activitypub._load_user: handle bad web ids

fixes https://console.cloud.google.com/errors/detail/CLaR2pODkb-KxAE;locations=global;time=P30D?project=bridgy-federated

activitypub.py

@@ -974,7 +974,12 @@ def _load_user(handle_or_id, create=False):
         id = handle_or_id
 
     assert id
-    user = proto.get_or_create(id) if create else proto.get_by_id(id)
+    try:
+        user = proto.get_or_create(id) if create else proto.get_by_id(id)
+    except ValueError as e:
+        logging.warning(e)
+        user = None
+
     if not user or not user.is_enabled(ActivityPub):
         error(f'{proto.LABEL} user {id} not found', status=404)
 

tests/test_activitypub.py

@@ -504,6 +504,12 @@ def test_actor_opted_out(self, *_):
         got = self.client.get('/user.com')
         self.assertEqual(404, got.status_code)
 
+    def test_actor_bad_id(self, *_):
+        # Web.get_or_create => urllib.parse.urlparse raises
+        # ValueError: Invalid IPv6 URL
+        got = self.client.get('/bsky]foo.bar')
+        self.assertEqual(404, got.status_code)
+
     def test_actor_protocol_bot_user(self, *_):
         """Web users are special cased to drop the /web/ prefix."""
         actor_as2 = json_loads(util.read('bsky.brid.gy.as2.json'))