssim_diff/processor.py

@@ -0,0 +1,244 @@
+"""
+Core fast screenshot comparison processor.
+
+Uses OpenCV with subprocess isolation for high-performance, low-memory
+image processing. All operations run in isolated subprocesses for complete
+memory cleanup and stability.
+"""
+
+import hashlib
+import time
+from loguru import logger
+from changedetectionio.processors.exceptions import ProcessorException
+from . import SCREENSHOT_COMPARISON_THRESHOLD_OPTIONS_DEFAULT, PROCESSOR_CONFIG_NAME, OPENCV_BLUR_SIGMA
+from ..base import difference_detection_processor, SCREENSHOT_FORMAT_PNG
+
+# All image operations now use OpenCV via isolated_opencv subprocess handler
+# Template matching temporarily disabled pending OpenCV implementation
+
+# Translation marker for extraction
+def _(x): return x
+name = _('Visual / Image screenshot change detection')
+description = _('Compares screenshots using fast OpenCV algorithm, 10-100x faster than SSIM')
+del _
+processor_weight = 2
+list_badge_text = "Visual"
+
+class perform_site_check(difference_detection_processor):
+    """Fast screenshot comparison processor using OpenCV."""
+
+    # Override to use PNG format for better image comparison (JPEG compression creates noise)
+    screenshot_format = SCREENSHOT_FORMAT_PNG
+
+    def run_changedetection(self, watch):
+        """
+        Perform screenshot comparison using OpenCV subprocess handler.
+
+        Returns:
+            tuple: (changed_detected, update_obj, screenshot_bytes)
+        """
+        now = time.time()
+        # Get the current screenshot
+        if not self.fetcher.screenshot:
+            raise ProcessorException(
+                message="No screenshot available. Ensure the watch is configured to use a real browser.",
+                url=watch.get('url')
+            )
+        self.screenshot = self.fetcher.screenshot
+        self.xpath_data = self.fetcher.xpath_data
+
+        # Quick MD5 check - skip expensive comparison if images are identical
+        from changedetectionio.content_fetchers.exceptions import checksumFromPreviousCheckWasTheSame
+        current_md5 = hashlib.md5(self.screenshot).hexdigest()
+        previous_md5 = watch.get('previous_md5')
+        if previous_md5 and current_md5 == previous_md5:
+            logger.debug(f"UUID: {watch.get('uuid')} - Screenshot MD5 unchanged ({current_md5}), skipping comparison")
+            raise checksumFromPreviousCheckWasTheSame()
+        else:
+            logger.debug(f"UUID: {watch.get('uuid')} - Screenshot MD5 changed")
+
+
+
+        # Check if bounding box is set (for drawn area mode)
+        # Read from processor-specific config JSON file (named after processor)
+        crop_region = None
+
+        processor_config = self.get_extra_watch_config(PROCESSOR_CONFIG_NAME)
+        bounding_box = processor_config.get('bounding_box') if processor_config else None
+
+
+        # Get pixel difference threshold sensitivity (per-watch > global)
+        # This controls how different a pixel must be (0-255 scale) to count as "changed"
+        pixel_difference_threshold_sensitivity = processor_config.get('pixel_difference_threshold_sensitivity')
+        if not pixel_difference_threshold_sensitivity:
+            pixel_difference_threshold_sensitivity = self.datastore.data['settings']['application'].get('pixel_difference_threshold_sensitivity', SCREENSHOT_COMPARISON_THRESHOLD_OPTIONS_DEFAULT)
+        try:
+            pixel_difference_threshold_sensitivity = int(pixel_difference_threshold_sensitivity)
+        except (ValueError, TypeError):
+            logger.warning(f"Invalid pixel_difference_threshold_sensitivity value '{pixel_difference_threshold_sensitivity}', using default")
+            pixel_difference_threshold_sensitivity = SCREENSHOT_COMPARISON_THRESHOLD_OPTIONS_DEFAULT
+
+
+        # Get minimum change percentage (per-watch > global > env var default)
+        # This controls what percentage of pixels must change to trigger a detection
+        min_change_percentage = processor_config.get('min_change_percentage')
+        if not min_change_percentage:
+            min_change_percentage = self.datastore.data['settings']['application'].get('min_change_percentage', 1)
