Merge pull request #41 from matrix-org/client_v2_sync

Client v2 sync

1 files changed, 434 insertions, 0 deletions

diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
new file mode 100644
index 0000000000..dc69b3cfe7
--- /dev/null
+++ b/synapse/handlers/sync.py
@@ -0,0 +1,434 @@
+# -*- coding: utf-8 -*-
+# Copyright 2015 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from ._base import BaseHandler
+
+from synapse.streams.config import PaginationConfig
+from synapse.api.constants import Membership, EventTypes
+
+from twisted.internet import defer
+
+import collections
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+SyncConfig = collections.namedtuple("SyncConfig", [
+    "user",
+    "client_info",
+    "limit",
+    "gap",
+    "sort",
+    "backfill",
+    "filter",
+])
+
+
+class RoomSyncResult(collections.namedtuple("RoomSyncResult", [
+    "room_id",
+    "limited",
+    "published",
+    "events",
+    "state",
+    "prev_batch",
+    "ephemeral",
+])):
+    __slots__ = []
+
+    def __nonzero__(self):
+        """Make the result appear empty if there are no updates. This is used
+        to tell if room needs to be part of the sync result.
+        """
+        return bool(self.events or self.state or self.ephemeral)
+
+
+class SyncResult(collections.namedtuple("SyncResult", [
+    "next_batch",  # Token for the next sync
+    "private_user_data",  # List of private events for the user.
+    "public_user_data",  # List of public events for all users.
+    "rooms",  # RoomSyncResult for each room.
+])):
+    __slots__ = []
+
+    def __nonzero__(self):
+        """Make the result appear empty if there are no updates. This is used
+        to tell if the notifier needs to wait for more events when polling for
+        events.
+        """
+        return bool(
+            self.private_user_data or self.public_user_data or self.rooms
+        )
+
+
+class SyncHandler(BaseHandler):
+
+    def __init__(self, hs):
+        super(SyncHandler, self).__init__(hs)
+        self.event_sources = hs.get_event_sources()
+        self.clock = hs.get_clock()
+
+    @defer.inlineCallbacks
+    def wait_for_sync_for_user(self, sync_config, since_token=None, timeout=0):
+        """Get the sync for a client if we have new data for it now. Otherwise
+        wait for new data to arrive on the server. If the timeout expires, then
+        return an empty sync result.
+        Returns:
+            A Deferred SyncResult.
+        """
+        if timeout == 0 or since_token is None:
+            result = yield self.current_sync_for_user(sync_config, since_token)
+            defer.returnValue(result)
+        else:
+            def current_sync_callback():
+                return self.current_sync_for_user(sync_config, since_token)
+
+            rm_handler = self.hs.get_handlers().room_member_handler
+            room_ids = yield rm_handler.get_rooms_for_user(sync_config.user)
+            result = yield self.notifier.wait_for_events(
+                sync_config.user, room_ids,
+                sync_config.filter, timeout, current_sync_callback
+            )
+            defer.returnValue(result)
+
+    def current_sync_for_user(self, sync_config, since_token=None):
+        """Get the sync for client needed to match what the server has now.
+        Returns:
+            A Deferred SyncResult.
+        """
+        if since_token is None:
+            return self.initial_sync(sync_config)
+        else:
+            if sync_config.gap:
+                return self.incremental_sync_with_gap(sync_config, since_token)
+            else:
+                #TODO(mjark): Handle gapless sync
+                raise NotImplementedError()
+
+    @defer.inlineCallbacks
+    def initial_sync(self, sync_config):
+        """Get a sync for a client which is starting without any state
+        Returns:
+            A Deferred SyncResult.
+        """
+        if sync_config.sort == "timeline,desc":
+            # TODO(mjark): Handle going through events in reverse order?.
+            # What does "most recent events" mean when applying the limits mean
+            # in this case?
+            raise NotImplementedError()
+
+        now_token = yield self.event_sources.get_current_token()
+
+        presence_stream = self.event_sources.sources["presence"]
+        # TODO (mjark): This looks wrong, shouldn't we be getting the presence
+        # UP to the present rather than after the present?
+        pagination_config = PaginationConfig(from_token=now_token)
+        presence, _ = yield presence_stream.get_pagination_rows(
+            user=sync_config.user,
+            pagination_config=pagination_config.get_source_config("presence"),
+            key=None
+        )
+        room_list = yield self.store.get_rooms_for_user_where_membership_is(
+            user_id=sync_config.user.to_string(),
+            membership_list=[Membership.INVITE, Membership.JOIN]
+        )
+
+        # TODO (mjark): Does public mean "published"?
