forked-synapse/synapse/events/auto_accept_invites.py
devonh 6a9a641fb8
Bring auto-accept invite logic into Synapse (#17147)
This PR ports the logic from the
[synapse_auto_accept_invite](https://github.com/matrix-org/synapse-auto-accept-invite)
module into synapse.

I went with the naive approach of injecting the "module" next to where
third party modules are currently loaded. If there is a better/preferred
way to handle this, I'm all ears. It wasn't obvious to me if there was a
better location to add this logic that would cleanly apply to all
incoming invite events.

Relies on https://github.com/element-hq/synapse/pull/17166 to fix linter
errors.
2024-05-21 20:09:17 +00:00

197 lines
7.2 KiB
Python

#
# This file is licensed under the Affero General Public License (AGPL) version 3.
#
# Copyright 2021 The Matrix.org Foundation C.I.C
# Copyright (C) 2024 New Vector, Ltd
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# See the GNU Affero General Public License for more details:
# <https://www.gnu.org/licenses/agpl-3.0.html>.
#
# Originally licensed under the Apache License, Version 2.0:
# <http://www.apache.org/licenses/LICENSE-2.0>.
#
# [This file includes modifications made by New Vector Limited]
#
#
import logging
from http import HTTPStatus
from typing import Any, Dict, Tuple
from synapse.api.constants import AccountDataTypes, EventTypes, Membership
from synapse.api.errors import SynapseError
from synapse.config.auto_accept_invites import AutoAcceptInvitesConfig
from synapse.module_api import EventBase, ModuleApi, run_as_background_process
logger = logging.getLogger(__name__)
class InviteAutoAccepter:
def __init__(self, config: AutoAcceptInvitesConfig, api: ModuleApi):
# Keep a reference to the Module API.
self._api = api
self._config = config
if not self._config.enabled:
return
should_run_on_this_worker = config.worker_to_run_on == self._api.worker_name
if not should_run_on_this_worker:
logger.info(
"Not accepting invites on this worker (configured: %r, here: %r)",
config.worker_to_run_on,
self._api.worker_name,
)
return
logger.info(
"Accepting invites on this worker (here: %r)", self._api.worker_name
)
# Register the callback.
self._api.register_third_party_rules_callbacks(
on_new_event=self.on_new_event,
)
async def on_new_event(self, event: EventBase, *args: Any) -> None:
"""Listens for new events, and if the event is an invite for a local user then
automatically accepts it.
Args:
event: The incoming event.
"""
# Check if the event is an invite for a local user.
is_invite_for_local_user = (
event.type == EventTypes.Member
and event.is_state()
and event.membership == Membership.INVITE
and self._api.is_mine(event.state_key)
)
# Only accept invites for direct messages if the configuration mandates it.
is_direct_message = event.content.get("is_direct", False)
is_allowed_by_direct_message_rules = (
not self._config.accept_invites_only_for_direct_messages
or is_direct_message is True
)
# Only accept invites from remote users if the configuration mandates it.
is_from_local_user = self._api.is_mine(event.sender)
is_allowed_by_local_user_rules = (
not self._config.accept_invites_only_from_local_users
or is_from_local_user is True
)
if (
is_invite_for_local_user
and is_allowed_by_direct_message_rules
and is_allowed_by_local_user_rules
):
# Make the user join the room. We run this as a background process to circumvent a race condition
# that occurs when responding to invites over federation (see https://github.com/matrix-org/synapse-auto-accept-invite/issues/12)
run_as_background_process(
"retry_make_join",
self._retry_make_join,
event.state_key,
event.state_key,
event.room_id,
"join",
bg_start_span=False,
)
if is_direct_message:
# Mark this room as a direct message!
await self._mark_room_as_direct_message(
event.state_key, event.sender, event.room_id
)
async def _mark_room_as_direct_message(
self, user_id: str, dm_user_id: str, room_id: str
) -> None:
"""
Marks a room (`room_id`) as a direct message with the counterparty `dm_user_id`
from the perspective of the user `user_id`.
Args:
user_id: the user for whom the membership is changing
dm_user_id: the user performing the membership change
room_id: room id of the room the user is invited to
"""
# This is a dict of User IDs to tuples of Room IDs
# (get_global will return a frozendict of tuples as it freezes the data,
# but we should accept either frozen or unfrozen variants.)
# Be careful: we convert the outer frozendict into a dict here,
# but the contents of the dict are still frozen (tuples in lieu of lists,
# etc.)
dm_map: Dict[str, Tuple[str, ...]] = dict(
await self._api.account_data_manager.get_global(
user_id, AccountDataTypes.DIRECT
)
or {}
)
if dm_user_id not in dm_map:
dm_map[dm_user_id] = (room_id,)
else:
dm_rooms_for_user = dm_map[dm_user_id]
assert isinstance(dm_rooms_for_user, (tuple, list))
dm_map[dm_user_id] = tuple(dm_rooms_for_user) + (room_id,)
await self._api.account_data_manager.put_global(
user_id, AccountDataTypes.DIRECT, dm_map
)
async def _retry_make_join(
self, sender: str, target: str, room_id: str, new_membership: str
) -> None:
"""
A function to retry sending the `make_join` request with an increasing backoff. This is
implemented to work around a race condition when receiving invites over federation.
Args:
sender: the user performing the membership change
target: the user for whom the membership is changing
room_id: room id of the room to join to
new_membership: the type of membership event (in this case will be "join")
"""
sleep = 0
retries = 0
join_event = None
while retries < 5:
try:
await self._api.sleep(sleep)
join_event = await self._api.update_room_membership(
sender=sender,
target=target,
room_id=room_id,
new_membership=new_membership,
)
except SynapseError as e:
if e.code == HTTPStatus.FORBIDDEN:
logger.debug(
f"Update_room_membership was forbidden. This can sometimes be expected for remote invites. Exception: {e}"
)
else:
logger.warn(
f"Update_room_membership raised the following unexpected (SynapseError) exception: {e}"
)
except Exception as e:
logger.warn(
f"Update_room_membership raised the following unexpected exception: {e}"
)
sleep = 2**retries
retries += 1
if join_event is not None:
break