+        try:
+            min_change_percentage = int(min_change_percentage)
+        except (ValueError, TypeError):
+            logger.warning(f"Invalid min_change_percentage value '{min_change_percentage}', using default 0.1")
+            min_change_percentage = 1
+
+        # Template matching for tracking content movement
+        template_matching_enabled = processor_config.get('auto_track_region', False) #@@todo disabled for now
+
+        if bounding_box:
+            try:
+                # Parse bounding box: "x,y,width,height"
+                parts = [int(p.strip()) for p in bounding_box.split(',')]
+                if len(parts) == 4:
+                    x, y, width, height = parts
+                    # Crop uses (left, top, right, bottom)
+                    crop_region = (max(0, x), max(0, y), x + width, y + height)
+                    logger.info(f"UUID: {watch.get('uuid')} - Bounding box enabled: cropping to region {crop_region} (x={x}, y={y}, w={width}, h={height})")
+                else:
+                    logger.warning(f"UUID: {watch.get('uuid')} - Invalid bounding box format: {bounding_box} (expected 4 values)")
+            except Exception as e:
+                logger.warning(f"UUID: {watch.get('uuid')} - Failed to parse bounding box '{bounding_box}': {e}")
+
+        # If no bounding box, check if visual selector (include_filters) is set for region-based comparison
+        if not crop_region:
+            include_filters = watch.get('include_filters', [])
+
+            if include_filters and len(include_filters) > 0:
+                # Get the first filter to use for cropping
+                first_filter = include_filters[0].strip()
+
+                if first_filter and self.xpath_data:
+                    try:
+                        import json
+                        # xpath_data is JSON string from browser
+                        xpath_data_obj = json.loads(self.xpath_data) if isinstance(self.xpath_data, str) else self.xpath_data
+
+                        # Find the bounding box for the first filter
+                        for element in xpath_data_obj.get('size_pos', []):
+                            # Match the filter with the element's xpath
+                            if element.get('xpath') == first_filter and element.get('highlight_as_custom_filter'):
+                                # Found the element - extract crop coordinates
+                                left = element.get('left', 0)
+                                top = element.get('top', 0)
+                                width = element.get('width', 0)
+                                height = element.get('height', 0)
+
+                                # Crop uses (left, top, right, bottom)
+                                crop_region = (max(0, left), max(0, top), left + width, top + height)
+
+                                logger.info(f"UUID: {watch.get('uuid')} - Visual selector enabled: cropping to region {crop_region} for filter: {first_filter}")
+                                break
+
+                    except Exception as e:
+                        logger.warning(f"UUID: {watch.get('uuid')} - Failed to parse xpath_data for visual selector: {e}")
+
+        # Store original crop region for template matching
+        original_crop_region = crop_region
+
+        # Check if this is the first check (no previous history)
+        history_keys = list(watch.history.keys())
+        if len(history_keys) == 0:
+            # First check - save baseline, no comparison
+            logger.info(f"UUID: {watch.get('uuid')} - First check for watch {watch.get('uuid')} - saving baseline screenshot")
+
+            # LibVIPS uses automatic reference counting - no explicit cleanup needed
+            update_obj = {
+                'previous_md5': hashlib.md5(self.screenshot).hexdigest(),
+                'last_error': False
+            }
+            logger.trace(f"Processed in {time.time() - now:.3f}s")
+            return False, update_obj, self.screenshot
+
+        # Get previous screenshot bytes from history
