Support filtering the /messages API by relation type (MSC3874). (#14148)

Gated behind an experimental configuration flag.

changelog.d/14148.feature

@@ -0,0 +1 @@
+Experimental support for [MSC3874](https://github.com/matrix-org/matrix-spec-proposals/pull/3874).

synapse/api/filtering.py

@@ -36,7 +36,7 @@
 from synapse.api.constants import EduTypes, EventContentFields
 from synapse.api.errors import SynapseError
 from synapse.api.presence import UserPresenceState
-from synapse.events import EventBase
+from synapse.events import EventBase, relation_from_event
 from synapse.types import JsonDict, RoomID, UserID
 
 if TYPE_CHECKING:
@@ -53,6 +53,12 @@
         # check types are valid event types
         "types": {"type": "array", "items": {"type": "string"}},
         "not_types": {"type": "array", "items": {"type": "string"}},
+        # MSC3874, filtering /messages.
+        "org.matrix.msc3874.rel_types": {"type": "array", "items": {"type": "string"}},
+        "org.matrix.msc3874.not_rel_types": {
+            "type": "array",
+            "items": {"type": "string"},
+        },
     },
 }
 
@@ -334,8 +340,15 @@ def __init__(self, hs: "HomeServer", filter_json: JsonDict):
         self.labels = filter_json.get("org.matrix.labels", None)
         self.not_labels = filter_json.get("org.matrix.not_labels", [])
 
-        self.related_by_senders = self.filter_json.get("related_by_senders", None)
-        self.related_by_rel_types = self.filter_json.get("related_by_rel_types", None)
+        self.related_by_senders = filter_json.get("related_by_senders", None)
+        self.related_by_rel_types = filter_json.get("related_by_rel_types", None)
+
+        # For compatibility with _check_fields.
+        self.rel_types = None
+        self.not_rel_types = []
+        if hs.config.experimental.msc3874_enabled:
+            self.rel_types = filter_json.get("org.matrix.msc3874.rel_types", None)
+            self.not_rel_types = filter_json.get("org.matrix.msc3874.not_rel_types", [])
 
     def filters_all_types(self) -> bool:
         return "*" in self.not_types
@@ -386,11 +399,19 @@ def _check(self, event: FilterEvent) -> bool:
             # check if there is a string url field in the content for filtering purposes
             labels = content.get(EventContentFields.LABELS, [])
 
+            # Check if the event has a relation.
+            rel_type = None
+            if isinstance(event, EventBase):
+                relation = relation_from_event(event)
+                if relation:
+                    rel_type = relation.rel_type
+
             field_matchers = {
                 "rooms": lambda v: room_id == v,
                 "senders": lambda v: sender == v,
                 "types": lambda v: _matches_wildcard(ev_type, v),
                 "labels": lambda v: v in labels,
+                "rel_types": lambda v: rel_type == v,
             }
 
             result = self._check_fields(field_matchers)

synapse/config/experimental.py

@@ -117,3 +117,6 @@ def read_config(self, config: JsonDict, **kwargs: Any) -> None:
         self.msc3882_token_timeout = self.parse_duration(
             experimental.get("msc3882_token_timeout", "5m")
         )
+
+        # MSC3874: Filtering /messages with rel_types / not_rel_types.
+        self.msc3874_enabled: bool = experimental.get("msc3874_enabled", False)

synapse/rest/client/versions.py

@@ -114,6 +114,8 @@ def on_GET(self, request: Request) -> Tuple[int, JsonDict]:
                     "org.matrix.msc3882": self.config.experimental.msc3882_enabled,
                     # Adds support for remotely enabling/disabling pushers, as per MSC3881
                     "org.matrix.msc3881": self.config.experimental.msc3881_enabled,
+                    # Adds support for filtering /messages by event relation.
+                    "org.matrix.msc3874": self.config.experimental.msc3874_enabled,
                 },
             },
         )

synapse/storage/databases/main/stream.py

@@ -357,6 +357,24 @@ def filter_to_clause(event_filter: Optional[Filter]) -> Tuple[str, List[str]]:
         )
         args.extend(event_filter.related_by_rel_types)
 
