glib.MessageBus

class dbus_fast.glib.MessageBus(bus_address: str | None = None, bus_type: BusType = BusType.SESSION, auth: Authenticator | None = None)

Bases: BaseMessageBus

The message bus implementation for use with the GLib main loop.

The message bus class is the entry point into all the features of the library. It sets up a connection to the DBus daemon and exposes an interface to send and receive messages and expose services.

You must call connect() or connect_sync() before using this message bus.

Parameters:

  • bus_type (BusType) – The type of bus to connect to. Affects the search path for the bus address.

  • bus_address – A specific bus address to connect to. Should not be used under normal circumstances.

  • auth (Authenticator) – The authenticator to use, defaults to an instance of AuthExternal.

Variables:

  • connected (bool) – True if this message bus is expected to be able to send and receive messages.

  • unique_name (str) – The unique name of the message bus connection. It will be None until the message bus connects.

add_message_handler(handler: Callable[[Message], Message | bool | None]) → None

Add a custom message handler for incoming messages.

The handler should be a callable that takes a Message. If the message is a method call, you may return another Message as a reply and it will be marked as handled. You may also return True to mark the message as handled without sending a reply.

Parameters:

handler (Callable or None) – A handler that will be run for every message the bus connection received.

call(msg: Message, reply_notify: Callable[[Message | None, Exception | None], None] | None = None)

Send a method call and asynchronously wait for a reply from the DBus daemon.

Parameters:

  • msg (Message) – The method call message to send.

  • reply_notify (Callable) – A callback that will be called with the reply to this message. May return an Exception on connection errors.

call_sync(msg: Message) → Message | None

Send a method call and synchronously wait for a reply from the DBus daemon.

Parameters:

msg (Message) – The method call message to send.

Returns:

A message in reply to the message sent. If the message does not expect a reply based on the message flags or type, returns None immediately.

Return type:

Message

Raises:

  • DBusError - If the service threw an error for the method call or returned an invalid result.

  • Exception - If a connection error occurred.

connect(connect_notify: Callable[[MessageBus, Exception | None], None] | None = None)

Connect this message bus to the DBus daemon.

This method or the synchronous version must be called before the message bus can be used.

Parameters:

connect_notify – A callback that will be called with this message bus. May return an Exception on connection errors or AuthError on authorization errors.

connect_sync() → MessageBus

Connect this message bus to the DBus daemon.

This method or the asynchronous version must be called before the message bus can be used.

Returns:

This message bus for convenience.

Return type:

MessageBus

Raises:

  • AuthError - If authorization to the DBus daemon failed.

  • Exception - If there was a connection error.

disconnect() → None

Disconnect the message bus by closing the underlying connection asynchronously.

All pending and future calls will error with a connection error.

export(path: str, interface: ServiceInterface) → None

Export the service interface on this message bus to make it available to other clients.

Parameters:

  • path (str) – The object path to export this interface on.

  • interface (ServiceInterface) – The service interface to export.

Raises:

  • InvalidObjectPathError - If the given object path is not valid.

  • ValueError - If an interface with this name is already exported on the message bus at this path

get_proxy_object(bus_name: str, path: str, introspection: Node) → ProxyObject

Get a proxy object for the path exported on the bus that owns the name. The object is expected to export the interfaces and nodes specified in the introspection data.

This is the entry point into the high-level client.

Parameters:

  • bus_name (str) – The name on the bus to get the proxy object for.

  • path (str) – The path on the client for the proxy object.

  • introspection (Node or str or ElementTree) – XML introspection data used to build the interfaces on the proxy object.

Returns:

A proxy object for the given path on the given name.

Return type:

BaseProxyObject

Raises:
introspect(bus_name: str, path: str, callback: Callable[[Node | None, Exception | None], None], check_callback_type: bool = True, validate_property_names: bool = True) → None

Get introspection data for the node at the given path from the given bus name.

Calls the standard org.freedesktop.DBus.Introspectable.Introspect on the bus for the path.

Parameters:

  • bus_name (str) – The name to introspect.

  • path (str) – The path to introspect.

  • callback (Callable) – A callback that will be called with the introspection data as a Node.

  • check_callback_type (bool) – Whether to check callback type or not.

  • validate_property_names (bool) – Whether to validate property names or not.

Raises:
introspect_sync(bus_name: str, path: str) → Node

Get introspection data for the node at the given path from the given bus name.

Calls the standard org.freedesktop.DBus.Introspectable.Introspect on the bus for the path.

Parameters:

  • bus_name (str) – The name to introspect.

  • path (str) – The path to introspect.

Returns:

The introspection data for the name at the path.

Return type:

Node

Raises:

  • InvalidObjectPathError - If the given object path is not valid.

  • InvalidBusNameError - If the given bus name is not valid.

  • DBusError - If the service threw an error for the method call or returned an invalid result.

  • Exception - If a connection error occurred.

next_serial()

Get the next serial for this bus. This can be used as the serial attribute of a Message to manually handle the serial of messages.

Returns:

The next serial for the bus.

Return type:

int

release_name(name: str, callback: Callable[[ReleaseNameReply | None, Exception | None], None] | None = None, check_callback_type: bool = True) → None

Request that this message bus release the given name.

Parameters:

  • name (str) – The name to release.

  • callback (Callable) – A callback that will be called with the reply of the release request as a ReleaseNameReply.

Raises:
release_name_sync(name: str) → ReleaseNameReply

Request that this message bus release the given name.

Parameters:

name (str) – The name to release.

Returns:

The reply to the release request.

Return type:

ReleaseNameReply

Raises:

  • InvalidBusNameError - If the given bus name is not valid.

  • DBusError - If the service threw an error for the method call or returned an invalid result.

  • Exception - If a connection error occurred.

remove_message_handler(handler: Callable[[Message], Message | bool | None]) → None

Remove a message handler that was previously added by add_message_handler().

Parameters:

handler (Callable) – A message handler.

request_name(name: str, flags: ~dbus_fast.constants.NameFlag = <NameFlag.NONE: 0>, callback: ~typing.Callable[[~dbus_fast.constants.RequestNameReply | None, Exception | None], None] | None = None, check_callback_type: bool = True) → None

Request that this message bus owns the given name.

Parameters:

  • name (str) – The name to request.

  • flags (NameFlag) – Name flags that affect the behavior of the name request.

  • callback (Callable) – A callback that will be called with the reply of the request as a RequestNameReply.

Raises:
request_name_sync(name: str, flags: ~dbus_fast.constants.NameFlag = <NameFlag.NONE: 0>) → RequestNameReply

Request that this message bus owns the given name.

Parameters:

  • name (str) – The name to request.

  • flags (NameFlag) – Name flags that affect the behavior of the name request.

Returns:

The reply to the name request.

Return type:

RequestNameReply

Raises:

  • InvalidBusNameError - If the given bus name is not valid.

  • DBusError - If the service threw an error for the method call or returned an invalid result.

  • Exception - If a connection error occurred.

send(msg: Message)

Asynchronously send a message on the message bus.

Parameters:

msg (Message) – The message to send.

unexport(path: str, interface: ServiceInterface | str | None = None) → None

Unexport the path or service interface to make it no longer available to clients.

Parameters:

  • path (str) – The object path to unexport.

  • interface (ServiceInterface or str or None) – The interface instance or the name of the interface to unexport. If None, unexport every interface on the path.

Raises: