activitypub.postprocess_as2_actor: handle user without handle

fixes https://console.cloud.google.com/errors/detail/CIT9-r3d-MKW5AE;time=P30D?project=bridgy-federated

activitypub.py

@@ -738,7 +738,9 @@ def postprocess_as2_actor(actor, wrap=True):
     # https://docs.joinmastodon.org/spec/webfinger/#mastodons-requirements-for-webfinger
     # https://github.com/snarfed/bridgy-fed/issues/302#issuecomment-1324305460
     # https://github.com/snarfed/bridgy-fed/issues/77
-    actor['preferredUsername'] = g.user.handle_as(ActivityPub).strip('@').split('@')[0]
+    handle = g.user.handle_as(ActivityPub)
+    if handle:
+        actor['preferredUsername'] = handle.strip('@').split('@')[0]
 
     # Override the label for their home page to be "Web site"
     for att in util.get_list(actor, 'attachment'):

atproto.py

@@ -79,10 +79,9 @@ class ATProto(User, Protocol):
     @ndb.ComputedProperty
     def handle(self):
         """Returns handle if the DID document includes one, otherwise None."""
-        did_obj = ATProto.load(self.key.id())
-        if did_obj:
-            handle, _, _ = parse_at_uri(
-                util.get_first(did_obj.raw, 'alsoKnownAs', ''))
+        if did_obj := ATProto.load(self.key.id()):
+            if aka := util.get_first(did_obj.raw, 'alsoKnownAs', ''):
+                handle, _, _ = parse_at_uri(aka)
                 if handle:
                     return handle
 

tests/test_activitypub.py

@@ -23,6 +23,7 @@ from .testutil import Fake, TestCase
 
 import activitypub
 from activitypub import ActivityPub, default_signature_user, postprocess_as2
+from atproto import ATProto
 import common
 from models import Follower, Object
 import protocol
@@ -428,6 +429,13 @@ class ActivityPubTest(TestCase):
             **ACTOR_FAKE,
         }, got.json, ignore=['publicKeyPem'])
 
+    def test_actor_no_handle(self, *_):
+        self.store_object(id='did:plc:user', raw={'foo': 'bar'})
+        self.make_user('did:plc:user', cls=ATProto)
+        got = self.client.get('/ap/did:plc:user', base_url='https://atproto.brid.gy/')
+        self.assertEqual(200, got.status_code)
+        self.assertNotIn('preferredUsername', got.json)
+
     def test_actor_handle_user_fetch_fails(self, _, __, ___):
         got = self.client.get('/ap/fake/fake:handle:nope')
         self.assertEqual(404, got.status_code)