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# -*- coding: utf-8 -*-
# Copyright 2014-2016 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 twisted.internet import defer
from synapse.util.logutils import log_function
from synapse.types import UserID
from synapse.events.utils import serialize_event
from ._base import BaseHandler
import logging
import random
logger = logging.getLogger(__name__)
def started_user_eventstream(distributor, user):
return distributor.fire("started_user_eventstream", user)
def stopped_user_eventstream(distributor, user):
return distributor.fire("stopped_user_eventstream", user)
class EventStreamHandler(BaseHandler):
def __init__(self, hs):
super(EventStreamHandler, self).__init__(hs)
# Count of active streams per user
self._streams_per_user = {}
# Grace timers per user to delay the "stopped" signal
self._stop_timer_per_user = {}
self.distributor = hs.get_distributor()
self.distributor.declare("started_user_eventstream")
self.distributor.declare("stopped_user_eventstream")
self.clock = hs.get_clock()
self.notifier = hs.get_notifier()
@defer.inlineCallbacks
def started_stream(self, user):
"""Tells the presence handler that we have started an eventstream for
the user:
Args:
user (User): The user who started a stream.
Returns:
A deferred that completes once their presence has been updated.
"""
if user not in self._streams_per_user:
# Make sure we set the streams per user to 1 here rather than
# setting it to zero and incrementing the value below.
# Otherwise this may race with stopped_stream causing the
# user to be erased from the map before we have a chance
# to increment it.
self._streams_per_user[user] = 1
if user in self._stop_timer_per_user:
try:
self.clock.cancel_call_later(
self._stop_timer_per_user.pop(user)
)
except:
logger.exception("Failed to cancel event timer")
else:
yield started_user_eventstream(self.distributor, user)
else:
self._streams_per_user[user] += 1
def stopped_stream(self, user):
"""If there are no streams for a user this starts a timer that will
notify the presence handler that we haven't got an event stream for
the user unless the user starts a new stream in 30 seconds.
Args:
user (User): The user who stopped a stream.
"""
self._streams_per_user[user] -= 1
if not self._streams_per_user[user]:
del self._streams_per_user[user]
# 30 seconds of grace to allow the client to reconnect again
# before we think they're gone
def _later():
logger.debug("_later stopped_user_eventstream %s", user)
self._stop_timer_per_user.pop(user, None)
return stopped_user_eventstream(self.distributor, user)
logger.debug("Scheduling _later: for %s", user)
self._stop_timer_per_user[user] = (
self.clock.call_later(30, _later)
)
@defer.inlineCallbacks
@log_function
def get_stream(self, auth_user_id, pagin_config, timeout=0,
as_client_event=True, affect_presence=True,
only_room_events=False, room_id=None, is_guest=False):
"""Fetches the events stream for a given user.
If `only_room_events` is `True` only room events will be returned.
"""
auth_user = UserID.from_string(auth_user_id)
try:
if affect_presence:
yield self.started_stream(auth_user)
if timeout:
# If they've set a timeout set a minimum limit.
timeout = max(timeout, 500)
# Add some randomness to this value to try and mitigate against
# thundering herds on restart.
timeout = random.randint(int(timeout*0.9), int(timeout*1.1))
events, tokens = yield self.notifier.get_events_for(
auth_user, pagin_config, timeout,
only_room_events=only_room_events,
is_guest=is_guest, explicit_room_id=room_id
)
time_now = self.clock.time_msec()
chunks = [
serialize_event(e, time_now, as_client_event) for e in events
]
chunk = {
"chunk": chunks,
"start": tokens[0].to_string(),
"end": tokens[1].to_string(),
}
defer.returnValue(chunk)
finally:
if affect_presence:
self.stopped_stream(auth_user)
class EventHandler(BaseHandler):
@defer.inlineCallbacks
def get_event(self, user, event_id):
"""Retrieve a single specified event.
Args:
user (synapse.types.UserID): The user requesting the event
event_id (str): The event ID to obtain.
Returns:
dict: An event, or None if there is no event matching this ID.
Raises:
SynapseError if there was a problem retrieving this event, or
AuthError if the user does not have the rights to inspect this
event.
"""
event = yield self.store.get_event(event_id)
if not event:
defer.returnValue(None)
return
if hasattr(event, "room_id"):
yield self.auth.check_joined_room(event.room_id, user.to_string())
defer.returnValue(event)
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