Split MessageHandler into read only and writers

This will let us call the read only parts from workers, and so be able
to move some APIs off of master, e.g. the `/state` API.

5 files changed, 176 insertions, 149 deletions

diff --git a/synapse/handlers/__init__.py b/synapse/handlers/__init__.py
index 4b9923d8c0..0bad3e0a2e 100644
--- a/synapse/handlers/__init__.py
+++ b/synapse/handlers/__init__.py
@@ -17,7 +17,6 @@ from .admin import AdminHandler
 from .directory import DirectoryHandler
 from .federation import FederationHandler
 from .identity import IdentityHandler
-from .message import MessageHandler
 from .register import RegistrationHandler
 from .room import RoomContextHandler
 from .search import SearchHandler
@@ -44,7 +43,6 @@ class Handlers(object):
 
     def __init__(self, hs):
         self.registration_handler = RegistrationHandler(hs)
-        self.message_handler = MessageHandler(hs)
         self.federation_handler = FederationHandler(hs)
         self.directory_handler = DirectoryHandler(hs)
         self.admin_handler = AdminHandler(hs)
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index a39b852ceb..3c6f9860d5 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -75,12 +75,159 @@ class PurgeStatus(object):
         }
 
 
-class MessageHandler(BaseHandler):
+class MessageHandler(object):
+    """Contains some read only APIs to get state about a room
+    """
 
     def __init__(self, hs):
-        super(MessageHandler, self).__init__(hs)
-        self.hs = hs
+        self.auth = hs.get_auth()
+        self.clock = hs.get_clock()
         self.state = hs.get_state_handler()
+        self.store = hs.get_datastore()
+
+    @defer.inlineCallbacks
+    def get_room_data(self, user_id=None, room_id=None,
+                      event_type=None, state_key="", is_guest=False):
+        """ Get data from a room.
+
+        Args:
+            event : The room path event
+        Returns:
+            The path data content.
+        Raises:
+            SynapseError if something went wrong.
+        """
+        membership, membership_event_id = yield self._check_in_room_or_world_readable(
+            room_id, user_id
+        )
+
+        if membership == Membership.JOIN:
+            data = yield self.state.get_current_state(
+                room_id, event_type, state_key
+            )
+        elif membership == Membership.LEAVE:
+            key = (event_type, state_key)
+            room_state = yield self.store.get_state_for_events(
+                [membership_event_id], [key]
+            )
+            data = room_state[membership_event_id].get(key)
+
+        defer.returnValue(data)
+
+    @defer.inlineCallbacks
+    def _check_in_room_or_world_readable(self, room_id, user_id):
+        try:
+            # check_user_was_in_room will return the most recent membership
+            # event for the user if:
+            #  * The user is a non-guest user, and was ever in the room
+            #  * The user is a guest user, and has joined the room
+            # else it will throw.
+            member_event = yield self.auth.check_user_was_in_room(room_id, user_id)
+            defer.returnValue((member_event.membership, member_event.event_id))
+            return
+        except AuthError:
+            visibility = yield self.state.get_current_state(
+                room_id, EventTypes.RoomHistoryVisibility, ""
+            )
+            if (
+                visibility and
+                visibility.content["history_visibility"] == "world_readable"
+            ):
+                defer.returnValue((Membership.JOIN, None))
+                return
+            raise AuthError(
+                403, "Guest access not allowed", errcode=Codes.GUEST_ACCESS_FORBIDDEN
+            )
+
+    @defer.inlineCallbacks
+    def get_state_events(self, user_id, room_id, is_guest=False):
+        """Retrieve all state events for a given room. If the user is
+        joined to the room then return the current state. If the user has
+        left the room return the state events from when they left.
+
+        Args:
+            user_id(str): The user requesting state events.
+            room_id(str): The room ID to get all state events from.
+        Returns:
+            A list of dicts representing state events. [{}, {}, {}]
+        """
+        membership, membership_event_id = yield self._check_in_room_or_world_readable(
+            room_id, user_id
+        )
+
+        if membership == Membership.JOIN:
+            room_state = yield self.state.get_current_state(room_id)
+        elif membership == Membership.LEAVE:
+            room_state = yield self.store.get_state_for_events(
+                [membership_event_id], None
+            )
+            room_state = room_state[membership_event_id]
+
+        now = self.clock.time_msec()
+        defer.returnValue(
+            [serialize_event(c, now) for c in room_state.values()]
+        )
+
+    @defer.inlineCallbacks
+    def get_joined_members(self, requester, room_id):
+        """Get all the joined members in the room and their profile information.
+
+        If the user has left the room return the state events from when they left.
+
+        Args:
+            requester(Requester): The user requesting state events.
+            room_id(str): The room ID to get all state events from.
+        Returns:
+            A dict of user_id to profile info
+        """
+        user_id = requester.user.to_string()
+        if not requester.app_service:
+            # We check AS auth after fetching the room membership, as it
+            # requires us to pull out all joined members anyway.
+            membership, _ = yield self._check_in_room_or_world_readable(
+                room_id, user_id
+            )
+            if membership != Membership.JOIN:
+                raise NotImplementedError(
+                    "Getting joined members after leaving is not implemented"
+                )
+
+        users_with_profile = yield self.state.get_current_user_in_room(room_id)
+
+        # If this is an AS, double check that they are allowed to see the members.
+        # This can either be because the AS user is in the room or because there
+        # is a user in the room that the AS is "interested in"
+        if requester.app_service and user_id not in users_with_profile:
+            for uid in users_with_profile:
+                if requester.app_service.is_interested_in_user(uid):
+                    break
+            else:
+                # Loop fell through, AS has no interested users in room
+                raise AuthError(403, "Appservice not in room")
+
+        defer.returnValue({
+            user_id: {
+                "avatar_url": profile.avatar_url,
+                "display_name": profile.display_name,
+            }
+            for user_id, profile in iteritems(users_with_profile)
+        })
+
+
+class PaginationHandler(MessageHandler):
+    """Handles pagination and purge history requests.
+
+    These are in the same handler due to the fact we need to block clients
+    paginating during a purge.
+
+    This subclasses MessageHandler to get at _check_in_room_or_world_readable
+    """
+
+    def __init__(self, hs):
+        super(PaginationHandler, self).__init__(hs)
+
+        self.hs = hs
+        self.store = hs.get_datastore()
         self.clock = hs.get_clock()
 
