PYTHON-SDBUS(1)

NAME
python-sdbus - python-sdbus

Python-sdbus is the python D-Bus library that aim to use the modern features of python

    •   Asyncio

    •   Type hints

    •   Based on fast sd-bus

    •   Unified client/server interface classes. Write interface class once.

    •   D-Bus methods can have keyword and default arguments.

D-BUS

D-Bus is the inter-process communication standard commonly used on Linux desktop.

This documentation expects you to be familiar with D-Bus concepts and conventions.

If you are unfamiliar with D-Bus you might want to read following pages:

Wikipedia page

Lennart Poettering post about D-Bus

D-Bus specification by freedesktop.org

Install D-Spy D-Bus debugger and observe services and objects on your D-Bus

  General Information

  Blocking vs Async

Python-sdbus supports both blocking and async IO.

Regular python functions are always blocking.

Asyncio is a part of python standard library that allows non-blocking io.

Asyncio documentation

Generally blocking IO should only be used for simple scripts and programs that interact with existing D-Bus objects.

  Blocking:

    •   Blocking is easier to initiate (no event loop)

    •   Properties behave exactly as Python properties do. (i.e. can assign with '=' operator)

    •   Only allows one request at a time.

    •   No D-Bus signals.

    •   Cannot serve objects, only interact with existing object on D-Bus.

Blocking quick start

Blocking API

  Asyncio:

    •   Calls need to be await ed.

    •   Multiple requests at the same time.

    •   Serve object on D-Bus for other programs.

    •   D-Bus Signals.

Asyncio quick start

Asyncio API

  D-Bus types conversion

D-Bus types reference

NOTE:
        Python integers are unlimited size but D-Bus integers are not. All integer types raise OverflowError if you try to pass number outside the type size.

        Unsigned integers range is 0 < (2**bit_size)-1.

        Signed integers range is -(2**(bit_size-1)) < (2**(bit_size-1))-1.
Name | D-Bus type | Python type | Description
Boolean | b | bool | True or False
Byte | y | int | Unsigned 8-bit integer. Note: array of bytes (ay) has different type in python domain.
Int16 | n | int | Signed 16-bit integer.
Uint16 | q | int | Unsigned 16-bit integer.
Int32 | i | int | Signed 32-bit integer.
Uint32 | u | int | Unsigned 32-bit integer.
Int64 | x | int | Signed 64-bit integer.
Uint64 | t | int | Unsigned 64-bit integer.
Double | d | float | Float point number
Unix FD | h | int | File descriptor
String | s | str | String
Object Path | o | str | Syntactically correct D-Bus object path
Signature | g | str | D-Bus type signature
Array | a | list | List of some single type. Example: as array of strings
Byte Array | ay | bytes | Array of bytes. Not a unique type in D-Bus but a different type in Python. Accepts both bytes and bytearray. Used for binary data.
Struct | () | tuple | Tuple. Example: (isax) tuple of int, string and array of int.
Dictionary | a{} | dict | Dictionary with key type and value type. Note: Dictionary is always a part of array. I.E. a{si} is the dict with string keys and integer values. {si} is NOT a valid signature.
Variant | v | tuple | Unknown type that can be any single type. In Python represented by a tuple of a signature string and a single type. Example: ("s", "test") variant of a single string

  Name conversions

D-Bus uses CamelCase for method names.

Python uses snake_case.

When decorating a method name will be automatically translated from snake_case to CamelCase. Example: close_notification -> CloseNotification

However, all decorators have a parameter to force D-Bus name to a specific value. See API documentation for a particular decorator.

  Default bus

Most object methods that take a bus as a parameter will use a thread-local default bus connection if a bus object is not explicitly passed.

Session bus is default bus when running as a user and system bus otherwise.

request_default_bus_name_async() can be used to acquire a service name on default bus.

Use sd_bus_open_user() and sd_bus_open_system() to acquire a specific bus connection.

Set the default connection to a new default with set_default_bus(). This should be done before any object that take bus as an init argument are created.

In the future there will be a better way to create and acquire new bus connections.

  Glossary

    •   Bus object representing connection to D-Bus.

    •

        Proxy Python object that represents an object on D-Bus.
            Without proxy you manipulate messages directly.

    •   Remote something that exists outside current Python process.

    •   Local something that exists inside current Python scope.

    •

        Service Name a well known name that an process can acquire on D-Bus.
            For example, systemd acquires org.freedesktop.systemd1 name.

    •   Signature D-Bus type definition. Represented by a string. See D-Bus types conversion.

  Contents

    •   Index

    •   API Index

    •   Search Page

  Common API

These calls are shared between async and blocking API.

  D-Bus connections calls

    async sdbus.request_default_bus_name_async(new_name, allow_replacement, replace_existing, queue)
        Acquire a name on the default bus async.

        Parameters

            •   new_name (str) -- the name to acquire. Must be a valid D-Bus service name.

            •   new_name -- the name to acquire. Must be a valid D-Bus service name.

            •   allow_replacement (bool) -- If name was acquired allow other peers to take away the name.

            •   replace_existing (bool) -- If current name owner allows, take away the name.

            •   queue (bool) -- Queue up for name acquisition. SdBusRequestNameInQueueError will be raised when successfully placed in queue. Ownership change signal should be monitored get notified when the name was acquired.

        Raises
            Name request exceptions and other D-Bus exceptions.

    sdbus.request_default_bus_name(new_name, allow_replacement, replace_existing, queue)
        Acquire a name on the default bus.

        Parameters

            •   new_name (str) -- the name to acquire. Must be a valid D-Bus service name.

            •   allow_replacement (bool) -- If name was acquired allow other peers to take away the name.

            •   replace_existing (bool) -- If current name owner allows, take away the name.

            •   queue (bool) -- Queue up for name acquisition. SdBusRequestNameInQueueError will be raised when successfully placed in queue. Ownership change signal should be monitored get notified when the name was acquired.

        Raises
            Name request exceptions and other D-Bus exceptions.

    sdbus.set_default_bus(new_default)
        Sets default bus.

        Should be called before you create any objects that might use default bus.

        Default bus can be replaced but the change will only affect newly created objects.

        Parameters
            new_default (SdBus) -- The bus object to set default to.

    sdbus.get_default_bus(new_default)
        Gets default bus.

        Returns
            default bus

        Return type
            SdBus

    sdbus.sd_bus_open_user()
        Opens a new user session bus connection.

        Returns
            session bus

        Return type
            SdBus

    sdbus.sd_bus_open_system()
        Opens a new system bus connection.

        Returns
            system bus

        Return type
            SdBus

    sdbus.sd_bus_open_system_remote(host)
        Opens a new system bus connection on a remote host through SSH. Host can be prefixed with username@ and followed by :port and /machine_name as in systemd-nspawn container name.

        Parameters
            host (str) -- Host name to connect.

        Returns
            Remote system bus

        Return type
            SdBus

    sdbus.sd_bus_open_system_machine(machine)
        Opens a new system bus connection in a systemd-nspawn container. Machine name can be prefixed with username@. Special machine name .host indicates local system.

        Parameters
            machine (str) -- Machine (container) name.

        Returns
            Remote system bus

        Return type
            SdBus

    sdbus.sd_bus_open_user_machine(machine)
        Opens a new user session bus connection in a systemd-nspawn container. Opens root user bus session or can be prefixed with username@ for a specific user.

        Parameters
            machine (str) -- Machine (container) name.

        Returns
            Remote system bus

        Return type
            SdBus

  Helper functions

    sdbus.encode_object_path(prefix, external)
        Encode that arbitrary string as a valid object path prefixed with prefix.

        Parameters

            •   prefix (str) -- Prefix path. Must be a valid object path.

            •   external (str) -- Arbitrary string to identify object.

        Returns
            valid object path

        Return type
            str

    Example on how systemd encodes unit names on D-Bus:

                from sdbus import encode_object_path

                # System uses /org/freedesktop/systemd1/unit as prefix of all units
                # dbus.service is a name of D-Bus unit but dot . is not a valid object path
                s = encode_object_path('/org/freedesktop/systemd1/unit', 'dbus.service')
                print(s)
                # Prints: /org/freedesktop/systemd1/unit/dbus_2eservice

    sdbus.decode_object_path(prefix, full_path)
        Decode object name that was encoded with encode_object_path().

        Parameters

            •   prefix (str) -- Prefix path. Must be a valid object path.

            •   full_path (str) -- Full path to be decoded.