+        previous_timestamp = history_keys[-1]
+        previous_screenshot_bytes = watch.get_history_snapshot(timestamp=previous_timestamp)
+
+        # Screenshots are stored as PNG, so this should be bytes
+        if isinstance(previous_screenshot_bytes, str):
+            # If it's a string (shouldn't be for screenshots, but handle it)
+            previous_screenshot_bytes = previous_screenshot_bytes.encode('utf-8')
+
+        # Template matching is temporarily disabled pending OpenCV implementation
+        # crop_region calculated above will be used as-is
+
+        # Perform comparison in isolated subprocess to prevent memory leaks
+        try:
+            from .image_handler import isolated_opencv as process_screenshot_handler
+
+# stuff in watch doesnt need to be there
+            logger.debug(f"UUID: {watch.get('uuid')} - Starting isolated subprocess comparison (crop_region={crop_region})")
+
+            # Compare using isolated subprocess with OpenCV (async-safe to avoid blocking event loop)
+            # Pass raw bytes and crop region - subprocess handles all image operations
+            import asyncio
+            import threading
+
+            # Async-safe wrapper: runs coroutine in new thread with its own event loop
+            # This prevents blocking the async update worker's event loop
+            def run_async_in_thread():
+                return asyncio.run(
+                    process_screenshot_handler.compare_images_isolated(
+                        img_bytes_from=previous_screenshot_bytes,
+                        img_bytes_to=self.screenshot,
+                        pixel_difference_threshold=pixel_difference_threshold_sensitivity,
+                        blur_sigma=OPENCV_BLUR_SIGMA,
+                        crop_region=crop_region  # Pass crop region for isolated cropping
+                    )
+                )
+
+            # Run in thread to avoid blocking event loop when called from async update worker
+            result_container = [None]
+            exception_container = [None]
+
+            def thread_target():
+                try:
+                    result_container[0] = run_async_in_thread()
+                except Exception as e:
+                    exception_container[0] = e
+
+            thread = threading.Thread(target=thread_target, daemon=True, name="ImageDiff-Processor")
+            thread.start()
+            thread.join(timeout=60)
+
+            if exception_container[0]:
+                raise exception_container[0]
+
+            # Subprocess returns only the change score - we decide if it's a "change"
+            change_score = result_container[0]
+            if change_score is None:
+                raise RuntimeError("Image comparison subprocess returned no result")
+
+            changed_detected = change_score > min_change_percentage
+            logger.info(f"UUID: {watch.get('uuid')} -  {process_screenshot_handler.IMPLEMENTATION_NAME}: {change_score:.2f}% pixels changed, pixel_diff_threshold_sensitivity: {pixel_difference_threshold_sensitivity:.0f} score={change_score:.2f}%, min_change_threshold={min_change_percentage}%")
+
+        except Exception as e:
+            logger.error(f"UUID: {watch.get('uuid')} - Failed to compare screenshots: {e}")
+            logger.trace(f"UUID: {watch.get('uuid')} - Processed in {time.time() - now:.3f}s")
+
+            raise ProcessorException(
+                message=f"UUID: {watch.get('uuid')} - Screenshot comparison failed: {e}",
+                url=watch.get('url')
+            )
+
+        # Return results
+        update_obj = {
+            'previous_md5': hashlib.md5(self.screenshot).hexdigest(),
+            'last_error': False
+        }
+
+        if changed_detected:
+            logger.info(f"UUID: {watch.get('uuid')} - Change detected using OpenCV! Score: {change_score:.2f}")
+        else:
+            logger.debug(f"UUID: {watch.get('uuid')} - No significant change using OpenCV. Score: {change_score:.2f}")
+        logger.trace(f"UUID: {watch.get('uuid')} - Processed in {time.time() - now:.3f}s")
+
+        return changed_detected, update_obj, self.screenshot
+

