forked-synapse/synapse/handlers/relations.py

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# Copyright 2021 The Matrix.org Foundation C.I.C.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import logging
from typing import TYPE_CHECKING, Optional
from synapse.api.errors import SynapseError
from synapse.types import JsonDict, Requester, StreamToken
if TYPE_CHECKING:
from synapse.server import HomeServer
logger = logging.getLogger(__name__)
class RelationsHandler:
def __init__(self, hs: "HomeServer"):
self._main_store = hs.get_datastores().main
self._auth = hs.get_auth()
self._clock = hs.get_clock()
self._event_handler = hs.get_event_handler()
self._event_serializer = hs.get_event_client_serializer()
async def get_relations(
self,
requester: Requester,
event_id: str,
room_id: str,
relation_type: Optional[str] = None,
event_type: Optional[str] = None,
aggregation_key: Optional[str] = None,
limit: int = 5,
direction: str = "b",
from_token: Optional[StreamToken] = None,
to_token: Optional[StreamToken] = None,
) -> JsonDict:
"""Get related events of a event, ordered by topological ordering.
TODO Accept a PaginationConfig instead of individual pagination parameters.
Args:
requester: The user requesting the relations.
event_id: Fetch events that relate to this event ID.
room_id: The room the event belongs to.
relation_type: Only fetch events with this relation type, if given.
event_type: Only fetch events with this event type, if given.
aggregation_key: Only fetch events with this aggregation key, if given.
limit: Only fetch the most recent `limit` events.
direction: Whether to fetch the most recent first (`"b"`) or the
oldest first (`"f"`).
from_token: Fetch rows from the given token, or from the start if None.
to_token: Fetch rows up to the given token, or up to the end if None.
Returns:
The pagination chunk.
"""
user_id = requester.user.to_string()
await self._auth.check_user_in_room_or_world_readable(
room_id, user_id, allow_departed_users=True
)
# This gets the original event and checks that a) the event exists and
# b) the user is allowed to view it.
event = await self._event_handler.get_event(requester.user, room_id, event_id)
if event is None:
raise SynapseError(404, "Unknown parent event.")
pagination_chunk = await self._main_store.get_relations_for_event(
event_id=event_id,
event=event,
room_id=room_id,
relation_type=relation_type,
event_type=event_type,
aggregation_key=aggregation_key,
limit=limit,
direction=direction,
from_token=from_token,
to_token=to_token,
)
events = await self._main_store.get_events_as_list(
[c["event_id"] for c in pagination_chunk.chunk]
)
now = self._clock.time_msec()
# Do not bundle aggregations when retrieving the original event because
# we want the content before relations are applied to it.
original_event = self._event_serializer.serialize_event(
event, now, bundle_aggregations=None
)
# The relations returned for the requested event do include their
# bundled aggregations.
aggregations = await self._main_store.get_bundled_aggregations(
events, requester.user.to_string()
)
serialized_events = self._event_serializer.serialize_events(
events, now, bundle_aggregations=aggregations
)
return_value = await pagination_chunk.to_dict(self._main_store)
return_value["chunk"] = serialized_events
return_value["original_event"] = original_event
return return_value