+    if event_filter.rel_types:
+        clauses.append(
+            "(%s)"
+            % " OR ".join(
+                "event_relation.relation_type = ?" for _ in event_filter.rel_types
+            )
+        )
+        args.extend(event_filter.rel_types)
+
+    if event_filter.not_rel_types:
+        clauses.append(
+            "((%s) OR event_relation.relation_type IS NULL)"
+            % " AND ".join(
+                "event_relation.relation_type != ?" for _ in event_filter.not_rel_types
+            )
+        )
+        args.extend(event_filter.not_rel_types)
+
     return " AND ".join(clauses), args
 
 
@@ -1278,8 +1296,8 @@ def _paginate_room_events_txn(
                 # Multiple labels could cause the same event to appear multiple times.
                 needs_distinct = True
 
-        # If there is a filter on relation_senders and relation_types join to the
-        # relations table.
+        # If there is a relation_senders and relation_types filter join to the
+        # relations table to get events related to the current event.
         if event_filter and (
             event_filter.related_by_senders or event_filter.related_by_rel_types
         ):
@@ -1294,6 +1312,13 @@ def _paginate_room_events_txn(
                     LEFT JOIN events AS related_event ON (relation.event_id = related_event.event_id)
                 """
 
+        # If there is a not_rel_types filter join to the relations table to get
+        # the event's relation information.
+        if event_filter and (event_filter.rel_types or event_filter.not_rel_types):
+            join_clause += """
+                LEFT JOIN event_relations AS event_relation USING (event_id)
+            """
+
         if needs_distinct:
             select_keywords += " DISTINCT"
 

tests/api/test_filtering.py

@@ -35,6 +35,8 @@ def MockEvent(**kwargs):
         kwargs["event_id"] = "fake_event_id"
     if "type" not in kwargs:
         kwargs["type"] = "fake_type"
+    if "content" not in kwargs:
+        kwargs["content"] = {}
     return make_event_from_dict(kwargs)
 
 
@@ -357,6 +359,66 @@ def test_filter_not_labels(self):
 
         self.assertTrue(Filter(self.hs, definition)._check(event))
 
+    @unittest.override_config({"experimental_features": {"msc3874_enabled": True}})
+    def test_filter_rel_type(self):
+        definition = {"org.matrix.msc3874.rel_types": ["m.thread"]}
+        event = MockEvent(
+            sender="@foo:bar",
+            type="m.room.message",
+            room_id="!secretbase:unknown",
+            content={},
+        )
+
+        self.assertFalse(Filter(self.hs, definition)._check(event))
+
+        event = MockEvent(
+            sender="@foo:bar",
+            type="m.room.message",
+            room_id="!secretbase:unknown",
+            content={"m.relates_to": {"event_id": "$abc", "rel_type": "m.reference"}},
+        )
+
+        self.assertFalse(Filter(self.hs, definition)._check(event))
+
+        event = MockEvent(
+            sender="@foo:bar",
+            type="m.room.message",
+            room_id="!secretbase:unknown",
+            content={"m.relates_to": {"event_id": "$abc", "rel_type": "m.thread"}},
+        )
+
+        self.assertTrue(Filter(self.hs, definition)._check(event))
+
+    @unittest.override_config({"experimental_features": {"msc3874_enabled": True}})
+    def test_filter_not_rel_type(self):
+        definition = {"org.matrix.msc3874.not_rel_types": ["m.thread"]}
+        event = MockEvent(
+            sender="@foo:bar",
+            type="m.room.message",
+            room_id="!secretbase:unknown",
+            content={"m.relates_to": {"event_id": "$abc", "rel_type": "m.thread"}},
+        )
+
+        self.assertFalse(Filter(self.hs, definition)._check(event))
+
+        event = MockEvent(
+            sender="@foo:bar",
+            type="m.room.message",
+            room_id="!secretbase:unknown",
+            content={},
+        )
+
+        self.assertTrue(Filter(self.hs, definition)._check(event))
+
+        event = MockEvent(
+            sender="@foo:bar",
+            type="m.room.message",
+            room_id="!secretbase:unknown",
+            content={"m.relates_to": {"event_id": "$abc", "rel_type": "m.reference"}},
+        )
+
+        self.assertTrue(Filter(self.hs, definition)._check(event))
+
     def test_filter_presence_match(self):
         user_filter_json = {"presence": {"types": ["m.*"]}}
         filter_id = self.get_success(
@@ -456,7 +518,6 @@ def test_filter_rooms(self):
 
