Support incoming retraction of ActivityPub shares

federation/entities/activitypub/mappers.py

@@ -21,7 +21,6 @@ MAPPINGS = {
     "Note": ActivitypubPost,
     "Page": ActivitypubPost,
     "Person": ActivitypubProfile,
-    "Undo": ActivitypubFollow,  # Technically not correct, but for now we support only undoing a follow of a profile
 }
 
 OBJECTS = (
@@ -31,15 +30,23 @@ OBJECTS = (
     "Person",
 )
 
+UNDO_MAPPINGS = {
+    "Follow": ActivitypubFollow,
+    "Announce": ActivitypubRetraction,
+}
 
 def element_to_objects(payload: Dict) -> List:
     """
     Transform an Element to a list of entities.
     """
+    cls = None
     entities = []
     is_object = True if payload.get('type') in OBJECTS else False
     if payload.get('type') == "Delete":
         cls = ActivitypubRetraction
+    elif payload.get('type') == "Undo":
+        if isinstance(payload.get('object'), dict):
+            cls = UNDO_MAPPINGS.get(payload["object"]["type"])
     elif isinstance(payload.get('object'), dict) and payload["object"].get('type'):
         if payload["object"]["type"] == "Note" and payload["object"].get("inReplyTo"):
             cls = ActivitypubComment
@@ -233,7 +240,7 @@ def transform_attribute(key: str, value: Union[str, Dict, int], transformed: Dic
         transformed["target_id"] = value
     elif key == "name":
         transformed["name"] = value
-    elif key == "object":
+    elif key == "object" and not is_object:
         if isinstance(value, dict):
             if cls == ActivitypubAccept:
                 transformed["target_id"] = value.get("id")

federation/tests/entities/activitypub/test_mappers.py

@@ -9,7 +9,7 @@ from federation.entities.activitypub.mappers import message_to_objects, get_outb
 from federation.entities.base import Accept, Follow, Profile, Post, Comment
 from federation.tests.fixtures.payloads import (
     ACTIVITYPUB_FOLLOW, ACTIVITYPUB_PROFILE, ACTIVITYPUB_PROFILE_INVALID, ACTIVITYPUB_UNDO_FOLLOW, ACTIVITYPUB_POST,
-    ACTIVITYPUB_COMMENT, ACTIVITYPUB_RETRACTION, ACTIVITYPUB_SHARE)
+    ACTIVITYPUB_COMMENT, ACTIVITYPUB_RETRACTION, ACTIVITYPUB_SHARE, ACTIVITYPUB_RETRACTION_SHARE)
 from federation.types import UserType, ReceiverVariant
 
 
@@ -180,6 +180,15 @@ class TestActivitypubEntityMappersReceive:
         assert entity.target_id == "https://friendica.feneas.org/objects/76158462-165d-3386-aa23-ba2090614385"
         assert entity.entity_type == "Object"
 
+    def test_message_to_objects_retraction__share(self):
+        entities = message_to_objects(ACTIVITYPUB_RETRACTION_SHARE, "https://mastodon.social/users/jaywink")
+        assert len(entities) == 1
+        entity = entities[0]
+        assert isinstance(entity, ActivitypubRetraction)
+        assert entity.actor_id == "https://mastodon.social/users/jaywink"
+        assert entity.target_id == "https://mastodon.social/users/jaywink/statuses/102571932479036987/activity"
+        assert entity.entity_type == "Object"
+
     @pytest.mark.skip
     def test_message_to_objects_reshare_extra_properties(self):
         entities = message_to_objects(DIASPORA_RESHARE_WITH_EXTRA_PROPERTIES, "alice@example.org")

federation/tests/fixtures/payloads/activitypub.py

@@ -183,6 +183,25 @@ ACTIVITYPUB_RETRACTION = {
     },
 }
 
+ACTIVITYPUB_RETRACTION_SHARE = {'@context': 'https://www.w3.org/ns/activitystreams',
+ 'id': 'https://mastodon.social/users/jaywink#announces/102571932479036987/undo',
+ 'type': 'Undo',
+ 'actor': 'https://mastodon.social/users/jaywink',
+ 'to': ['https://www.w3.org/ns/activitystreams#Public'],
+ 'object': {'id': 'https://mastodon.social/users/jaywink/statuses/102571932479036987/activity',
+  'type': 'Announce',
+  'actor': 'https://mastodon.social/users/jaywink',
+  'published': '2019-08-06T20:31:21Z',
+  'to': ['https://www.w3.org/ns/activitystreams#Public'],
+  'cc': ['https://mastodon.art/users/asterii',
+   'https://mastodon.social/users/jaywink/followers'],
+  'object': 'https://mastodon.art/users/asterii/statuses/102571181579804095',
+  'atomUri': 'https://mastodon.social/users/jaywink/statuses/102571932479036987/activity'},
+ 'signature': {'type': 'RsaSignature2017',
+  'creator': 'https://mastodon.social/users/jaywink#main-key',
+  'created': '2019-08-06T20:32:23Z',
+  'signatureValue': 'erI90OrrLqK1DiTqb4OO72XLcE7m74Fs4cH6s0plKKELHa7BZFQmtQYXKEgA9LwIUdSRrIurAUiaDWAw2sQZDg7opYo9x3z+GJDMZ3KxhBND7iHO8ZeGhV1ZBBKUMuBb3BfhOkd3ADp+RQ/fHcw6kOcViV2VsQduinAgQRpiutmGCLd/7eshqSF/aL4tFoAOyCskkm/5JDMNp2nnHNoXXJ+SZf7a8C6YPNDxWd7GzyQNeWkTBBdCJBPvS4HI0wQrTWemBvy6uP8k5QQ7FnqrrRrk/7zrcibFSInuYxiRTRV++rQ3irIbXNtoLhWQd36Iu5U22BclmkS1AAVBDUIj8w=='}}
+
 ACTIVITYPUB_SHARE = {
     '@context': 'https://www.w3.org/ns/activitystreams',
     'id': 'https://mastodon.social/users/jaywink/statuses/102560701449465612/activity',