mirror of
https://mau.dev/maunium/synapse.git
synced 2024-08-27 20:52:30 +00:00
![Brendan Abolivier](/assets/img/avatar_default.png)
Port the third-party event rules interface to the generic module interface introduced in v1.37.0
354 lines
14 KiB
Markdown
354 lines
14 KiB
Markdown
# Modules
|
|
|
|
Synapse supports extending its functionality by configuring external modules.
|
|
|
|
## Using modules
|
|
|
|
To use a module on Synapse, add it to the `modules` section of the configuration file:
|
|
|
|
```yaml
|
|
modules:
|
|
- module: my_super_module.MySuperClass
|
|
config:
|
|
do_thing: true
|
|
- module: my_other_super_module.SomeClass
|
|
config: {}
|
|
```
|
|
|
|
Each module is defined by a path to a Python class as well as a configuration. This
|
|
information for a given module should be available in the module's own documentation.
|
|
|
|
**Note**: When using third-party modules, you effectively allow someone else to run
|
|
custom code on your Synapse homeserver. Server admins are encouraged to verify the
|
|
provenance of the modules they use on their homeserver and make sure the modules aren't
|
|
running malicious code on their instance.
|
|
|
|
Also note that we are currently in the process of migrating module interfaces to this
|
|
system. While some interfaces might be compatible with it, others still require
|
|
configuring modules in another part of Synapse's configuration file. Currently, only the
|
|
spam checker interface is compatible with this new system.
|
|
|
|
## Writing a module
|
|
|
|
A module is a Python class that uses Synapse's module API to interact with the
|
|
homeserver. It can register callbacks that Synapse will call on specific operations, as
|
|
well as web resources to attach to Synapse's web server.
|
|
|
|
When instantiated, a module is given its parsed configuration as well as an instance of
|
|
the `synapse.module_api.ModuleApi` class. The configuration is a dictionary, and is
|
|
either the output of the module's `parse_config` static method (see below), or the
|
|
configuration associated with the module in Synapse's configuration file.
|
|
|
|
See the documentation for the `ModuleApi` class
|
|
[here](https://github.com/matrix-org/synapse/blob/master/synapse/module_api/__init__.py).
|
|
|
|
### Handling the module's configuration
|
|
|
|
A module can implement the following static method:
|
|
|
|
```python
|
|
@staticmethod
|
|
def parse_config(config: dict) -> dict
|
|
```
|
|
|
|
This method is given a dictionary resulting from parsing the YAML configuration for the
|
|
module. It may modify it (for example by parsing durations expressed as strings (e.g.
|
|
"5d") into milliseconds, etc.), and return the modified dictionary. It may also verify
|
|
that the configuration is correct, and raise an instance of
|
|
`synapse.module_api.errors.ConfigError` if not.
|
|
|
|
### Registering a web resource
|
|
|
|
Modules can register web resources onto Synapse's web server using the following module
|
|
API method:
|
|
|
|
```python
|
|
def ModuleApi.register_web_resource(path: str, resource: IResource) -> None
|
|
```
|
|
|
|
The path is the full absolute path to register the resource at. For example, if you
|
|
register a resource for the path `/_synapse/client/my_super_module/say_hello`, Synapse
|
|
will serve it at `http(s)://[HS_URL]/_synapse/client/my_super_module/say_hello`. Note
|
|
that Synapse does not allow registering resources for several sub-paths in the `/_matrix`
|
|
namespace (such as anything under `/_matrix/client` for example). It is strongly
|
|
recommended that modules register their web resources under the `/_synapse/client`
|
|
namespace.
|
|
|
|
The provided resource is a Python class that implements Twisted's [IResource](https://twistedmatrix.com/documents/current/api/twisted.web.resource.IResource.html)
|
|
interface (such as [Resource](https://twistedmatrix.com/documents/current/api/twisted.web.resource.Resource.html)).
