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632 lines
24 KiB
Python
632 lines
24 KiB
Python
# Copyright 2021 The Matrix.org Foundation C.I.C.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import itertools
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import logging
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import re
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from collections import deque
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from typing import TYPE_CHECKING, Iterable, List, Optional, Sequence, Set, Tuple
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import attr
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from synapse.api.constants import (
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EventContentFields,
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EventTypes,
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HistoryVisibility,
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Membership,
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)
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from synapse.events import EventBase
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from synapse.events.utils import format_event_for_client_v2
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from synapse.types import JsonDict
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if TYPE_CHECKING:
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from synapse.server import HomeServer
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logger = logging.getLogger(__name__)
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# number of rooms to return. We'll stop once we hit this limit.
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MAX_ROOMS = 50
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# max number of events to return per room.
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MAX_ROOMS_PER_SPACE = 50
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# max number of federation servers to hit per room
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MAX_SERVERS_PER_SPACE = 3
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class SpaceSummaryHandler:
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def __init__(self, hs: "HomeServer"):
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self._clock = hs.get_clock()
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self._auth = hs.get_auth()
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self._event_auth_handler = hs.get_event_auth_handler()
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self._store = hs.get_datastore()
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self._event_serializer = hs.get_event_client_serializer()
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self._server_name = hs.hostname
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self._federation_client = hs.get_federation_client()
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async def get_space_summary(
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self,
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requester: str,
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room_id: str,
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suggested_only: bool = False,
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max_rooms_per_space: Optional[int] = None,
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) -> JsonDict:
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"""
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Implementation of the space summary C-S API
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Args:
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requester: user id of the user making this request
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room_id: room id to start the summary at
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suggested_only: whether we should only return children with the "suggested"
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flag set.
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max_rooms_per_space: an optional limit on the number of child rooms we will
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return. This does not apply to the root room (ie, room_id), and
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is overridden by MAX_ROOMS_PER_SPACE.
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Returns:
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summary dict to return
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"""
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# first of all, check that the user is in the room in question (or it's
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# world-readable)
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await self._auth.check_user_in_room_or_world_readable(room_id, requester)
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# the queue of rooms to process
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room_queue = deque((_RoomQueueEntry(room_id, ()),))
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# rooms we have already processed
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processed_rooms = set() # type: Set[str]
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# events we have already processed. We don't necessarily have their event ids,
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# so instead we key on (room id, state key)
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processed_events = set() # type: Set[Tuple[str, str]]
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rooms_result = [] # type: List[JsonDict]
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events_result = [] # type: List[JsonDict]
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while room_queue and len(rooms_result) < MAX_ROOMS:
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queue_entry = room_queue.popleft()
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room_id = queue_entry.room_id
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if room_id in processed_rooms:
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# already done this room
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continue
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logger.debug("Processing room %s", room_id)
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is_in_room = await self._store.is_host_joined(room_id, self._server_name)
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# The client-specified max_rooms_per_space limit doesn't apply to the
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# room_id specified in the request, so we ignore it if this is the
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# first room we are processing.
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max_children = max_rooms_per_space if processed_rooms else None
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if is_in_room:
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room, events = await self._summarize_local_room(
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requester, None, room_id, suggested_only, max_children
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)
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logger.debug(
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"Query of local room %s returned events %s",
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room_id,
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["%s->%s" % (ev["room_id"], ev["state_key"]) for ev in events],
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)
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if room:
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rooms_result.append(room)
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else:
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fed_rooms, fed_events = await self._summarize_remote_room(
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queue_entry,
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suggested_only,
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max_children,
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exclude_rooms=processed_rooms,
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)
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# The results over federation might include rooms that the we,
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# as the requesting server, are allowed to see, but the requesting
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# user is not permitted see.
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#
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# Filter the returned results to only what is accessible to the user.
