Support outgoing retraction of shares in ActivityPub

federation/entities/activitypub/entities.py

@@ -209,17 +209,29 @@ class ActivitypubProfile(ActivitypubEntityMixin, Profile):
 
 
 class ActivitypubRetraction(ActivitypubEntityMixin, Retraction):
-    _type = ObjectType.TOMBSTONE.value
+    def resolve_object_type(self):
+        return {
+            "Comment": ObjectType.TOMBSTONE.value,
+            "Post": ObjectType.TOMBSTONE.value,
+            "Share": ActivityType.ANNOUNCE.value,
+        }.get(self.entity_type)
+
+    def resolve_type(self):
+        return {
+            "Comment": ActivityType.DELETE.value,
+            "Post": ActivityType.DELETE.value,
+            "Share": ActivityType.UNDO.value,
+        }.get(self.entity_type)
 
     def to_as2(self) -> Dict:
         as2 = {
             "@context": CONTEXTS_DEFAULT,
             "id": self.activity_id,
-            "type": ActivityType.DELETE.value,
+            "type": self.resolve_type(),
             "actor": self.actor_id,
             "object": {
                 "id": self.target_id,
-                "type": self._type,
+                "type": self.resolve_object_type(),
             },
             "published": self.created_at.isoformat(),
         }

federation/tests/entities/activitypub/test_entities.py

@@ -166,6 +166,22 @@ class TestEntitiesConvertToAS2:
             'published': '2019-04-27T00:00:00',
         }
 
+    def test_retraction_to_as2__announce(self, activitypubretraction_announce):
+        result = activitypubretraction_announce.to_as2()
+        assert result == {
+            '@context': [
+                'https://www.w3.org/ns/activitystreams',
+            ],
+            'type': 'Undo',
+            'id': 'http://127.0.0.1:8000/post/123456/#delete',
+            'actor': 'http://127.0.0.1:8000/profile/123456/',
+            'object': {
+                'id': 'http://127.0.0.1:8000/post/123456/activity',
+                'type': 'Announce',
+            },
+            'published': '2019-04-27T00:00:00',
+        }
+
 
 class TestEntitiesPostReceive:
     @patch("federation.utils.activitypub.retrieve_and_parse_profile", autospec=True)

federation/tests/fixtures/entities.py

@@ -93,6 +93,17 @@ def activitypubretraction():
         )
 
 
+@pytest.fixture
+def activitypubretraction_announce():
+    with freeze_time("2019-04-27"):
+        return ActivitypubRetraction(
+            target_id="http://127.0.0.1:8000/post/123456/activity",
+            activity_id="http://127.0.0.1:8000/post/123456/#delete",
+            actor_id="http://127.0.0.1:8000/profile/123456/",
+            entity_type="Share",
+        )
+
+
 @pytest.fixture
 def activitypubundofollow():
     return ActivitypubFollow(