2 files changed, 58 insertions, 0 deletions
diff --git a/synapse/rest/admin/__init__.py b/synapse/rest/admin/__init__.py
index b1e49d51b7..9be9e33c8e 100644
--- a/synapse/rest/admin/__init__.py
+++ b/synapse/rest/admin/__init__.py
@@ -41,6 +41,7 @@ from synapse.rest.admin.event_reports import (
     EventReportsRestServlet,
 )
 from synapse.rest.admin.federation import (
+    DestinationMembershipRestServlet,
     DestinationResetConnectionRestServlet,
     DestinationRestServlet,
     ListDestinationsRestServlet,
@@ -268,6 +269,7 @@ def register_servlets(hs: "HomeServer", http_server: HttpServer) -> None:
     ListRegistrationTokensRestServlet(hs).register(http_server)
     NewRegistrationTokenRestServlet(hs).register(http_server)
     RegistrationTokenRestServlet(hs).register(http_server)
+    DestinationMembershipRestServlet(hs).register(http_server)
     DestinationResetConnectionRestServlet(hs).register(http_server)
     DestinationRestServlet(hs).register(http_server)
     ListDestinationsRestServlet(hs).register(http_server)
diff --git a/synapse/rest/admin/federation.py b/synapse/rest/admin/federation.py
index 0f33f9e4da..d162e0081e 100644
--- a/synapse/rest/admin/federation.py
+++ b/synapse/rest/admin/federation.py
@@ -148,6 +148,62 @@ class DestinationRestServlet(RestServlet):
         return HTTPStatus.OK, response
 
 
+class DestinationMembershipRestServlet(RestServlet):
+    """Get list of rooms of a destination.
+    This needs user to have administrator access in Synapse.
+
+    GET /_synapse/admin/v1/federation/destinations/<destination>/rooms?from=0&limit=10
+
+    returns:
+        200 OK with a list of rooms if success otherwise an error.
+
+    The parameters `from` and `limit` are required only for pagination.
+    By default, a `limit` of 100 is used.
+    """
+
+    PATTERNS = admin_patterns("/federation/destinations/(?P<destination>[^/]*)/rooms$")
+
+    def __init__(self, hs: "HomeServer"):
+        self._auth = hs.get_auth()
+        self._store = hs.get_datastore()
+
+    async def on_GET(
+        self, request: SynapseRequest, destination: str
+    ) -> Tuple[int, JsonDict]:
+        await assert_requester_is_admin(self._auth, request)
+
+        if not await self._store.is_destination_known(destination):
+            raise NotFoundError("Unknown destination")
+
+        start = parse_integer(request, "from", default=0)
+        limit = parse_integer(request, "limit", default=100)
+
+        if start < 0:
+            raise SynapseError(
+                HTTPStatus.BAD_REQUEST,
+                "Query parameter from must be a string representing a positive integer.",
+                errcode=Codes.INVALID_PARAM,
+            )
+
+        if limit < 0:
+            raise SynapseError(
+                HTTPStatus.BAD_REQUEST,
+                "Query parameter limit must be a string representing a positive integer.",
+                errcode=Codes.INVALID_PARAM,
+            )
+
+        direction = parse_string(request, "dir", default="f", allowed_values=("f", "b"))
+
+        rooms, total = await self._store.get_destination_rooms_paginate(
+            destination, start, limit, direction
+        )
+        response = {"rooms": rooms, "total": total}
+        if (start + limit) < total:
+            response["next_token"] = str(start + len(rooms))
+
+        return HTTPStatus.OK, response
+
+
 class DestinationResetConnectionRestServlet(RestServlet):
     """Reset destinations' connection timeouts and wake it up.
     This needs user to have administrator access in Synapse.