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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 enum
- import logging
- from typing import (
- TYPE_CHECKING,
- Collection,
- Dict,
- FrozenSet,
- Iterable,
- List,
- Mapping,
- Optional,
- Sequence,
- )
-
- import attr
-
- from synapse.api.constants import Direction, EventTypes, RelationTypes
- from synapse.api.errors import SynapseError
- from synapse.events import EventBase, relation_from_event
- from synapse.events.utils import SerializeEventConfig
- from synapse.logging.context import make_deferred_yieldable, run_in_background
- from synapse.logging.opentracing import trace
- from synapse.storage.databases.main.relations import ThreadsNextBatch, _RelatedEvent
- from synapse.streams.config import PaginationConfig
- from synapse.types import JsonDict, Requester, UserID
- from synapse.util.async_helpers import gather_results
- from synapse.visibility import filter_events_for_client
-
- if TYPE_CHECKING:
- from synapse.server import HomeServer
-
-
- logger = logging.getLogger(__name__)
-
-
- class ThreadsListInclude(str, enum.Enum):
- """Valid values for the 'include' flag of /threads."""
-
- all = "all"
- participated = "participated"
-
-
- @attr.s(slots=True, frozen=True, auto_attribs=True)
- class _ThreadAggregation:
- # The latest event in the thread.
- latest_event: EventBase
- # The total number of events in the thread.
- count: int
- # True if the current user has sent an event to the thread.
- current_user_participated: bool
-
-
- @attr.s(slots=True, auto_attribs=True)
- class BundledAggregations:
- """
- The bundled aggregations for an event.
-
- Some values require additional processing during serialization.
- """
-
- references: Optional[JsonDict] = None
- replace: Optional[EventBase] = None
- thread: Optional[_ThreadAggregation] = None
-
- def __bool__(self) -> bool:
- return bool(self.references or self.replace or self.thread)
-
-
- class RelationsHandler:
- def __init__(self, hs: "HomeServer"):
- self._main_store = hs.get_datastores().main
- self._storage_controllers = hs.get_storage_controllers()
- 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()
- self._event_creation_handler = hs.get_event_creation_handler()
-
- async def get_relations(
- self,
- requester: Requester,
- event_id: str,
- room_id: str,
- pagin_config: PaginationConfig,
- recurse: bool,
- include_original_event: bool,
- relation_type: Optional[str] = None,
- event_type: Optional[str] = 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.
- pagin_config: The pagination config rules to apply, if any.
- recurse: Whether to recursively find relations.
- include_original_event: Whether to include the parent event.
- relation_type: Only fetch events with this relation type, if given.
- event_type: Only fetch events with this event type, if given.
-
- Returns:
- The pagination chunk.
- """
-
- user_id = requester.user.to_string()
-
- # TODO Properly handle a user leaving a room.
- (_, member_event_id) = await self._auth.check_user_in_room_or_world_readable(
- room_id, requester, 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.")
-
- # Note that ignored users are not passed into get_relations_for_event
- # below. Ignored users are handled in filter_events_for_client (and by
- # not passing them in here we should get a better cache hit rate).
- related_events, next_token = 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,
- limit=pagin_config.limit,
- direction=pagin_config.direction,
- from_token=pagin_config.from_token,
- to_token=pagin_config.to_token,
- recurse=recurse,
- )
-
- events = await self._main_store.get_events_as_list(
- [e.event_id for e in related_events]
- )
-
- events = await filter_events_for_client(
- self._storage_controllers,
- user_id,
- events,
- is_peeking=(member_event_id is None),
- )
-
- # The relations returned for the requested event do include their
- # bundled aggregations.
- aggregations = await self.get_bundled_aggregations(
- events, requester.user.to_string()
- )
-
- now = self._clock.time_msec()
- serialize_options = SerializeEventConfig(requester=requester)
- return_value: JsonDict = {
- "chunk": await self._event_serializer.serialize_events(
- events,
- now,
- bundle_aggregations=aggregations,
- config=serialize_options,
- ),
- }
- if include_original_event:
- # Do not bundle aggregations when retrieving the original event because
- # we want the content before relations are applied to it.