         self.pagination_lock = ReadWriteLock()
@@ -274,134 +421,6 @@ class MessageHandler(BaseHandler):
 
         defer.returnValue(chunk)
 
-    @defer.inlineCallbacks
-    def get_room_data(self, user_id=None, room_id=None,
-                      event_type=None, state_key="", is_guest=False):
-        """ Get data from a room.
-
-        Args:
-            event : The room path event
-        Returns:
-            The path data content.
-        Raises:
-            SynapseError if something went wrong.
-        """
-        membership, membership_event_id = yield self._check_in_room_or_world_readable(
-            room_id, user_id
-        )
-
-        if membership == Membership.JOIN:
-            data = yield self.state_handler.get_current_state(
-                room_id, event_type, state_key
-            )
-        elif membership == Membership.LEAVE:
-            key = (event_type, state_key)
-            room_state = yield self.store.get_state_for_events(
-                [membership_event_id], [key]
-            )
-            data = room_state[membership_event_id].get(key)
-
-        defer.returnValue(data)
-
-    @defer.inlineCallbacks
-    def _check_in_room_or_world_readable(self, room_id, user_id):
-        try:
-            # check_user_was_in_room will return the most recent membership
-            # event for the user if:
-            #  * The user is a non-guest user, and was ever in the room
-            #  * The user is a guest user, and has joined the room
-            # else it will throw.
-            member_event = yield self.auth.check_user_was_in_room(room_id, user_id)
-            defer.returnValue((member_event.membership, member_event.event_id))
-            return
-        except AuthError:
-            visibility = yield self.state_handler.get_current_state(
-                room_id, EventTypes.RoomHistoryVisibility, ""
-            )
-            if (
-                visibility and
-                visibility.content["history_visibility"] == "world_readable"
-            ):
-                defer.returnValue((Membership.JOIN, None))
-                return
-            raise AuthError(
-                403, "Guest access not allowed", errcode=Codes.GUEST_ACCESS_FORBIDDEN
-            )
-
-    @defer.inlineCallbacks
-    def get_state_events(self, user_id, room_id, is_guest=False):
-        """Retrieve all state events for a given room. If the user is
-        joined to the room then return the current state. If the user has
-        left the room return the state events from when they left.
-
-        Args:
-            user_id(str): The user requesting state events.
-            room_id(str): The room ID to get all state events from.
-        Returns:
-            A list of dicts representing state events. [{}, {}, {}]
-        """
-        membership, membership_event_id = yield self._check_in_room_or_world_readable(
-            room_id, user_id
-        )
-
-        if membership == Membership.JOIN:
-            room_state = yield self.state_handler.get_current_state(room_id)
-        elif membership == Membership.LEAVE:
-            room_state = yield self.store.get_state_for_events(
-                [membership_event_id], None
-            )
-            room_state = room_state[membership_event_id]
-
-        now = self.clock.time_msec()
-        defer.returnValue(
-            [serialize_event(c, now) for c in room_state.values()]
-        )
-
-    @defer.inlineCallbacks
-    def get_joined_members(self, requester, room_id):
-        """Get all the joined members in the room and their profile information.
-
-        If the user has left the room return the state events from when they left.
-
-        Args:
-            requester(Requester): The user requesting state events.
-            room_id(str): The room ID to get all state events from.
-        Returns:
-            A dict of user_id to profile info
-        """
-        user_id = requester.user.to_string()
-        if not requester.app_service:
-            # We check AS auth after fetching the room membership, as it
-            # requires us to pull out all joined members anyway.
-            membership, _ = yield self._check_in_room_or_world_readable(
-                room_id, user_id
-            )
-            if membership != Membership.JOIN:
-                raise NotImplementedError(
-                    "Getting joined members after leaving is not implemented"
-                )
-
-        users_with_profile = yield self.state.get_current_user_in_room(room_id)
-
-        # If this is an AS, double check that they are allowed to see the members.
-        # This can either be because the AS user is in the room or because there
-        # is a user in the room that the AS is "interested in"
-        if requester.app_service and user_id not in users_with_profile:
-            for uid in users_with_profile:
-                if requester.app_service.is_interested_in_user(uid):
-                    break
-            else:
-                # Loop fell through, AS has no interested users in room
-                raise AuthError(403, "Appservice not in room")
-
-        defer.returnValue({
-            user_id: {
-                "avatar_url": profile.avatar_url,
-                "display_name": profile.display_name,
-            }
-            for user_id, profile in iteritems(users_with_profile)
-        })
-
 