        Returns
            Arbitrary name

        Return type
            str

    Example decoding systemd unit name:

                from sdbus import decode_object_path

                s = decode_object_path(
                    '/org/freedesktop/systemd1/unit',
                    '/org/freedesktop/systemd1/unit/dbus_2eservice'
                )
                print(s)
                # Prints: dbus.service

  Flags

Flags are int values that should be ORed to combine.

Example, DbusDeprecatedFlag plus DbusHiddenFlag: DbusDeprecatedFlag | DbusHiddenFlag

    sdbus.DbusDeprecatedFlag: int
        Mark this method or property as deprecated in introspection data.

    sdbus.DbusHiddenFlag: int
        Method or property will not show up in introspection data.

    sdbus.DbusUnprivilegedFlag: int
        Mark this method or property as unprivileged. This means anyone can call it. Only works for system bus as user session bus is fully trusted by default.

    sdbus.DbusNoReplyFlag: int
        This method does not have a reply message. It instantly returns and does not have any errors.

    sdbus.DbusPropertyConstFlag: int
        Mark that this property does not change during object life time.

    sdbus.DbusPropertyEmitsChangeFlag: int
        This property emits signal when it changes.

    sdbus.DbusPropertyEmitsInvalidationFlag: int
        This property emits signal when it invalidates. (means the value changed but does not include new value in the signal)

    sdbus.DbusPropertyExplicitFlag: int
        This property is too heavy to calculate so its not included in GetAll method call.

    sdbus.DbusSensitiveFlag: int
        Data in messages in sensitive and will be scrubbed from memory after message is red.

  Blocking quick start

  Interface classes

Python-sdbus works by declaring interface classes.

Interface classes for blocking IO should be derived from DbusInterfaceCommon.

The class constructor takes interface_name keyword to determine the D-Bus interface name for all D-Bus elements declared in the class body.

Example:

            class ExampleInterface(DbusInterfaceCommon,
                                   interface_name='org.example.myinterface'
                                   ):
                ...

Interface class body should contain the definitions of methods and properties using the decorators dbus_method() and dbus_property() respectively.

Example:

            from sdbus import (DbusInterfaceCommon,
                               dbus_method, dbus_property)

            class ExampleInterface(DbusInterfaceCommon,
                                   interface_name='org.example.myinterface'
                                   ):
                # Method that takes an integer and does not return anything
                @dbus_method('u')
                def close_notification(self, an_int: int) -> None:
                    raise NotImplementedError

                # Read only property of int
                @dbus_property()
                def test_int(self) -> int:
                    raise NotImplementedError

This is an interface of that defines a one D-Bus method and one property.

The actual body of the decorated function will not be called. Instead the call will be routed through D-Bus to a another process. Interface can have non-decorated functions that will act as regular methods.

Blocking IO can only interact with existing D-Bus objects and can not be served for other processes to interact with. See Blocking vs Async

  Initiating proxy

DbusInterfaceCommon.__init__() method takes service_name and object_path of the remote object that the object will proxy to.

Example creating a proxy and calling method:

            ...
            # Initialize the object
            d = ExampleInterface(
                service_name='org.example.test',
                object_path='/',
            )

            d.close_notification(1234)

NOTE:
        Successfully initiating a proxy object does NOT guarantee that the D-Bus object exists.

  Methods

Methods are functions wrapped with dbus_method() decorator.

If the remote object sends an error reply an exception with base of DbusFailedError will be raised. See Exceptions for list of exceptions.

The wrapped function will not be called. Its recommended to set the function to raise NotImplementedError.

Example:

            from sdbus import DbusInterfaceCommon, dbus_method

            class ExampleInterface(...):

                ...
                # Body of some class

                @dbus_method('u')
                def close_notification(self, an_int: int) -> None:
                    raise NotImplementedError

  Properties

D-Bus property is defined by wrapping a function with dbus_property() decorator.

Example:

            from sdbus import DbusInterfaceCommon, dbus_property

            class ExampleInterface(...):

                ...
                # Body of some class

                # Property of str
                @dbus_property('s')
                def test_string(self) -> str:
                    raise NotImplementedError

The new property behaves very similar to Pythons property() decorator.

            # Initialize the proxy
            d = ExampleInterface(
                service_name='org.example.test',
                object_path='/',
            )

            # Print it
            print(d.test_string)

            # Assign new string
            d.test_string = 'some_string'

If property is read-only when DbusPropertyReadOnlyError will be raised.

  Multiple interfaces

A D-Bus object can have multiple interfaces with different methods and properties.

To implement this define multiple interface classes and do a multiple inheritance on all interfaces the object has.

Example:

            from sdbus import DbusInterfaceCommon, dbus_method

            class ExampleInterface(DbusInterfaceCommon,
                                   interface_name='org.example.myinterface'
                                   ):

                @dbus_method('i')
                def example_method(self, an_int: int) -> None:
                    raise NotImplementedError

            class TestInterface(DbusInterfaceCommon,
                                interface_name='org.example.test'
                                ):

                @dbus_method('as')
                def test_method(self, str_array: List[str]) -> None:
                    raise NotImplementedError

            class MultipleInterfaces(TestInterface, ExampleInterface):
                ...

MultipleInterfaces class will have both test_method and example_method that will be proxied to correct interface names. (org.example.myinterface and org.example.test respectively)

  Blocking API

  Classes

    class sdbus.DbusInterfaceCommon(interface_name)
        D-Bus interface class. D-Bus methods and properties should be defined using dbus_property() and dbus_method() decorators.

        Parameters
            interface_name (str) -- Sets the D-Bus interface name that will be used for all properties and methods defined in the body of the class

        __init__(service_name, object_path[, bus])
            Init will create a proxy to a remote object

            Parameters

                •   service_name (str) -- Remote object D-Bus connection name. For example, systemd uses org.freedesktop.systemd1

                •   object_path (str) -- Remote object D-Bus path. Should be a forward slash separated path. Starting object is usually /. Example: /org/freedesktop/systemd/unit/dbus_2eservice

                •   bus (SdBus) -- Optional D-Bus connection object. If not passed the default D-Bus will be used.

        dbus_ping()
            Pings the remote service using D-Bus.

            Useful to test if connection or remote service is alive.

            WARNING:
                This method is ignores the particular object path meaning it can NOT be used to test if object exist.

        dbus_machine_id()
            Returns the machine UUID of D-Bus the object is connected to.

            Returns
                machine UUID

            Return type
                str

        dbus_introspect()
            Get D-Bus introspection XML.

            It is users responsibility to parse that data.

            Returns
                string with introspection XML

            Return type
                str

        properties_get_all_dict()
            Get all object properties as a dictionary where keys are member names and values are properties values.

            Equivalent to GetAll method of the org.freedesktop.DBus.Properties interface but the member names are automatically translated to python names. (internally calls it for each interface used in class definition)

            Parameters
                on_unknown_member (str) -- If an unknown D-Bus property was encountered either raise an "error" (default), "ignore" the property or "reuse" the D-Bus name for the member.

            Returns
                dictionary of properties

            Return type
                Dict[str, Any]

    Example:

                from sdbus import (DbusInterfaceCommon,
                                   dbus_method, dbus_property)

                class ExampleInterface(DbusInterfaceCommon,
                                       interface_name='org.example.my'
                                       ):

                    # Method that takes an integer and does not return anything
                    @dbus_method('u')
                    def close_notification(self, an_int: int) -> None:
                        raise NotImplementedError

                    # Method that does not take any arguments and returns a list of str
                    @dbus_method()
                    def get_capabilities(self) -> List[str]:
                        raise NotImplementedError

                    # Method that takes a dict of {str: str} and returns an int
                    @dbus_method('a{ss}')
                    def count_entries(self, a_dict: Dict[str, str]) -> int:
                        raise NotImplementedError

                    # Read only property of int
                    @dbus_property()
                    def test_int(self) -> int:
                        raise NotImplementedError

                    # Read/Write property of str
                    @dbus_property('s')
                    def test_string(self) -> str:
                        raise NotImplementedError

    class sdbus.DbusObjectManagerInterface(interface_name)
        This class is almost identical to DbusInterfaceCommon but implements ObjectManager interface.

        get_managed_objects()
            Get the objects this object manager in managing.

            Returns
                Triple nested dictionary that contains all the objects paths with their properties values.

