anonymousland-synapse/synapse/events/presence_router.py
Andrew Morgan 04819239ba
Add a Synapse Module for configuring presence update routing (#9491)
At the moment, if you'd like to share presence between local or remote users, those users must be sharing a room together. This isn't always the most convenient or useful situation though.

This PR adds a module to Synapse that will allow deployments to set up extra logic on where presence updates should be routed. The module must implement two methods, `get_users_for_states` and `get_interested_users`. These methods are given presence updates or user IDs and must return information that Synapse will use to grant passing presence updates around.

A method is additionally added to `ModuleApi` which allows triggering a set of users to receive the current, online presence information for all users they are considered interested in. This is the equivalent of that user receiving presence information during an initial sync. 

The goal of this module is to be fairly generic and useful for a variety of applications, with hard requirements being:

* Sending state for a specific set or all known users to a defined set of local and remote users.
* The ability to trigger an initial sync for specific users, so they receive all current state.
2021-04-06 14:38:30 +01:00

105 lines
4.0 KiB
Python

# -*- coding: utf-8 -*-
# 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.
from typing import TYPE_CHECKING, Dict, Iterable, Set, Union
from synapse.api.presence import UserPresenceState
if TYPE_CHECKING:
from synapse.server import HomeServer
class PresenceRouter:
"""
A module that the homeserver will call upon to help route user presence updates to
additional destinations. If a custom presence router is configured, calls will be
passed to that instead.
"""
ALL_USERS = "ALL"
def __init__(self, hs: "HomeServer"):
self.custom_presence_router = None
# Check whether a custom presence router module has been configured
if hs.config.presence_router_module_class:
# Initialise the module
self.custom_presence_router = hs.config.presence_router_module_class(
config=hs.config.presence_router_config, module_api=hs.get_module_api()
)
# Ensure the module has implemented the required methods
required_methods = ["get_users_for_states", "get_interested_users"]
for method_name in required_methods:
if not hasattr(self.custom_presence_router, method_name):
raise Exception(
"PresenceRouter module '%s' must implement all required methods: %s"
% (
hs.config.presence_router_module_class.__name__,
", ".join(required_methods),
)
)
async def get_users_for_states(
self,
state_updates: Iterable[UserPresenceState],
) -> Dict[str, Set[UserPresenceState]]:
"""
Given an iterable of user presence updates, determine where each one
needs to go.
Args:
state_updates: An iterable of user presence state updates.
Returns:
A dictionary of user_id -> set of UserPresenceState, indicating which
presence updates each user should receive.
"""
if self.custom_presence_router is not None:
# Ask the custom module
return await self.custom_presence_router.get_users_for_states(
state_updates=state_updates
)
# Don't include any extra destinations for presence updates
return {}
async def get_interested_users(self, user_id: str) -> Union[Set[str], ALL_USERS]:
"""
Retrieve a list of users that `user_id` is interested in receiving the
presence of. This will be in addition to those they share a room with.
Optionally, the object PresenceRouter.ALL_USERS can be returned to indicate
that this user should receive all incoming local and remote presence updates.
Note that this method will only be called for local users, but can return users
that are local or remote.
Args:
user_id: A user requesting presence updates.
Returns:
A set of user IDs to return presence updates for, or ALL_USERS to return all
known updates.
"""
if self.custom_presence_router is not None:
# Ask the custom module for interested users
return await self.custom_presence_router.get_interested_users(
user_id=user_id
)
# A custom presence router is not defined.
# Don't report any additional interested users
return set()