524 lines
19 KiB
Python
524 lines
19 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2014 - 2016 OpenMarket Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import logging
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from collections import namedtuple
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from prometheus_client import Counter
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from twisted.internet import defer
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from synapse.api.constants import EventTypes, Membership
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from synapse.api.errors import AuthError
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from synapse.handlers.presence import format_user_presence_state
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from synapse.logging.context import PreserveLoggingContext
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from synapse.logging.utils import log_function
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from synapse.metrics import LaterGauge
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from synapse.metrics.background_process_metrics import run_as_background_process
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from synapse.types import StreamToken
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from synapse.util.async_helpers import ObservableDeferred, timeout_deferred
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from synapse.util.metrics import Measure
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from synapse.visibility import filter_events_for_client
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logger = logging.getLogger(__name__)
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notified_events_counter = Counter("synapse_notifier_notified_events", "")
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users_woken_by_stream_counter = Counter(
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"synapse_notifier_users_woken_by_stream", "", ["stream"]
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)
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# TODO(paul): Should be shared somewhere
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def count(func, l):
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"""Return the number of items in l for which func returns true."""
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n = 0
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for x in l:
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if func(x):
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n += 1
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return n
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class _NotificationListener(object):
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""" This represents a single client connection to the events stream.
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The events stream handler will have yielded to the deferred, so to
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notify the handler it is sufficient to resolve the deferred.
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"""
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__slots__ = ["deferred"]
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def __init__(self, deferred):
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self.deferred = deferred
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class _NotifierUserStream(object):
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"""This represents a user connected to the event stream.
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It tracks the most recent stream token for that user.
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At a given point a user may have a number of streams listening for
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events.
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This listener will also keep track of which rooms it is listening in
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so that it can remove itself from the indexes in the Notifier class.
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"""
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def __init__(self, user_id, rooms, current_token, time_now_ms):
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self.user_id = user_id
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self.rooms = set(rooms)
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self.current_token = current_token
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# The last token for which we should wake up any streams that have a
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# token that comes before it. This gets updated everytime we get poked.
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# We start it at the current token since if we get any streams
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# that have a token from before we have no idea whether they should be
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# woken up or not, so lets just wake them up.
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self.last_notified_token = current_token
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self.last_notified_ms = time_now_ms
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with PreserveLoggingContext():
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self.notify_deferred = ObservableDeferred(defer.Deferred())
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def notify(self, stream_key, stream_id, time_now_ms):
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"""Notify any listeners for this user of a new event from an
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event source.
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Args:
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stream_key(str): The stream the event came from.
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stream_id(str): The new id for the stream the event came from.
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time_now_ms(int): The current time in milliseconds.
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"""
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self.current_token = self.current_token.copy_and_advance(stream_key, stream_id)
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self.last_notified_token = self.current_token
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self.last_notified_ms = time_now_ms
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noify_deferred = self.notify_deferred
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users_woken_by_stream_counter.labels(stream_key).inc()
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with PreserveLoggingContext():
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self.notify_deferred = ObservableDeferred(defer.Deferred())
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noify_deferred.callback(self.current_token)
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def remove(self, notifier):
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""" Remove this listener from all the indexes in the Notifier
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it knows about.
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"""
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for room in self.rooms:
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lst = notifier.room_to_user_streams.get(room, set())
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lst.discard(self)
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notifier.user_to_user_stream.pop(self.user_id)
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def count_listeners(self):
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return len(self.notify_deferred.observers())
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def new_listener(self, token):
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"""Returns a deferred that is resolved when there is a new token
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greater than the given token.
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Args:
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token: The token from which we are streaming from, i.e. we shouldn't
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notify for things that happened before this.
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"""
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# Immediately wake up stream if something has already since happened
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# since their last token.
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if self.last_notified_token.is_after(token):
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return _NotificationListener(defer.succeed(self.current_token))
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else:
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return _NotificationListener(self.notify_deferred.observe())
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class EventStreamResult(namedtuple("EventStreamResult", ("events", "tokens"))):
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def __nonzero__(self):
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return bool(self.events)
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__bool__ = __nonzero__ # python3
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class Notifier(object):
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""" This class is responsible for notifying any listeners when there are
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new events available for it.
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Primarily used from the /events stream.
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"""
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UNUSED_STREAM_EXPIRY_MS = 10 * 60 * 1000
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def __init__(self, hs):
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self.user_to_user_stream = {}
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self.room_to_user_streams = {}
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self.hs = hs
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self.event_sources = hs.get_event_sources()
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self.store = hs.get_datastore()
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self.pending_new_room_events = []
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self.replication_callbacks = []
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self.clock = hs.get_clock()
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self.appservice_handler = hs.get_application_service_handler()
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if hs.should_send_federation():
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self.federation_sender = hs.get_federation_sender()
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else:
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self.federation_sender = None
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self.state_handler = hs.get_state_handler()
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self.clock.looping_call(
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self.remove_expired_streams, self.UNUSED_STREAM_EXPIRY_MS
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)
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# This is not a very cheap test to perform, but it's only executed
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# when rendering the metrics page, which is likely once per minute at
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# most when scraping it.
