Add an unstable servlet, gated behind experimental config flag

Author: anoadragon453

synapse/config/experimental.py

@@ -556,6 +556,9 @@ def read_config(
         # MSC4133: Custom profile fields
         self.msc4133_enabled: bool = experimental.get("msc4133_enabled", False)
 
+        # MSC4143: Matrix RTC Transport using Livekit Backend
+        self.msc4143_enabled: bool = experimental.get("msc4143_enabled", False)
+
         # MSC4169: Backwards-compatible redaction sending using `/send`
         self.msc4169_enabled: bool = experimental.get("msc4169_enabled", False)
 

synapse/rest/__init__.py

@@ -42,6 +42,7 @@
     login,
     login_token_request,
     logout,
+    matrixrtc,
     mutual_rooms,
     notifications,
     openid,
@@ -89,6 +90,7 @@
     presence.register_servlets,
     directory.register_servlets,
     voip.register_servlets,
+    matrixrtc.register_servlets,
     pusher.register_servlets,
     push_rule.register_servlets,
     logout.register_servlets,

synapse/rest/client/matrixrtc.py

@@ -0,0 +1,52 @@
+#
+# This file is licensed under the Affero General Public License (AGPL) version 3.
+#
+# Copyright (C) 2025 New Vector, Ltd
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# See the GNU Affero General Public License for more details:
+# <https://www.gnu.org/licenses/agpl-3.0.html>.
+#
+# [This file includes modifications made by New Vector Limited]
+#
+#
+
+from typing import TYPE_CHECKING, Tuple
+
+from synapse.http.server import HttpServer
+from synapse.http.servlet import RestServlet
+from synapse.http.site import SynapseRequest
+from synapse.rest.client._base import client_patterns
+from synapse.types import JsonDict
+
+if TYPE_CHECKING:
+    from synapse.server import HomeServer
+
+
+class MatrixRTCRestServlet(RestServlet):
+    PATTERNS = client_patterns(r"/org\.matrix\.msc4143/rtc/transports$", releases=())
+    CATEGORY = "Client API requests"
+
+    def __init__(self, hs: "HomeServer"):
+        super().__init__()
+        self._hs = hs
+        self._auth = hs.get_auth()
+        self._transports = hs.config.matrix_rtc.transports
+
+    async def on_GET(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
+        # Require authentication for this endpoint.
+        await self._auth.get_user_by_req(request)
+
+        if self._transports:
+            return 200, {"rtc_transports": self._transports}
+
+        return 200, {}
+
+
+def register_servlets(hs: "HomeServer", http_server: HttpServer) -> None:
+    if hs.config.experimental.msc4143_enabled:
+        MatrixRTCRestServlet(hs).register(http_server)