                Dict[ObjectPath, Dict[InterfaceName, Dict[PropertyName, PropertyValue]]]

            Return type
                Dict[str, Dict[str, Dict[str, Any]]]

  Decorators

    @sdbus.dbus_method([input_signature[, flags[, method_name]]])
        Define D-Bus method

        Decorated function becomes linked to D-Bus method. Always use round brackets () even when not passing any arguments.

        Parameters

            •   input_signature (str) -- D-Bus input signature. Defaults to "" meaning method takes no arguments. Required if method takes any arguments.

            •   flags (int) --

                modifies behavior. No effect on remote connections. Defaults to 0 meaning no special behavior.

                See Flags .

            •   method_name (str) -- Explicitly define remote method name. Usually not required as remote method name will be constructed based on original method name.

    Defining methods example:

                from sdbus import DbusInterfaceCommon, dbus_method

                class ExampleInterface(DbusInterfaceCommon,
                                       interface_name='org.example.my'
                                       ):

                    # Method that takes an integer and does not return anything
                    @dbus_method('u')
                    def close_notification(self, an_int: int) -> None:
                        raise NotImplementedError

                    # Method that does not take any arguments and returns a list of str
                    @dbus_method()
                    def get_capabilities(self) -> List[str]:
                        raise NotImplementedError

                    # Method that takes a dict of {str: str} and returns an int
                    @dbus_method('a{ss}')
                    def count_entries(self, a_dict: Dict[str, str]) -> int:
                        raise NotImplementedError

    Calling methods example:

                # Initialize the object
                d = ExampleInterface(
                    service_name='org.example.test',
                    object_path='/',
                )

                d.close_notification(1234)

                l = d.get_capabilities()

                d.count_entries({'a': 'asdasdasd', 'b': 'hgterghead213d'})

    @sdbus.dbus_property([property_signature[, flags[, property_name]]])
        Define D-Bus property

        Property works just like @property decorator would. Always use round brackets () even when not passing any arguments.

        Read only property can be indicated by passing empty D-Bus signature "".

        Trying to assign a read only property will raise AttributeError

        Parameters

            •   property_signature (str) -- D-Bus property signature. Empty signature "" indicates read-only property. Defaults to empty signature "". Required only for writable properties.

            •   flags (int) --

                modifies behavior. No effect on remote connections. Defaults to 0 meaning no special behavior.

                See Flags .

            •   property_name (str) -- Explicitly define remote property name. Usually not required as remote property name will be constructed based on original method name.

    Defining properties example:

                from sdbus import DbusInterfaceCommon, dbus_property

                class ExampleInterface(DbusInterfaceCommon,
                                       interface_name='org.example.myproperty'
                                       ):

                    # Property of int
                    @dbus_property('i')
                    def test_int(self) -> int:
                        raise NotImplementedError

                    # Property of str
                    @dbus_property('s')
                    def test_string(self) -> str:
                        raise NotImplementedError

    Properties usage example:

                # Initialize the object
                d = ExampleInterface(
                    service_name='org.example.test',
                    object_path='/',
                )

                # Print the int
                print(d.test_int)

                # Assign new string
                d.test_string = 'some_string'

                # Print it
                print(d.test_string)

    •   Index

    •   Module Index

    •   Search Page

  Asyncio quick start

  Interface classes

Python-sdbus works by declaring interface classes.

Interface classes for async IO should be derived from DbusInterfaceCommonAsync.

The class constructor takes interface_name keyword to determine the D-Bus interface name for all D-Bus elements declared in the class body.

Example:

            from sdbus import DbusInterfaceCommonAsync

            class ExampleInterface(DbusInterfaceCommonAsync,
                                   interface_name='org.example.myinterface'
                                   ):
                ...

Interface class body should contain the definitions of methods, properties and signals using decorators such as dbus_method_async(), dbus_property_async() and dbus_signal_async().

Example:

            from sdbus import (DbusInterfaceCommonAsync, dbus_method_async,
                               dbus_property_async, dbus_signal_async)

            class ExampleInterface(DbusInterfaceCommonAsync,
                                   interface_name='org.example.myinterface'
                                   ):
                # Method that takes an integer and multiplies it by 2
                @dbus_method_async('i', 'i')
                async def double_int(self, an_int: int) -> None:
                    return an_int * 2

                # Read only property of str
                @dbus_property_async('s')
                def read_string(self) -> int:
                    return 'Test'

                # Signal with a list of strings
                @dbus_signal_async('as')
                def str_signal(self) -> List[str]:
                    raise NotImplementedError

  Initiating proxy

DbusInterfaceCommonAsync provides two methods for proxying remote objects.

DbusInterfaceCommonAsync.new_proxy() class method bypasses the class __init__ and returns proxy object.

DbusInterfaceCommonAsync._proxify() should be used inside the __init__ methods if your class is a proxy only.

Recommended to create proxy classes that a subclass of the interface:

            from sdbus import DbusInterfaceCommonAsync

            class ExampleInterface(...):
                # Some interface class
                ...

            class ExampleClient(ExampleInterface):
                def __init__(self) -> None:
                    # Your client init can proxy to any object based on passed arguments.
                    self._proxify('org.example.test', '/')

NOTE:
        Successfully initiating a proxy object does NOT guarantee that the D-Bus object exists.

  Serving objects

DbusInterfaceCommonAsync.export_to_dbus() method will export the object to the D-Bus. After calling it the object becomes visible on D-Bus for other processes to call.

Example using ExampleInterface from before:

            from sdbus import request_default_bus_name_async

            loop = get_event_loop()

            i = ExampleInterface()

            async def start() -> None:
                # Acquire a name on the bus
                await request_default_bus_name_async('org.example.test')
                # Start serving at / path
                i.export_to_dbus('/')

            loop.run_until_complete(start())
            loop.run_forever()

  Connection transparency

The interface objects are designed to be transparent to their connection status. This means if the object not proxied to remote the calls to decorated methods will still work in the local scope.

This is the call to local object:

            i = ExampleInterface()

            async def test() -> None:
                print(await i.double_int(5))  # Will print 10

This is a call to remote object at 'org.example.test' service name and '/' path:

            i = ExampleInterface.new_proxy('org.example.test', '/')

            async def test() -> None:
                print(await i.double_int(5))  # Will print 10

  Methods

Methods are async function calls wrapped with dbus_method_async() decorator. (see the API reference for decorator parameters)

Methods have to be async function, otherwise AssertionError will be raised.

While method calls are async there is a inherit timeout timer for any method call.

To return an error to caller you need to raise exception which has a DbusFailedError as base. Regular exceptions will not propagate.

See Exceptions.

Example:

            from sdbus import DbusInterfaceCommonAsync, dbus_method_async

            class ExampleInterface(...):

                ...
                # Body of some class

                # Method that takes a string
                # and returns uppercase of that string
                @dbus_method_async(
                    input_signature='s',
                    result_signature='s',
                    result_args_names=('uppercased', )  # This is optional but
                                                        # makes arguments have names in
                                                        # introspection data.
                )
                async def upper(self, str_to_up: str) -> str:
                    return str_to_up.upper()

Methods behave exact same way as Python methods would:

            print(await example_object.upper('test'))  # prints TEST

  Properties

Properties are a single value that can be read and write.

To declare a read only property you need to decorate a regular function with dbus_property_async() decorator.

Example:

            from sdbus import DbusInterfaceCommonAsync, dbus_property_async

            class ExampleInterface(...):

                ...
                # Body of some class

                # Read only property. No setter defined.
                @dbus_property_async('i')
                def read_only_number(self) -> int:
                    return 10

To create a read/write property you need to decorate the setter function with the setter attribute of your getter function.

Example:

            from sdbus import DbusInterfaceCommonAsync, dbus_property_async

            class ExampleInterface(...):

                ...
                # Body of some class

                # Read/write property. First define getter.
                @dbus_property_async('s')
                def read_write_str(self) -> str:
                    return self.s

                # Now create setter. Method name does not matter.
                @read_write_str.setter  # Use the property setter method as decorator
                def read_write_str_setter(self, new_str: str) -> None:
                    self.s = new_str

Properties are supposed to be lightweight. Make sure you don't block event loop with getter or setter.

Async properties do not behave the same way as property() decorator does.

To get the value of the property you can either directly await on property or use get_async() method. (also need to be awaited)

To set property use set_async() method.

Example:

            ...
            # Somewhere in async function
            # Assume we have example_object of class defined above
            print(await example_object.read_write_str)  # Print the value of read_write_str

            ...
            # Set read_write_str to new value
            await example_object.read_write_str.set_async('test')

  Signals

To define a D-Bus signal wrap a function with dbus_signal_async() decorator.

