227 lines
		
	
	
		
			7.9 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			227 lines
		
	
	
		
			7.9 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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from twisted.internet import defer
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from synapse.api.constants import Membership, EventTypes
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from synapse.util.logcontext import preserve_fn, preserve_context_over_deferred
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import logging
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logger = logging.getLogger(__name__)
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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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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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@defer.inlineCallbacks
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def filter_events_for_clients(store, user_tuples, events, event_id_to_state,
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                              always_include_ids=frozenset()):
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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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    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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        always_include_ids (set(event_id)): set of event ids to specifically
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            include (unless sender is ignored)
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    """
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    forgotten = yield preserve_context_over_deferred(defer.gatherResults([
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        defer.maybeDeferred(
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            preserve_fn(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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    # 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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    ignore_dict_content = yield store.get_global_account_data_by_type_for_users(
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        "m.ignored_user_list", user_ids=[user_id for user_id, _ in user_tuples]
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    )
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    # FIXME: This will explode if people upload something incorrect.
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    ignore_dict = {
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        user_id: frozenset(
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            content.get("ignored_users", {}).keys() if content else []
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        )
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        for user_id, content in ignore_dict_content.items()
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    }
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    def allowed(event, user_id, is_peeking, ignore_list):
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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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            ignore_list (list): list of users to ignore
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        """
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        if not event.is_state() and event.sender in ignore_list:
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            return False
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        if event.event_id in always_include_ids:
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            return True
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        state = event_id_to_state[event.event_id]
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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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        if visibility not in VISIBILITY_PRIORITY:
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            visibility = "shared"
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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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        # 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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            if prev_visibility not in VISIBILITY_PRIORITY:
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                prev_visibility = "shared"
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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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        # 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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            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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            # Always allow the user to see their own leave events, otherwise
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            # they won't see the room disappear if they reject the invite
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            if membership == "leave" and (
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                prev_membership == "join" or prev_membership == "invite"
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            ):
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                return True
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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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        # 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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        # 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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        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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        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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        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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    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, ignore_dict.get(user_id, []))
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        ]
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        for user_id, is_peeking in user_tuples
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    })
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@defer.inlineCallbacks
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def filter_events_for_client(store, user_id, events, is_peeking=False,
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                             always_include_ids=frozenset()):
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    """
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    Check which events a user is allowed to see
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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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    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 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 filter_events_for_clients(
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        store, [(user_id, is_peeking)], events, event_id_to_state,
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        always_include_ids=always_include_ids,
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    )
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    defer.returnValue(res.get(user_id, []))
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