370 lines
		
	
	
		
			13 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			370 lines
		
	
	
		
			13 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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| 
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| from twisted.internet import defer
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| 
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| from synapse.api.errors import LimitExceededError, SynapseError, AuthError
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| from synapse.crypto.event_signing import add_hashes_and_signatures
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| from synapse.api.constants import Membership, EventTypes
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| from synapse.types import UserID, RoomAlias
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| from synapse.push.action_generator import ActionGenerator
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| 
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| from synapse.util.logcontext import PreserveLoggingContext
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| 
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| import logging
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| 
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| 
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| logger = logging.getLogger(__name__)
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| 
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| 
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| class BaseHandler(object):
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|     """
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|     Common base class for the event handlers.
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| 
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|     :type store: synapse.storage.events.StateStore
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|     :type state_handler: synapse.state.StateHandler
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|     """
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| 
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|     def __init__(self, hs):
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|         self.store = hs.get_datastore()
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|         self.auth = hs.get_auth()
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|         self.notifier = hs.get_notifier()
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|         self.state_handler = hs.get_state_handler()
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|         self.distributor = hs.get_distributor()
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|         self.ratelimiter = hs.get_ratelimiter()
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|         self.clock = hs.get_clock()
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|         self.hs = hs
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| 
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|         self.signing_key = hs.config.signing_key[0]
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|         self.server_name = hs.hostname
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| 
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|         self.event_builder_factory = hs.get_event_builder_factory()
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| 
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|     @defer.inlineCallbacks
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|     def _filter_events_for_clients(self, user_tuples, events):
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|         """ Returns dict of user_id -> list of events that user is allowed to
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|         see.
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|         """
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|         # If there is only one user, just get the state for that one user,
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|         # otherwise just get all the state.
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|         if len(user_tuples) == 1:
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|             types = (
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|                 (EventTypes.RoomHistoryVisibility, ""),
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|                 (EventTypes.Member, user_tuples[0][0]),
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|             )
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|         else:
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|             types = None
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| 
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|         event_id_to_state = yield self.store.get_state_for_events(
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|             frozenset(e.event_id for e in events),
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|             types=types
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|         )
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| 
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|         forgotten = yield defer.gatherResults([
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|             self.store.who_forgot_in_room(
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|                 room_id,
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|             )
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|             for room_id in frozenset(e.room_id for e in events)
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|         ], consumeErrors=True)
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| 
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|         # Set of membership event_ids that have been forgotten
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|         event_id_forgotten = frozenset(
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|             row["event_id"] for rows in forgotten for row in rows
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|         )
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| 
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|         def allowed(event, user_id, is_peeking):
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|             state = event_id_to_state[event.event_id]
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| 
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|             visibility_event = state.get((EventTypes.RoomHistoryVisibility, ""), None)
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|             if visibility_event:
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|                 visibility = visibility_event.content.get("history_visibility", "shared")
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|             else:
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|                 visibility = "shared"
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| 
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|             if visibility == "world_readable":
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|                 return True
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| 
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|             if is_peeking:
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|                 return False
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| 
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|             membership_event = state.get((EventTypes.Member, user_id), None)
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|             if membership_event:
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|                 if membership_event.event_id in event_id_forgotten:
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|                     membership = None
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|                 else:
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|                     membership = membership_event.membership
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|             else:
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|                 membership = None
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| 
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|             if membership == Membership.JOIN:
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|                 return True
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| 
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|             if event.type == EventTypes.RoomHistoryVisibility:
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|                 return not is_peeking
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| 
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|             if visibility == "shared":
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|                 return True
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|             elif visibility == "joined":
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|                 return membership == Membership.JOIN
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|             elif visibility == "invited":
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|                 return membership == Membership.INVITE
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| 
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|             return True
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| 
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|         defer.returnValue({
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|             user_id: [
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|                 event
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|                 for event in events
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|                 if allowed(event, user_id, is_peeking)
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|             ]
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|             for user_id, is_peeking in user_tuples
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|         })
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| 
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|     @defer.inlineCallbacks
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|     def _filter_events_for_client(self, user_id, events, is_peeking=False):
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|         # Assumes that user has at some point joined the room if not is_guest.