changedetectionio/processors/image_ssim_diff/templates/image_ssim_diff/diff.html

@@ -0,0 +1,235 @@
+{% extends 'base.html' %}
+{% from '_helpers.html' import render_field, render_checkbox_field, render_button %}
+
+{% block content %}
+<link rel="stylesheet" href="{{url_for('static_content', group='styles', filename='diff-image.css')}}?v={{ get_css_version() }}">
+<script src="{{url_for('static_content', group='js', filename='diff-overview.js')}}" defer></script>
+
+<div id="settings">
+    <form class="pure-form " action="{{ url_for('ui.ui_diff.diff_history_page', uuid=uuid) }}" method="GET" id="diff-form">
+        <fieldset class="diff-fieldset">
+            {% if versions|length >= 1 %}
+                <span style="white-space: nowrap;">
+                <label id="change-from" for="diff-from-version" class="from-to-label">From</label>
+                <select id="diff-from-version" name="from_version" class="needs-localtime">
+                    {%- for version in versions|reverse -%}
+                        <option value="{{ version }}" {% if version== from_version %} selected="" {% endif %}>
+                            {{ version }}
+                        </option>
+                    {%- endfor -%}
+                </select>
+                </span>
+                <span style="white-space: nowrap;">
+                <label id="change-to" for="diff-to-version" class="from-to-label">To</label>
+                <select id="diff-to-version" name="to_version" class="needs-localtime">
+                    {%- for version in versions|reverse -%}
+                        <option value="{{ version }}" {% if version== to_version %} selected="" {% endif %}>
+                            {{ version }}
+                        </option>
+                    {%- endfor -%}
+                </select>
+                </span>
+            {% endif %}
+        </fieldset>
+        <fieldset id="diff-style">
+            <span>
+                <strong>Change Detection:</strong> {{ "%.2f"|format(change_percentage) }}% of pixels changed
+                {% if change_percentage > 0.1 %}
+                    <span class="change-detected">⚠ Change Detected</span>
+                {% else %}
+                    <span class="no-change">✓ No Significant Change</span>
+                {% endif %}
+            </span>
+        </fieldset>
+        {%- if versions|length >= 2 -%}
+            <div id="keyboard-nav">
+                <strong>Keyboard: </strong>
+                <a href="" class="pure-button pure-button-primary" id="btn-previous"> &larr; Previous</a>
+                &nbsp; <a class="pure-button pure-button-primary" id="btn-next" href=""> &rarr; Next</a>
+            </div>
+        {%- endif -%}
+    </form>
+</div>
+
+<div id="screenshot-comparison">
+    <!-- Two-panel layout: Interactive slider + Static diff -->
+    <div class="comparison-grid">
+        <!-- Panel 1: Interactive Comparison Slider (Previous ↔ Current) -->
+        <div class="screenshot-panel">
+            <h3>Interactive Comparison</h3>
+            <div class="comparison-description">
+                Drag slider to compare Previous ({{ from_version|format_timestamp_timeago }})
+                vs Current ({{ to_version|format_timestamp_timeago }})
+            </div>
+            <div style="text-align: center; margin-bottom: 0.5em; display: flex; justify-content: center; gap: 1em;">
+                <a href="#" onclick="downloadImage('img-before', '{{ from_version }}'); return false;" class="download-link" title="Download previous snapshot">
+                    <svg width="14" height="14" viewBox="0 0 16 16" fill="currentColor" style="display: inline-block;">
+                        <path d="M8 12L3 7h3V1h4v6h3z"/>
+                        <path d="M1 14h14v2H1z"/>
+                    </svg>
+                    Previous
+                </a>
+                <a href="#" onclick="downloadImage('img-after', '{{ to_version }}'); return false;" class="download-link" title="Download current snapshot">
+                    <svg width="14" height="14" viewBox="0 0 16 16" fill="currentColor" style="display: inline-block;">
+                        <path d="M8 12L3 7h3V1h4v6h3z"/>
+                        <path d="M1 14h14v2H1z"/>
+                    </svg>
+                    Current
+                </a>
+            </div>
+
+            <div class="image-comparison" id="comparison-container">
+                <!-- Before image wrapper (Previous snapshot) -->
+                <div class="comparison-image-wrapper">
+                    <img id="img-before" src="{{ url_for('ui.ui_diff.processor_asset', uuid=uuid, asset_name='before', from_version=from_version, to_version=to_version) }}" alt="Previous screenshot">
+                </div>
+
+                <!-- After image wrapper (Current snapshot) -->
+                <div class="comparison-image-wrapper comparison-after">
+                    <img id="img-after" src="{{ url_for('ui.ui_diff.processor_asset', uuid=uuid, asset_name='after', from_version=from_version, to_version=to_version) }}" alt="Current screenshot">
+                </div>
+
+                <!-- Labels -->
+                <div class="comparison-labels">
+                    <span class="comparison-label">Previous</span>
