Handle deleted actors in the notifications

app.py

@@ -67,6 +67,7 @@ from little_boxes.activitypub import clean_activity
 from little_boxes.activitypub import get_backend
 from little_boxes.content_helper import parse_markdown
 from little_boxes.errors import ActivityNotFoundError
+from little_boxes.errors import ActivityGoneError
 from little_boxes.errors import Error
 from little_boxes.errors import NotFromOutboxError
 from little_boxes.httpsig import HTTPSigAuth
@@ -265,8 +266,10 @@ def get_actor(url):
     if not url:
         return None
     print(f"GET_ACTOR {url}")
+    try:
         return ACTOR_SERVICE.get(url)
-
+    except (ActivityNotFoundError, ActivityGoneError):
+        return f"Deleted<{url}>"
 
 @app.template_filter()
 def format_time(val):