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room_ids = set()
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events = []
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for room in fed_rooms:
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fed_room_id = room.get("room_id")
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if not fed_room_id or not isinstance(fed_room_id, str):
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continue
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# The room should only be included in the summary if:
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# a. the user is in the room;
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# b. the room is world readable; or
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# c. the user is in a space that has been granted access to
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# the room.
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#
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# Note that we know the user is not in the root room (which is
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# why the remote call was made in the first place), but the user
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# could be in one of the children rooms and we just didn't know
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# about the link.
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include_room = room.get("world_readable") is True
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# Check if the user is a member of any of the allowed spaces
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# from the response.
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allowed_rooms = room.get("allowed_spaces")
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if (
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not include_room
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and allowed_rooms
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and isinstance(allowed_rooms, list)
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):
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include_room = await self._event_auth_handler.is_user_in_rooms(
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allowed_rooms, requester
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)
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# Finally, if this isn't the requested room, check ourselves
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# if we can access the room.
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if not include_room and fed_room_id != queue_entry.room_id:
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include_room = await self._is_room_accessible(
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fed_room_id, requester, None
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)
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# The user can see the room, include it!
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if include_room:
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rooms_result.append(room)
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room_ids.add(fed_room_id)
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# All rooms returned don't need visiting again (even if the user
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# didn't have access to them).
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processed_rooms.add(fed_room_id)
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for event in fed_events:
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if event.get("room_id") in room_ids:
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events.append(event)
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logger.debug(
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"Query of %s returned rooms %s, events %s",
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room_id,
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[room.get("room_id") for room in fed_rooms],
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["%s->%s" % (ev["room_id"], ev["state_key"]) for ev in fed_events],
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)
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# the room we queried may or may not have been returned, but don't process
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# it again, anyway.
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processed_rooms.add(room_id)
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# XXX: is it ok that we blindly iterate through any events returned by
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# a remote server, whether or not they actually link to any rooms in our
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# tree?
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for ev in events:
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# remote servers might return events we have already processed
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# (eg, Dendrite returns inward pointers as well as outward ones), so
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# we need to filter them out, to avoid returning duplicate links to the
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# client.
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ev_key = (ev["room_id"], ev["state_key"])
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if ev_key in processed_events:
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continue
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events_result.append(ev)
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# add the child to the queue. we have already validated
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# that the vias are a list of server names.
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room_queue.append(
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_RoomQueueEntry(ev["state_key"], ev["content"]["via"])
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)
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processed_events.add(ev_key)
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# Before returning to the client, remove the allowed_spaces key for any
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# rooms.
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for room in rooms_result:
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room.pop("allowed_spaces", None)
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return {"rooms": rooms_result, "events": events_result}
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async def federation_space_summary(
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self,
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origin: str,
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room_id: str,
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suggested_only: bool,
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max_rooms_per_space: Optional[int],
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exclude_rooms: Iterable[str],
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) -> JsonDict:
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"""
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Implementation of the space summary Federation API
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Args:
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origin: The server requesting the spaces summary.
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room_id: room id to start the summary at
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suggested_only: whether we should only return children with the "suggested"
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flag set.
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max_rooms_per_space: an optional limit on the number of child rooms we will
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return. Unlike the C-S API, this applies to the root room (room_id).
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It is clipped to MAX_ROOMS_PER_SPACE.
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exclude_rooms: a list of rooms to skip over (presumably because the
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calling server has already seen them).
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Returns:
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summary dict to return
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"""
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# the queue of rooms to process
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room_queue = deque((room_id,))
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# the set of rooms that we should not walk further. Initialise it with the
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# excluded-rooms list; we will add other rooms as we process them so that
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# we do not loop.
