Remove the /send_relation endpoint. (#11682)

This was removed from MSC2674 before that was approved
and is not used by any known clients.

3 files changed, 19 insertions, 133 deletions

diff --git a/changelog.d/11682.removal b/changelog.d/11682.removal
new file mode 100644
index 0000000000..50bdf35b20
--- /dev/null
+++ b/changelog.d/11682.removal
@@ -0,0 +1 @@
+Remove the unstable `/send_relation` endpoint.
diff --git a/synapse/rest/client/relations.py b/synapse/rest/client/relations.py
index 5815650ee6..3823498012 100644
--- a/synapse/rest/client/relations.py
+++ b/synapse/rest/client/relations.py
@@ -19,28 +19,20 @@ any time to reflect changes in the MSC.
 """
 
 import logging
-from typing import TYPE_CHECKING, Awaitable, Optional, Tuple
+from typing import TYPE_CHECKING, Optional, Tuple
 
-from synapse.api.constants import EventTypes, RelationTypes
-from synapse.api.errors import ShadowBanError, SynapseError
+from synapse.api.constants import RelationTypes
+from synapse.api.errors import SynapseError
 from synapse.http.server import HttpServer
-from synapse.http.servlet import (
-    RestServlet,
-    parse_integer,
-    parse_json_object_from_request,
-    parse_string,
-)
+from synapse.http.servlet import RestServlet, parse_integer, parse_string
 from synapse.http.site import SynapseRequest
-from synapse.rest.client.transactions import HttpTransactionCache
+from synapse.rest.client._base import client_patterns
 from synapse.storage.relations import (
     AggregationPaginationToken,
     PaginationChunk,
     RelationPaginationToken,
 )
 from synapse.types import JsonDict
-from synapse.util.stringutils import random_string
-
-from ._base import client_patterns
 
 if TYPE_CHECKING:
     from synapse.server import HomeServer
@@ -48,112 +40,6 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-class RelationSendServlet(RestServlet):
-    """Helper API for sending events that have relation data.
-
-    Example API shape to send a 👍 reaction to a room:
-
-        POST /rooms/!foo/send_relation/$bar/m.annotation/m.reaction?key=%F0%9F%91%8D
-        {}
-
-        {
-            "event_id": "$foobar"
-        }
-    """
-
-    PATTERN = (
-        "/rooms/(?P<room_id>[^/]*)/send_relation"
-        "/(?P<parent_id>[^/]*)/(?P<relation_type>[^/]*)/(?P<event_type>[^/]*)"
-    )
-
-    def __init__(self, hs: "HomeServer"):
-        super().__init__()
-        self.auth = hs.get_auth()
-        self.event_creation_handler = hs.get_event_creation_handler()
-        self.txns = HttpTransactionCache(hs)
-
-    def register(self, http_server: HttpServer) -> None:
-        http_server.register_paths(
-            "POST",
-            client_patterns(self.PATTERN + "$", releases=()),
-            self.on_PUT_or_POST,
-            self.__class__.__name__,
-        )
-        http_server.register_paths(
-            "PUT",
-            client_patterns(self.PATTERN + "/(?P<txn_id>[^/]*)$", releases=()),
-            self.on_PUT,
-            self.__class__.__name__,
-        )
-
-    def on_PUT(
-        self,
-        request: SynapseRequest,
-        room_id: str,
-        parent_id: str,
-        relation_type: str,
-        event_type: str,
-        txn_id: Optional[str] = None,
-    ) -> Awaitable[Tuple[int, JsonDict]]:
-        return self.txns.fetch_or_execute_request(
-            request,
-            self.on_PUT_or_POST,
-            request,
-            room_id,
-            parent_id,
-            relation_type,
-            event_type,
-            txn_id,
-        )
-
-    async def on_PUT_or_POST(
-        self,
-        request: SynapseRequest,
-        room_id: str,
-        parent_id: str,
-        relation_type: str,
-        event_type: str,
-        txn_id: Optional[str] = None,
-    ) -> Tuple[int, JsonDict]:
-        requester = await self.auth.get_user_by_req(request, allow_guest=True)
-
-        if event_type == EventTypes.Member:
-            # Add relations to a membership is meaningless, so we just deny it
-            # at the CS API rather than trying to handle it correctly.
-            raise SynapseError(400, "Cannot send member events with relations")
-
-        content = parse_json_object_from_request(request)
-
-        aggregation_key = parse_string(request, "key", encoding="utf-8")
-
-        content["m.relates_to"] = {
-            "event_id": parent_id,
-            "rel_type": relation_type,
-        }
-        if aggregation_key is not None:
-            content["m.relates_to"]["key"] = aggregation_key
-
-        event_dict = {
-            "type": event_type,
-            "content": content,
-            "room_id": room_id,
-            "sender": requester.user.to_string(),
-        }
-
-        try:
-            (
-                event,
-                _,
-            ) = await self.event_creation_handler.create_and_send_nonmember_event(
-                requester, event_dict=event_dict, txn_id=txn_id
-            )
-            event_id = event.event_id
-        except ShadowBanError:
-            event_id = "$" + random_string(43)
-
-        return 200, {"event_id": event_id}
-
-
 class RelationPaginationServlet(RestServlet):
     """API to paginate relations on an event by topological ordering, optionally
     filtered by relation type and event type.
@@ -431,7 +317,6 @@ class RelationAggregationGroupPaginationServlet(RestServlet):
 