The function is only used for type hints information. It is recommended to just put raise NotImplementedError in to the body of the function.

Example:

            from sdbus import DbusInterfaceCommonAsync, dbus_signal_async

            class ExampleInterface(...):

                    ...
                    # Body of some class
                    @dbus_signal_async('s')
                    def name_changed(self) -> str:
                        raise NotImplementedError

To catch a signal use async for loop:

            async for x in example_object.name_changed:
                print(x)

WARNING:
        If you are creating an asyncio task to listen on signals make sure to bind it to a variable and keep it referenced otherwise garbage collector will destroy your task.

A signal can be emitted with emit method.

Example:

            example_object.name_changed.emit('test')

Signals can also be caught from multiple D-Bus objects using catch_anywhere method. The async iterator will yield the path of the object that emitted the signal and the signal data.

catch_anywhere can be called from class but in such case the service name must be provided.

Example:

            async for path, x in ExampleInterface.name_changed.catch_anywhere('org.example.test'):
                print(f"On {path} caught: {x}")

  Subclass Overrides

If you define a subclass which overrides a declared D-Bus method or property you need to use dbus_method_async_override() and dbus_property_async_override() decorators. Overridden property can decorate a new setter.

Overridden methods should take same number and type of arguments.

Example:

            from sdbus import (dbus_method_async_override,
                               dbus_property_async_override)

            # Some subclass
            class SubclassInterface(...):

                ...
                @dbus_method_async_override()
                async def upper(self, str_to_up: str) -> str:
                    return 'Upper: ' + str_to_up.upper()

                @dbus_property_async_override()
                def str_prop(self) -> str:
                    return 'Test property' + self.s

                # Setter needs to be decorated again to override
                @str_prop.setter
                def str_prop_setter(self, new_s: str) -> None:
                    self.s = new_s.upper()

  Multiple interfaces

A D-Bus object can have multiple interfaces with different methods and properties.

To implement this define multiple interface classes and do a multiple inheritance on all interfaces the object has.

Example:

            from sdbus import DbusInterfaceCommonAsync

            class ExampleInterface(DbusInterfaceCommonAsync,
                                   interface_name='org.example.myinterface'
                                   ):

                @dbus_method_async('i', 'i')
                async def double_int(self, an_int: int) -> None:
                    return an_int * 2

            class TestInterface(DbusInterfaceCommonAsync,
                                interface_name='org.example.test'
                                ):

                @dbus_method_async('as', 's')
                async def join_str(self, str_array: List[str]) -> str:
                    return ''.join(str_array)

            class MultipleInterfaces(TestInterface, ExampleInterface):
                ...

MultipleInterfaces class will have both test_method and example_method that will be wired to correct interface names. (org.example.myinterface and org.example.test respectively)

  Asyncio API

  Classes

    class sdbus.DbusInterfaceCommonAsync(interface_name)
        D-Bus async interface class. D-Bus methods and properties should be defined using dbus_property_async(), dbus_signal_async(), and dbus_method_async() decorators.

        NOTE:
            Don't forget to call super().__init__() in derived classes init calls as it sets up important attributes.

        Parameters

            •   interface_name (str) -- Sets the D-Bus interface name that will be used for all properties, methods and signals defined in the body of the class.

            •   serving_enabled (bool) -- If set to True the interface will not be served on D-Bus. Mostly used for interfaces that sd-bus already provides such as org.freedesktop.DBus.Peer.

        async dbus_ping()
            Pings the remote service using D-Bus.

            Useful to test if connection or remote service is alive.

            WARNING:
                This method is ignores the particular object path meaning it can NOT be used to test if object exist.

        async dbus_machine_id()
            Returns the machine UUID of D-Bus the object is connected to.

            Returns
                machine UUID

            Return type
                str

        async dbus_introspect()
            Get D-Bus introspection XML.

            It is users responsibility to parse that data.

            Returns
                string with introspection XML

            Return type
                str

        async properties_get_all_dict()
            Get all object properties as a dictionary where keys are member names and values are properties values.

            Equivalent to GetAll method of the org.freedesktop.DBus.Properties interface but the member names are automatically translated to python names. (internally calls it for each interface used in class definition)

            Parameters
                on_unknown_member (str) -- If an unknown D-Bus property was encountered either raise an "error" (default), "ignore" the property or "reuse" the D-Bus name for the member.

            Returns
                dictionary of properties

            Return type
                Dict[str, Any]

        properties_changed: Tuple[str, Dict[str, Tuple[str, Any]], List[str]]
            Signal when one of the objects properties changes.

            sdbus.utils.parse.parse_properties_changed() can be used to transform this signal data in to an easier to work with dictionary.

            Signal data is:

            Interface name (str)
                Name of the interface where property changed

            Changed properties (Dict[str, Tuple[str, Any]])
                Dictionary there keys are names of properties changed and values are variants of new value.

            Invalidated properties (List[str])
                List of property names changed but no new value had been provided

        _proxify(bus, service_name, object_path)
            Begin proxying to a remote D-Bus object.

            Parameters

                •   service_name (str) -- Remote object D-Bus connection name. For example, systemd uses org.freedesktop.systemd1

                •   object_path (str) -- Remote object D-Bus path. Should be a forward slash separated path. Starting object is usually /. Example: /org/freedesktop/systemd/unit/dbus_2eservice

                •   bus (SdBus) -- Optional D-Bus connection object. If not passed the default D-Bus will be used.

        classmethod new_proxy(bus, service_name, object_path)
            Create new proxy object and bypass __init__.

            Parameters

                •   service_name (str) -- Remote object D-Bus connection name. For example, systemd uses org.freedesktop.systemd1

                •   object_path (str) -- Remote object D-Bus path. Should be a forward slash separated path. Starting object is usually /. Example: /org/freedesktop/systemd/unit/dbus_2eservice

                •   bus (SdBus) -- Optional D-Bus connection object. If not passed the default D-Bus will be used.

        export_to_dbus(object_path, bus)
            Object will appear and become callable on D-Bus.

            Returns a handle that can either be used as a context manager to remove the object from D-Bus or .stop() method of the handle can be called to remove object from D-Bus.

            Returns a handle that can be used to remove object from D-Bus by either using it as a context manager or by calling .stop() method of the handle.

                    with dbus_object.export_to_dbus("/"):
                        # dbus_object can be called from D-Bus inside this
                        # with block.
                        ...

                    ...

                    handle = dbus_object2.export_to_dbus("/")
                    # dbus_object2 can be called from D-Bus between these statements
                    handle.stop()

                    ...

                    dbus_object3.export_to_dbus("/")
                    # dbus_object3 can be called from D-Bus until all references are
                    # dropped.
                    del dbus_object3

        If the handle is discarded the object will remain exported until it gets deallocated.

        Changed in version 0.12.0: Added a handle return.

            Parameters

                •   object_path (str) -- Object path that it will be available at.

                •   bus (SdBus) -- Optional D-Bus connection object. If not passed the default D-Bus will be used.

            Returns
                Handle to control the export.

    class sdbus.DbusObjectManagerInterfaceAsync(interface_name)
        This class is almost identical to DbusInterfaceCommonAsync but implements ObjectManager interface.

        Example of serving objects with ObjectManager:

                my_object_manager = DbusObjectManagerInterfaceAsync()
                my_object_manager.export_to_dbus('/object/manager')

                managed_object = DbusInterfaceCommonAsync()
                my_object_manager.export_with_manager('/object/manager/example')

        async get_managed_objects()
            Get the objects this object manager in managing.

            sdbus.utils.parse.parse_get_managed_objects() can be used to make returned data easier to work with.

            Returns
                Triple nested dictionary that contains all the objects paths with their properties values.

                Dict[ObjectPath, Dict[InterfaceName, Dict[PropertyName, PropertyValue]]]

            Return type
                Dict[str, Dict[str, Dict[str, Any]]]

        interfaces_added: Tuple[str, Dict[str, Dict[str, Any]]]
            Signal when a new object is added or and existing object gains a new interface.

            sdbus.utils.parse.parse_interfaces_added() can be used to make signal data easier to work with.

            Signal data is:

            Object path (str)
                Path to object that was added or modified.

            Object interfaces and properties (Dict[str, Dict[str, Any]]])
                Dict[InterfaceName, Dict[PropertyName, PropertyValue]]

        interfaces_removed: Tuple[str, List[str]]
            Signal when existing object or and interface of existing object is removed.

            sdbus.utils.parse.parse_interfaces_removed() can be used to make signal data easier to work with.