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processed_rooms = set(exclude_rooms) # type: Set[str]
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rooms_result = [] # type: List[JsonDict]
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events_result = [] # type: List[JsonDict]
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while room_queue and len(rooms_result) < MAX_ROOMS:
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room_id = room_queue.popleft()
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if room_id in processed_rooms:
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# already done this room
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continue
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logger.debug("Processing room %s", room_id)
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room, events = await self._summarize_local_room(
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None, origin, room_id, suggested_only, max_rooms_per_space
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)
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processed_rooms.add(room_id)
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if room:
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rooms_result.append(room)
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events_result.extend(events)
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# add any children to the queue
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room_queue.extend(edge_event["state_key"] for edge_event in events)
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return {"rooms": rooms_result, "events": events_result}
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async def _summarize_local_room(
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self,
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requester: Optional[str],
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origin: Optional[str],
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room_id: str,
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suggested_only: bool,
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max_children: Optional[int],
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) -> Tuple[Optional[JsonDict], Sequence[JsonDict]]:
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"""
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Generate a room entry and a list of event entries for a given room.
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Args:
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requester:
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The user requesting the summary, if it is a local request. None
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if this is a federation request.
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origin:
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The server requesting the summary, if it is a federation request.
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None if this is a local request.
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room_id: The room ID to summarize.
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suggested_only: True if only suggested children should be returned.
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Otherwise, all children are returned.
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max_children:
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The maximum number of children rooms to include. This is capped
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to a server-set limit.
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Returns:
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A tuple of:
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An iterable of a single value of the room.
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An iterable of the sorted children events. This may be limited
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to a maximum size or may include all children.
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"""
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if not await self._is_room_accessible(room_id, requester, origin):
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return None, ()
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room_entry = await self._build_room_entry(room_id)
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# look for child rooms/spaces.
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child_events = await self._get_child_events(room_id)
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if suggested_only:
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# we only care about suggested children
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child_events = filter(_is_suggested_child_event, child_events)
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if max_children is None or max_children > MAX_ROOMS_PER_SPACE:
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max_children = MAX_ROOMS_PER_SPACE
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now = self._clock.time_msec()
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events_result = [] # type: List[JsonDict]
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for edge_event in itertools.islice(child_events, max_children):
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events_result.append(
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await self._event_serializer.serialize_event(
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edge_event,
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time_now=now,
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event_format=format_event_for_client_v2,
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)
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)
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return room_entry, events_result
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async def _summarize_remote_room(
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self,
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room: "_RoomQueueEntry",
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suggested_only: bool,
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max_children: Optional[int],
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exclude_rooms: Iterable[str],
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) -> Tuple[Sequence[JsonDict], Sequence[JsonDict]]:
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"""
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Request room entries and a list of event entries for a given room by querying a remote server.
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Args:
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room: The room to summarize.
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suggested_only: True if only suggested children should be returned.
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Otherwise, all children are returned.
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max_children:
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The maximum number of children rooms to include. This is capped
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to a server-set limit.
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exclude_rooms:
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Rooms IDs which do not need to be summarized.
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Returns:
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A tuple of:
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An iterable of rooms.
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An iterable of the sorted children events. This may be limited
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to a maximum size or may include all children.
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"""
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room_id = room.room_id
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logger.info("Requesting summary for %s via %s", room_id, room.via)
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# we need to make the exclusion list json-serialisable
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exclude_rooms = list(exclude_rooms)
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via = itertools.islice(room.via, MAX_SERVERS_PER_SPACE)
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try:
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res = await self._federation_client.get_space_summary(
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via,
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room_id,
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suggested_only=suggested_only,
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max_rooms_per_space=max_children,
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exclude_rooms=exclude_rooms,
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)
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except Exception as e:
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logger.warning(
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"Unable to get summary of %s via federation: %s",
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room_id,
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e,
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exc_info=logger.isEnabledFor(logging.DEBUG),
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)
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return (), ()
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return res.rooms, tuple(
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ev.data for ev in res.events if ev.event_type == EventTypes.SpaceChild
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)
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async def _is_room_accessible(
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self, room_id: str, requester: Optional[str], origin: Optional[str]
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) -> bool:
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"""
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Calculate whether the room should be shown in the spaces summary.
