diff --git a/changelog.d/17322.feature b/changelog.d/17322.feature
new file mode 100644
index 0000000000..85386c2df7
--- /dev/null
+++ b/changelog.d/17322.feature
@@ -0,0 +1 @@
+Add support for via query parameter from MSC415.
diff --git a/synapse/config/experimental.py b/synapse/config/experimental.py
index 24546171e5..23e96da6a3 100644
--- a/synapse/config/experimental.py
+++ b/synapse/config/experimental.py
@@ -439,3 +439,6 @@ class ExperimentalConfig(Config):
# MSC4151: Report room API (Client-Server API)
self.msc4151_enabled: bool = experimental.get("msc4151_enabled", False)
+
+ # MSC4156: Migrate server_name to via
+ self.msc4156_enabled: bool = experimental.get("msc4156_enabled", False)
diff --git a/synapse/rest/client/knock.py b/synapse/rest/client/knock.py
index ff52a9bf8c..e31687fc13 100644
--- a/synapse/rest/client/knock.py
+++ b/synapse/rest/client/knock.py
@@ -53,6 +53,7 @@ class KnockRoomAliasServlet(RestServlet):
super().__init__()
self.room_member_handler = hs.get_room_member_handler()
self.auth = hs.get_auth()
+ self._support_via = hs.config.experimental.msc4156_enabled
async def on_POST(
self,
@@ -74,6 +75,13 @@ class KnockRoomAliasServlet(RestServlet):
remote_room_hosts = parse_strings_from_args(
args, "server_name", required=False
)
+ if self._support_via:
+ remote_room_hosts = parse_strings_from_args(
+ args,
+ "org.matrix.msc4156.via",
+ default=remote_room_hosts,
+ required=False,
+ )
elif RoomAlias.is_valid(room_identifier):
handler = self.room_member_handler
room_alias = RoomAlias.from_string(room_identifier)
diff --git a/synapse/rest/client/room.py b/synapse/rest/client/room.py
index 61fdf71a27..c98241f6ce 100644
--- a/synapse/rest/client/room.py
+++ b/synapse/rest/client/room.py
@@ -417,6 +417,7 @@ class JoinRoomAliasServlet(ResolveRoomIdMixin, TransactionRestServlet):
super().__init__(hs)
super(ResolveRoomIdMixin, self).__init__(hs) # ensure the Mixin is set up
self.auth = hs.get_auth()
+ self._support_via = hs.config.experimental.msc4156_enabled
def register(self, http_server: HttpServer) -> None:
# /join/$room_identifier[/$txn_id]
@@ -435,6 +436,13 @@ class JoinRoomAliasServlet(ResolveRoomIdMixin, TransactionRestServlet):
# twisted.web.server.Request.args is incorrectly defined as Optional[Any]
args: Dict[bytes, List[bytes]] = request.args # type: ignore
remote_room_hosts = parse_strings_from_args(args, "server_name", required=False)
+ if self._support_via:
+ remote_room_hosts = parse_strings_from_args(
+ args,
+ "org.matrix.msc4156.via",
+ default=remote_room_hosts,
+ required=False,
+ )
room_id, remote_room_hosts = await self.resolve_room_id(
room_identifier,
remote_room_hosts,
|