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Diffstat (limited to 'synapse/handlers/pagination.py')
| -rw-r--r-- | synapse/handlers/pagination.py | 265 |
1 files changed, 265 insertions, 0 deletions
diff --git a/synapse/handlers/pagination.py b/synapse/handlers/pagination.py new file mode 100644 index 0000000000..b2849783ed --- /dev/null +++ b/synapse/handlers/pagination.py @@ -0,0 +1,265 @@ +# -*- coding: utf-8 -*- +# Copyright 2014 - 2016 OpenMarket Ltd +# Copyright 2017 - 2018 New Vector 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. +import logging + +from twisted.internet import defer +from twisted.python.failure import Failure + +from synapse.api.constants import Membership +from synapse.api.errors import SynapseError +from synapse.events.utils import serialize_event +from synapse.types import RoomStreamToken +from synapse.util.async import ReadWriteLock +from synapse.util.logcontext import run_in_background +from synapse.util.stringutils import random_string +from synapse.visibility import filter_events_for_client + +logger = logging.getLogger(__name__) + + +class PurgeStatus(object): + """Object tracking the status of a purge request + + This class contains information on the progress of a purge request, for + return by get_purge_status. + + Attributes: + status (int): Tracks whether this request has completed. One of + STATUS_{ACTIVE,COMPLETE,FAILED} + """ + + STATUS_ACTIVE = 0 + STATUS_COMPLETE = 1 + STATUS_FAILED = 2 + + STATUS_TEXT = { + STATUS_ACTIVE: "active", + STATUS_COMPLETE: "complete", + STATUS_FAILED: "failed", + } + + def __init__(self): + self.status = PurgeStatus.STATUS_ACTIVE + + def asdict(self): + return { + "status": PurgeStatus.STATUS_TEXT[self.status] + } + + +class PaginationHandler(object): + """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. + """ + + def __init__(self, hs): + self.hs = hs + self.auth = hs.get_auth() + self.store = hs.get_datastore() + self.clock = hs.get_clock() + + self.pagination_lock = ReadWriteLock() + self._purges_in_progress_by_room = set() + # map from purge id to PurgeStatus + self._purges_by_id = {} + + def start_purge_history(self, room_id, token, + delete_local_events=False): + """Start off a history purge on a room. + + Args: + room_id (str): The room to purge from + + token (str): topological token to delete events before + delete_local_events (bool): True to delete local events as well as + remote ones + + Returns: + str: unique ID for this purge transaction. + """ + if room_id in self._purges_in_progress_by_room: + raise SynapseError( + 400, + "History purge already in progress for %s" % (room_id, ), + ) + + purge_id = random_string(16) + + # we log the purge_id here so that it can be tied back to the + # request id in the log lines. + logger.info("[purge] starting purge_id %s", purge_id) + + self._purges_by_id[purge_id] = PurgeStatus() + run_in_background( + self._purge_history, + purge_id, room_id, token, delete_local_events, + ) + return purge_id + + @defer.inlineCallbacks + def _purge_history(self, purge_id, room_id, token, + delete_local_events): + """Carry out a history purge on a room. + + Args: + purge_id (str): The id for this purge + room_id (str): The room to purge from + token (str): topological token to delete events before + delete_local_events (bool): True to delete local events as well as + remote ones + + Returns: + Deferred + """ + self._purges_in_progress_by_room.add(room_id) + try: + with (yield self.pagination_lock.write(room_id)): + yield self.store.purge_history( + room_id, token, delete_local_events, + ) + logger.info("[purge] complete") + self._purges_by_id[purge_id].status = PurgeStatus.STATUS_COMPLETE + except Exception: + logger.error("[purge] failed: %s", Failure().getTraceback().rstrip()) + self._purges_by_id[purge_id].status = PurgeStatus.STATUS_FAILED + finally: + self._purges_in_progress_by_room.discard(room_id) + + # remove the purge from the list 24 hours after it completes + def clear_purge(): + del self._purges_by_id[purge_id] + self.hs.get_reactor().callLater(24 * 3600, clear_purge) + + def get_purge_status(self, purge_id): + """Get the current status of an active purge + + Args: + purge_id (str): purge_id returned by start_purge_history + + Returns: + PurgeStatus|None + """ + return self._purges_by_id.get(purge_id) + + @defer.inlineCallbacks + def get_messages(self, requester, room_id=None, pagin_config=None, + as_client_event=True, event_filter=None): + """Get messages in a room. + + Args: + requester (Requester): The user requesting messages. + room_id (str): The room they want messages from. + pagin_config (synapse.api.streams.PaginationConfig): The pagination + config rules to apply, if any. + as_client_event (bool): True to get events in client-server format. + event_filter (Filter): Filter to apply to results or None + Returns: + dict: Pagination API results + """ + user_id = requester.user.to_string() + + if pagin_config.from_token: + room_token = pagin_config.from_token.room_key + else: + pagin_config.from_token = ( + yield self.hs.get_event_sources().get_current_token_for_room( + room_id=room_id + ) + ) + room_token = pagin_config.from_token.room_key + + room_token = RoomStreamToken.parse(room_token) + + pagin_config.from_token = pagin_config.from_token.copy_and_replace( + "room_key", str(room_token) + ) + + source_config = pagin_config.get_source_config("room") + + with (yield self.pagination_lock.read(room_id)): + membership, member_event_id = yield self.auth.check_in_room_or_world_readable( + room_id, user_id + ) + + if source_config.direction == 'b': + # if we're going backwards, we might need to backfill. This + # requires that we have a topo token. + if room_token.topological: + max_topo = room_token.topological + else: + max_topo = yield self.store.get_max_topological_token( + room_id, room_token.stream + ) + + if membership == Membership.LEAVE: + # If they have left the room then clamp the token to be before + # they left the room, to save the effort of loading from the + # database. + leave_token = yield self.store.get_topological_token_for_event( + member_event_id + ) + leave_token = RoomStreamToken.parse(leave_token) + if leave_token.topological < max_topo: + source_config.from_key = str(leave_token) + + yield self.hs.get_handlers().federation_handler.maybe_backfill( + room_id, max_topo + ) + + events, next_key = yield self.store.paginate_room_events( + room_id=room_id, + from_key=source_config.from_key, + to_key=source_config.to_key, + direction=source_config.direction, + limit=source_config.limit, + event_filter=event_filter, + ) + + next_token = pagin_config.from_token.copy_and_replace( + "room_key", next_key + ) + + if not events: + defer.returnValue({ + "chunk": [], + "start": pagin_config.from_token.to_string(), + "end": next_token.to_string(), + }) + + if event_filter: + events = event_filter.filter(events) + + events = yield filter_events_for_client( + self.store, + user_id, + events, + is_peeking=(member_event_id is None), + ) + + time_now = self.clock.time_msec() + + chunk = { + "chunk": [ + serialize_event(e, time_now, as_client_event) + for e in events + ], + "start": pagin_config.from_token.to_string(), + "end": next_token.to_string(), + } + + defer.returnValue(chunk) |