New feature - Restock / stock / out of stock monitor option/mode

changedetectionio/processors/README.md

@@ -0,0 +1,11 @@
+# Change detection post-processors
+
+The concept here is to be able to switch between different domain specific problems to solve.
+
+- `text_json_diff` The traditional text and JSON comparison handler
+- `restock_diff` Only cares about detecting if a product looks like it has some text that suggests that it's out of stock, otherwise assumes that it's in stock.
+
+Some suggestions for the future
+
+- `graphical` 
+- `restock_and_price` - extract price AND stock text

changedetectionio/processors/__init__.py

@@ -0,0 +1,24 @@
+from abc import abstractmethod
+import hashlib
+
+
+class difference_detection_processor():
+
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+    @abstractmethod
+    def run(self, uuid, skip_when_checksum_same=True):
+        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 available_processors():
+    from . import restock_diff, text_json_diff
+    x=[('text_json_diff', text_json_diff.name), ('restock_diff', restock_diff.name)]
+    # @todo Make this smarter with introspection of sorts.
+    return x

changedetectionio/processors/restock_diff.py

@@ -0,0 +1,125 @@
+
+import hashlib
+import os
+import re
+import urllib3
+from . import difference_detection_processor
+from changedetectionio import content_fetcher
+from copy import deepcopy
+
+urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)
+
+name = 'Re-stock detection'
+description = 'Detects if the product goes back to in-stock'
+
+class perform_site_check(difference_detection_processor):
+    screenshot = None
+    xpath_data = None
+
+    def __init__(self, *args, datastore, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.datastore = datastore
+
+    def run(self, uuid, skip_when_checksum_same=True):
+
+        # DeepCopy so we can be sure we don't accidently change anything by reference
+        watch = deepcopy(self.datastore.data['watching'].get(uuid))
+
+        if not watch:
+            raise Exception("Watch no longer exists.")
+
+        # Protect against file:// access
+        if re.search(r'^file', watch.get('url', ''), re.IGNORECASE) and not os.getenv('ALLOW_FILE_URI', False):
+            raise Exception(
+                "file:// type access is denied for security reasons."
+            )
+
+        # Unset any existing notification error
+        update_obj = {'last_notification_error': False, 'last_error': False}
+        extra_headers = watch.get('headers', [])
+
+        # Tweak the base config with the per-watch ones
+        request_headers = deepcopy(self.datastore.data['settings']['headers'])
+        request_headers.update(extra_headers)
+
+        # 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', '')
+
+        timeout = self.datastore.data['settings']['requests'].get('timeout')
+
+        url = watch.link
+
+        request_body = self.datastore.data['watching'][uuid].get('body')
+        request_method = self.datastore.data['watching'][uuid].get('method')
+        ignore_status_codes = self.datastore.data['watching'][uuid].get('ignore_status_codes', False)
+
+        # Pluggable content fetcher
+        prefer_backend = watch.get_fetch_backend
+        if not prefer_backend or prefer_backend == 'system':
+            prefer_backend = self.datastore.data['settings']['application']['fetch_backend']
+
+        if hasattr(content_fetcher, prefer_backend):
+            klass = getattr(content_fetcher, prefer_backend)
+        else:
+            # If the klass doesnt exist, just use a default
+            klass = getattr(content_fetcher, "html_requests")
+
+        proxy_id = self.datastore.get_preferred_proxy_for_watch(uuid=uuid)
+        proxy_url = None
+        if proxy_id:
+            proxy_url = self.datastore.proxy_list.get(proxy_id).get('url')
+            print("UUID {} Using proxy {}".format(uuid, proxy_url))
+
+        fetcher = klass(proxy_override=proxy_url)
+
+        # 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 watch['webdriver_delay'] is not None:
+            fetcher.render_extract_delay = watch.get('webdriver_delay')
+        elif system_webdriver_delay is not None:
+            fetcher.render_extract_delay = system_webdriver_delay
+
+        # Could be removed if requests/plaintext could also return some info?
