Consolidate logic for parsing relations. (#12693)

Parse the `m.relates_to` event content field (which describes relations)
in a single place, this is used during:

* Event persistence.
* Validation of the Client-Server API.
* Fetching bundled aggregations.
* Processing of push rules.

Each of these separately implement the logic and each made slightly
different assumptions about what was valid. Some had minor / potential
bugs.
This commit is contained in:
Patrick Cloke 2022-05-16 08:42:45 -04:00 committed by GitHub
parent cde8af9a49
commit 86a515ccbf
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7 changed files with 98 additions and 61 deletions

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@ -44,7 +44,7 @@ from synapse.api.errors import (
from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, RoomVersions
from synapse.api.urls import ConsentURIBuilder
from synapse.event_auth import validate_event_for_room_version
from synapse.events import EventBase
from synapse.events import EventBase, relation_from_event
from synapse.events.builder import EventBuilder
from synapse.events.snapshot import EventContext
from synapse.events.validator import EventValidator
@ -1060,20 +1060,11 @@ class EventCreationHandler:
SynapseError if the event is invalid.
"""
relation = event.content.get("m.relates_to")
relation = relation_from_event(event)
if not relation:
return
relation_type = relation.get("rel_type")
if not relation_type:
return
# Ensure the parent is real.
relates_to = relation.get("event_id")
if not relates_to:
return
parent_event = await self.store.get_event(relates_to, allow_none=True)
parent_event = await self.store.get_event(relation.parent_id, allow_none=True)
if parent_event:
# And in the same room.
if parent_event.room_id != event.room_id:
@ -1082,28 +1073,31 @@ class EventCreationHandler:
else:
# There must be some reason that the client knows the event exists,
# see if there are existing relations. If so, assume everything is fine.
if not await self.store.event_is_target_of_relation(relates_to):
if not await self.store.event_is_target_of_relation(relation.parent_id):
# Otherwise, the client can't know about the parent event!
raise SynapseError(400, "Can't send relation to unknown event")
# If this event is an annotation then we check that that the sender
# can't annotate the same way twice (e.g. stops users from liking an
# event multiple times).
if relation_type == RelationTypes.ANNOTATION:
aggregation_key = relation["key"]
if relation.rel_type == RelationTypes.ANNOTATION:
aggregation_key = relation.aggregation_key
if aggregation_key is None:
raise SynapseError(400, "Missing aggregation key")
if len(aggregation_key) > 500:
raise SynapseError(400, "Aggregation key is too long")
already_exists = await self.store.has_user_annotated_event(
relates_to, event.type, aggregation_key, event.sender
relation.parent_id, event.type, aggregation_key, event.sender
)
if already_exists:
raise SynapseError(400, "Can't send same reaction twice")
# Don't attempt to start a thread if the parent event is a relation.
elif relation_type == RelationTypes.THREAD:
if await self.store.event_includes_relation(relates_to):
elif relation.rel_type == RelationTypes.THREAD:
if await self.store.event_includes_relation(relation.parent_id):
raise SynapseError(
400, "Cannot start threads from an event with a relation"
)