Allow enabling sliding sync per-user (#17393)

Based on #17392

2 files changed, 13 insertions, 5 deletions

diff --git a/synapse/rest/admin/experimental_features.py b/synapse/rest/admin/experimental_features.py
index c1559c92f7..d7913896d9 100644
--- a/synapse/rest/admin/experimental_features.py
+++ b/synapse/rest/admin/experimental_features.py
@@ -42,10 +42,13 @@ class ExperimentalFeature(str, Enum):
     """
 
     MSC3881 = "msc3881"
+    MSC3575 = "msc3575"
 
     def is_globally_enabled(self, config: "HomeServerConfig") -> bool:
         if self is ExperimentalFeature.MSC3881:
             return config.experimental.msc3881_enabled
+        if self is ExperimentalFeature.MSC3575:
+            return config.experimental.msc3575_enabled
 
         assert_never(self)
 
diff --git a/synapse/rest/client/sync.py b/synapse/rest/client/sync.py
index e52e771538..2a22bc14ec 100644
--- a/synapse/rest/client/sync.py
+++ b/synapse/rest/client/sync.py
@@ -53,6 +53,7 @@ from synapse.http.servlet import (
 )
 from synapse.http.site import SynapseRequest
 from synapse.logging.opentracing import trace_with_opname
+from synapse.rest.admin.experimental_features import ExperimentalFeature
 from synapse.types import JsonDict, Requester, StreamToken
 from synapse.types.rest.client import SlidingSyncBody
 from synapse.util import json_decoder
@@ -673,7 +674,9 @@ class SlidingSyncE2eeRestServlet(RestServlet):
         )
 
     async def on_GET(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
-        requester = await self.auth.get_user_by_req(request, allow_guest=True)
+        requester = await self.auth.get_user_by_req_experimental_feature(
+            request, allow_guest=True, feature=ExperimentalFeature.MSC3575
+        )
         user = requester.user
         device_id = requester.device_id
 
@@ -873,7 +876,10 @@ class SlidingSyncRestServlet(RestServlet):
         self.event_serializer = hs.get_event_client_serializer()
 
     async def on_POST(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
-        requester = await self.auth.get_user_by_req(request, allow_guest=True)
+        requester = await self.auth.get_user_by_req_experimental_feature(
+            request, allow_guest=True, feature=ExperimentalFeature.MSC3575
+        )
+
         user = requester.user
         device_id = requester.device_id
 
@@ -1051,6 +1057,5 @@ class SlidingSyncRestServlet(RestServlet):
 def register_servlets(hs: "HomeServer", http_server: HttpServer) -> None:
     SyncRestServlet(hs).register(http_server)
 
-    if hs.config.experimental.msc3575_enabled:
-        SlidingSyncRestServlet(hs).register(http_server)
-        SlidingSyncE2eeRestServlet(hs).register(http_server)
+    SlidingSyncRestServlet(hs).register(http_server)
+    SlidingSyncE2eeRestServlet(hs).register(http_server)