Inline _do_join as it now only has one caller

Also, consistently apply rate limiting.

Again, ugly, but a step in the right direction.

synapse/handlers/room.py

@@ -492,69 +492,6 @@ class RoomMemberHandler(BaseHandler):
                 if not is_guest_access_allowed:
                     raise AuthError(403, "Guest access not allowed")
 
-            yield self._do_join(event, context, room_hosts=room_hosts)
-        else:
-            if event.membership == Membership.LEAVE:
-                is_host_in_room = yield self.is_host_in_room(room_id, context)
-                if not is_host_in_room:
-                    # Rejecting an invite, rather than leaving a joined room
-                    handler = self.hs.get_handlers().federation_handler
-                    inviter = yield self.get_inviter(event)
-                    if not inviter:
-                        # return the same error as join_room_alias does
-                        raise SynapseError(404, "No known servers")
-                    yield handler.do_remotely_reject_invite(
-                        [inviter.domain],
-                        room_id,
-                        event.user_id
-                    )
-                    defer.returnValue({"room_id": room_id})
-                    return
-
-            # FIXME: This isn't idempotency.
-            if prev_state and prev_state.membership == event.membership:
-                # double same action, treat this event as a NOOP.
-                defer.returnValue({})
-                return
-
-            yield self._do_local_membership_update(
-                event,
-                context=context,
-            )
-
-            if prev_state and prev_state.membership == Membership.JOIN:
-                user = UserID.from_string(event.user_id)
-                user_left_room(self.distributor, user, event.room_id)
-
-        defer.returnValue({"room_id": room_id})
-
-    @defer.inlineCallbacks
-    def lookup_room_alias(self, room_alias):
-        """
-        Get the room ID associated with a room alias.
-
-        Args:
-            room_alias (RoomAlias): The alias to look up.
-        Returns:
-            The room ID as a RoomID object.
-        Raises:
-            SynapseError if room alias could not be found.
-        """
-        directory_handler = self.hs.get_handlers().directory_handler
-        mapping = yield directory_handler.get_association(room_alias)
-
-        if not mapping:
-            raise SynapseError(404, "No such room alias")
-
-        room_id = mapping["room_id"]
-        hosts = mapping["servers"]
-        if not hosts:
-            raise SynapseError(404, "No known servers")
-
-        defer.returnValue((RoomID.from_string(room_id), hosts))
-
-    @defer.inlineCallbacks
-    def _do_join(self, event, context, room_hosts=None):
             room_id = event.room_id
 
             # XXX: We don't do an auth check if we are doing an invite
@@ -589,6 +526,7 @@ class RoomMemberHandler(BaseHandler):
                 yield self._do_local_membership_update(
                     event,
                     context=context,
+                    ratelimit=ratelimit,
                 )
 
             prev_state = context.current_state.get((event.type, event.state_key))
@@ -598,6 +536,66 @@ class RoomMemberHandler(BaseHandler):
                 # info.
                 user = UserID.from_string(event.user_id)
                 yield user_joined_room(self.distributor, user, room_id)
+        else:
+            if event.membership == Membership.LEAVE:
+                is_host_in_room = yield self.is_host_in_room(room_id, context)
+                if not is_host_in_room:
+                    # Rejecting an invite, rather than leaving a joined room
+                    handler = self.hs.get_handlers().federation_handler
+                    inviter = yield self.get_inviter(event)
+                    if not inviter:
+                        # return the same error as join_room_alias does
+                        raise SynapseError(404, "No known servers")
+                    yield handler.do_remotely_reject_invite(
+                        [inviter.domain],
+                        room_id,
+                        event.user_id
+                    )
+                    defer.returnValue({"room_id": room_id})
+                    return
+
+            # FIXME: This isn't idempotency.
+            if prev_state and prev_state.membership == event.membership:
+                # double same action, treat this event as a NOOP.
+                defer.returnValue({})
+                return
+
+            yield self._do_local_membership_update(
+                event,
+                context=context,
+                ratelimit=ratelimit,
+            )
+
+            if prev_state and prev_state.membership == Membership.JOIN:
+                user = UserID.from_string(event.user_id)
+                user_left_room(self.distributor, user, event.room_id)
+
+        defer.returnValue({"room_id": room_id})
+
+    @defer.inlineCallbacks
+    def lookup_room_alias(self, room_alias):
+        """
+        Get the room ID associated with a room alias.
+
+        Args:
+            room_alias (RoomAlias): The alias to look up.
+        Returns:
+            The room ID as a RoomID object.
+        Raises:
+            SynapseError if room alias could not be found.
+        """
+        directory_handler = self.hs.get_handlers().directory_handler
+        mapping = yield directory_handler.get_association(room_alias)
+
+        if not mapping:
+            raise SynapseError(404, "No such room alias")
+
+        room_id = mapping["room_id"]
+        hosts = mapping["servers"]
+        if not hosts:
+            raise SynapseError(404, "No known servers")
+
+        defer.returnValue((RoomID.from_string(room_id), hosts))
 
     @defer.inlineCallbacks
     def get_inviter(self, event):
@@ -653,7 +651,7 @@ class RoomMemberHandler(BaseHandler):
         defer.returnValue(room_ids)
 
     @defer.inlineCallbacks
-    def _do_local_membership_update(self, event, context):
+    def _do_local_membership_update(self, event, context, ratelimit=True):
         yield run_on_reactor()
 
         target_user = UserID.from_string(event.state_key)
@@ -662,6 +660,7 @@ class RoomMemberHandler(BaseHandler):
             event,
             context,
             extra_users=[target_user],
+            ratelimit=ratelimit,
         )
 
     @defer.inlineCallbacks