|
|
|
|
Only one resource can be registered for a given path. If several modules attempt to
|
|
register a resource for the same path, the module that appears first in Synapse's
|
|
configuration file takes priority.
|
|
|
|
Modules **must** register their web resources in their `__init__` method.
|
|
|
|
### Registering a callback
|
|
|
|
Modules can use Synapse's module API to register callbacks. Callbacks are functions that
|
|
Synapse will call when performing specific actions. Callbacks must be asynchronous, and
|
|
are split in categories. A single module may implement callbacks from multiple categories,
|
|
and is under no obligation to implement all callbacks from the categories it registers
|
|
callbacks for.
|
|
|
|
Modules can register callbacks using one of the module API's `register_[...]_callbacks`
|
|
methods. The callback functions are passed to these methods as keyword arguments, with
|
|
the callback name as the argument name and the function as its value. This is demonstrated
|
|
in the example below. A `register_[...]_callbacks` method exists for each module type
|
|
documented in this section.
|
|
|
|
#### Spam checker callbacks
|
|
|
|
Spam checker callbacks allow module developers to implement spam mitigation actions for
|
|
Synapse instances. Spam checker callbacks can be registered using the module API's
|
|
`register_spam_checker_callbacks` method.
|
|
|
|
The available spam checker callbacks are:
|
|
|
|
```python
|
|
async def check_event_for_spam(event: "synapse.events.EventBase") -> Union[bool, str]
|
|
```
|
|
|
|
Called when receiving an event from a client or via federation. The module can return
|
|
either a `bool` to indicate whether the event must be rejected because of spam, or a `str`
|
|
to indicate the event must be rejected because of spam and to give a rejection reason to
|
|
forward to clients.
|
|
|
|
```python
|
|
async def user_may_invite(inviter: str, invitee: str, room_id: str) -> bool
|
|
```
|
|
|
|
Called when processing an invitation. The module must return a `bool` indicating whether
|
|
the inviter can invite the invitee to the given room. Both inviter and invitee are
|
|
represented by their Matrix user ID (e.g. `@alice:example.com`).
|
|
|
|
```python
|
|
async def user_may_create_room(user: str) -> bool
|
|
```
|
|
|
|
Called when processing a room creation request. The module must return a `bool` indicating
|
|
whether the given user (represented by their Matrix user ID) is allowed to create a room.
|
|
|
|
```python
|
|
async def user_may_create_room_alias(user: str, room_alias: "synapse.types.RoomAlias") -> bool
|
|
```
|
|
|
|
Called when trying to associate an alias with an existing room. The module must return a
|
|
`bool` indicating whether the given user (represented by their Matrix user ID) is allowed
|
|
to set the given alias.
|
|
|
|
```python
|
|
async def user_may_publish_room(user: str, room_id: str) -> bool
|
|
```
|
|
|
|
Called when trying to publish a room to the homeserver's public rooms directory. The
|
|
module must return a `bool` indicating whether the given user (represented by their
|
|
Matrix user ID) is allowed to publish the given room.
|
|
|
|
```python
|
|
async def check_username_for_spam(user_profile: Dict[str, str]) -> bool
|
|
```
|
|
|
|
Called when computing search results in the user directory. The module must return a
|
|
`bool` indicating whether the given user profile can appear in search results. The profile
|
|
is represented as a dictionary with the following keys:
|
|
|
|
* `user_id`: The Matrix ID for this user.
|
|
* `display_name`: The user's display name.
|
|
* `avatar_url`: The `mxc://` URL to the user's avatar.
|
|
|
|
The module is given a copy of the original dictionary, so modifying it from within the
|
|
module cannot modify a user's profile when included in user directory search results.
|
|
|
|
```python
|
|
async def check_registration_for_spam(
|
|
email_threepid: Optional[dict],
|
|
username: Optional[str],
|
|
request_info: Collection[Tuple[str, str]],
|
|
auth_provider_id: Optional[str] = None,
|
|
) -> "synapse.spam_checker_api.RegistrationBehaviour"
|
|
```
|
|
|
|
Called when registering a new user. The module must return a `RegistrationBehaviour`
|
|
indicating whether the registration can go through or must be denied, or whether the user
|
|
may be allowed to register but will be shadow banned.
