diff --git a/synapse/federation/transport/server/federation.py b/synapse/federation/transport/server/federation.py
index 66e915228c..77bfd88ad0 100644
--- a/synapse/federation/transport/server/federation.py
+++ b/synapse/federation/transport/server/federation.py
@@ -174,6 +174,46 @@ class FederationBackfillServlet(BaseFederationServerServlet):
return await self.handler.on_backfill_request(origin, room_id, versions, limit)
+class FederationTimestampLookupServlet(BaseFederationServerServlet):
+ """
+ API endpoint to fetch the `event_id` of the closest event to the given
+ timestamp (`ts` query parameter) in the given direction (`dir` query
+ parameter).
+
+ Useful for other homeservers when they're unable to find an event locally.
+
+ `ts` is a timestamp in milliseconds where we will find the closest event in
+ the given direction.
+
+ `dir` can be `f` or `b` to indicate forwards and backwards in time from the
+ given timestamp.
+
+ GET /_matrix/federation/unstable/org.matrix.msc3030/timestamp_to_event/<roomID>?ts=<timestamp>&dir=<direction>
+ {
+ "event_id": ...
+ }
+ """
+
+ PATH = "/timestamp_to_event/(?P<room_id>[^/]*)/?"
+ PREFIX = FEDERATION_UNSTABLE_PREFIX + "/org.matrix.msc3030"
+
+ async def on_GET(
+ self,
+ origin: str,
+ content: Literal[None],
+ query: Dict[bytes, List[bytes]],
+ room_id: str,
+ ) -> Tuple[int, JsonDict]:
+ timestamp = parse_integer_from_args(query, "ts", required=True)
+ direction = parse_string_from_args(
+ query, "dir", default="f", allowed_values=["f", "b"], required=True
+ )
+
+ return await self.handler.on_timestamp_to_event_request(
+ origin, room_id, timestamp, direction
+ )
+
+
class FederationQueryServlet(BaseFederationServerServlet):
PATH = "/query/(?P<query_type>[^/]*)"
@@ -683,6 +723,7 @@ FEDERATION_SERVLET_CLASSES: Tuple[Type[BaseFederationServlet], ...] = (
FederationStateV1Servlet,
FederationStateIdsServlet,
FederationBackfillServlet,
+ FederationTimestampLookupServlet,
FederationQueryServlet,
FederationMakeJoinServlet,
FederationMakeLeaveServlet,
|