            Signal data is:

            Object path (str)
                Path to object that was removed or modified.

            Interfaces list (List[str])
                Interfaces names that were removed.

        export_with_manager(object_path, object_to_export, bus)
            Export object to D-Bus and emit a signal that it was added.

            ObjectManager must be exported first.

            Path should be a subpath of where ObjectManager was exported. Example, if ObjectManager exported to /object/manager, the managed object can be exported at /object/manager/test.

            ObjectManager will keep the reference to the object.

            Returns a handle that can be used to remove object from D-Bus and drop reference to it by either using it as a context manager or by calling .stop() method of the handle. Signal will be emitted once the object is stopped being exported.

                    manager = DbusObjectManagerInterfaceAsync()
                    manager.export_to_dbus('/object/manager')

                    with manager.export_with_manager("/object/manager/example", dbus_object):
                        # dbus_object can be called from D-Bus inside this
                        # with block.
                        ...

                    # Removed signal will be emitted once the with block exits

                    ...

                    handle = manager.export_with_manager("/object/manager/example", dbus_object2)
                    # dbus_object2 can be called from D-Bus between these statements
                    handle.stop()
                    # Removed signal will be emitted once the .stop() method is called

        If the handle is discarded the object will remain exported until it gets removed from manager with remove_managed_object() and the object gets deallocated.

        Changed in version 0.12.0: Added a handle return.

            Parameters

                •   object_path (str) -- Object path that it will be available at.

                •   object_to_export (DbusInterfaceCommonAsync) -- Object to export to D-Bus.

                •   bus (SdBus) -- Optional D-Bus connection object. If not passed the default D-Bus will be used.

            Raises
                RuntimeError -- ObjectManager was not exported.

            Returns
                Handle to control the export.

        remove_managed_object(managed_object)
            Emit signal that object was removed.

            Releases reference to the object.

            CAUTION:
                The object will still be accessible over D-Bus until all references to it will be removed.

            Parameters
                managed_object (DbusInterfaceCommonAsync) -- Object to remove from ObjectManager.

            Raises

                •   RuntimeError -- ObjectManager was not exported.

                •   KeyError -- Passed object is not managed by ObjectManager.

  Decorators

    @sdbus.dbus_method_async([input_signature[, result_signature[, flags[, result_args_names[, input_args_names[, method_name]]]]]])
        Define a method.

        Underlying function must be a coroutine function.

        Parameters

            •   input_signature (str) -- D-Bus input signature. Defaults to "" meaning method takes no arguments. Required if you intend to connect to a remote object.

            •   result_signature (str) -- D-Bus result signature. Defaults to "" meaning method returns empty reply on success. Required if you intend to serve the object.

            •   flags (int) --

                modifies behavior. No effect on remote connections. Defaults to 0 meaning no special behavior.

                See Flags .

            •   result_args_names (Sequence[str]) --

                sequence of result argument names.

                These names will show up in introspection data but otherwise have no effect.

                Sequence can be list, tuple, etc... Number of elements in the sequence should match the number of result arguments otherwise SdBusLibraryError will be raised.

                Defaults to result arguments being nameless.

            •   input_args_names (Sequence[str]) --

                sequence of input argument names.

                These names will show up in introspection data but otherwise have no effect.

                Sequence can be list, tuple, etc... Number of elements in the sequence should match the number of result arguments otherwise RuntimeError will be raised.

                If result_args_names has been passed when Python function argument names will be used otherwise input arguments will be nameless

            •   method_name (str) -- Force specific D-Bus method name instead of being based on Python function name.

    Example:

                from sdbus import DbusInterfaceCommonAsync, dbus_method_async

                class ExampleInterface(DbusInterfaceCommonAsync,
                                       interface_name='org.example.test'
                                       ):

                    # Method that takes a string
                    # and returns uppercase of that string
                    @dbus_method_async(
                        input_signature='s',
                        result_signature='s',
                        result_args_names=('uppercased', )  # This is optional but
                                                            # makes arguments have names in
                                                            # introspection data.
                    )
                    async def upper(self, str_to_up: str) -> str:
                        return str_to_up.upper()

    @sdbus.dbus_property_async(property_signature[, flags[, property_name]])
        Declare a D-Bus property.

        The underlying function has to be a regular def function.

        The property will be read-only or read/write based on if setter was declared.

        WARNING:
            Properties are supposed to be lightweight to get or set. Make sure property getter or setter does not perform heavy IO or computation as that will block other methods or properties.

        Parameters

            •   property_signature (str) -- Property D-Bus signature. Has to be a single type or container.

            •   flags (int) --

                modifies behavior. No effect on remote connections. Defaults to 0 meaning no special behavior.

                See Flags .

            •   property_name (str) -- Force specific property name instead of constructing it based on Python function name.

    Example:

                from sdbus import DbusInterfaceCommonAsync, dbus_property_async

                class ExampleInterface(DbusInterfaceCommonAsync,
                                       interface_name='org.example.test'
                                       ):

                    def __init__(self) -> None:
                        # This is just a generic init
                        self.i = 12345
                        self.s = 'test'

                    # Read only property. No setter defined.
                    @dbus_property_async('i')
                    def read_only_number(self) -> int:
                        return self.i

                    # Read/write property. First define getter.
                    @dbus_property_async('s')
                    def read_write_str(self) -> str:
                        return self.s

                    # Now create setter. Method name does not matter.
                    @read_write_str.setter  # Use the property setter method as decorator
                    def read_write_str_setter(self, new_str: str) -> None:
                        self.s = new_str

        class sdbus.DbusPropertyAsync
            Properties have following methods:

            @setter(set_function)
                Defines the setter function. This makes the property read/write instead of read-only.

                See example on how to use.

            @setter_private(set_function)
                Defines the private setter function. The setter can be called locally but property will be read-only from D-Bus.

                Calling the setter locally will emit properties_changed signal to D-Bus.

                Changed in version 0.12.0: can now be used in overrides.

            async get_async()
                Get the property value.

                The property can also be directly await ed instead of calling this method.

            async set_async(new_value)
                Set property value.

    @sdbus.dbus_signal_async([signal_signature[, signal_args_names[, flags[, signal_name]]]])
        Defines a D-Bus signal.

        Underlying function return type hint is used for signal type hints.

        Parameters

            •   signal_signature (str) -- signal D-Bus signature. Defaults to empty signal.

            •   signal_args_names (Sequence[str]) --

                sequence of signal argument names.

                These names will show up in introspection data but otherwise have no effect.

                Sequence can be list, tuple, etc... Number of elements in the sequence should match the number of result arguments otherwise RuntimeError will be raised.

                Defaults to result arguments being nameless.

            •   flags (int) --

                modifies behavior. No effect on remote connections. Defaults to 0 meaning no special behavior.

                See Flags .

            •   signal_name (str) -- Forces specific signal name instead of being based on Python function name.

    Example:

                from sdbus import DbusInterfaceCommonAsync, dbus_signal_async

                class ExampleInterface(DbusInterfaceCommonAsync,
                                       interface_name='org.example.signal'
                                       ):

                    @dbus_signal_async('s')
                    def name_changed(self) -> str:
                        raise NotImplementedError

        class sdbus.DbusSignalAsync
            Signals have following methods:

            catch()
                Catch D-Bus signals using the async generator for loop: async for x in something.some_signal.catch():

                This is main way to await for new events.

                Both remote and local objects operate the same way.

                Signal objects can also be async iterated directly: async for x in something.some_signal

            catch_anywhere(service_name, bus)
                Catch signal independent of path. Yields tuple of path of the object that emitted signal and signal data.

                async for path, data in something.some_signal.catch_anywhere():

                This method can be called from both an proxy object and class. However, it cannot be called on local objects and will raise NotImplementedError.

                Parameters

                    •   service_name (str) -- Service name of which signals belong to. Required if called from class. When called from proxy object the service name of the proxy will be used.

                    •   bus (str) -- Optional D-Bus connection object. If not passed when called from proxy the bus connected to proxy will be used or when called from class default bus will be used.

            emit(args)
                Emit a new signal with args data.

    @sdbus.dbus_method_async_override
        Override the method.

        Method name should match the super class method name that you want to override.

        New method should take same arguments.

        You must add round brackets to decorator.