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It should be included if:
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* The requester is joined or invited to the room.
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* The requester can join without an invite (per MSC3083).
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* The origin server has any user that is joined or invited to the room.
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* The history visibility is set to world readable.
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Args:
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room_id: The room ID to summarize.
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requester:
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The user requesting the summary, if it is a local request. None
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if this is a federation request.
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origin:
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The server requesting the summary, if it is a federation request.
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None if this is a local request.
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Returns:
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True if the room should be included in the spaces summary.
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"""
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state_ids = await self._store.get_current_state_ids(room_id)
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# If there's no state for the room, it isn't known.
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if not state_ids:
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logger.info("room %s is unknown, omitting from summary", room_id)
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return False
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room_version = await self._store.get_room_version(room_id)
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# if we have an authenticated requesting user, first check if they are able to view
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# stripped state in the room.
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if requester:
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member_event_id = state_ids.get((EventTypes.Member, requester), None)
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# If they're in the room they can see info on it.
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member_event = None
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if member_event_id:
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member_event = await self._store.get_event(member_event_id)
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if member_event.membership in (Membership.JOIN, Membership.INVITE):
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return True
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# Otherwise, check if they should be allowed access via membership in a space.
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if self._event_auth_handler.has_restricted_join_rules(
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state_ids, room_version
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):
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allowed_rooms = (
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await self._event_auth_handler.get_rooms_that_allow_join(state_ids)
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)
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if await self._event_auth_handler.is_user_in_rooms(
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allowed_rooms, requester
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):
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return True
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# If this is a request over federation, check if the host is in the room or
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# is in one of the spaces specified via the join rules.
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elif origin:
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if await self._auth.check_host_in_room(room_id, origin):
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return True
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# Alternately, if the host has a user in any of the spaces specified
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# for access, then the host can see this room (and should do filtering
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# if the requester cannot see it).
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if await self._event_auth_handler.has_restricted_join_rules(
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state_ids, room_version
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):
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allowed_rooms = (
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await self._event_auth_handler.get_rooms_that_allow_join(state_ids)
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)
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for space_id in allowed_rooms:
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if await self._auth.check_host_in_room(space_id, origin):
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return True
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# otherwise, check if the room is peekable
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hist_vis_event_id = state_ids.get((EventTypes.RoomHistoryVisibility, ""), None)
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if hist_vis_event_id:
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hist_vis_ev = await self._store.get_event(hist_vis_event_id)
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hist_vis = hist_vis_ev.content.get("history_visibility")
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if hist_vis == HistoryVisibility.WORLD_READABLE:
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return True
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logger.info(
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"room %s is unpeekable and user %s is not a member / not allowed to join, omitting from summary",
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room_id,
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requester,
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)
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return False
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async def _build_room_entry(self, room_id: str) -> JsonDict:
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"""Generate en entry suitable for the 'rooms' list in the summary response"""
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stats = await self._store.get_room_with_stats(room_id)
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# currently this should be impossible because we call
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# check_user_in_room_or_world_readable on the room before we get here, so
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# there should always be an entry
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assert stats is not None, "unable to retrieve stats for %s" % (room_id,)
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current_state_ids = await self._store.get_current_state_ids(room_id)
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create_event = await self._store.get_event(
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current_state_ids[(EventTypes.Create, "")]
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)
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room_version = await self._store.get_room_version(room_id)
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allowed_rooms = None
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if await self._event_auth_handler.has_restricted_join_rules(
|
||
current_state_ids, room_version
|
||
):
|
||
allowed_rooms = await self._event_auth_handler.get_rooms_that_allow_join(
|
||
current_state_ids
|
||
)
|
||
|
||
entry = {
|
||
"room_id": stats["room_id"],
|
||
"name": stats["name"],
|
||
"topic": stats["topic"],
|
||
"canonical_alias": stats["canonical_alias"],
|
||
"num_joined_members": stats["joined_members"],
|
||
"avatar_url": stats["avatar"],
|
||
"world_readable": (
|
||
stats["history_visibility"] == HistoryVisibility.WORLD_READABLE
|
||
),
|
||
"guest_can_join": stats["guest_access"] == "can_join",
|
||
"creation_ts": create_event.origin_server_ts,
|
||
"room_type": create_event.content.get(EventContentFields.ROOM_TYPE),
|
||
"allowed_spaces": allowed_rooms,
|
||
}
|
||
|
||
# Filter out Nones – rather omit the field altogether
|
||
room_entry = {k: v for k, v in entry.items() if v is not None}
|
||
|
||
return room_entry
|
||
|
||
async def _get_child_events(self, room_id: str) -> Iterable[EventBase]:
|
||
"""
|
||
Get the child events for a given room.