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def count_listeners():
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all_user_streams = set()
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for x in list(self.room_to_user_streams.values()):
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all_user_streams |= x
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for x in list(self.user_to_user_stream.values()):
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all_user_streams.add(x)
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return sum(stream.count_listeners() for stream in all_user_streams)
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LaterGauge("synapse_notifier_listeners", "", [], count_listeners)
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LaterGauge(
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"synapse_notifier_rooms",
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"",
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[],
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lambda: count(bool, list(self.room_to_user_streams.values())),
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)
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LaterGauge(
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"synapse_notifier_users", "", [], lambda: len(self.user_to_user_stream)
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)
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def add_replication_callback(self, cb):
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"""Add a callback that will be called when some new data is available.
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Callback is not given any arguments. It should *not* return a Deferred - if
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it needs to do any asynchronous work, a background thread should be started and
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wrapped with run_as_background_process.
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"""
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self.replication_callbacks.append(cb)
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def on_new_room_event(
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self, event, room_stream_id, max_room_stream_id, extra_users=[]
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):
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""" Used by handlers to inform the notifier something has happened
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in the room, room event wise.
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This triggers the notifier to wake up any listeners that are
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listening to the room, and any listeners for the users in the
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`extra_users` param.
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The events can be peristed out of order. The notifier will wait
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until all previous events have been persisted before notifying
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the client streams.
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"""
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self.pending_new_room_events.append((room_stream_id, event, extra_users))
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self._notify_pending_new_room_events(max_room_stream_id)
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self.notify_replication()
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def _notify_pending_new_room_events(self, max_room_stream_id):
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"""Notify for the room events that were queued waiting for a previous
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event to be persisted.
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Args:
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max_room_stream_id(int): The highest stream_id below which all
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events have been persisted.
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"""
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pending = self.pending_new_room_events
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self.pending_new_room_events = []
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for room_stream_id, event, extra_users in pending:
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if room_stream_id > max_room_stream_id:
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self.pending_new_room_events.append(
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(room_stream_id, event, extra_users)
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)
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else:
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self._on_new_room_event(event, room_stream_id, extra_users)
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def _on_new_room_event(self, event, room_stream_id, extra_users=[]):
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"""Notify any user streams that are interested in this room event"""
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# poke any interested application service.
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run_as_background_process(
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"notify_app_services", self._notify_app_services, room_stream_id
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)
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if self.federation_sender:
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self.federation_sender.notify_new_events(room_stream_id)
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if event.type == EventTypes.Member and event.membership == Membership.JOIN:
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self._user_joined_room(event.state_key, event.room_id)
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self.on_new_event(
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"room_key", room_stream_id, users=extra_users, rooms=[event.room_id]
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)
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@defer.inlineCallbacks
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def _notify_app_services(self, room_stream_id):
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try:
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yield self.appservice_handler.notify_interested_services(room_stream_id)
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except Exception:
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logger.exception("Error notifying application services of event")
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def on_new_event(self, stream_key, new_token, users=[], rooms=[]):
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""" Used to inform listeners that something has happened event wise.
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Will wake up all listeners for the given users and rooms.
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"""
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with PreserveLoggingContext():
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with Measure(self.clock, "on_new_event"):
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user_streams = set()
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for user in users:
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user_stream = self.user_to_user_stream.get(str(user))
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if user_stream is not None:
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user_streams.add(user_stream)
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for room in rooms:
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user_streams |= self.room_to_user_streams.get(room, set())
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time_now_ms = self.clock.time_msec()
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for user_stream in user_streams:
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try:
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user_stream.notify(stream_key, new_token, time_now_ms)
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except Exception:
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logger.exception("Failed to notify listener")
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self.notify_replication()
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def on_new_replication_data(self):
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"""Used to inform replication listeners that something has happend
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without waking up any of the normal user event streams"""
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self.notify_replication()
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@defer.inlineCallbacks
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def wait_for_events(
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self, user_id, timeout, callback, room_ids=None, from_token=StreamToken.START
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):
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"""Wait until the callback returns a non empty response or the
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timeout fires.
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"""
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user_stream = self.user_to_user_stream.get(user_id)
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if user_stream is None:
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current_token = yield self.event_sources.get_current_token()
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if room_ids is None:
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room_ids = yield self.store.get_rooms_for_user(user_id)
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user_stream = _NotifierUserStream(
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user_id=user_id,
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rooms=room_ids,
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current_token=current_token,
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time_now_ms=self.clock.time_msec(),
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)
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self._register_with_keys(user_stream)
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result = None
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prev_token = from_token
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if timeout:
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end_time = self.clock.time_msec() + timeout
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while not result:
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try:
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now = self.clock.time_msec()
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if end_time <= now:
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break
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# Now we wait for the _NotifierUserStream to be told there
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# is a new token.
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listener = user_stream.new_listener(prev_token)
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listener.deferred = timeout_deferred(
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listener.deferred,
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(end_time - now) / 1000.0,
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self.hs.get_reactor(),
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)
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with PreserveLoggingContext():
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yield listener.deferred
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current_token = user_stream.current_token
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result = yield callback(prev_token, current_token)
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if result:
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break
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# Update the prev_token to the current_token since nothing
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# has happened between the old prev_token and the current_token
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prev_token = current_token
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except defer.TimeoutError:
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break
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except defer.CancelledError:
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break
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if result is None:
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# This happened if there was no timeout or if the timeout had
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# already expired.