+                    <span class="comparison-label">Current</span>
+                </div>
+
+                <!-- Draggable slider -->
+                <div class="comparison-slider" id="comparison-slider">
+                    <div class="comparison-handle"></div>
+                </div>
+            </div>
+        </div>
+
+        <!-- Panel 2: Difference Visualization (Static) -->
+        <div class="screenshot-panel diff">
+            <h3>Difference Visualization</h3>
+            <div class="diff-section-header">
+                <span>Red = Changed Pixels</span>
+            </div>
+            <div style="text-align: center; margin-bottom: 0.5em;">
+                <a href="#" onclick="downloadImage('diff-image', '{{ to_version }}_diff'); return false;" class="download-link" title="Download difference image">
+                    <svg width="14" height="14" viewBox="0 0 16 16" fill="currentColor" style="display: inline-block;">
+                        <path d="M8 12L3 7h3V1h4v6h3z"/>
+                        <path d="M1 14h14v2H1z"/>
+                    </svg>
+                    Download
+                </a>
+            </div>
+            <img id="diff-image" src="{{ url_for('ui.ui_diff.processor_asset', uuid=uuid, asset_name='rendered_diff', from_version=from_version, to_version=to_version) }}" alt="Difference visualization with red highlights">
+        </div>
+    </div>
+
+    {% if comparison_data and comparison_data.get('history') and comparison_data.history|length > 1 %}
+    <div class="comparison-history-section">
+        <h3>Comparison History</h3>
+        <p>Recent comparison results (last {{ comparison_data.history|length }} checks)</p>
+        <div style="overflow-x: auto;">
+            <table class="pure-table pure-table-striped" style="width: 100%;">
+                <thead>
+                    <tr>
+                        <th>Timestamp</th>
+                        <th>Change %</th>
+                        <th>Method</th>
+                        <th>Changed?</th>
+                    </tr>
+                </thead>
+                <tbody>
+                    {% for entry in comparison_data.history|reverse %}
+                    <tr>
+                        <td>{{ entry.timestamp|format_timestamp_timeago }}</td>
+                        <td>{{ "%.2f"|format(entry.change_percentage) }}%</td>
+                        <td>{{ entry.method }}</td>
+                        <td>
+                            {% if entry.changed %}
+                                <span class="history-changed-yes">Yes</span>
+                            {% else %}
+                                <span class="history-changed-no">No</span>
+                            {% endif %}
+                        </td>
+                    </tr>
+                    {% endfor %}
+                </tbody>
+            </table>
+        </div>
+    </div>
+    {% endif %}
+</div>
+
+<script>
+function downloadImage(imageId, filename) {
+    // Get the image element
+    const img = document.getElementById(imageId);
+    const base64Data = img.src;
+
+    // Convert base64 to blob
+    const byteString = atob(base64Data.split(',')[1]);
+    const mimeString = base64Data.split(',')[0].split(':')[1].split(';')[0];
+
+    const ab = new ArrayBuffer(byteString.length);
+    const ia = new Uint8Array(ab);
+    for (let i = 0; i < byteString.length; i++) {
+        ia[i] = byteString.charCodeAt(i);
+    }
+
+    const blob = new Blob([ab], { type: mimeString });
+
+    // Determine file extension from MIME type
+    const extension = mimeString.includes('jpeg') ? '.jpeg' : '.png';
+
+    // Create download link
+    const url = URL.createObjectURL(blob);
+    const a = document.createElement('a');
+    a.href = url;
+    a.download = filename + extension;
+    document.body.appendChild(a);
+    a.click();
+
+    // Cleanup
+    setTimeout(() => {
+        document.body.removeChild(a);
+        URL.revokeObjectURL(url);
+    }, 100);
+}
+
+/**
+ * Synchronize comparison slider width with diff image width
+ * This ensures both panels display images at the same max-width
+ */
+function syncComparisonWidth() {
+    const diffImage = document.getElementById('diff-image');
+    const comparisonContainer = document.getElementById('comparison-container');
+
+    if (!diffImage || !comparisonContainer) return;
+
+    // Wait for diff image to load to get its actual rendered width
+    if (diffImage.complete) {
+        applyWidth();
+    } else {
+        diffImage.addEventListener('load', applyWidth);
+    }
+
+    function applyWidth() {
+        const diffImageWidth = diffImage.offsetWidth;
+        if (diffImageWidth > 0) {
+            comparisonContainer.style.maxWidth = diffImageWidth + 'px';
+            comparisonContainer.style.margin = '0 auto';
+        }
+    }
+}
+
+// Run on page load
+if (document.readyState === 'loading') {
+    document.addEventListener('DOMContentLoaded', syncComparisonWidth);
+} else {
+    syncComparisonWidth();
+}
+
+// Re-sync on window resize
+window.addEventListener('resize', syncComparisonWidth);
+</script>
+
+<script src="{{ url_for('static_content', group='js', filename='comparison-slider.js') }}" defer></script>
+
+{% endblock %}

