changedetection.io/changedetectionio/notification/handler.py

import os
import time
import apprise
from loguru import logger
from .apprise_plugin.assets import apprise_asset, APPRISE_AVATAR_URL
from changedetectionio.safe_jinja import render as jinja_render


def _populate_notification_tokens(n_object, datastore):
    """
    Populate notification tokens (diff, current_snapshot, etc.) if not already present.
    This ensures both queued notifications and test notifications have the same data.
    """
    from changedetectionio import diff
    from changedetectionio.notification import default_notification_format_for_watch
    
    watch_uuid = n_object.get('uuid')
    if not watch_uuid:
        return
        
    watch = datastore.data['watching'].get(watch_uuid)
    if not watch:
        return

    dates = []
    trigger_text = ''
    watch_html_link = ''

    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 we ended up here with "System default"
    if n_object.get('notification_format') == default_notification_format_for_watch:
        n_object['notification_format'] = datastore.data['settings']['application'].get('notification_format')

    html_colour_enable = False
    # HTML needs linebreak, but MarkDown and Text can use a linefeed
    if n_object.get('notification_format') == 'HTML':
        line_feed_sep = "<br>"
        # Snapshot will be plaintext on the disk, convert to some kind of HTML
        snapshot_contents = snapshot_contents.replace('\n', line_feed_sep)
    elif n_object.get('notification_format') == 'HTML Color':
        line_feed_sep = "<br>"
        # Snapshot will be plaintext on the disk, convert to some kind of HTML
        snapshot_contents = snapshot_contents.replace('\n', line_feed_sep)
        html_colour_enable = True
    else:
        line_feed_sep = "\n"

    triggered_text = ''
    if len(trigger_text):
        from changedetectionio import html_tools
        triggered_text = html_tools.get_triggered_text(content=snapshot_contents, trigger_text=trigger_text)
        if triggered_text:
            triggered_text = line_feed_sep.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])

    if watch:
        v = {'url': watch.get('url'), 'label': watch.label}
        watch_html_link = jinja_render(template_str='<a href="{{ label or url | e }}" rel="noopener noreferrer">{{ url | e }}</a>', **v)


    n_object.update({
        'current_snapshot': snapshot_contents,
        'diff': diff.render_diff(prev_snapshot, current_snapshot, line_feed_sep=line_feed_sep, html_colour=html_colour_enable),
        'diff_added': diff.render_diff(prev_snapshot, current_snapshot, include_removed=False, line_feed_sep=line_feed_sep),
        'diff_full': diff.render_diff(prev_snapshot, current_snapshot, include_equal=True, line_feed_sep=line_feed_sep, html_colour=html_colour_enable),
        'diff_patch': diff.render_diff(prev_snapshot, current_snapshot, line_feed_sep=line_feed_sep, patch_format=True),
        'diff_removed': diff.render_diff(prev_snapshot, current_snapshot, include_added=False, line_feed_sep=line_feed_sep),
        'screenshot': watch.get_screenshot() if watch and watch.get('notification_screenshot') else None,
        'triggered_text': triggered_text,
        'watch_html_link': watch_html_link,
        'watch_url': watch.link,
        'watch_url_raw': watch.get('url'),
    })

    if watch:
        n_object.update(watch.extra_notification_token_values())

def process_notification(n_object, datastore):
    from . import default_notification_format_for_watch, default_notification_format, valid_notification_formats
    # be sure its registered
    from .apprise_plugin.custom_handlers import apprise_http_custom_handler, apprise_null_custom_handler

    n_body = ''
    n_title = ''

    now = time.time()
    if n_object.get('notification_timestamp'):
        logger.trace(f"Time since queued {now-n_object['notification_timestamp']:.3f}s")

    n_format = valid_notification_formats.get(
        n_object.get('notification_format', default_notification_format),
        valid_notification_formats[default_notification_format],
    )
    # If we arrived with 'System default' then look it up
    if n_format == default_notification_format_for_watch and datastore.data['settings']['application'].get('notification_format') != default_notification_format_for_watch:
        # Initially text or whatever
        n_format = datastore.data['settings']['application'].get('notification_format', valid_notification_formats[default_notification_format])

    # Ensure diff rendering is done if not already present (for test notifications)
    if not n_object.get('diff') and n_object.get('uuid'):
        _populate_notification_tokens(n_object, datastore)

    # Insert variables into the notification content
    notification_parameters = create_notification_parameters(n_object, datastore)


    logger.trace(f"Complete notification body including Jinja and placeholders calculated in  {time.time() - now:.2f}s")

    # https://github.com/caronc/apprise/wiki/Development_LogCapture
    # Anything higher than or equal to WARNING (which covers things like Connection errors)
    # raise it as an exception

    sent_objs = []

    if 'as_async' in n_object:
        apprise_asset.async_mode = n_object.get('as_async')

    apobj = apprise.Apprise(debug=True, asset=apprise_asset)

    if not n_object.get('notification_urls'):
        return None

    # Check for notification.html template in datastore directory
    notification_template_path = os.path.join(datastore.datastore_path, 'notification.html')
    notification_template = None
    if os.path.exists(notification_template_path):
        try:
            with open(notification_template_path, 'r', encoding='utf-8') as f:
                notification_template = f.read()
                logger.info(f"Using notification template from {notification_template_path}")
        except Exception as e:
            logger.warning(f"Failed to load notification template {notification_template_path}: {e}")

    with apprise.LogCapture(level=apprise.logging.DEBUG) as logs:
        for url in n_object['notification_urls']:

            # Get the notification body from datastore
            n_body = jinja_render(template_str=n_object.get('notification_body', ''), **notification_parameters)

            # Apply notification template wrapper if it exists (the one from the disk)
            if notification_template:
                template_params = notification_parameters.copy()
                template_params['notification_body'] = n_body
                template_params['notification_url_current'] = url
                n_body = jinja_render(template_str=notification_template, **template_params)
            
            if n_object.get('notification_format', '').startswith('HTML'):
                n_body = n_body.replace("\n", '<br>')
            n_title = jinja_render(template_str=n_object.get('notification_title', ''), **notification_parameters)

            url = url.strip()
            if url.startswith('#'):
                logger.trace(f"Skipping commented out notification URL - {url}")
                continue

            if not url:
                logger.warning(f"Process Notification: skipping empty notification URL.")
                continue

            logger.info(f">> Process Notification: AppRise notifying {url}")
            url = jinja_render(template_str=url, **notification_parameters)

            # 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 -
            #     200 bytes for the overhead of the _entire_ json payload, 200 bytes for {tts, wait, content} etc headers
            #     Length of URL - Incase they specify a longer custom avatar_url

            # So if no avatar_url is specified, add one so it can be correctly calculated into the total payload
            k = '?' if not '?' in url else '&'
            if not 'avatar_url' in url \
                    and not url.startswith('mail') \
                    and not url.startswith('post') \
                    and not url.startswith('get') \
                    and not url.startswith('delete') \
                    and not url.startswith('put'):
                url += k + f"avatar_url={APPRISE_AVATAR_URL}"

            if url.startswith('tgram://'):
                # Telegram only supports a limit subset of HTML, remove the '<br>' we place in.
                # re https://github.com/dgtlmoon/changedetection.io/issues/555
                # @todo re-use an existing library we have already imported to strip all non-allowed tags
                n_body = n_body.replace('<br>', '\n')
                n_body = n_body.replace('</br>', '\n')
                # real limit is 4096, but minus some for extra metadata
                payload_max_size = 3600
                body_limit = max(0, payload_max_size - len(n_title))
                n_title = n_title[0:payload_max_size]
                n_body = n_body[0:body_limit]

            elif url.startswith('discord://') or url.startswith('https://discordapp.com/api/webhooks') or url.startswith(
                    'https://discord.com/api'):
                # real limit is 2000, but minus some for extra metadata
                payload_max_size = 1700
                body_limit = max(0, payload_max_size - len(n_title))
                n_title = n_title[0:payload_max_size]
                n_body = n_body[0:body_limit]

            elif url.startswith('mailto'):
                # Apprise will default to HTML, so we need to override it
                # So that whats' generated in n_body is in line with what is going to be sent.
                # https://github.com/caronc/apprise/issues/633#issuecomment-1191449321
                if not 'format=' in url and (n_format == 'Text' or n_format == 'Markdown'):
                    prefix = '?' if not '?' in url else '&'
                    # Apprise format is lowercase text https://github.com/caronc/apprise/issues/633
                    n_format = n_format.lower()
                    url = f"{url}{prefix}format={n_format}"
                # If n_format == HTML, then apprise email should default to text/html and we should be sending HTML only

            apobj.add(url)

            sent_objs.append({'title': n_title,
                              'body': n_body,
                              'url': url,
                              'body_format': n_format})

        if n_object.get('notification_urls'):
            # Blast off the notifications tht are set in .add()
            apobj.notify(
                title=n_title,
                body=n_body,
                body_format=n_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()

        if log_value and 'WARNING' in log_value or 'ERROR' in log_value:
            logger.critical(log_value)
            raise Exception(log_value)

    # Return what was sent for better logging - after the for loop
    return sent_objs


# Notification title + body content parameters get created here.
# ( Where we prepare the tokens in the notification to be replaced with actual values )
def create_notification_parameters(n_object, datastore):
    from copy import deepcopy
    from . import valid_tokens

    # in the case we send a test notification from the main settings, there is no UUID.
    uuid = n_object['uuid'] if 'uuid' in n_object else ''

    if uuid:
        watch_title = datastore.data['watching'][uuid].get('title', '')
        tag_list = []
        tags = datastore.get_all_tags_for_watch(uuid)
        if tags:
            for tag_uuid, tag in tags.items():
                tag_list.append(tag.get('title'))
        watch_tag = ', '.join(tag_list)
    else:
        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, uuid)
    preview_url = "{}/preview/{}".format(base_url, uuid)

    # Not sure deepcopy is needed here, but why not
    tokens = deepcopy(valid_tokens)

    # Valid_tokens also used as a field validator
    tokens.update(
        {
            'base_url': base_url,
            'diff_url': diff_url,
            'preview_url': preview_url,
            '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,
            'watch_uuid': uuid,
        })

    # n_object will contain diff, diff_added etc etc
    tokens.update(n_object)

    if uuid:
        tokens.update(datastore.data['watching'].get(uuid).extra_notification_token_values())

    return tokens