        Example:

                from sdbus import (DbusInterfaceCommonAsync, dbus_method_async
                                   dbus_method_async_override)

                class ExampleInterface(DbusInterfaceCommonAsync,
                                       interface_name='org.example.test'
                                       ):

                    # Original call
                    @dbus_method_async('s', 's')
                    async def upper(self, str_to_up: str) -> str:
                        return str_to_up.upper()

                class ExampleOverride(ExampleInterface):

                    @dbus_method_async_override()
                    async def upper(self, str_to_up: str) -> str:
                        return 'Upper: ' + str_to_up.upper()

    @sdbus.dbus_property_async_override
        Override property.

        You must add round brackets to decorator.

        Example:

                from sdbus import (DbusInterfaceCommonAsync, dbus_property_async
                                   dbus_property_async_override)

                class ExampleInterface(DbusInterfaceCommonAsync,
                                       interface_name='org.example.test'
                                       ):

                    def __init__(self) -> None:
                        self.s = 'aaaaaaaaa'

                    # Original property
                    @dbus_property_async('s')
                    def str_prop(self) -> str:
                        return self.s

                    @str_prop.setter
                    def str_prop_setter(self, new_s: str) -> None:
                        self.s = new_s

                class ExampleOverride(ExampleInterface):

                    @dbus_property_async_override()
                    def str_prop(self) -> str:
                        return 'Test property' + self.s

                    # Setter needs to be decorated again to override
                    @str_prop.setter
                    def str_prop_setter(self, new_s: str) -> None:
                        self.s = new_s.upper()

  Asyncio advanced topics

  Signals without data

D-Bus allows signals to not carry any data. Such signals have the type signature of "". (empty string)

To emit such signals the emit must be explicitly called with None.

Example of an empty signal:

            from asyncio import new_event_loop
            from sdbus import DbusInterfaceCommonAsync, dbus_signal_async

            class ExampleInterface(
                DbusInterfaceCommonAsync,
                interface_name="org.example.signal"
            ):

                @dbus_signal_async("")
                def name_invalidated(self) -> None:
                    raise NotImplementedError

            test_object = ExampleInterface()

            async def emit_empty_signal() -> None:
                test_object.export_to_dbus("/")

                test_object.name_invalidated.emit(None)

            loop = new_event_loop()
            loop.run_until_complete(emit_empty_signal())

  Exceptions

  Error name bound exceptions

These exceptions are bound to specific D-Bus error names. For example, DbusFailedError is bound to org.freedesktop.DBus.Error.Failed error name.

This means if the remote object sends an error message with this error name the Python will receive this exception.

When raised in a method callback an error message will be sent back to caller.

See list of error exceptions.

  New error bound exceptions

If you want to create a new error bound exception you should subclass it from DbusFailedError and provide a unique dbus_error_name attribute in the exception body definition.

Example:

            class DbusExampleError(DbusFailedError):
                dbus_error_name = 'org.example.Error'

If dbus_error_name is not unique the ValueError will be raised.

Defining an exception will automatically bind incoming error message to this new exception.

Existing exceptions can be manually binded using map_exception_to_dbus_error() function.

  Python built-in exceptions

All Python built-in exceptions are mapped to D-Bus errors.

The D-Bus error name is created by appending org.python.Error. to the exception name.

For example, AssertionError is bound to org.python.Error.AssertionError name.

  Functions

    sdbus.exceptions.map_exception_to_dbus_error(exception, dbus_error_name)
        Map exception to a D-bus error. Error name must be unique.

        Parameters

            •   exception (Type[Exception]) -- Exception to bind.

            •   dbus_error_name (str) -- D-Bus error name to bind to.

  Other exceptions

    exception sdbus.exceptions.SdBusBaseError
        Base exceptions for all exceptions defined in sdbus.

    exception sdbus.exceptions.SdBusUnmappedMessageError
        Message error that is unmapped.

        The exceptions argument is a tuple of error name and error message.

    exception sdbus.exceptions.SdBusLibraryError
        sd-bus library returned error.

        Exception message contains line number and the error name.

  Name request exceptions

These exceptions will be raise if an error related to ownership of D-Bus names occurs when calling request_default_bus_name_async() or request_default_bus_name().

    exception sdbus.exceptions.SdBusRequestNameError
        Common base exception for any name ownership error.

    exception sdbus.exceptions.SdBusRequestNameInQueueError
        Someone already owns the name but the request has been placed in queue.

    exception sdbus.exceptions.SdBusRequestNameExistsError
        Someone already owns the name.

    exception sdbus.exceptions.SdBusRequestNameAlreadyOwnerError
        The caller already owns the name.

  Error name exception list

    exception sdbus.exceptions.DbusFailedError
        Generic failure exception.

        Recommended to subclass to create a new exception.

        dbus_error_name: str = org.freedesktop.DBus.Error.Failed

    exception sdbus.exceptions.DbusNoMemoryError
        Remote object is out of memory.

        dbus_error_name: str = org.freedesktop.DBus.Error.NoMemory

    exception sdbus.exceptions.DbusServiceUnknownError
        No service with such name exists.

        Probably should only be raised by bus daemon.

        dbus_error_name: str = org.freedesktop.DBus.Error.ServiceUnknown

    exception sdbus.exceptions.DbusNameHasNoOwnerError
        No process owns the name you called.

        Probably should only be raised by bus daemon.

        dbus_error_name: str = org.freedesktop.DBus.Error.NameHasNoOwner

    exception sdbus.exceptions.DbusNoReplyError
        Timeout on reply.

        dbus_error_name: str = org.freedesktop.DBus.Error.NoReply

    exception sdbus.exceptions.DbusIOError
        Input/Output error.

        dbus_error_name: str = org.freedesktop.DBus.Error.IOError

    exception sdbus.exceptions.DbusBadAddressError
        Bad address.

        dbus_error_name: str = org.freedesktop.DBus.Error.BadAddress

    exception sdbus.exceptions.DbusNotSupportedError
        Something is unsupported on this platform.

        dbus_error_name: str = org.freedesktop.DBus.Error.NotSupported

    exception sdbus.exceptions.DbusLimitsExceededError
        Some resource was exhausted. (for example, file descriptors)

        dbus_error_name: str = org.freedesktop.DBus.Error.LimitsExceeded

    exception sdbus.exceptions.DbusAccessDeniedError
        Caller does not have enough privileges.

        dbus_error_name: str = org.freedesktop.DBus.Error.AccessDenied

    exception sdbus.exceptions.DbusAuthFailedError
        Authentication failed.

        dbus_error_name: str = org.freedesktop.DBus.Error.AuthFailed

    exception sdbus.exceptions.DbusNoServerError
        Unable to connect to bus.

        dbus_error_name: str = org.freedesktop.DBus.Error.NoServer

    exception sdbus.exceptions.DbusTimeoutError
        Socket timeout.

        This is different from DbusNoReplyError as here the connection to bus timeout not the remote object not replying.

        dbus_error_name: str = org.freedesktop.DBus.Error.Timeout

    exception sdbus.exceptions.DbusNoNetworkError
        No network access.

        Encountered you use D-Bus over TCP or SSH.

        dbus_error_name: str = org.freedesktop.DBus.Error.NoNetwork

    exception sdbus.exceptions.DbusAddressInUseError
        Address in use.

        dbus_error_name: str = org.freedesktop.DBus.Error.AddressInUse

    exception sdbus.exceptions.DbusDisconnectedError
        Disconnected from bus.

        dbus_error_name: str = org.freedesktop.DBus.Error.Disconnected

    exception sdbus.exceptions.DbusInvalidArgsError
        Method call args are invalid.

        dbus_error_name: str = org.freedesktop.DBus.Error.InvalidArgs

    exception sdbus.exceptions.DbusFileNotFoundError
        File not found.

        dbus_error_name: str = org.freedesktop.DBus.Error.FileNotFound

    exception sdbus.exceptions.DbusFileExistsError
        Generic failure exception.