changedetectionio/processors/image_ssim_diff/templates/image_ssim_diff/preview.html

@@ -0,0 +1,35 @@
+{% extends 'base.html' %}
+
+{% block content %}
+<script src="{{ url_for('static_content', group='js', filename='preview.js') }}" defer></script>
+    {% if versions|length >= 2 %}
+        <div id="diff-form" style="text-align: center;">
+            <form class="pure-form " action="" method="GET">
+                <fieldset>
+                    <label for="preview-version">Select timestamp</label> <select id="preview-version"
+                                                                                 name="version"
+                                                                                 class="needs-localtime">
+                    {% for version in versions|reverse %}
+                        <option value="{{ version }}" {% if version == timestamp %} selected="" {% endif %}>
+                            {{ version }}
+                        </option>
+                    {% endfor %}
+                </select>
+                    <button type="submit" class="pure-button pure-button-primary">Go</button>
+
+                </fieldset>
+            </form>
+                <br>
+                <strong>Keyboard: </strong><a href="" class="pure-button pure-button-primary" id="btn-previous">
+                &larr; Previous</a> &nbsp; <a class="pure-button pure-button-primary" id="btn-next" href="">
+                &rarr; Next</a>
+        </div>
+    {% endif %}
+
+    <div id="screenshot-container" style="text-align: center; border: 1px solid #ddd; padding: 2em; background: #fafafa; border-radius: 4px;">
+        <h3 style="margin-top: 0;">Screenshot from {{ timestamp|format_timestamp_timeago }}</h3>
+        <img src="{{ url_for('ui.ui_preview.processor_asset', uuid=uuid, asset_name='screenshot', version=timestamp) }}"
+             alt="Screenshot preview"
+             style="max-width: 100%; height: auto; border: 1px solid #ccc; box-shadow: 0 2px 8px rgba(0,0,0,0.1); border-radius: 2px;">
+    </div>
+{% endblock %}

changedetectionio/processors/image_ssim_diff/util.py

@@ -0,0 +1,22 @@
+"""
+DEPRECATED: All multiprocessing functions have been removed.
+
+The image_ssim_diff processor now uses LibVIPS via ImageDiffHandler abstraction,
+which provides superior performance and memory efficiency through streaming
+architecture and automatic threading.
+
+All image operations are now handled by:
+- imagehandler.py: Abstract base class defining the interface
+- libvips_handler.py: LibVIPS implementation with streaming and threading
+
+Historical note: This file previously contained multiprocessing workers for:
+- Template matching (find_region_with_template_matching_isolated)
+- Template regeneration (regenerate_template_isolated)
+- Image cropping (crop_image_isolated, crop_pil_image_isolated)
+
+These have been replaced by handler methods which are:
+- Faster (no subprocess overhead)
+- More memory efficient (LibVIPS streaming)
+- Cleaner (no multiprocessing deadlocks)
+- Better tested (no logger/forking issues)
+"""

changedetectionio/processors/magic.py

@@ -103,15 +103,15 @@ class guess_stream_type():
             self.is_json = True
         elif 'pdf' in magic_content_header:
             self.is_pdf = True
-        elif has_html_patterns or http_content_header == 'text/html':
-            self.is_html = True
-        elif any(s in magic_content_header for s in JSON_CONTENT_TYPES):
-            self.is_json = True
         # magic will call a rss document 'xml'
         # Rarely do endpoints give the right header, usually just text/xml, so we check also for <rss
         # This also triggers the automatic CDATA text parser so the RSS goes back a nice content list
         elif '<rss' in test_content_normalized or '<feed' in test_content_normalized or any(s in magic_content_header for s in RSS_XML_CONTENT_TYPES) or '<rdf:' in test_content_normalized:
             self.is_rss = True
+        elif has_html_patterns or http_content_header == 'text/html':
+            self.is_html = True
+        elif any(s in magic_content_header for s in JSON_CONTENT_TYPES):
+            self.is_json = True
         elif any(s in http_content_header for s in XML_CONTENT_TYPES):
             # Only mark as generic XML if not already detected as RSS
             if not self.is_rss:

changedetectionio/processors/restock_diff/forms.py

@@ -6,34 +6,35 @@ from wtforms import (
 from wtforms.fields.choices import RadioField
 from wtforms.fields.form import FormField
 from wtforms.form import Form
+from flask_babel import lazy_gettext as _l
 
 from changedetectionio.forms import processor_text_json_diff_form
 
 
 class RestockSettingsForm(Form):
-    in_stock_processing = RadioField(label='Re-stock detection', choices=[
-        ('in_stock_only', "In Stock only (Out Of Stock -> In Stock only)"),
-        ('all_changes', "Any availability changes"),
-        ('off', "Off, don't follow availability/restock"),
+    in_stock_processing = RadioField(label=_l('Re-stock detection'), choices=[
+        ('in_stock_only', _l("In Stock only (Out Of Stock -> In Stock only)")),
+        ('all_changes', _l("Any availability changes")),
+        ('off', _l("Off, don't follow availability/restock")),
     ], default="in_stock_only")
 
-    price_change_min = FloatField('Below price to trigger notification', [validators.Optional()],
-                                  render_kw={"placeholder": "No limit", "size": "10"})
-    price_change_max = FloatField('Above price to trigger notification', [validators.Optional()],
-                                  render_kw={"placeholder": "No limit", "size": "10"})
-    price_change_threshold_percent = FloatField('Threshold in % for price changes since the original price', validators=[
+    price_change_min = FloatField(_l('Below price to trigger notification'), [validators.Optional()],
+                                  render_kw={"placeholder": _l("No limit"), "size": "10"})
+    price_change_max = FloatField(_l('Above price to trigger notification'), [validators.Optional()],
+                                  render_kw={"placeholder": _l("No limit"), "size": "10"})
+    price_change_threshold_percent = FloatField(_l('Threshold in %% for price changes since the original price'), validators=[
 
         validators.Optional(),
-        validators.NumberRange(min=0, max=100, message="Should be between 0 and 100"),
+        validators.NumberRange(min=0, max=100, message=_l("Should be between 0 and 100")),
     ], render_kw={"placeholder": "0%", "size": "5"})
 
-    follow_price_changes = BooleanField('Follow price changes', default=True)
+    follow_price_changes = BooleanField(_l('Follow price changes'), default=True)
 
 class processor_settings_form(processor_text_json_diff_form):
     restock_settings = FormField(RestockSettingsForm)
 
     def extra_tab_content(self):
-        return 'Restock & Price Detection'
+        return _l('Restock & Price Detection')
 
     def extra_form_content(self):
         output = ""

changedetectionio/processors/restock_diff/processor.py

@@ -1,4 +1,4 @@
-from .. import difference_detection_processor
+from ..base import difference_detection_processor
 from ..exceptions import ProcessorException
 from . import Restock
 from loguru import logger
@@ -7,8 +7,14 @@ import urllib3
 import time
 
 urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)
-name = 'Re-stock & Price detection for pages with a SINGLE product'
-description = 'Detects if the product goes back to in-stock'
+# Translatable strings - extracted by pybabel, translated at runtime in __init__.py
+# Use a marker function so pybabel can extract these strings
+def _(x): return x  # Translation marker for extraction only
+name = _('Re-stock & Price detection for pages with a SINGLE product')
+description = _('Detects if the product goes back to in-stock')
+del _  # Remove marker function
+processor_weight = 1
+list_badge_text = "Restock"  # _()
 
 class UnableToExtractRestockData(Exception):
     def __init__(self, status_code):
@@ -187,6 +193,8 @@ class perform_site_check(difference_detection_processor):
 
 
         itemprop_availability = {}
+
+        # Try built-in extraction first, this will scan metadata in the HTML
         try:
             itemprop_availability = get_itemprop_availability(self.fetcher.content)
         except MoreThanOnePriceFound as e:
@@ -198,6 +206,33 @@ class perform_site_check(difference_detection_processor):
                                      xpath_data=self.fetcher.xpath_data
                                      )
 
