496 lines
		
	
	
		
			18 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			496 lines
		
	
	
		
			18 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, Requester
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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, preserve_fn
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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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| VISIBILITY_PRIORITY = (
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|     "world_readable",
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|     "shared",
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|     "invited",
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|     "joined",
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| )
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| 
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| 
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| MEMBERSHIP_PRIORITY = (
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|     Membership.JOIN,
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|     Membership.INVITE,
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|     Membership.KNOCK,
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|     Membership.LEAVE,
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|     Membership.BAN,
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| )
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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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|     Attributes:
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|         store (synapse.storage.events.StateStore):
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|         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, event_id_to_state):
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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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|         Args:
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|             user_tuples (str, bool): (user id, is_peeking) for each user to be
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|                 checked. is_peeking should be true if:
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|                 * the user is not currently a member of the room, and:
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|                 * the user has not been a member of the room since the
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|                 given events
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|             events ([synapse.events.EventBase]): list of events to filter
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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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|             """
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|             Args:
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|                 event (synapse.events.EventBase): event to check
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|                 user_id (str)
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|                 is_peeking (bool)
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|             """
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|             state = event_id_to_state[event.event_id]
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| 
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|             # get the room_visibility at the time of the event.
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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 not in VISIBILITY_PRIORITY:
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|                 visibility = "shared"
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| 
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|             # if it was world_readable, it's easy: everyone can read it
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|             if visibility == "world_readable":
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|                 return True
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| 
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|             # Always allow history visibility events on boundaries. This is done
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|             # by setting the effective visibility to the least restrictive
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|             # of the old vs new.
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|             if event.type == EventTypes.RoomHistoryVisibility:
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|                 prev_content = event.unsigned.get("prev_content", {})
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|                 prev_visibility = prev_content.get("history_visibility", None)
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| 
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|                 if prev_visibility not in VISIBILITY_PRIORITY:
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|                     prev_visibility = "shared"
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| 
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|                 new_priority = VISIBILITY_PRIORITY.index(visibility)
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|                 old_priority = VISIBILITY_PRIORITY.index(prev_visibility)
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|                 if old_priority < new_priority:
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|                     visibility = prev_visibility
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| 
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|             # likewise, if the event is the user's own membership event, use
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|             # the 'most joined' membership
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|             membership = None
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|             if event.type == EventTypes.Member and event.state_key == user_id:
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|                 membership = event.content.get("membership", None)
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|                 if membership not in MEMBERSHIP_PRIORITY:
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|                     membership = "leave"
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| 
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|                 prev_content = event.unsigned.get("prev_content", {})
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|                 prev_membership = prev_content.get("membership", None)
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|                 if prev_membership not in MEMBERSHIP_PRIORITY:
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|                     prev_membership = "leave"
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| 
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|                 new_priority = MEMBERSHIP_PRIORITY.index(membership)
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|                 old_priority = MEMBERSHIP_PRIORITY.index(prev_membership)
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|                 if old_priority < new_priority:
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|                     membership = prev_membership
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| 
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|             # otherwise, get the user's membership at the time of the event.
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|             if membership is None:
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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 not in event_id_forgotten:
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|                         membership = membership_event.membership
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| 
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|             # if the user was a member of the room at the time of the event,
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|             # they can see it.
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|             if membership == Membership.JOIN:
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|                 return True
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| 
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|             if visibility == "joined":
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|                 # we weren't a member at the time of the event, so we can't
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|                 # see this event.
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|                 return False
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| 
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|             elif visibility == "invited":
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|                 # user can also see the event if they were *invited* at the time
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|                 # of the event.
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|                 return membership == Membership.INVITE
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| 
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|             else:
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|                 # visibility is shared: user can also see the event if they have
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|                 # become a member since the event
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|                 #
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|                 # XXX: if the user has subsequently joined and then left again,
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|                 # ideally we would share history up to the point they left. But
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|                 # we don't know when they left.
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|                 return not is_peeking
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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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|         """
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|         Check which events a user is allowed to see
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| 
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|         Args:
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|             user_id(str): user id to be checked
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|             events([synapse.events.EventBase]): list of events to be checked
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|             is_peeking(bool): should be True if:
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|               * the user is not currently a member of the room, and:
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|               * the user has not been a member of the room since the given
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|                 events
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| 
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|         Returns:
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|             [synapse.events.EventBase]
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|         """
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|         types = (
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|             (EventTypes.RoomHistoryVisibility, ""),
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|             (EventTypes.Member, user_id),
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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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|         res = yield self.filter_events_for_clients(
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|             [(user_id, is_peeking)], events, event_id_to_state
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|         )
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|         defer.returnValue(res.get(user_id, []))
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| 
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|     def ratelimit(self, requester):
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|         time_now = self.clock.time()
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|         allowed, time_allowed = self.ratelimiter.send_message(
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|             requester.user.to_string(), 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, prev_event_ids=None):
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|         if prev_event_ids:
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|             prev_events = yield self.store.add_event_hashes(prev_event_ids)
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|             prev_max_depth = yield self.store.get_max_depth_of_events(prev_event_ids)
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|             depth = prev_max_depth + 1
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|         else:
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|             latest_ret = yield self.store.get_latest_event_ids_and_hashes_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 = [
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|                 (event_id, prev_hashes)
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|                 for event_id, prev_hashes, _ in latest_ret
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|             ]
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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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|     def is_host_in_room(self, current_state):
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|         room_members = [
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|             (state_key, event.membership)
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|             for ((event_type, state_key), event) in current_state.items()
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|             if event_type == EventTypes.Member
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|         ]
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|         if len(room_members) == 0:
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|             # Have we just created the room, and is this about to be the very
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|             # first member event?
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|             create_event = current_state.get(("m.room.create", ""))
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|             if create_event:
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|                 return True
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|         for (state_key, membership) in room_members:
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|             if (
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|                 UserID.from_string(state_key).domain == self.hs.hostname
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|                 and membership == Membership.JOIN
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|             ):
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|                 return True
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|         return False
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| 
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|     @defer.inlineCallbacks
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|     def handle_new_client_event(
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|         self,
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|         requester,
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|         event,
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|         context,
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|         ratelimit=True,
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|         extra_users=[]
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|     ):
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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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|         if ratelimit:
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|             self.ratelimit(requester)
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| 
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|         try:
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|             self.auth.check(event, auth_events=context.current_state)
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|         except AuthError as err:
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|             logger.warn("Denying new event %r because %s", event, err)
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|             raise err
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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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|                 def is_inviter_member_event(e):
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|                     return (
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|                         e.type == EventTypes.Member and
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|                         e.sender == event.sender
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|                     )
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| 
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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 self.hs.config.room_invite_state_types
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|                     or is_inviter_member_event(e)
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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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|         if event.type == EventTypes.Create and context.current_state:
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|             raise AuthError(
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|                 403,
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|                 "Changing the room create event is forbidden",
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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, context, self
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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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|         # this intentionally does not yield: we don't care about the result
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|         # and don't need to wait for it.
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|         preserve_fn(self.hs.get_pusherpool().on_new_notifications)(
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|             event_stream_id, max_stream_id
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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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|             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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|         # 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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|                 target_user = UserID.from_string(member_event.state_key)
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|                 if not self.hs.is_mine(target_user):
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|                     continue
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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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| 
 | |
|                 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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|                 requester = Requester(target_user, "", True)
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|                 handler = self.hs.get_handlers().room_member_handler
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|                 yield handler.update_membership(
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|                     requester,
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|                     target_user,
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|                     member_event.room_id,
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|                     "leave",
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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,))
 |