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current_token = user_stream.current_token
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result = yield callback(prev_token, current_token)
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return result
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@defer.inlineCallbacks
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def get_events_for(
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self,
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user,
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pagination_config,
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timeout,
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only_keys=None,
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is_guest=False,
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explicit_room_id=None,
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):
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""" For the given user and rooms, return any new events for them. If
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there are no new events wait for up to `timeout` milliseconds for any
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new events to happen before returning.
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If `only_keys` is not None, events from keys will be sent down.
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If explicit_room_id is not set, the user's joined rooms will be polled
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for events.
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If explicit_room_id is set, that room will be polled for events only if
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it is world readable or the user has joined the room.
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"""
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from_token = pagination_config.from_token
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if not from_token:
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from_token = yield self.event_sources.get_current_token()
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limit = pagination_config.limit
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room_ids, is_joined = yield self._get_room_ids(user, explicit_room_id)
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is_peeking = not is_joined
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@defer.inlineCallbacks
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def check_for_updates(before_token, after_token):
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if not after_token.is_after(before_token):
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return EventStreamResult([], (from_token, from_token))
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events = []
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end_token = from_token
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for name, source in self.event_sources.sources.items():
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keyname = "%s_key" % name
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before_id = getattr(before_token, keyname)
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after_id = getattr(after_token, keyname)
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if before_id == after_id:
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continue
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if only_keys and name not in only_keys:
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continue
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new_events, new_key = yield source.get_new_events(
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user=user,
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from_key=getattr(from_token, keyname),
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limit=limit,
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is_guest=is_peeking,
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room_ids=room_ids,
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explicit_room_id=explicit_room_id,
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)
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if name == "room":
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new_events = yield filter_events_for_client(
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self.store, user.to_string(), new_events, is_peeking=is_peeking
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)
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elif name == "presence":
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now = self.clock.time_msec()
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new_events[:] = [
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{
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"type": "m.presence",
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"content": format_user_presence_state(event, now),
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}
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for event in new_events
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]
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events.extend(new_events)
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end_token = end_token.copy_and_replace(keyname, new_key)
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return EventStreamResult(events, (from_token, end_token))
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user_id_for_stream = user.to_string()
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if is_peeking:
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# Internally, the notifier keeps an event stream per user_id.
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# This is used by both /sync and /events.
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# We want /events to be used for peeking independently of /sync,
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# without polluting its contents. So we invent an illegal user ID
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# (which thus cannot clash with any real users) for keying peeking
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# over /events.
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#
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# I am sorry for what I have done.
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user_id_for_stream = "_PEEKING_%s_%s" % (
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explicit_room_id,
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user_id_for_stream,
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)
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result = yield self.wait_for_events(
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user_id_for_stream,
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timeout,
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check_for_updates,
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room_ids=room_ids,
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from_token=from_token,
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)
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return result
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@defer.inlineCallbacks
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def _get_room_ids(self, user, explicit_room_id):
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joined_room_ids = yield self.store.get_rooms_for_user(user.to_string())
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if explicit_room_id:
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if explicit_room_id in joined_room_ids:
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return [explicit_room_id], True
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if (yield self._is_world_readable(explicit_room_id)):
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return [explicit_room_id], False
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raise AuthError(403, "Non-joined access not allowed")
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return joined_room_ids, True
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@defer.inlineCallbacks
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def _is_world_readable(self, room_id):
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state = yield self.state_handler.get_current_state(
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room_id, EventTypes.RoomHistoryVisibility, ""
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)
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if state and "history_visibility" in state.content:
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return state.content["history_visibility"] == "world_readable"
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else:
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return False
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@log_function
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def remove_expired_streams(self):
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time_now_ms = self.clock.time_msec()
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expired_streams = []
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expire_before_ts = time_now_ms - self.UNUSED_STREAM_EXPIRY_MS
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for stream in self.user_to_user_stream.values():
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if stream.count_listeners():
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continue
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if stream.last_notified_ms < expire_before_ts:
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expired_streams.append(stream)
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for expired_stream in expired_streams:
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expired_stream.remove(self)
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@log_function
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def _register_with_keys(self, user_stream):
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self.user_to_user_stream[user_stream.user_id] = user_stream
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for room in user_stream.rooms:
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s = self.room_to_user_streams.setdefault(room, set())
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s.add(user_stream)
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def _user_joined_room(self, user_id, room_id):
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new_user_stream = self.user_to_user_stream.get(user_id)
|
|
if new_user_stream is not None:
|
|
room_streams = self.room_to_user_streams.setdefault(room_id, set())
|
|
room_streams.add(new_user_stream)
|
|
new_user_stream.rooms.add(room_id)
|
|
|
|
def notify_replication(self):
|
|
"""Notify the any replication listeners that there's a new event"""
|
|
for cb in self.replication_callbacks:
|
|
cb()
|