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|         res = yield self._filter_events_for_clients([(user_id, is_peeking)], events)
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|         defer.returnValue(res.get(user_id, []))
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| 
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|     def ratelimit(self, user_id):
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|         time_now = self.clock.time()
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|         allowed, time_allowed = self.ratelimiter.send_message(
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|             user_id, time_now,
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|             msg_rate_hz=self.hs.config.rc_messages_per_second,
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|             burst_count=self.hs.config.rc_message_burst_count,
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|         )
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|         if not allowed:
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|             raise LimitExceededError(
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|                 retry_after_ms=int(1000*(time_allowed - time_now)),
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|             )
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| 
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|     @defer.inlineCallbacks
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|     def _create_new_client_event(self, builder):
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|         latest_ret = yield self.store.get_latest_events_in_room(
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|             builder.room_id,
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|         )
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| 
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|         if latest_ret:
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|             depth = max([d for _, _, d in latest_ret]) + 1
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|         else:
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|             depth = 1
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| 
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|         prev_events = [(e, h) for e, h, _ in latest_ret]
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| 
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|         builder.prev_events = prev_events
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|         builder.depth = depth
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| 
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|         state_handler = self.state_handler
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| 
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|         context = yield state_handler.compute_event_context(builder)
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| 
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|         if builder.is_state():
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|             builder.prev_state = yield self.store.add_event_hashes(
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|                 context.prev_state_events
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|             )
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| 
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|         yield self.auth.add_auth_events(builder, context)
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| 
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|         add_hashes_and_signatures(
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|             builder, self.server_name, self.signing_key
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|         )
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| 
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|         event = builder.build()
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| 
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|         logger.debug(
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|             "Created event %s with current state: %s",
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|             event.event_id, context.current_state,
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|         )
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| 
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|         defer.returnValue(
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|             (event, context,)
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|         )
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| 
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|     @defer.inlineCallbacks
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|     def handle_new_client_event(self, event, context, extra_users=[]):
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|         # We now need to go and hit out to wherever we need to hit out to.
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| 
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|         self.auth.check(event, auth_events=context.current_state)
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| 
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|         yield self.maybe_kick_guest_users(event, context.current_state.values())
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| 
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|         if event.type == EventTypes.CanonicalAlias:
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|             # Check the alias is acually valid (at this time at least)
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|             room_alias_str = event.content.get("alias", None)
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|             if room_alias_str:
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|                 room_alias = RoomAlias.from_string(room_alias_str)
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|                 directory_handler = self.hs.get_handlers().directory_handler
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|                 mapping = yield directory_handler.get_association(room_alias)
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| 
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|                 if mapping["room_id"] != event.room_id:
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|                     raise SynapseError(
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|                         400,
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|                         "Room alias %s does not point to the room" % (
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|                             room_alias_str,
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|                         )
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|                     )
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| 
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|         federation_handler = self.hs.get_handlers().federation_handler
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| 
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|         if event.type == EventTypes.Member:
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|             if event.content["membership"] == Membership.INVITE:
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|                 event.unsigned["invite_room_state"] = [
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|                     {
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|                         "type": e.type,
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|                         "state_key": e.state_key,
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|                         "content": e.content,
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|                         "sender": e.sender,
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|                     }
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|                     for k, e in context.current_state.items()
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|                     if e.type in (
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|                         EventTypes.JoinRules,
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|                         EventTypes.CanonicalAlias,
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|                         EventTypes.RoomAvatar,
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|                         EventTypes.Name,
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|                     )
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|                 ]
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| 
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|                 invitee = UserID.from_string(event.state_key)
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|                 if not self.hs.is_mine(invitee):
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|                     # TODO: Can we add signature from remote server in a nicer
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|                     # way? If we have been invited by a remote server, we need
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|                     # to get them to sign the event.
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| 
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|                     returned_invite = yield federation_handler.send_invite(
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|                         invitee.domain,
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|                         event,
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|                     )
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| 
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|                     event.unsigned.pop("room_state", None)
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| 
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|                     # TODO: Make sure the signatures actually are correct.