|
||
|
||
The returned results are sorted for stability.
|
||
|
||
Args:
|
||
room_id: The room id to get the children of.
|
||
|
||
Returns:
|
||
An iterable of sorted child events.
|
||
"""
|
||
|
||
# look for child rooms/spaces.
|
||
current_state_ids = await self._store.get_current_state_ids(room_id)
|
||
|
||
events = await self._store.get_events_as_list(
|
||
[
|
||
event_id
|
||
for key, event_id in current_state_ids.items()
|
||
if key[0] == EventTypes.SpaceChild
|
||
]
|
||
)
|
||
|
||
# filter out any events without a "via" (which implies it has been redacted),
|
||
# and order to ensure we return stable results.
|
||
return sorted(filter(_has_valid_via, events), key=_child_events_comparison_key)
|
||
|
||
|
||
@attr.s(frozen=True, slots=True)
|
||
class _RoomQueueEntry:
|
||
room_id = attr.ib(type=str)
|
||
via = attr.ib(type=Sequence[str])
|
||
|
||
|
||
def _has_valid_via(e: EventBase) -> bool:
|
||
via = e.content.get("via")
|
||
if not via or not isinstance(via, Sequence):
|
||
return False
|
||
for v in via:
|
||
if not isinstance(v, str):
|
||
logger.debug("Ignoring edge event %s with invalid via entry", e.event_id)
|
||
return False
|
||
return True
|
||
|
||
|
||
def _is_suggested_child_event(edge_event: EventBase) -> bool:
|
||
suggested = edge_event.content.get("suggested")
|
||
if isinstance(suggested, bool) and suggested:
|
||
return True
|
||
logger.debug("Ignorning not-suggested child %s", edge_event.state_key)
|
||
return False
|
||
|
||
|
||
# Order may only contain characters in the range of \x20 (space) to \x7E (~) inclusive.
|
||
_INVALID_ORDER_CHARS_RE = re.compile(r"[^\x20-\x7E]")
|
||
|
||
|
||
def _child_events_comparison_key(child: EventBase) -> Tuple[bool, Optional[str], str]:
|
||
"""
|
||
Generate a value for comparing two child events for ordering.
|
||
|
||
The rules for ordering are supposed to be:
|
||
|
||
1. The 'order' key, if it is valid.
|
||
2. The 'origin_server_ts' of the 'm.room.create' event.
|
||
3. The 'room_id'.
|
||
|
||
But we skip step 2 since we may not have any state from the room.
|
||
|
||
Args:
|
||
child: The event for generating a comparison key.
|
||
|
||
Returns:
|
||
The comparison key as a tuple of:
|
||
False if the ordering is valid.
|
||
The ordering field.
|
||
The room ID.
|
||
"""
|
||
order = child.content.get("order")
|
||
# If order is not a string or doesn't meet the requirements, ignore it.
|
||
if not isinstance(order, str):
|
||
order = None
|
||
elif len(order) > 50 or _INVALID_ORDER_CHARS_RE.search(order):
|
||
order = None
|
||
|
||
# Items without an order come last.
|
||
return (order is None, order, child.room_id)
|