         self.assertEqual(filtered_room_ids, ["!allowed:example.com"])
 
-    @unittest.override_config({"experimental_features": {"msc3440_enabled": True}})
     def test_filter_relations(self):
         events = [
             # An event without a relation.

tests/rest/client/test_relations.py

@@ -1677,7 +1677,6 @@ def test_redact_parent_annotation(self) -> None:
             {"chunk": [{"type": "m.reaction", "key": "👍", "count": 1}]},
         )
 
-    @unittest.override_config({"experimental_features": {"msc3440_enabled": True}})
     def test_redact_parent_thread(self) -> None:
         """
         Test that thread replies are still available when the root event is redacted.

tests/rest/client/test_rooms.py

@@ -35,7 +35,6 @@
     EventTypes,
     Membership,
     PublicRoomsFilterFields,
-    RelationTypes,
     RoomTypes,
 )
 from synapse.api.errors import Codes, HttpResponseException
@@ -50,6 +49,7 @@
 
 from tests import unittest
 from tests.http.server._base import make_request_with_cancellation_test
+from tests.storage.test_stream import PaginationTestCase
 from tests.test_utils import make_awaitable
 
 PATH_PREFIX = b"/_matrix/client/api/v1"
@@ -2915,149 +2915,20 @@ def _send_labelled_messages_in_room(self) -> str:
         return event_id
 
 
-class RelationsTestCase(unittest.HomeserverTestCase):
-    servlets = [
-        synapse.rest.admin.register_servlets_for_client_rest_resource,
-        room.register_servlets,
-        login.register_servlets,
-    ]
-
-    def default_config(self) -> Dict[str, Any]:
-        config = super().default_config()
-        config["experimental_features"] = {"msc3440_enabled": True}
-        return config
-
-    def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
-        self.user_id = self.register_user("test", "test")
-        self.tok = self.login("test", "test")
-        self.room_id = self.helper.create_room_as(self.user_id, tok=self.tok)
-
-        self.second_user_id = self.register_user("second", "test")
-        self.second_tok = self.login("second", "test")
-        self.helper.join(
-            room=self.room_id, user=self.second_user_id, tok=self.second_tok
-        )
-
-        self.third_user_id = self.register_user("third", "test")
-        self.third_tok = self.login("third", "test")
-        self.helper.join(room=self.room_id, user=self.third_user_id, tok=self.third_tok)
-
-        # An initial event with a relation from second user.
-        res = self.helper.send_event(
-            room_id=self.room_id,
-            type=EventTypes.Message,
-            content={"msgtype": "m.text", "body": "Message 1"},
-            tok=self.tok,
-        )
-        self.event_id_1 = res["event_id"]
-        self.helper.send_event(
-            room_id=self.room_id,
-            type="m.reaction",
-            content={
-                "m.relates_to": {
-                    "rel_type": RelationTypes.ANNOTATION,
-                    "event_id": self.event_id_1,
-                    "key": "👍",
-                }
-            },
-            tok=self.second_tok,
-        )
-
-        # Another event with a relation from third user.
-        res = self.helper.send_event(
-            room_id=self.room_id,
-            type=EventTypes.Message,
-            content={"msgtype": "m.text", "body": "Message 2"},
-            tok=self.tok,
-        )
-        self.event_id_2 = res["event_id"]
-        self.helper.send_event(
-            room_id=self.room_id,
-            type="m.reaction",
-            content={
-                "m.relates_to": {
-                    "rel_type": RelationTypes.REFERENCE,
-                    "event_id": self.event_id_2,
-                }
-            },
-            tok=self.third_tok,
-        )
-
-        # An event with no relations.
-        self.helper.send_event(
-            room_id=self.room_id,
-            type=EventTypes.Message,
-            content={"msgtype": "m.text", "body": "No relations"},
-            tok=self.tok,
-        )
-
-    def _filter_messages(self, filter: JsonDict) -> List[JsonDict]:
+class RelationsTestCase(PaginationTestCase):
+    def _filter_messages(self, filter: JsonDict) -> List[str]:
         """Make a request to /messages with a filter, returns the chunk of events."""
+        from_token = self.get_success(
+            self.from_token.to_string(self.hs.get_datastores().main)
+        )
         channel = self.make_request(
             "GET",
-            "/rooms/%s/messages?filter=%s&dir=b" % (self.room_id, json.dumps(filter)),
+            f"/rooms/{self.room_id}/messages?filter={json.dumps(filter)}&dir=f&from={from_token}",
             access_token=self.tok,
         )
         self.assertEqual(channel.code, HTTPStatus.OK, channel.result)
 