+        # If built-in extraction didn't get both price AND availability, try plugin override
+        # Only check plugin if this watch is using a fetcher that might provide better data
+        has_price = itemprop_availability.get('price') is not None
+        has_availability = itemprop_availability.get('availability') is not None
+
+        # @TODO !!! some setting like "Use as fallback" or "always use", "t
+        if not (has_price and has_availability) or True:
+            from changedetectionio.pluggy_interface import get_itemprop_availability_from_plugin
+            fetcher_name = watch.get('fetch_backend', 'html_requests')
+
+            # Only try plugin override if not using system default (which might be anything)
+            if fetcher_name and fetcher_name != 'system':
+                logger.debug("Calling extra plugins for getting item price/availability")
+                plugin_availability = get_itemprop_availability_from_plugin(self.fetcher.content, fetcher_name, self.fetcher, watch.link)
+
+                if plugin_availability:
+                    # Plugin provided better data, use it
+                    plugin_has_price = plugin_availability.get('price') is not None
+                    plugin_has_availability = plugin_availability.get('availability') is not None
+
+                    # Only use plugin data if it's actually better than what we have
+                    if plugin_has_price or plugin_has_availability:
+                        itemprop_availability = plugin_availability
+                        logger.info(f"Using plugin-provided availability data for fetcher '{fetcher_name}' (built-in had price={has_price}, availability={has_availability}; plugin has price={plugin_has_price}, availability={plugin_has_availability})")
+                if not plugin_availability:
+                    logger.debug("No item price/availability from plugins")
+
         # Something valid in get_itemprop_availability() by scraping metadata ?
         if itemprop_availability.get('price') or itemprop_availability.get('availability'):
             # Store for other usage

changedetectionio/processors/templates/extract.html

@@ -0,0 +1,47 @@
+{% extends 'base.html' %}
+{% from '_helpers.html' import render_field, render_checkbox_field, render_button %}
+{% block content %}
+    <div class="tabs">
+    <ul>
+        {% if last_error_text %}<li class="tab" id="error-text-tab"><a href="{{ url_for('ui.ui_diff.diff_history_page', uuid=uuid)}}#error-text">Error Text</a></li> {% endif %}
+        {% if last_error_screenshot %}<li class="tab" id="error-screenshot-tab"><a href="{{ url_for('ui.ui_diff.diff_history_page', uuid=uuid)}}#error-screenshot">Error Screenshot</a></li> {% endif %}
+        <li class="tab" id=""><a href="{{ url_for('ui.ui_diff.diff_history_page', uuid=uuid)}}#text">Text</a></li>
+        <li class="tab" id="screenshot-tab"><a href="{{ url_for('ui.ui_diff.diff_history_page', uuid=uuid)}}#screenshot">Screenshot</a></li>
+        <li class="tab active" id="extract-tab"><a href="{{ url_for('ui.ui_diff.diff_history_page_extract_GET', uuid=uuid)}}">Extract Data</a></li>
+    </ul>
+</div>
+
+    <div id="diff-ui">
+
+ <div class="xxxxtab-pane-inner" id="extract">
+        <form id="extract-data-form" class="pure-form pure-form-stacked edit-form"  action="{{ url_for('ui.ui_diff.diff_history_page_extract_POST', uuid=uuid) }}"  method="POST">
+            <input type="hidden" name="csrf_token" value="{{ csrf_token() }}">
+
+            <p>This tool will extract text data from all of the watch history.</p>
+
+            <div class="pure-control-group">
+                {{ render_field(extract_form.extract_regex) }}
+                <span class="pure-form-message-inline">
+                    A <strong>RegEx</strong> is a pattern that identifies exactly which part inside of the text that you want to extract.<br>
+
+                    <p>
+                        For example, to extract only the numbers from text &dash;<br>
+                        <strong>Raw text</strong>: <code>Temperature <span style="color: red">5.5</span>°C in Sydney</code><br>
+                        <strong>RegEx to extract:</strong> <code>Temperature <span style="color: red">([0-9\.]+)</span></code><br>
+                    </p>
+                    <p>
+                        <a href="https://RegExr.com/">Be sure to test your RegEx here.</a>
+                    </p>
+                    <p>
+                        Each RegEx group bracket <code>()</code> will be in its own column, the first column value is always the date.
+                    </p>
+                </span>
+            </div>
+            <div class="pure-control-group">
+                {{ render_button(extract_form.extract_submit_button) }}
+            </div>
+        </form>
+    </div>
+</div>
+
+{% endblock %}