 
 def register_servlets(hs: "HomeServer", http_server: HttpServer) -> None:
-    RelationSendServlet(hs).register(http_server)
     RelationPaginationServlet(hs).register(http_server)
     RelationAggregationPaginationServlet(hs).register(http_server)
     RelationAggregationGroupPaginationServlet(hs).register(http_server)
diff --git a/tests/rest/client/test_relations.py b/tests/rest/client/test_relations.py
index c026d526ef..ff4e81d069 100644
--- a/tests/rest/client/test_relations.py
+++ b/tests/rest/client/test_relations.py
@@ -93,11 +93,6 @@ class RelationsTestCase(unittest.HomeserverTestCase):
             channel.json_body,
         )
 
-    def test_deny_membership(self):
-        """Test that we deny relations on membership events"""
-        channel = self._send_relation(RelationTypes.ANNOTATION, EventTypes.Member)
-        self.assertEquals(400, channel.code, channel.json_body)
-
     def test_deny_invalid_event(self):
         """Test that we deny relations on non-existant events"""
         channel = self._send_relation(
@@ -1119,7 +1114,8 @@ class RelationsTestCase(unittest.HomeserverTestCase):
             relation_type: One of `RelationTypes`
             event_type: The type of the event to create
             key: The aggregation key used for m.annotation relation type.
-            content: The content of the created event.
+            content: The content of the created event. Will be modified to configure
+                the m.relates_to key based on the other provided parameters.
             access_token: The access token used to send the relation, defaults
                 to `self.user_token`
             parent_id: The event_id this relation relates to. If None, then self.parent_id
@@ -1130,17 +1126,21 @@ class RelationsTestCase(unittest.HomeserverTestCase):
         if not access_token:
             access_token = self.user_token
 
-        query = ""
-        if key:
-            query = "?key=" + urllib.parse.quote_plus(key.encode("utf-8"))
-
         original_id = parent_id if parent_id else self.parent_id
 
+        if content is None:
+            content = {}
+        content["m.relates_to"] = {
+            "event_id": original_id,
+            "rel_type": relation_type,
+        }
+        if key is not None:
+            content["m.relates_to"]["key"] = key
+
         channel = self.make_request(
             "POST",
-            "/_matrix/client/unstable/rooms/%s/send_relation/%s/%s/%s%s"
-            % (self.room, original_id, relation_type, event_type, query),
-            content or {},
+            f"/_matrix/client/v3/rooms/{self.room}/send/{event_type}",
+            content,
             access_token=access_token,
         )
         return channel