- return_value[
- "original_event"
- ] = await self._event_serializer.serialize_event(
- event,
- now,
- bundle_aggregations=None,
- config=serialize_options,
- )
-
- if next_token:
- return_value["next_batch"] = await next_token.to_string(self._main_store)
-
- if pagin_config.from_token:
- return_value["prev_batch"] = await pagin_config.from_token.to_string(
- self._main_store
- )
-
- return return_value
-
- async def redact_events_related_to(
- self,
- requester: Requester,
- event_id: str,
- initial_redaction_event: EventBase,
- relation_types: List[str],
- ) -> None:
- """Redacts all events related to the given event ID with one of the given
- relation types.
-
- This method is expected to be called when redacting the event referred to by
- the given event ID.
-
- If an event cannot be redacted (e.g. because of insufficient permissions), log
- the error and try to redact the next one.
-
- Args:
- requester: The requester to redact events on behalf of.
- event_id: The event IDs to look and redact relations of.
- initial_redaction_event: The redaction for the event referred to by
- event_id.
- relation_types: The types of relations to look for. If "*" is in the list,
- all related events will be redacted regardless of the type.
-
- Raises:
- ShadowBanError if the requester is shadow-banned
- """
- if "*" in relation_types:
- related_event_ids = await self._main_store.get_all_relations_for_event(
- event_id
- )
- else:
- related_event_ids = (
- await self._main_store.get_all_relations_for_event_with_types(
- event_id, relation_types
- )
- )
-
- for related_event_id in related_event_ids:
- try:
- await self._event_creation_handler.create_and_send_nonmember_event(
- requester,
- {
- "type": EventTypes.Redaction,
- "content": initial_redaction_event.content,
- "room_id": initial_redaction_event.room_id,
- "sender": requester.user.to_string(),
- "redacts": related_event_id,
- },
- ratelimit=False,
- )
- except SynapseError as e:
- logger.warning(
- "Failed to redact event %s (related to event %s): %s",
- related_event_id,
- event_id,
- e.msg,
- )
-
- async def get_references_for_events(
- self, event_ids: Collection[str], ignored_users: FrozenSet[str] = frozenset()
- ) -> Mapping[str, Sequence[_RelatedEvent]]:
- """Get a list of references to the given events.
-
- Args:
- event_ids: Fetch events that relate to this event ID.
- ignored_users: The users ignored by the requesting user.
-
- Returns:
- A map of event IDs to a list related events.
- """
-
- related_events = await self._main_store.get_references_for_events(event_ids)
-
- # Avoid additional logic if there are no ignored users.
- if not ignored_users:
- return {
- event_id: results
- for event_id, results in related_events.items()
- if results
- }
-
- # Filter out ignored users.
- results = {}
- for event_id, events in related_events.items():
- # If no references, skip.
- if not events:
- continue
-
- # Filter ignored users out.
- events = [event for event in events if event.sender not in ignored_users]
- # If there are no events left, skip this event.
- if not events:
- continue
-
- results[event_id] = events
-
- return results
-
- async def _get_threads_for_events(
- self,
- events_by_id: Dict[str, EventBase],
- relations_by_id: Dict[str, str],
- user_id: str,
- ignored_users: FrozenSet[str],
- ) -> Dict[str, _ThreadAggregation]:
- """Get the bundled aggregations for threads for the requested events.
-
- Args:
- events_by_id: A map of event_id to events to get aggregations for threads.
- relations_by_id: A map of event_id to the relation type, if one exists
- for that event.
- user_id: The user requesting the bundled aggregations.
- ignored_users: The users ignored by the requesting user.
-
- Returns:
- A dictionary mapping event ID to the thread information.
-
- May not contain a value for all requested event IDs.
- """
- user = UserID.from_string(user_id)
-
- # It is not valid to start a thread on an event which itself relates to another event.
- event_ids = [eid for eid in events_by_id.keys() if eid not in relations_by_id]
-
- # Fetch thread summaries.
- summaries = await self._main_store.get_thread_summaries(event_ids)
-
- # Limit fetching whether the requester has participated in a thread to
- # events which are thread roots.
- thread_event_ids = [
- event_id for event_id, summary in summaries.items() if summary
- ]
-
- # Pre-seed thread participation with whether the requester sent the event.
- participated = {
- event_id: events_by_id[event_id].sender == user_id
- for event_id in thread_event_ids
- }
- # For events the requester did not send, check the database for whether
- # the requester sent a threaded reply.
- participated.update(
- await self._main_store.get_threads_participated(
- [
- event_id
- for event_id in thread_event_ids
- if not participated[event_id]
- ],
- user_id,
- )
- )
-
- # Then subtract off the results for any ignored users.
- ignored_results = await self._main_store.get_threaded_messages_per_user(
- thread_event_ids, ignored_users
- )
-
- # A map of event ID to the thread aggregation.
- results = {}
-
- for event_id, summary in summaries.items():
- # If no thread, skip.
- if not summary:
- continue
-
- thread_count, latest_thread_event = summary
-
- # Subtract off the count of any ignored users.
- for ignored_user in ignored_users:
- thread_count -= ignored_results.get((event_id, ignored_user), 0)
-
- # This is gnarly, but if the latest event is from an ignored user,
- # attempt to find one that isn't from an ignored user.
- if latest_thread_event.sender in ignored_users:
- room_id = latest_thread_event.room_id
-
- # If the root event is not found, something went wrong, do
- # not include a summary of the thread.
- event = await self._event_handler.get_event(user, room_id, event_id)
- if event is None:
- continue
-
- # Attempt to find another event to use as the latest event.
- potential_events, _ = await self._main_store.get_relations_for_event(
- event_id,
- event,
- room_id,
- RelationTypes.THREAD,
- direction=Direction.FORWARDS,
- )
-
- # Filter out ignored users.
- potential_events = [
- event
- for event in potential_events
- if event.sender not in ignored_users
- ]
-
- # If all found events are from ignored users, do not include
- # a summary of the thread.
- if not potential_events:
- continue
-
- # The *last* event returned is the one that is cared about.
- event = await self._event_handler.get_event(
- user, room_id, potential_events[-1].event_id
- )
- # It is unexpected that the event will not exist.
- if event is None:
- logger.warning(
- "Unable to fetch latest event in a thread with event ID: %s",
- potential_events[-1].event_id,
- )
- continue
- latest_thread_event = event
-
- results[event_id] = _ThreadAggregation(
- latest_event=latest_thread_event,
- count=thread_count,
- # If there's a thread summary it must also exist in the
- # participated dictionary.
- current_user_participated=events_by_id[event_id].sender == user_id
- or participated[event_id],
- )
-
- return results
-
- @trace
- async def get_bundled_aggregations(
- self, events: Iterable[EventBase], user_id: str
- ) -> Dict[str, BundledAggregations]:
- """Generate bundled aggregations for events.
-
- Args:
- events: The iterable of events to calculate bundled aggregations for.
- user_id: The user requesting the bundled aggregations.
-
- Returns:
- A map of event ID to the bundled aggregations for the event.
-
- Not all requested events may exist in the results (if they don't have
- bundled aggregations).
-
- The results may include additional events which are related to the
- requested events.
- """
- # De-duplicated events by ID to handle the same event requested multiple times.
- events_by_id = {}
- # A map of event ID to the relation in that event, if there is one.
- relations_by_id: Dict[str, str] = {}
- for event in events:
- # State events do not get bundled aggregations.
- if event.is_state():
- continue
-
- relates_to = relation_from_event(event)
- if relates_to:
- # An event which is a replacement (ie edit) or annotation (ie,
- # reaction) may not have any other event related to it.
- if relates_to.rel_type in (
- RelationTypes.ANNOTATION,
- RelationTypes.REPLACE,
- ):
- continue
-
- # Track the event's relation information for later.
- relations_by_id[event.event_id] = relates_to.rel_type
-
- # The event should get bundled aggregations.
- events_by_id[event.event_id] = event
-
- # event ID -> bundled aggregation in non-serialized form.
- results: Dict[str, BundledAggregations] = {}
-
- # Fetch any ignored users of the requesting user.
- ignored_users = await self._main_store.ignored_users(user_id)
-
- # Threads are special as the latest event of a thread might cause additional
- # events to be fetched. Thus, we check those first!
-
- # Fetch thread summaries (but only for the directly requested events).