-        return channel.json_body["chunk"]
-
-    def test_filter_relation_senders(self) -> None:
-        # Messages which second user reacted to.
-        filter = {"related_by_senders": [self.second_user_id]}
-        chunk = self._filter_messages(filter)
-        self.assertEqual(len(chunk), 1, chunk)
-        self.assertEqual(chunk[0]["event_id"], self.event_id_1)
-
-        # Messages which third user reacted to.
-        filter = {"related_by_senders": [self.third_user_id]}
-        chunk = self._filter_messages(filter)
-        self.assertEqual(len(chunk), 1, chunk)
-        self.assertEqual(chunk[0]["event_id"], self.event_id_2)
-
-        # Messages which either user reacted to.
-        filter = {"related_by_senders": [self.second_user_id, self.third_user_id]}
-        chunk = self._filter_messages(filter)
-        self.assertEqual(len(chunk), 2, chunk)
-        self.assertCountEqual(
-            [c["event_id"] for c in chunk], [self.event_id_1, self.event_id_2]
-        )
-
-    def test_filter_relation_type(self) -> None:
-        # Messages which have annotations.
-        filter = {"related_by_rel_types": [RelationTypes.ANNOTATION]}
-        chunk = self._filter_messages(filter)
-        self.assertEqual(len(chunk), 1, chunk)
-        self.assertEqual(chunk[0]["event_id"], self.event_id_1)
-
-        # Messages which have references.
-        filter = {"related_by_rel_types": [RelationTypes.REFERENCE]}
-        chunk = self._filter_messages(filter)
-        self.assertEqual(len(chunk), 1, chunk)
-        self.assertEqual(chunk[0]["event_id"], self.event_id_2)
-
-        # Messages which have either annotations or references.
-        filter = {
-            "related_by_rel_types": [
-                RelationTypes.ANNOTATION,
-                RelationTypes.REFERENCE,
-            ]
-        }
-        chunk = self._filter_messages(filter)
-        self.assertEqual(len(chunk), 2, chunk)
-        self.assertCountEqual(
-            [c["event_id"] for c in chunk], [self.event_id_1, self.event_id_2]
-        )
-
-    def test_filter_relation_senders_and_type(self) -> None:
-        # Messages which second user reacted to.
-        filter = {
-            "related_by_senders": [self.second_user_id],
-            "related_by_rel_types": [RelationTypes.ANNOTATION],
-        }
-        chunk = self._filter_messages(filter)
-        self.assertEqual(len(chunk), 1, chunk)
-        self.assertEqual(chunk[0]["event_id"], self.event_id_1)
+        return [ev["event_id"] for ev in channel.json_body["chunk"]]
 
 
 class ContextTestCase(unittest.HomeserverTestCase):