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			9.1 KiB
		
	
	
	
		
			Markdown
		
	
	
			
		
		
	
	
			248 lines
		
	
	
		
			9.1 KiB
		
	
	
	
		
			Markdown
		
	
	
| <h2 style="color:red">
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| This page of the Synapse documentation is now deprecated. For up to date
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| documentation on setting up or writing a presence router module, please see
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| <a href="modules.md">this page</a>.
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| </h2>
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| 
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| # Presence Router Module
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| 
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| Synapse supports configuring a module that can specify additional users
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| (local or remote) to should receive certain presence updates from local
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| users.
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| 
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| Note that routing presence via Application Service transactions is not
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| currently supported.
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| 
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| The presence routing module is implemented as a Python class, which will
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| be imported by the running Synapse.
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| 
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| ## Python Presence Router Class
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| 
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| The Python class is instantiated with two objects:
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| 
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| * A configuration object of some type (see below).
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| * An instance of `synapse.module_api.ModuleApi`.
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| 
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| It then implements methods related to presence routing.
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| 
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| Note that one method of `ModuleApi` that may be useful is:
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| 
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| ```python
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| async def ModuleApi.send_local_online_presence_to(users: Iterable[str]) -> None
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| ```
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| 
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| which can be given a list of local or remote MXIDs to broadcast known, online user
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| presence to (for those users that the receiving user is considered interested in). 
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| It does not include state for users who are currently offline, and it can only be
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| called on workers that support sending federation. Additionally, this method must
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| only be called from the process that has been configured to write to the
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| the [presence stream](workers.md#stream-writers).
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| By default, this is the main process, but another worker can be configured to do
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| so.
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| 
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| ### Module structure
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| 
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| Below is a list of possible methods that can be implemented, and whether they are
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| required.
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| 
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| #### `parse_config`
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| 
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| ```python
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| def parse_config(config_dict: dict) -> Any
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| ```
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| 
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| **Required.** A static method that is passed a dictionary of config options, and
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|   should return a validated config object. This method is described further in
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|   [Configuration](#configuration).
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| 
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| #### `get_users_for_states`
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| 
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| ```python
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| async def get_users_for_states(
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|     self,
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|     state_updates: Iterable[UserPresenceState],
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| ) -> Dict[str, Set[UserPresenceState]]:
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| ```
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| 
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| **Required.** An asynchronous method that is passed an iterable of user presence
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| state. This method can determine whether a given presence update should be sent to certain
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| users. It does this by returning a dictionary with keys representing local or remote
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| Matrix User IDs, and values being a python set
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| of `synapse.handlers.presence.UserPresenceState` instances.
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| 
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| Synapse will then attempt to send the specified presence updates to each user when
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| possible.
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| 
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| #### `get_interested_users`
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| 
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| ```python
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| async def get_interested_users(self, user_id: str) -> Union[Set[str], str]
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| ```
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| 
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| **Required.** An asynchronous method that is passed a single Matrix User ID. This
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| method is expected to return the users that the passed in user may be interested in the
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| presence of. Returned users may be local or remote. The presence routed as a result of
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| what this method returns is sent in addition to the updates already sent between users
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| that share a room together. Presence updates are deduplicated.
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| 
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| This method should return a python set of Matrix User IDs, or the object
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| `synapse.events.presence_router.PresenceRouter.ALL_USERS` to indicate that the passed
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| user should receive presence information for *all* known users.
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| 
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| For clarity, if the user `@alice:example.org` is passed to this method, and the Set
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| `{"@bob:example.com", "@charlie:somewhere.org"}` is returned, this signifies that Alice
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| should receive presence updates sent by Bob and Charlie, regardless of whether these
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| users share a room.
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| 
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| ### Example
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| 
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| Below is an example implementation of a presence router class.
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| 
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| ```python
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| from typing import Dict, Iterable, Set, Union
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| from synapse.events.presence_router import PresenceRouter
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| from synapse.handlers.presence import UserPresenceState
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| from synapse.module_api import ModuleApi
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| 
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| class PresenceRouterConfig:
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|     def __init__(self):
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|         # Config options with their defaults
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|         # A list of users to always send all user presence updates to
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|         self.always_send_to_users = []  # type: List[str]
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|         
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|         # A list of users to ignore presence updates for. Does not affect
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|         # shared-room presence relationships
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|         self.blacklisted_users = []  # type: List[str]
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| 
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| class ExamplePresenceRouter:
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|     """An example implementation of synapse.presence_router.PresenceRouter.
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|     Supports routing all presence to a configured set of users, or a subset
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|     of presence from certain users to members of certain rooms.
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| 
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|     Args:
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|         config: A configuration object.
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|         module_api: An instance of Synapse's ModuleApi.