+        if prefer_backend != 'html_webdriver':
+            raise Exception("Re-stock detection requires Chrome or compatible webdriver/playwright fetcher to work")
+
+        if watch.get('webdriver_js_execute_code') is not None and watch.get('webdriver_js_execute_code').strip():
+            fetcher.webdriver_js_execute_code = watch.get('webdriver_js_execute_code')
+
+        fetcher.run(url, timeout, request_headers, request_body, request_method, ignore_status_codes, watch.get('include_filters'))
+        fetcher.quit()
+
+        self.screenshot = fetcher.screenshot
+        self.xpath_data = fetcher.xpath_data
+
+        # Track the content type
+        update_obj['content_type'] = fetcher.headers.get('Content-Type', '')
+        update_obj["last_check_status"] = fetcher.get_last_status_code()
+
+        # Main detection method
+        fetched_md5 = None
+        if fetcher.instock_data:
+            fetched_md5 = hashlib.md5(fetcher.instock_data.encode('utf-8')).hexdigest()
+            # 'Possibly in stock' comes from stock-not-in-stock.js when no string found above the fold.
+            update_obj["in_stock"] = True if fetcher.instock_data == 'Possibly in stock' else False
+
+
+        # The main thing that all this at the moment comes down to :)
+        changed_detected = False
+
+        if watch.get('previous_md5') and watch.get('previous_md5') != fetched_md5:
+            # Yes if we only care about it going to instock, AND we are in stock
+            if watch.get('in_stock_only') and update_obj["in_stock"]:
+                changed_detected = True
+
+            if not watch.get('in_stock_only'):
+                # All cases
+                changed_detected = True
+
+        # Always record the new checksum
+        update_obj["previous_md5"] = fetched_md5
+
+        return changed_detected, update_obj, fetcher.instock_data.encode('utf-8')

changedetectionio/processors/text_json_diff.py

@@ -0,0 +1,387 @@
+# HTML to TEXT/JSON DIFFERENCE FETCHER
+
+import hashlib
+import json
+import logging
+import os
+import re
+import urllib3
+
+from changedetectionio import content_fetcher, html_tools
+from changedetectionio.blueprint.price_data_follower import PRICE_DATA_TRACK_ACCEPT, PRICE_DATA_TRACK_REJECT
+from copy import deepcopy
+from . import difference_detection_processor
+
+urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)
+
+
+name =  'Webpage Text/HTML, JSON and PDF changes'
+description = 'Detects all text changes where possible'
+
+class FilterNotFoundInResponse(ValueError):
+    def __init__(self, msg):
+        ValueError.__init__(self, msg)
+
+class PDFToHTMLToolNotFound(ValueError):
+    def __init__(self, msg):
+        ValueError.__init__(self, msg)
+
+
+# Some common stuff here that can be moved to a base class
+# (set_proxy_from_list)
+class perform_site_check(difference_detection_processor):
+    screenshot = None
+    xpath_data = None
+
+    def __init__(self, *args, datastore, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.datastore = datastore
+
+    # Doesn't look like python supports forward slash auto enclosure in re.findall
+    # So convert it to inline flag "foobar(?i)" type configuration
+    def forward_slash_enclosed_regex_to_options(self, regex):
+        res = re.search(r'^/(.*?)/(\w+)$', regex, re.IGNORECASE)
+
+        if res:
+            regex = res.group(1)
+            regex += '(?{})'.format(res.group(2))
+        else:
+            regex += '(?{})'.format('i')
+
+        return regex
+
+    def run(self, uuid, skip_when_checksum_same=True):
+        changed_detected = False
+        screenshot = False  # as bytes
+        stripped_text_from_html = ""
+
+        # DeepCopy so we can be sure we don't accidently change anything by reference
+        watch = deepcopy(self.datastore.data['watching'].get(uuid))
+
+        if not watch:
+            raise Exception("Watch no longer exists.")
+
+        # Protect against file:// access
+        if re.search(r'^file', watch.get('url', ''), re.IGNORECASE) and not os.getenv('ALLOW_FILE_URI', False):
+            raise Exception(
+                "file:// type access is denied for security reasons."