 class EventCreationHandler(object):
     def __init__(self, hs):
diff --git a/synapse/rest/client/v1/admin.py b/synapse/rest/client/v1/admin.py
index 2dc50e582b..13fd63a5b2 100644
--- a/synapse/rest/client/v1/admin.py
+++ b/synapse/rest/client/v1/admin.py
@@ -123,7 +123,7 @@ class PurgeHistoryRestServlet(ClientV1RestServlet):
             hs (synapse.server.HomeServer)
         """
         super(PurgeHistoryRestServlet, self).__init__(hs)
-        self.handlers = hs.get_handlers()
+        self.pagination_handler = hs.get_pagination_handler()
         self.store = hs.get_datastore()
 
     @defer.inlineCallbacks
@@ -198,7 +198,7 @@ class PurgeHistoryRestServlet(ClientV1RestServlet):
                 errcode=Codes.BAD_JSON,
             )
 
-        purge_id = yield self.handlers.message_handler.start_purge_history(
+        purge_id = yield self.pagination_handler.start_purge_history(
             room_id, token,
             delete_local_events=delete_local_events,
         )
@@ -220,7 +220,7 @@ class PurgeHistoryStatusRestServlet(ClientV1RestServlet):
             hs (synapse.server.HomeServer)
         """
         super(PurgeHistoryStatusRestServlet, self).__init__(hs)
-        self.handlers = hs.get_handlers()
+        self.pagination_handler = hs.get_pagination_handler()
 
     @defer.inlineCallbacks
     def on_GET(self, request, purge_id):
@@ -230,7 +230,7 @@ class PurgeHistoryStatusRestServlet(ClientV1RestServlet):
         if not is_admin:
             raise AuthError(403, "You are not a server admin")
 
-        purge_status = self.handlers.message_handler.get_purge_status(purge_id)
+        purge_status = self.pagination_handler.get_purge_status(purge_id)
         if purge_status is None:
             raise NotFoundError("purge id '%s' not found" % purge_id)
 
diff --git a/synapse/rest/client/v1/room.py b/synapse/rest/client/v1/room.py
index 3d62447854..8b6be9da96 100644
--- a/synapse/rest/client/v1/room.py
+++ b/synapse/rest/client/v1/room.py
@@ -90,6 +90,7 @@ class RoomStateEventRestServlet(ClientV1RestServlet):
         self.handlers = hs.get_handlers()
         self.event_creation_hander = hs.get_event_creation_handler()
         self.room_member_handler = hs.get_room_member_handler()
+        self.message_handler = hs.get_message_handler()
 
     def register(self, http_server):
         # /room/$roomid/state/$eventtype
@@ -124,7 +125,7 @@ class RoomStateEventRestServlet(ClientV1RestServlet):
         format = parse_string(request, "format", default="content",
                               allowed_values=["content", "event"])
 