        Recommended to subclass to create a new exception.

        dbus_error_name: str = org.freedesktop.DBus.Error.FileExists

    exception sdbus.exceptions.DbusUnknownMethodError
        Unknown D-Bus method.

        dbus_error_name: str = org.freedesktop.DBus.Error.UnknownMethod

    exception sdbus.exceptions.DbusUnknownObjectError
        Unknown D-Bus object.

        dbus_error_name: str = org.freedesktop.DBus.Error.UnknownObject

    exception sdbus.exceptions.DbusUnknownInterfaceError
        Unknown D-Bus interface.

        dbus_error_name: str = org.freedesktop.DBus.Error.UnknownInterface

    exception sdbus.exceptions.DbusUnknownPropertyError
        Unknown D-Bus property.

        dbus_error_name: str = org.freedesktop.DBus.Error.UnknownProperty

    exception sdbus.exceptions.DbusPropertyReadOnlyError
        D-Bus property is read only.

        dbus_error_name: str = org.freedesktop.DBus.Error.PropertyReadOnly

    exception sdbus.exceptions.DbusUnixProcessIdUnknownError
        PID does not exists.

        dbus_error_name: str = org.freedesktop.DBus.Error.UnixProcessIdUnknown

    exception sdbus.exceptions.DbusInvalidSignatureError
        Invalid D-Bus type signature.

        dbus_error_name: str = org.freedesktop.DBus.Error.InvalidSignature

    exception sdbus.exceptions.DbusInvalidFileContentError
        Invalid file content.

        dbus_error_name: str = org.freedesktop.DBus.Error.InvalidFileContent

    exception sdbus.exceptions.DbusInconsistentMessageError
        D-Bus message is malformed.

        dbus_error_name: str = org.freedesktop.DBus.Error.InconsistentMessage

    exception sdbus.exceptions.DbusMatchRuleNotFound
        Match rule does not exist.

        dbus_error_name: str = org.freedesktop.DBus.Error.MatchRuleNotFound

    exception sdbus.exceptions.DbusMatchRuleInvalidError
        Match rule is invalid.

        dbus_error_name: str = org.freedesktop.DBus.Error.MatchRuleInvalid

    exception sdbus.exceptions.DbusInteractiveAuthorizationRequiredError
        Requires interactive authorization.

        dbus_error_name: str = org.freedesktop.DBus.Error.InteractiveAuthorizationRequired

  Utilities

  Parsing utilities

Parse unweildy D-Bus structures in to Python native objects and names. Available under sdbus.utils.parse subpackage.

    sdbus.utils.parse.parse_properties_changed(interface, properties_changed_data, on_unknown_member='error')
        Parse data from properties_changed signal.

        Member names will be translated to python defined names. Invalidated properties will have a value of None.

        Parameters

            •   interface (DbusInterfaceBaseAsync) -- Takes either D-Bus interface or interface class.

            •   properties_changed_data (Tuple) -- Tuple caught from signal.

            •   on_unknown_member (str) -- If an unknown D-Bus property was encountered either raise an "error" (default), "ignore" the property or "reuse" the D-Bus name for the member.

        Return type
            Dict[str, Any]

        Returns
            Dictionary of changed properties with keys translated to python names. Invalidated properties will have value of None.

    sdbus.utils.parse.parse_interfaces_added(interfaces, interfaces_added_data, on_unknown_interface='error', on_unknown_member='error')
        Parse data from interfaces_added signal.

        Takes an iterable of D-Bus interface classes (or a single class) and the signal data. Returns the path of new object, the class of the added object (if it matched one of passed interface classes) and the dictionary of python named properties and their values.

        Parameters

            •   interfaces (Iterable[DbusInterfaceBaseAsync]) -- Possible interfaces that were added. Can accept classes with multiple interfaces defined.

            •   interfaces_added_data (Tuple) -- Tuple caught from signal.

            •   on_unknown_interface (str) -- If an unknown D-Bus interface was encountered either raise an "error" (default) or return "none" instead of interface class.

            •   on_unknown_member (str) -- If an unknown D-Bus property was encountered either raise an "error" (default), "ignore" the property or "reuse" the D-Bus name for the member.

        Return type
            Tuple[str, Optional[Type[DbusInterfaceBaseAsync]], Dict[str, Any]]

        Returns
            Path of new added object, object's class (or None) and dictionary of python translated members and their values.

    sdbus.utils.parse.parse_interfaces_removed(interfaces, interfaces_removed_data, on_unknown_interface='error')
        Parse data from interfaces_added signal.

        Takes an iterable of D-Bus interface classes (or a single class) and the signal data. Returns the path of removed object and the class of the added object. (if it matched one of passed interface classes)

        Parameters

            •   interfaces (Iterable[DbusInterfaceBaseAsync]) -- Possible interfaces that were removed. Can accept classes with multiple interfaces defined.

            •   interfaces_added_data (Tuple) -- Tuple caught from signal.

            •   on_unknown_member (str) -- If an unknown D-Bus interface was encountered either raise an "error" (default) or return "none" instead of interface class.

        Return type
            Tuple[str, Optional[Type[DbusInterfaceBaseAsync]]]

        Returns
            Path of removed object and object's class (or None).

    sdbus.utils.parse.parse_get_managed_objects(interfaces, managed_objects_data, on_unknown_interface='error', on_unknown_member='error')
        Parse data from get_managed_objects call.

        Takes an iterable of D-Bus interface classes (or a single class) and the method returned data. Returns a dictionary where keys a paths of the managed objects and value is a tuple of class of the object and dictionary of its python named properties and their values.

        Parameters

            •   interfaces (Iterable[DbusInterfaceBaseAsync]) -- Possible interfaces of the managed objects. Can accept classes with multiple interfaces defined.

            •   managed_objects_data (Dict) -- Data returned by get_managed_objects call.

            •   on_unknown_interface (str) -- If an unknown D-Bus interface was encountered either raise an "error" (default) or return "none" instead of interface class.

            •   on_unknown_member (str) -- If an unknown D-Bus property was encountered either raise an "error" (default), "ignore" the property or "reuse" the D-Bus name for the member.

        Return type
            Dict[str, Tuple[Optional[Type[DbusInterfaceBaseAsync], Dict[str, Any]]]]

        Returns
            Dictionary where keys are paths and values are tuples of managed objects classes and their properties data.

    New in version 0.12.0.

  Inspect utilities

Inspect D-Bus objects and retrieve their D-Bus related attributes such as D-Bus object paths and etc... Available under sdbus.utils.inspect subpackage.

    sdbus.utils.inspect.inspect_dbus_path(obj, bus=None)
        Returns the D-Bus path of an object.

        If called on a D-Bus proxy returns path of the proxied object.

        If called on a local D-Bus object returns the exported D-Bus path. If object is not exported raises LookupError.

        If called on an object that is unrelated to D-Bus raises TypeError.

        The object's path is inspected in the context of the given bus and if the object is attached to a different bus the LookupError will be raised. If the bus argument is not given or is None the default bus will be checked against.

        Parameters

            •   obj (object) -- Object to inspect.

            •   bus (SdBus) -- Bus to inspect against. If not given or None the default bus will be used.

        Return type
            str

        Returns
            D-Bus path of the object.

    New in version 0.13.0.

  Examples

  Asyncio client and server

In this example we create a simple example server and client.

There are 3 files:

    •   example_interface.py File that contains the interface definition.

    •   example_server.py Server.

    •   example_client.py Client.

example_interface.py file:

            from sdbus import (DbusInterfaceCommonAsync, dbus_method_async,
                                   dbus_property_async, dbus_signal_async)

            # This is file only contains interface definition for easy import
            # in server and client files

            class ExampleInterface(
                DbusInterfaceCommonAsync,
                interface_name='org.example.interface'
            ):
                @dbus_method_async(
                    input_signature='s',
                    result_signature='s',
                )
                async def upper(self, string: str) -> str:
                    return string.upper()

                @dbus_property_async(
                    property_signature='s',
                )
                def hello_world(self) -> str:
                    return 'Hello, World!'

                @dbus_signal_async(
                    signal_signature='i'
                )
                def clock(self) -> int:
                    raise NotImplementedError

example_server.py file:

            from asyncio import get_event_loop, sleep
            from random import randint
            from time import time

            from example_interface import ExampleInterface

            from sdbus import request_default_bus_name_async

            loop = get_event_loop()

            export_object = ExampleInterface()

            async def clock() -> None:
                """
                This coroutine will sleep a random time and emit a signal with current clock
                """
                while True:
                    await sleep(randint(2, 7))  # Sleep a random time
                    current_time = int(time())  # The interface we defined uses integers
                    export_object.clock.emit(current_time)

            async def startup() -> None:
                """Perform async startup actions"""
                # Acquire a known name on the bus
                # Clients will use that name to address to this server
                await request_default_bus_name_async('org.example.test')
                # Export the object to D-Bus
                export_object.export_to_dbus('/')

            loop.run_until_complete(startup())
            task_clock = loop.create_task(clock())
            loop.run_forever()

example_client.py file:

            from asyncio import get_event_loop

            from example_interface import ExampleInterface

            # Create a new proxy object
            example_object = ExampleInterface.new_proxy('org.example.test', '/')

            async def print_clock() -> None:
                # Use async for loop to print clock signals we receive
                async for x in example_object.clock:
                    print('Got clock: ', x)

            async def call_upper() -> None:
                s = 'test string'
                s_after = await example_object.upper(s)

                print('Initial string: ', s)
                print('After call: ', s_after)

            async def get_hello_world() -> None:
                print('Remote property: ', await example_object.hello_world)

            loop = get_event_loop()

            # Always binds your tasks to a variable
            task_upper = loop.create_task(call_upper())
            task_clock = loop.create_task(print_clock())
            task_hello_world = loop.create_task(get_hello_world())

            loop.run_forever()

Start server before client. python example_server.py

In separated terminal start client. python example_client.py

Use CTRL-C to close client and server.