+            )
+
+        # Unset any existing notification error
+        update_obj = {'last_notification_error': False, 'last_error': False}
+
+        extra_headers = watch.get('headers', [])
+
+        # Tweak the base config with the per-watch ones
+        request_headers = deepcopy(self.datastore.data['settings']['headers'])
+        request_headers.update(extra_headers)
+
+        # 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', '')
+
+        timeout = self.datastore.data['settings']['requests'].get('timeout')
+
+        url = watch.link
+
+        request_body = self.datastore.data['watching'][uuid].get('body')
+        request_method = self.datastore.data['watching'][uuid].get('method')
+        ignore_status_codes = self.datastore.data['watching'][uuid].get('ignore_status_codes', False)
+
+        # source: support
+        is_source = False
+        if url.startswith('source:'):
+            url = url.replace('source:', '')
+            is_source = True
+
+        # Pluggable content fetcher
+        prefer_backend = watch.get_fetch_backend
+        if not prefer_backend or prefer_backend == 'system':
+            prefer_backend = self.datastore.data['settings']['application']['fetch_backend']
+
+        if hasattr(content_fetcher, prefer_backend):
+            klass = getattr(content_fetcher, prefer_backend)
+        else:
+            # If the klass doesnt exist, just use a default
+            klass = getattr(content_fetcher, "html_requests")
+
+        proxy_id = self.datastore.get_preferred_proxy_for_watch(uuid=uuid)
+        proxy_url = None
+        if proxy_id:
+            proxy_url = self.datastore.proxy_list.get(proxy_id).get('url')
+            print("UUID {} Using proxy {}".format(uuid, proxy_url))
+
+        fetcher = klass(proxy_override=proxy_url)
+
+        # 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 watch['webdriver_delay'] is not None:
+            fetcher.render_extract_delay = watch.get('webdriver_delay')
+        elif system_webdriver_delay is not None:
+            fetcher.render_extract_delay = system_webdriver_delay
+
+        # Possible conflict
+        if prefer_backend == 'html_webdriver':
+            fetcher.browser_steps = watch.get('browser_steps', None)
+            fetcher.browser_steps_screenshot_path = os.path.join(self.datastore.datastore_path, uuid)
+
+        if watch.get('webdriver_js_execute_code') is not None and watch.get('webdriver_js_execute_code').strip():
+            fetcher.webdriver_js_execute_code = watch.get('webdriver_js_execute_code')
+
+        # requests for PDF's, images etc should be passwd the is_binary flag
+        is_binary = watch.is_pdf
+
+        fetcher.run(url, timeout, request_headers, request_body, request_method, ignore_status_codes, watch.get('include_filters'), is_binary=is_binary)
+        fetcher.quit()
+
+        self.screenshot = fetcher.screenshot
+        self.xpath_data = fetcher.xpath_data
+
+        # Track the content type
+        update_obj['content_type'] = fetcher.headers.get('Content-Type', '')
+
+        # Watches added automatically in the queue manager will skip if its the same checksum as the previous run
+        # Saves a lot of CPU
+        update_obj['previous_md5_before_filters'] = hashlib.md5(fetcher.content.encode('utf-8')).hexdigest()
+        if skip_when_checksum_same:
+            if update_obj['previous_md5_before_filters'] == watch.get('previous_md5_before_filters'):
+                raise content_fetcher.checksumFromPreviousCheckWasTheSame()
+
+
+        # Fetching complete, now filters
+        # @todo move to class / maybe inside of fetcher abstract base?
+
+        # @note: I feel like the following should be in a more obvious chain system
+        #  - Check filter text
+        #  - Is the checksum different?
+        #  - Do we convert to JSON?
+        # https://stackoverflow.com/questions/41817578/basic-method-chaining ?
+        # return content().textfilter().jsonextract().checksumcompare() ?
+
+        is_json = 'application/json' in fetcher.headers.get('Content-Type', '')
+        is_html = not is_json
+
+        # source: support, basically treat it as plaintext
+        if is_source:
+            is_html = False
+            is_json = False
+
+        if watch.is_pdf or 'application/pdf' in fetcher.headers.get('Content-Type', '').lower():
+            from shutil import which
+            tool = os.getenv("PDF_TO_HTML_TOOL", "pdftohtml")
+            if not which(tool):
+                raise PDFToHTMLToolNotFound("Command-line `{}` tool was not found in system PATH, was it installed?".format(tool))
+
+            import subprocess
+            proc = subprocess.Popen(
+                [tool, '-stdout', '-', '-s', 'out.pdf', '-i'],
+                stdout=subprocess.PIPE,
+                stdin=subprocess.PIPE)
+            proc.stdin.write(fetcher.raw_content)
+            proc.stdin.close()
+            fetcher.content = proc.stdout.read().decode('utf-8')
+            proc.wait(timeout=60)
+
+            # Add a little metadata so we know if the file changes (like if an image changes, but the text is the same
+            # @todo may cause problems with non-UTF8?