-        msg_handler = self.handlers.message_handler
+        msg_handler = self.message_handler
         data = yield msg_handler.get_room_data(
             user_id=requester.user.to_string(),
             room_id=room_id,
@@ -377,14 +378,13 @@ class RoomMemberListRestServlet(ClientV1RestServlet):
 
     def __init__(self, hs):
         super(RoomMemberListRestServlet, self).__init__(hs)
-        self.handlers = hs.get_handlers()
+        self.message_handler = hs.get_message_handler()
 
     @defer.inlineCallbacks
     def on_GET(self, request, room_id):
         # TODO support Pagination stream API (limit/tokens)
         requester = yield self.auth.get_user_by_req(request)
-        handler = self.handlers.message_handler
-        events = yield handler.get_state_events(
+        events = yield self.message_handler.get_state_events(
             room_id=room_id,
             user_id=requester.user.to_string(),
         )
@@ -406,7 +406,7 @@ class JoinedRoomMemberListRestServlet(ClientV1RestServlet):
 
     def __init__(self, hs):
         super(JoinedRoomMemberListRestServlet, self).__init__(hs)
-        self.message_handler = hs.get_handlers().message_handler
+        self.message_handler = hs.get_message_handler()
 
     @defer.inlineCallbacks
     def on_GET(self, request, room_id):
@@ -427,7 +427,7 @@ class RoomMessageListRestServlet(ClientV1RestServlet):
 
     def __init__(self, hs):
         super(RoomMessageListRestServlet, self).__init__(hs)
-        self.handlers = hs.get_handlers()
+        self.pagination_handler = hs.get_pagination_handler()
 
     @defer.inlineCallbacks
     def on_GET(self, request, room_id):
@@ -442,8 +442,7 @@ class RoomMessageListRestServlet(ClientV1RestServlet):
             event_filter = Filter(json.loads(filter_json))
         else:
             event_filter = None
-        handler = self.handlers.message_handler
-        msgs = yield handler.get_messages(
+        msgs = yield self.pagination_handler.get_messages(
             room_id=room_id,
             requester=requester,
             pagin_config=pagination_config,
@@ -460,14 +459,13 @@ class RoomStateRestServlet(ClientV1RestServlet):
 
     def __init__(self, hs):
         super(RoomStateRestServlet, self).__init__(hs)
-        self.handlers = hs.get_handlers()
+        self.message_handler = hs.get_message_handler()
 
     @defer.inlineCallbacks
     def on_GET(self, request, room_id):
         requester = yield self.auth.get_user_by_req(request, allow_guest=True)
-        handler = self.handlers.message_handler
         # Get all the current state for this room
-        events = yield handler.get_state_events(
+        events = yield self.message_handler.get_state_events(
             room_id=room_id,
             user_id=requester.user.to_string(),
             is_guest=requester.is_guest,
diff --git a/synapse/server.py b/synapse/server.py
index 92bea96c5c..b93bd6d7d9 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -52,7 +52,11 @@ from synapse.handlers.e2e_keys import E2eKeysHandler
 from synapse.handlers.events import EventHandler, EventStreamHandler
 from synapse.handlers.groups_local import GroupsLocalHandler
 from synapse.handlers.initial_sync import InitialSyncHandler
-from synapse.handlers.message import EventCreationHandler
+from synapse.handlers.message import (
+    EventCreationHandler,
+    MessageHandler,
+    PaginationHandler,
+)
 from synapse.handlers.presence import PresenceHandler
 from synapse.handlers.profile import ProfileHandler
 from synapse.handlers.read_marker import ReadMarkerHandler
@@ -163,6 +167,8 @@ class HomeServer(object):
         'federation_registry',
         'server_notices_manager',
         'server_notices_sender',
+        'message_handler',
+        'pagination_handler',
     ]
 
     def __init__(self, hostname, reactor=None, **kwargs):
@@ -426,6 +432,12 @@ class HomeServer(object):
             return WorkerServerNoticesSender(self)
         return ServerNoticesSender(self)
 
+    def build_message_handler(self):
+        return MessageHandler(self)
+
+    def build_pagination_handler(self):
+        return PaginationHandler(self)
+
     def remove_pusher(self, app_id, push_key, user_id):
         return self.get_pusherpool().remove_pusher(app_id, push_key, user_id)