Fix #509. Allow semi easy override of filtering logic with custom python code so it can be extended by end users

tubesync/sync/filtering.py

@@ -6,6 +6,7 @@ from common.logger import log
 from .models import Media
 from datetime import datetime, timedelta
 from django.utils import timezone
+from .overrides.custom_filter import filter_custom
 
 
 # Check the filter conditions for instance, return is if the Skip property has changed so we can do other things
@@ -33,6 +34,10 @@ def filter_media(instance: Media):
     if filter_duration(instance):
         skip = True
 
+    # If we aren't already skipping the file, call our custom function that can be overridden
+    if not skip and filter_custom(instance):
+        skip = True
+
     # Check if skipping
     if instance.skip != skip:
         instance.skip = skip

tubesync/sync/overrides/custom_filter.py

@@ -0,0 +1,27 @@
+"""
+    This file can be overridden with a docker volume to allow specifying a custom filter function to call. This allows
+    for higher order filtering for those that really want advanced controls, without exposing the web interface to
+    potential RCE issues.
+
+    You are simply provided with an instance of Media, and need to return True to skip it, or False to allow it to be
+    downloaded.
+
+    To use this custom file, download this file and modify the function to do your check for skipping a media item.
+    Then use docker volumes to override /app/sync/overrides/ with your custom file (it must be called
+    `custom_filter.py`)
+    e.g. your `docker run` could have `-v /some/directory/tubesync-overrides:/app/sync/overrides`
+    or docker-compose could have
+        volumes:
+            - /some/directory/tubesync-overrides:/app/sync/overrides
+
+
+    The logic is that if any condition marks an item to be skipped, it will be skipped. To save resources, this
+    custom filter won't be called if any other filter as already marked it to be skipped
+"""
+
+from ..models import Media
+
+
+def filter_custom(instance: Media) -> bool:
+    # Return True to skip, or False to allow the media item to be downloaded
+    return False