+        published_rooms = yield self.store.get_rooms(is_public=True)
+        published_room_ids = set(r["room_id"] for r in published_rooms)
+
+        rooms = []
+        for event in room_list:
+            room_sync = yield self.initial_sync_for_room(
+                event.room_id, sync_config, now_token, published_room_ids
+            )
+            rooms.append(room_sync)
+
+        defer.returnValue(SyncResult(
+            public_user_data=presence,
+            private_user_data=[],
+            rooms=rooms,
+            next_batch=now_token,
+        ))
+
+    @defer.inlineCallbacks
+    def initial_sync_for_room(self, room_id, sync_config, now_token,
+                              published_room_ids):
+        """Sync a room for a client which is starting without any state
+        Returns:
+            A Deferred RoomSyncResult.
+        """
+
+        recents, prev_batch_token, limited = yield self.load_filtered_recents(
+            room_id, sync_config, now_token,
+        )
+
+        current_state_events = yield self.state_handler.get_current_state(
+            room_id
+        )
+
+        defer.returnValue(RoomSyncResult(
+            room_id=room_id,
+            published=room_id in published_room_ids,
+            events=recents,
+            prev_batch=prev_batch_token,
+            state=current_state_events,
+            limited=limited,
+            ephemeral=[],
+        ))
+
+    @defer.inlineCallbacks
+    def incremental_sync_with_gap(self, sync_config, since_token):
+        """ Get the incremental delta needed to bring the client up to
+        date with the server.
+        Returns:
+            A Deferred SyncResult.
+        """
+        if sync_config.sort == "timeline,desc":
+            # TODO(mjark): Handle going through events in reverse order?.
+            # What does "most recent events" mean when applying the limits mean
+            # in this case?
+            raise NotImplementedError()
+
+        now_token = yield self.event_sources.get_current_token()
+
+        presence_source = self.event_sources.sources["presence"]
+        presence, presence_key = yield presence_source.get_new_events_for_user(
+            user=sync_config.user,
+            from_key=since_token.presence_key,
+            limit=sync_config.limit,
+        )
+        now_token = now_token.copy_and_replace("presence_key", presence_key)
+
+        typing_source = self.event_sources.sources["typing"]
+        typing, typing_key = yield typing_source.get_new_events_for_user(
+            user=sync_config.user,
+            from_key=since_token.typing_key,
+            limit=sync_config.limit,
+        )
+        now_token = now_token.copy_and_replace("typing_key", typing_key)
+
+        typing_by_room = {event["room_id"]: [event] for event in typing}
+        for event in typing:
+            event.pop("room_id")
+        logger.debug("Typing %r", typing_by_room)
+
+        rm_handler = self.hs.get_handlers().room_member_handler
+        room_ids = yield rm_handler.get_rooms_for_user(sync_config.user)
+
+        # TODO (mjark): Does public mean "published"?
+        published_rooms = yield self.store.get_rooms(is_public=True)
+        published_room_ids = set(r["room_id"] for r in published_rooms)
+
+        room_events, _ = yield self.store.get_room_events_stream(
+            sync_config.user.to_string(),
+            from_key=since_token.room_key,
+            to_key=now_token.room_key,
+            room_id=None,
+            limit=sync_config.limit + 1,
+        )
+
+        rooms = []
+        if len(room_events) <= sync_config.limit:
+            # There is no gap in any of the rooms. Therefore we can just
+            # partition the new events by room and return them.
+            events_by_room_id = {}
+            for event in room_events:
+                events_by_room_id.setdefault(event.room_id, []).append(event)
+
+            for room_id in room_ids:
+                recents = events_by_room_id.get(room_id, [])
+                state = [event for event in recents if event.is_state()]
+                if recents:
+                    prev_batch = now_token.copy_and_replace(
+                        "room_key", recents[0].internal_metadata.before
+                    )
+                else:
+                    prev_batch = now_token
+
+                state = yield self.check_joined_room(
+                    sync_config, room_id, state
+                )
+
+                room_sync = RoomSyncResult(
+                    room_id=room_id,
+                    published=room_id in published_room_ids,
+                    events=recents,
+                    prev_batch=prev_batch,
+                    state=state,
+                    limited=False,
+                    ephemeral=typing_by_room.get(room_id, [])
+                )
+                if room_sync:
+                    rooms.append(room_sync)
+        else:
+            for room_id in room_ids:
+                room_sync = yield self.incremental_sync_with_gap_for_room(
+                    room_id, sync_config, since_token, now_token,
+                    published_room_ids, typing_by_room
+                )
+                if room_sync:
+                    rooms.append(room_sync)
+
+        defer.returnValue(SyncResult(
+            public_user_data=presence,
+            private_user_data=[],
+            rooms=rooms,
+            next_batch=now_token,
+        ))
+
+    @defer.inlineCallbacks
+    def load_filtered_recents(self, room_id, sync_config, now_token,
+                              since_token=None):
+        limited = True
+        recents = []
+        filtering_factor = 2
+        load_limit = max(sync_config.limit * filtering_factor, 100)
+        max_repeat = 3  # Only try a few times per room, otherwise
+        room_key = now_token.room_key
+
+        while limited and len(recents) < sync_config.limit and max_repeat:
+            events, keys = yield self.store.get_recent_events_for_room(
+                room_id,
+                limit=load_limit + 1,
+                from_token=since_token.room_key if since_token else None,
+                end_token=room_key,
+            )
+            (room_key, _) = keys
+            loaded_recents = sync_config.filter.filter_room_events(events)
+            loaded_recents.extend(recents)
+            recents = loaded_recents
+            if len(events) <= load_limit:
+                limited = False
+            max_repeat -= 1
+
+        if len(recents) > sync_config.limit:
+            recents = recents[-sync_config.limit:]
+            room_key = recents[0].internal_metadata.before
+
+        prev_batch_token = now_token.copy_and_replace(
+            "room_key", room_key
+        )
+
+        defer.returnValue((recents, prev_batch_token, limited))
+
+    @defer.inlineCallbacks
+    def incremental_sync_with_gap_for_room(self, room_id, sync_config,
+                                           since_token, now_token,
+                                           published_room_ids, typing_by_room):
+        """ Get the incremental delta needed to bring the client up to date for
+        the room. Gives the client the most recent events and the changes to
+        state.
+        Returns:
+            A Deferred RoomSyncResult
+        """
+
+        # TODO(mjark): Check for redactions we might have missed.
+
+        recents, prev_batch_token, limited = yield self.load_filtered_recents(
+            room_id, sync_config, now_token, since_token,
+        )
+
+        logging.debug("Recents %r", recents)
+
+        # TODO(mjark): This seems racy since this isn't being passed a
+        # token to indicate what point in the stream this is
+        current_state_events = yield self.state_handler.get_current_state(
+            room_id
+        )
+
+        state_at_previous_sync = yield self.get_state_at_previous_sync(
+            room_id, since_token=since_token
+        )
+
+        state_events_delta = yield self.compute_state_delta(
+            since_token=since_token,
+            previous_state=state_at_previous_sync,
+            current_state=current_state_events,
+        )
+
+        state_events_delta = yield self.check_joined_room(
+            sync_config, room_id, state_events_delta
+        )
+
+        room_sync = RoomSyncResult(
+            room_id=room_id,
+            published=room_id in published_room_ids,
+            events=recents,
+            prev_batch=prev_batch_token,
+            state=state_events_delta,
+            limited=limited,
+            ephemeral=typing_by_room.get(room_id, None)
+        )
+
+        logging.debug("Room sync: %r", room_sync)
+
+        defer.returnValue(room_sync)
+
+    @defer.inlineCallbacks
+    def get_state_at_previous_sync(self, room_id, since_token):
+        """ Get the room state at the previous sync the client made.
+        Returns:
+            A Deferred list of Events.
+        """
+        last_events, token = yield self.store.get_recent_events_for_room(
+            room_id, end_token=since_token.room_key, limit=1,
+        )
+
+        if last_events:
+            last_event = last_events[0]
+            last_context = yield self.state_handler.compute_event_context(
+                last_event
+            )
+            if last_event.is_state():
+                state = [last_event] + last_context.current_state.values()
+            else:
+                state = last_context.current_state.values()
+        else:
+            state = ()
+        defer.returnValue(state)
+
+    def compute_state_delta(self, since_token, previous_state, current_state):
+        """ Works out the differnce in state between the current state and the
+        state the client got when it last performed a sync.
+        Returns:
+            A list of events.
+        """
+        # TODO(mjark) Check if the state events were received by the server
+        # after the previous sync, since we need to include those state
+        # updates even if they occured logically before the previous event.
+        # TODO(mjark) Check for new redactions in the state events.
+        previous_dict = {event.event_id: event for event in previous_state}
+        state_delta = []
+        for event in current_state:
+            if event.event_id not in previous_dict:
+                state_delta.append(event)
+        return state_delta
+
+    @defer.inlineCallbacks
+    def check_joined_room(self, sync_config, room_id, state_delta):
+        joined = False
+        for event in state_delta:
+            if (
+                event.type == EventTypes.Member
+                and event.state_key == sync_config.user.to_string()
+            ):
+                if event.content["membership"] == Membership.JOIN:
+                    joined = True
+
+        if joined:
+            state_delta = yield self.state_handler.get_current_state(room_id)
+
+        defer.returnValue(state_delta)