|
|
|
|
The arguments passed to this callback are:
|
|
|
|
* `email_threepid`: The email address used for registering, if any.
|
|
* `username`: The username the user would like to register. Can be `None`, meaning that
|
|
Synapse will generate one later.
|
|
* `request_info`: A collection of tuples, which first item is a user agent, and which
|
|
second item is an IP address. These user agents and IP addresses are the ones that were
|
|
used during the registration process.
|
|
* `auth_provider_id`: The identifier of the SSO authentication provider, if any.
|
|
|
|
```python
|
|
async def check_media_file_for_spam(
|
|
file_wrapper: "synapse.rest.media.v1.media_storage.ReadableFileWrapper",
|
|
file_info: "synapse.rest.media.v1._base.FileInfo",
|
|
) -> bool
|
|
```
|
|
|
|
Called when storing a local or remote file. The module must return a boolean indicating
|
|
whether the given file can be stored in the homeserver's media store.
|
|
|
|
#### Account validity callbacks
|
|
|
|
Account validity callbacks allow module developers to add extra steps to verify the
|
|
validity on an account, i.e. see if a user can be granted access to their account on the
|
|
Synapse instance. Account validity callbacks can be registered using the module API's
|
|
`register_account_validity_callbacks` method.
|
|
|
|
The available account validity callbacks are:
|
|
|
|
```python
|
|
async def is_user_expired(user: str) -> Optional[bool]
|
|
```
|
|
|
|
Called when processing any authenticated request (except for logout requests). The module
|
|
can return a `bool` to indicate whether the user has expired and should be locked out of
|
|
their account, or `None` if the module wasn't able to figure it out. The user is
|
|
represented by their Matrix user ID (e.g. `@alice:example.com`).
|
|
|
|
If the module returns `True`, the current request will be denied with the error code
|
|
`ORG_MATRIX_EXPIRED_ACCOUNT` and the HTTP status code 403. Note that this doesn't
|
|
invalidate the user's access token.
|
|
|
|
```python
|
|
async def on_user_registration(user: str) -> None
|
|
```
|
|
|
|
Called after successfully registering a user, in case the module needs to perform extra
|
|
operations to keep track of them. (e.g. add them to a database table). The user is
|
|
represented by their Matrix user ID.
|
|
|
|
#### Third party rules callbacks
|
|
|
|
Third party rules callbacks allow module developers to add extra checks to verify the
|
|
validity of incoming events. Third party event rules callbacks can be registered using
|
|
the module API's `register_third_party_rules_callbacks` method.
|
|
|
|
The available third party rules callbacks are:
|
|
|
|
```python
|
|
async def check_event_allowed(
|
|
event: "synapse.events.EventBase",
|
|
state_events: "synapse.types.StateMap",
|
|
) -> Tuple[bool, Optional[dict]]
|
|
```
|
|
|
|
**<span style="color:red">
|
|
This callback is very experimental and can and will break without notice. Module developers
|
|
are encouraged to implement `check_event_for_spam` from the spam checker category instead.
|
|
</span>**
|
|
|
|
Called when processing any incoming event, with the event and a `StateMap`
|
|
representing the current state of the room the event is being sent into. A `StateMap` is
|
|
a dictionary that maps tuples containing an event type and a state key to the
|
|
corresponding state event. For example retrieving the room's `m.room.create` event from
|
|
the `state_events` argument would look like this: `state_events.get(("m.room.create", ""))`.
|
|
The module must return a boolean indicating whether the event can be allowed.