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|     """
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|     def __init__(self, config: PresenceRouterConfig, module_api: ModuleApi):
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|         self._config = config
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|         self._module_api = module_api
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| 
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|     @staticmethod
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|     def parse_config(config_dict: dict) -> PresenceRouterConfig:
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|         """Parse a configuration dictionary from the homeserver config, do
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|         some validation and return a typed PresenceRouterConfig.
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| 
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|         Args:
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|             config_dict: The configuration dictionary.
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| 
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|         Returns:
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|             A validated config object.
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|         """
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|         # Initialise a typed config object
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|         config = PresenceRouterConfig()
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|         always_send_to_users = config_dict.get("always_send_to_users")
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|         blacklisted_users = config_dict.get("blacklisted_users")
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| 
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|         # Do some validation of config options... otherwise raise a
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|         # synapse.config.ConfigError.
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|         config.always_send_to_users = always_send_to_users
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|         config.blacklisted_users = blacklisted_users
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| 
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|         return config
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| 
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|     async def get_users_for_states(
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|         self,
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|         state_updates: Iterable[UserPresenceState],
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|     ) -> Dict[str, Set[UserPresenceState]]:
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|         """Given an iterable of user presence updates, determine where each one
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|         needs to go. Returned results will not affect presence updates that are
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|         sent between users who share a room.
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| 
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|         Args:
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|             state_updates: An iterable of user presence state updates.
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| 
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|         Returns:
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|           A dictionary of user_id -> set of UserPresenceState that the user should 
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|           receive.
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|         """
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|         destination_users = {}  # type: Dict[str, Set[UserPresenceState]
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| 
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|         # Ignore any updates for blacklisted users
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|         desired_updates = set()
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|         for update in state_updates:
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|             if update.state_key not in self._config.blacklisted_users:
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|                 desired_updates.add(update)
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| 
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|         # Send all presence updates to specific users
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|         for user_id in self._config.always_send_to_users:
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|             destination_users[user_id] = desired_updates
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| 
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|         return destination_users
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| 
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|     async def get_interested_users(
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|         self,
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|         user_id: str,
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|     ) -> Union[Set[str], PresenceRouter.ALL_USERS]:
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|         """
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|         Retrieve a list of users that `user_id` is interested in receiving the
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|         presence of. This will be in addition to those they share a room with.
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|         Optionally, the object PresenceRouter.ALL_USERS can be returned to indicate
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|         that this user should receive all incoming local and remote presence updates.
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| 
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|         Note that this method will only be called for local users.
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| 
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|         Args:
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|           user_id: A user requesting presence updates.
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| 
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|         Returns:
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|           A set of user IDs to return additional presence updates for, or
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|           PresenceRouter.ALL_USERS to return presence updates for all other users.
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|         """
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|         if user_id in self._config.always_send_to_users:
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|             return PresenceRouter.ALL_USERS
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| 
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|         return set()
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| ```
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| 
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| #### A note on `get_users_for_states` and `get_interested_users`
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| 
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| Both of these methods are effectively two different sides of the same coin. The logic
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| regarding which users should receive updates for other users should be the same 
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| between them.
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| 
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| `get_users_for_states` is called when presence updates come in from either federation 
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| or local users, and is used to either direct local presence to remote users, or to
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| wake up the sync streams of local users to collect remote presence.
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| 
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| In contrast, `get_interested_users` is used to determine the users that presence should
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| be fetched for when a local user is syncing. This presence is then retrieved, before
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| being fed through `get_users_for_states` once again, with only the syncing user's
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| routing information pulled from the resulting dictionary.
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| 
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| Their routing logic should thus line up, else you may run into unintended behaviour.
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| 
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| ## Configuration
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| 
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| Once you've crafted your module and installed it into the same Python environment as
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| Synapse, amend your homeserver config file with the following.
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| 
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| ```yaml
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| presence:
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|   enabled: true
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| 
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|   presence_router:
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|     module: my_module.ExamplePresenceRouter
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|     config:
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|       # Any configuration options for your module. The below is an example.
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|       # of setting options for ExamplePresenceRouter.
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|       always_send_to_users: ["@presence_gobbler:example.org"]
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|       blacklisted_users:
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|         - "@alice:example.com"
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|         - "@bob:example.com"
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|       ...
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| ```
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| 
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| The contents of `config` will be passed as a Python dictionary to the static
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| `parse_config` method of your class. The object returned by this method will
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| then be passed to the `__init__` method of your module as `config`.
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