Support pagination API in client_reader worker

changelog.d/5505.feature

@@ -0,0 +1 @@
+Add support for handling pagination APIs on client reader worker.

docs/workers.rst

@@ -239,6 +239,13 @@ be routed to the same instance::
 
     ^/_matrix/client/(r0|unstable)/register$
 
+Pagination requests can also be handled, but all requests with the same path
+room must be routed to the same instance. Additionally, care must be taken to
+ensure that the purge history admin API is not used while pagination requests
+for the room are not in flight::
+
+    ^/_matrix/client/(api/v1|r0|unstable)/rooms/.*/messages$
+
 
 ``synapse.app.user_dir``
 ~~~~~~~~~~~~~~~~~~~~~~~~

synapse/app/client_reader.py

@@ -52,6 +52,7 @@
     PublicRoomListRestServlet,
     RoomEventContextServlet,
     RoomMemberListRestServlet,
+    RoomMessageListRestServlet,
     RoomStateRestServlet,
 )
 from synapse.rest.client.v1.voip import VoipRestServlet
@@ -109,6 +110,7 @@ def _listen_http(self, listener_config):
                     JoinedRoomMemberListRestServlet(self).register(resource)
                     RoomStateRestServlet(self).register(resource)
                     RoomEventContextServlet(self).register(resource)
+                    RoomMessageListRestServlet(self).register(resource)
                     RegisterRestServlet(self).register(resource)
                     LoginRestServlet(self).register(resource)
                     ThreepidRestServlet(self).register(resource)