|
|
|
|
Note that this callback function processes incoming events coming via federation
|
|
traffic (on top of client traffic). This means denying an event might cause the local
|
|
copy of the room's history to diverge from that of remote servers. This may cause
|
|
federation issues in the room. It is strongly recommended to only deny events using this
|
|
callback function if the sender is a local user, or in a private federation in which all
|
|
servers are using the same module, with the same configuration.
|
|
|
|
If the boolean returned by the module is `True`, it may also tell Synapse to replace the
|
|
event with new data by returning the new event's data as a dictionary. In order to do
|
|
that, it is recommended the module calls `event.get_dict()` to get the current event as a
|
|
dictionary, and modify the returned dictionary accordingly.
|
|
|
|
Note that replacing the event only works for events sent by local users, not for events
|
|
received over federation.
|
|
|
|
```python
|
|
async def on_create_room(
|
|
requester: "synapse.types.Requester",
|
|
request_content: dict,
|
|
is_requester_admin: bool,
|
|
) -> None
|
|
```
|
|
|
|
Called when processing a room creation request, with the `Requester` object for the user
|
|
performing the request, a dictionary representing the room creation request's JSON body
|
|
(see [the spec](https://matrix.org/docs/spec/client_server/latest#post-matrix-client-r0-createroom)
|
|
for a list of possible parameters), and a boolean indicating whether the user performing
|
|
the request is a server admin.
|
|
|
|
Modules can modify the `request_content` (by e.g. adding events to its `initial_state`),
|
|
or deny the room's creation by raising a `module_api.errors.SynapseError`.
|
|
|
|
|
|
### Porting an existing module that uses the old interface
|
|
|
|
In order to port a module that uses Synapse's old module interface, its author needs to:
|
|
|
|
* ensure the module's callbacks are all asynchronous.
|
|
* register their callbacks using one or more of the `register_[...]_callbacks` methods
|
|
from the `ModuleApi` class in the module's `__init__` method (see [this section](#registering-a-callback)
|
|
for more info).
|
|
|
|
Additionally, if the module is packaged with an additional web resource, the module
|
|
should register this resource in its `__init__` method using the `register_web_resource`
|
|
method from the `ModuleApi` class (see [this section](#registering-a-web-resource) for
|
|
more info).
|
|
|
|
The module's author should also update any example in the module's configuration to only
|
|
use the new `modules` section in Synapse's configuration file (see [this section](#using-modules)
|
|
for more info).
|
|
|
|
### Example
|
|
|
|
The example below is a module that implements the spam checker callback
|
|
`user_may_create_room` to deny room creation to user `@evilguy:example.com`, and registers
|
|
a web resource to the path `/_synapse/client/demo/hello` that returns a JSON object.
|
|
|
|
```python
|
|
import json
|
|
|
|
from twisted.web.resource import Resource
|
|
from twisted.web.server import Request
|
|
|
|
from synapse.module_api import ModuleApi
|
|
|
|
|
|
class DemoResource(Resource):
|
|
def __init__(self, config):
|
|
super(DemoResource, self).__init__()
|
|
self.config = config
|
|
|
|
def render_GET(self, request: Request):
|
|
name = request.args.get(b"name")[0]
|
|
request.setHeader(b"Content-Type", b"application/json")
|
|
return json.dumps({"hello": name})
|
|
|
|
|
|
class DemoModule:
|
|
def __init__(self, config: dict, api: ModuleApi):
|
|
self.config = config
|
|
self.api = api
|
|
|
|
self.api.register_web_resource(
|
|
path="/_synapse/client/demo/hello",
|
|
resource=DemoResource(self.config),
|
|
)
|
|
|
|
self.api.register_spam_checker_callbacks(
|
|
user_may_create_room=self.user_may_create_room,
|
|
)
|
|
|
|
@staticmethod
|
|
def parse_config(config):
|
|
return config
|
|
|
|
async def user_may_create_room(self, user: str) -> bool:
|
|
if user == "@evilguy:example.com":
|
|
return False
|
|
|
|
return True
|
|
```
|