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|                     event.signatures.update(
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|                         returned_invite.signatures
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|                     )
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| 
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|         if event.type == EventTypes.Redaction:
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|             if self.auth.check_redaction(event, auth_events=context.current_state):
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|                 original_event = yield self.store.get_event(
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|                     event.redacts,
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|                     check_redacted=False,
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|                     get_prev_content=False,
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|                     allow_rejected=False,
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|                     allow_none=False
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|                 )
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|                 if event.user_id != original_event.user_id:
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|                     raise AuthError(
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|                         403,
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|                         "You don't have permission to redact events"
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|                     )
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| 
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|         (event_stream_id, max_stream_id) = yield self.store.persist_event(
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|             event, context=context
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|         )
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| 
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|         action_generator = ActionGenerator(self.hs)
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|         yield action_generator.handle_push_actions_for_event(
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|             event, self
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|         )
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| 
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|         destinations = set()
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|         for k, s in context.current_state.items():
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|             try:
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|                 if k[0] == EventTypes.Member:
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|                     if s.content["membership"] == Membership.JOIN:
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|                         destinations.add(
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|                             UserID.from_string(s.state_key).domain
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|                         )
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|             except SynapseError:
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|                 logger.warn(
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|                     "Failed to get destination from event %s", s.event_id
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|                 )
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| 
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|         with PreserveLoggingContext():
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|             # Don't block waiting on waking up all the listeners.
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|             notify_d = self.notifier.on_new_room_event(
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|                 event, event_stream_id, max_stream_id,
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|                 extra_users=extra_users
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|             )
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| 
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|         def log_failure(f):
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|             logger.warn(
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|                 "Failed to notify about %s: %s",
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|                 event.event_id, f.value
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|             )
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| 
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|         notify_d.addErrback(log_failure)
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| 
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|         # If invite, remove room_state from unsigned before sending.
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|         event.unsigned.pop("invite_room_state", None)
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| 
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|         federation_handler.handle_new_event(
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|             event, destinations=destinations,
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|         )
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| 
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|     @defer.inlineCallbacks
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|     def maybe_kick_guest_users(self, event, current_state):
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|         # Technically this function invalidates current_state by changing it.
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|         # Hopefully this isn't that important to the caller.
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|         if event.type == EventTypes.GuestAccess:
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|             guest_access = event.content.get("guest_access", "forbidden")
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|             if guest_access != "can_join":
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|                 yield self.kick_guest_users(current_state)
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| 
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|     @defer.inlineCallbacks
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|     def kick_guest_users(self, current_state):
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|         for member_event in current_state:
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|             try:
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|                 if member_event.type != EventTypes.Member:
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|                     continue
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| 
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|                 if not self.hs.is_mine(UserID.from_string(member_event.state_key)):
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|                     continue
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| 
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|                 if member_event.content["membership"] not in {
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|                     Membership.JOIN,
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|                     Membership.INVITE
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|                 }:
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|                     continue
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| 
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|                 if (
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|                     "kind" not in member_event.content
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|                     or member_event.content["kind"] != "guest"
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|                 ):
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|                     continue
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| 
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|                 # We make the user choose to leave, rather than have the
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|                 # event-sender kick them. This is partially because we don't
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|                 # need to worry about power levels, and partially because guest
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|                 # users are a concept which doesn't hugely work over federation,
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|                 # and having homeservers have their own users leave keeps more
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|                 # of that decision-making and control local to the guest-having
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|                 # homeserver.
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|                 message_handler = self.hs.get_handlers().message_handler
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|                 yield message_handler.create_and_send_event(
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|                     {
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|                         "type": EventTypes.Member,
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|                         "state_key": member_event.state_key,
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|                         "content": {
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|                             "membership": Membership.LEAVE,
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|                             "kind": "guest"
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|                         },
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|                         "room_id": member_event.room_id,
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|                         "sender": member_event.state_key
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|                     },
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|                     ratelimit=False,
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|                 )
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|             except Exception as e:
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|                 logger.warn("Error kicking guest user: %s" % (e,))
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