+            metadata = "<p>Added by changedetection.io: Document checksum - {} Filesize - {} bytes</p>".format(
+                hashlib.md5(fetcher.raw_content).hexdigest().upper(),
+                len(fetcher.content))
+
+            fetcher.content = fetcher.content.replace('</body>', metadata + '</body>')
+
+
+        include_filters_rule = deepcopy(watch.get('include_filters', []))
+        # include_filters_rule = watch['include_filters']
+        subtractive_selectors = watch.get(
+            "subtractive_selectors", []
+        ) + self.datastore.data["settings"]["application"].get(
+            "global_subtractive_selectors", []
+        )
+
+        # Inject a virtual LD+JSON price tracker rule
+        if watch.get('track_ldjson_price_data', '') == PRICE_DATA_TRACK_ACCEPT:
+            include_filters_rule.append(html_tools.LD_JSON_PRODUCT_OFFER_SELECTOR)
+
+        has_filter_rule = include_filters_rule and len("".join(include_filters_rule).strip())
+        has_subtractive_selectors = subtractive_selectors and len(subtractive_selectors[0].strip())
+
+        if is_json and not has_filter_rule:
+            include_filters_rule.append("json:$")
+            has_filter_rule = True
+
+        if is_json:
+            # Sort the JSON so we dont get false alerts when the content is just re-ordered
+            try:
+                fetcher.content = json.dumps(json.loads(fetcher.content), sort_keys=True)
+            except Exception as e:
+                # Might have just been a snippet, or otherwise bad JSON, continue
+                pass
+
+        if has_filter_rule:
+            json_filter_prefixes = ['json:', 'jq:']
+            for filter in include_filters_rule:
+                if any(prefix in filter for prefix in json_filter_prefixes):
+                    stripped_text_from_html += html_tools.extract_json_as_string(content=fetcher.content, json_filter=filter)
+                    is_html = False
+
+
+
+        if is_html or is_source:
+
+            # CSS Filter, extract the HTML that matches and feed that into the existing inscriptis::get_text
+            fetcher.content = html_tools.workarounds_for_obfuscations(fetcher.content)
+            html_content = fetcher.content
+
+            # If not JSON,  and if it's not text/plain..
+            if 'text/plain' in fetcher.headers.get('Content-Type', '').lower():
+                # Don't run get_text or xpath/css filters on plaintext
+                stripped_text_from_html = html_content
+            else:
+                # Does it have some ld+json price data? used for easier monitoring
+                update_obj['has_ldjson_price_data'] = html_tools.has_ldjson_product_info(fetcher.content)
+
+                # Then we assume HTML
+                if has_filter_rule:
+                    html_content = ""
+
+                    for filter_rule in include_filters_rule:
+                        # For HTML/XML we offer xpath as an option, just start a regular xPath "/.."
+                        if filter_rule[0] == '/' or filter_rule.startswith('xpath:'):
+                            html_content += html_tools.xpath_filter(xpath_filter=filter_rule.replace('xpath:', ''),
+                                                                    html_content=fetcher.content,
+                                                                    append_pretty_line_formatting=not is_source)
+                        else:
+                            # CSS Filter, extract the HTML that matches and feed that into the existing inscriptis::get_text
+                            html_content += html_tools.include_filters(include_filters=filter_rule,
+                                                                       html_content=fetcher.content,
+                                                                       append_pretty_line_formatting=not is_source)
+
+                    if not html_content.strip():
+                        raise FilterNotFoundInResponse(include_filters_rule)
+
+                if has_subtractive_selectors:
+                    html_content = html_tools.element_removal(subtractive_selectors, html_content)
+
+                if is_source:
+                    stripped_text_from_html = html_content
+                else:
+                    # extract text
+                    do_anchor = self.datastore.data["settings"]["application"].get("render_anchor_tag_content", False)
+                    stripped_text_from_html = \
+                        html_tools.html_to_text(
+                            html_content,
+                            render_anchor_tag_content=do_anchor
+                        )
+
+        # Re #340 - return the content before the 'ignore text' was applied
+        text_content_before_ignored_filter = stripped_text_from_html.encode('utf-8')
+
+        # Treat pages with no renderable text content as a change? No by default
+        empty_pages_are_a_change = self.datastore.data['settings']['application'].get('empty_pages_are_a_change', False)
+        if not is_json and not empty_pages_are_a_change and len(stripped_text_from_html.strip()) == 0:
+            raise content_fetcher.ReplyWithContentButNoText(url=url, status_code=fetcher.get_last_status_code(), screenshot=screenshot)
+
+        # We rely on the actual text in the html output.. many sites have random script vars etc,
+        # in the future we'll implement other mechanisms.
