1 files changed, 3 insertions, 5 deletions
diff --git a/synapse/rest/admin/rooms.py b/synapse/rest/admin/rooms.py
index 25f89e4685..9f01cb20cd 100644
--- a/synapse/rest/admin/rooms.py
+++ b/synapse/rest/admin/rooms.py
@@ -14,7 +14,6 @@
 # limitations under the License.
 import logging
 from http import HTTPStatus
-from typing import List, Optional
 
 from synapse.api.constants import EventTypes, JoinRules
 from synapse.api.errors import Codes, NotFoundError, SynapseError
@@ -23,6 +22,7 @@ from synapse.http.servlet import (
     assert_params_in_dict,
     parse_integer,
     parse_json_object_from_request,
+    parse_list_from_args,
     parse_string,
 )
 from synapse.rest.admin._base import (
@@ -305,10 +305,8 @@ class JoinRoomAliasServlet(RestServlet):
         if RoomID.is_valid(room_identifier):
             room_id = room_identifier
             try:
-                remote_room_hosts = [
-                    x.decode("ascii") for x in request.args[b"server_name"]
-                ]  # type: Optional[List[str]]
-            except Exception:
+                remote_room_hosts = parse_list_from_args(request.args, "server_name")
+            except KeyError:
                 remote_room_hosts = None
         elif RoomAlias.is_valid(room_identifier):
             handler = self.room_member_handler