- threads = await self._get_threads_for_events(
- events_by_id,
- relations_by_id,
- user_id,
- ignored_users,
- )
- for event_id, thread in threads.items():
- results.setdefault(event_id, BundledAggregations()).thread = thread
-
- # If the latest event in a thread is not already being fetched,
- # add it. This ensures that the bundled aggregations for the
- # latest thread event is correct.
- latest_thread_event = thread.latest_event
- if latest_thread_event and latest_thread_event.event_id not in events_by_id:
- events_by_id[latest_thread_event.event_id] = latest_thread_event
- # Keep relations_by_id in sync with events_by_id:
- #
- # We know that the latest event in a thread has a thread relation
- # (as that is what makes it part of the thread).
- relations_by_id[latest_thread_event.event_id] = RelationTypes.THREAD
-
- async def _fetch_references() -> None:
- """Fetch any references to bundle with this event."""
- references_by_event_id = await self.get_references_for_events(
- events_by_id.keys(), ignored_users=ignored_users
- )
- for event_id, references in references_by_event_id.items():
- if references:
- results.setdefault(event_id, BundledAggregations()).references = {
- "chunk": [{"event_id": ev.event_id} for ev in references]
- }
-
- async def _fetch_edits() -> None:
- """
- Fetch any edits (but not for redacted events).
-
- Note that there is no use in limiting edits by ignored users since the
- parent event should be ignored in the first place if the user is ignored.
- """
- edits = await self._main_store.get_applicable_edits(
- [
- event_id
- for event_id, event in events_by_id.items()
- if not event.internal_metadata.is_redacted()
- ]
- )
- for event_id, edit in edits.items():
- results.setdefault(event_id, BundledAggregations()).replace = edit
-
- # Parallelize the calls for annotations, references, and edits since they
- # are unrelated.
- await make_deferred_yieldable(
- gather_results(
- (
- run_in_background(_fetch_references),
- run_in_background(_fetch_edits),
- )
- )
- )
-
- return results
-
- async def get_threads(
- self,
- requester: Requester,
- room_id: str,
- include: ThreadsListInclude,
- limit: int = 5,
- from_token: Optional[ThreadsNextBatch] = None,
- ) -> JsonDict:
- """Get related events of a event, ordered by topological ordering.
-
- Args:
- requester: The user requesting the relations.
- room_id: The room the event belongs to.
- include: One of "all" or "participated" to indicate which threads should
- be returned.
- limit: Only fetch the most recent `limit` events.
- from_token: Fetch rows from the given token, or from the start if None.
-
- Returns:
- The pagination chunk.
- """
-
- user_id = requester.user.to_string()
-
- # TODO Properly handle a user leaving a room.
- (_, member_event_id) = await self._auth.check_user_in_room_or_world_readable(
- room_id, requester, allow_departed_users=True
- )
-
- # Note that ignored users are not passed into get_threads
- # below. Ignored users are handled in filter_events_for_client (and by
- # not passing them in here we should get a better cache hit rate).
- thread_roots, next_batch = await self._main_store.get_threads(
- room_id=room_id, limit=limit, from_token=from_token
- )
-
- events = await self._main_store.get_events_as_list(thread_roots)
-
- if include == ThreadsListInclude.participated:
- # Pre-seed thread participation with whether the requester sent the event.
- participated = {event.event_id: event.sender == user_id for event in events}
- # For events the requester did not send, check the database for whether
- # the requester sent a threaded reply.
- participated.update(
- await self._main_store.get_threads_participated(
- [eid for eid, p in participated.items() if not p],
- user_id,
- )
- )
-
- # Limit the returned threads to those the user has participated in.
- events = [event for event in events if participated[event.event_id]]
-
- events = await filter_events_for_client(
- self._storage_controllers,
- user_id,
- events,
- is_peeking=(member_event_id is None),
- )
-
- aggregations = await self.get_bundled_aggregations(
- events, requester.user.to_string()
- )
-
- now = self._clock.time_msec()
- serialized_events = await self._event_serializer.serialize_events(
- events, now, bundle_aggregations=aggregations
- )
-
- return_value: JsonDict = {"chunk": serialized_events}
-
- if next_batch:
- return_value["next_batch"] = str(next_batch)
-
- return return_value
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