+
+        update_obj["last_check_status"] = fetcher.get_last_status_code()
+
+        # If there's text to skip
+        # @todo we could abstract out the get_text() to handle this cleaner
+        text_to_ignore = watch.get('ignore_text', []) + self.datastore.data['settings']['application'].get('global_ignore_text', [])
+        if len(text_to_ignore):
+            stripped_text_from_html = html_tools.strip_ignore_text(stripped_text_from_html, text_to_ignore)
+        else:
+            stripped_text_from_html = stripped_text_from_html.encode('utf8')
+
+        # 615 Extract text by regex
+        extract_text = watch.get('extract_text', [])
+        if len(extract_text) > 0:
+            regex_matched_output = []
+            for s_re in extract_text:
+                # incase they specified something in '/.../x'
+                regex = self.forward_slash_enclosed_regex_to_options(s_re)
+                result = re.findall(regex.encode('utf-8'), stripped_text_from_html)
+
+                for l in result:
+                    if type(l) is tuple:
+                        # @todo - some formatter option default (between groups)
+                        regex_matched_output += list(l) + [b'\n']
+                    else:
+                        # @todo - some formatter option default (between each ungrouped result)
+                        regex_matched_output += [l] + [b'\n']
+
+            # Now we will only show what the regex matched
+            stripped_text_from_html = b''
+            text_content_before_ignored_filter = b''
+            if regex_matched_output:
+                # @todo some formatter for presentation?
+                stripped_text_from_html = b''.join(regex_matched_output)
+                text_content_before_ignored_filter = stripped_text_from_html
+
+        # Re #133 - if we should strip whitespaces from triggering the change detected comparison
+        if self.datastore.data['settings']['application'].get('ignore_whitespace', False):
+            fetched_md5 = hashlib.md5(stripped_text_from_html.translate(None, b'\r\n\t ')).hexdigest()
+        else:
+            fetched_md5 = hashlib.md5(stripped_text_from_html).hexdigest()
+
+        ############ Blocking rules, after checksum #################
+        blocked = False
+
+        trigger_text = watch.get('trigger_text', [])
+        if len(trigger_text):
+            # Assume blocked
+            blocked = True
+            # Filter and trigger works the same, so reuse it
+            # It should return the line numbers that match
+            result = html_tools.strip_ignore_text(content=str(stripped_text_from_html),
+                                                  wordlist=trigger_text,
+                                                  mode="line numbers")
+            # Unblock if the trigger was found
+            if result:
+                blocked = False
+
+        text_should_not_be_present = watch.get('text_should_not_be_present', [])
+        if len(text_should_not_be_present):
+            # If anything matched, then we should block a change from happening
+            result = html_tools.strip_ignore_text(content=str(stripped_text_from_html),
+                                                  wordlist=text_should_not_be_present,
+                                                  mode="line numbers")
+            if result:
+                blocked = True
+
+        # The main thing that all this at the moment comes down to :)
+        if watch.get('previous_md5') != fetched_md5:
+            changed_detected = True
+
+        # Looks like something changed, but did it match all the rules?
+        if blocked:
+            changed_detected = False
+
+        # Extract title as title
+        if is_html:
+            if self.datastore.data['settings']['application'].get('extract_title_as_title') or watch['extract_title_as_title']:
+                if not watch['title'] or not len(watch['title']):
+                    update_obj['title'] = html_tools.extract_element(find='title', html_content=fetcher.content)
+
+        if changed_detected:
+            if watch.get('check_unique_lines', False):
+                has_unique_lines = watch.lines_contain_something_unique_compared_to_history(lines=stripped_text_from_html.splitlines())
+                # One or more lines? unsure?
+                if not has_unique_lines:
+                    logging.debug("check_unique_lines: UUID {} didnt have anything new setting change_detected=False".format(uuid))
+                    changed_detected = False
+                else:
+                    logging.debug("check_unique_lines: UUID {} had unique content".format(uuid))
+
+        # Always record the new checksum
+        update_obj["previous_md5"] = fetched_md5
+
+        # On the first run of a site, watch['previous_md5'] will be None, set it the current one.
+        if not watch.get('previous_md5'):
+            watch['previous_md5'] = fetched_md5
+
+        return changed_detected, update_obj, text_content_before_ignored_filter