You can also use ExampleInterface as a local object:

            from asyncio import run
            from example_interface import ExampleInterface

            example_object = ExampleInterface()

            async def test() -> None:
                print(await example_object.upper('test'))

                print(await example_object.hello_world)

            run(test())

  Interfaces repository

python-sdbus includes two namespace packages sdbus_async and sdbus_block which are used for proxies.

For example, D-Bus daemon interface (which comes by default) can be found under sdbus_async.dbus_daemon for async binds and sdbus_block.dbus_daemon for blocking binds.

  Known proxies

  D-Bus daemon interface

    class sdbus_async.dbus_daemon.FreedesktopDbus(bus=None)
        D-Bus daemon.

        This is the D-Bus daemon interface. Used for querying D-Bus state.

        D-Bus interface object path and service name is predetermined. (at 'org.freedesktop.DBus', '/org/freedesktop/DBus')

        Parameters
            bus (SdBus) -- Optional D-Bus connection. If not passed the default D-Bus will be used.

        async get_connection_pid(service_name)
            D-Bus Method

            Get process ID that owns a specified name.

            Parameters
                service_name (str) -- Service name to query.

            Returns
                PID of name owner

            Raises
                DbusNameHasNoOwnerError -- Nobody owns that name

            Return type
                int

        async get_connection_uid(service_name)
            D-Bus Method

            Get process user ID that owns a specified name.

            Parameters
                service_name (str) -- Service name to query.

            Returns
                User ID of name owner

            Raises
                DbusNameHasNoOwnerError -- Nobody owns that name

            Return type
                int

        async get_id()
            D-Bus Method

            Returns machine id where bus is run. (stored in /etc/machine-id)

            Returns
                Machine id

            Return type
                str

        async get_name_owner(service_name)
            D-Bus Method

            Returns unique bus name (i.e. ':1.94') for given service name.

            Parameters
                service_name (str) -- Service name to query.

            Returns
                Unique bus name.

            Raises
                DbusNameHasNoOwnerError -- Nobody owns that name

            Return type
                str

        async list_activatable_names()
            D-Bus Method

            Lists all activatable services names.

            Returns
                List of all names.

            Return type
                List[str]

        async list_names()
            D-Bus Method

            List all services and connections currently of the bus.

            Returns
                List of all current names.

            Return type
                List[str]

        async name_has_owner(service_name)
            D-Bus Method

            Return True if someone already owns the name, False if nobody does.

            Parameters
                service_name (str) -- Service name to query.

            Returns
                Is the name owned?

            Return type
                bool

        async start_service_by_name(service_name, flags=0)
            D-Bus Method

            Starts a specified service.

            Flags parameter is not used currently and should be omitted or set to 0.

            Parameters

                •   service_name (str) -- Service name to start.

                •   flags (int) -- Not used. Omit or pass 0.

            Returns
                1 on success, 2 if already started.

            Return type
                int

        features
            D-Bus property

            Python type: List[str]

            D-Bus type: as

            List of D-Bus daemon features.

            Features include:

            •   'AppArmor' - Messages filtered by AppArmor on this bus.

            •   'HeaderFiltering' - Messages are filtered if they have incorrect header fields.

            •   'SELinux' - Messages filtered by SELinux on this bus.

            •   'SystemdActivation' - services activated by systemd if their .service file specifies a D-Bus name.

        interfaces
            D-Bus property

            Python type: List[str]

            D-Bus type: as

            Extra D-Bus daemon interfaces

        name_acquired
            D-Bus signal

            Python type: str

            D-Bus type: s

            Signal when current process acquires a bus name.

        name_lost
            D-Bus signal

            Python type: str

            D-Bus type: s

            Signal when current process loses a bus name.

        name_owner_changed
            D-Bus signal

            Python type: Tuple[str, str, str]

            D-Bus type: sss

            Signal when some name on a bus changes owner.

            Is a tuple of:

            •   The name that acquired or lost

            •   Old owner (by unique bus name) or empty string if no one owned it

            •   New owner (by unique bus name) or empty string if no one owns it now

This list contains the known python-sdbus interface collections:

    •   D-Bus daemon interface. Built-in.

    •   Notifications.

    •   NetworkManager.

    •   Secrets.

  Interface code generator

Python-sdbus is able to generate the interfaces code from the D-Bus introspection XML. (either from a file or live object on D-Bus) Currently async interfaces code is generated by default. Blocking interfaces can be generated by passing --block option.

Running code generator requires Jinja to be installed.

WARNING:
        Do NOT send the generator result to exec() function. Interface code MUST be inspected before running.

The generated interfaces code will be syntactically correct but NOT stylistically. It is recommended running a code formatter on the generated code. (for example black)

  Generating from XML files

To run generator on files (such as found under /usr/share/dbus-1/interfaces/ folder) execute the sdbus module with gen-from-file first argument and file paths to introspection XML files:

            python -m sdbus gen-from-file /usr/share/dbus-1/interfaces/org.gnome.Shell.Screenshot.xml

The generated interface code will be printed in to stdout. You can use shell redirection > to save it in to file.

Multiple interface files can be passed which generates a file containing multiple interfaces.

  Generating from run-time introspection

To run generator on some service on the D-Bus execute the sdbus module with gen-from-connection first argument, the service connection name as second and one or more object paths:

            python -m sdbus gen-from-connection org.freedesktop.systemd1 /org/freedesktop/systemd1

The generated interface code will be printed in to stdout. You can use shell redirection > to save it in to file.

Multiple object paths can be passed which generates a file containing all interfaces encountered in the objects.

Pass --system option to use system bus instead of session bus.

  Renaming interfaces and members

New in version 0.13.0.

Some interface and member names might conflict with Python keywords when converted from D-Bus introspection to Python code by gerator. The CLI interface allow to override the particular interface and member names using the --select-* and --set-name options. The selector options move the cursor to a particular interface and member

Available override options:

    •

        --set-name
            Sets the name of currently selected element as it would be in generated Python code. Can be used if either interface or member is selected.

    •

        --select-interface
            Selects the interface using its D-Bus name.

    •

        --select-method
            Selects the method using its D-Bus name. An interface must be selected first.

    •

        --select-property
            Selects the property using its D-Bus name. An interface must be selected first.

    •

        --select-signal
            Selects the signal using its D-Bus name. An interface must be selected first.

For example, an org.example.Interface interface has a property called Class. When automatically converted the name will become class which is a reserved Python keyword.

Using these CLI options it is possible to override the name of the property and class:

            python -m sdbus gen-from-file \
                org.example.interface.xml \
                    --select-interface org.example.Interface \
                        --set-name Example \
                        --select-property Class \
                            --set-name example_class

This will generate following Python code:

            class Example:
                @dbus_property_async(
                    property_signature="s",
                )
                def example_class(self) -> str:
                    raise NotImplementedError

  Autodoc extensions

Python-sdbus has an extension for Sphinx autodoc that can document D-Bus interfaces.

To use it include "sdbus.autodoc" extension in your conf.py file.

            extensions = ['sdbus.autodoc']

The extension can document interface class bodies. For example, python-sdbus-networkmanager uses it to document the classes.

            .. autoclass:: sdbus_async.networkmanager.NetworkManagerDeviceBluetoothInterfaceAsync
                :members:

WARNING:
        Autodoc extension is early in development and has multiple issues. For example, the inheritance :inherited-members: does not work on the D-Bus elements.

  Writing docstrings

The D-Bus methods should be documented same way as the regular function would. See Sphinx documentation on possible fields

Example docstring for a D-Bus method:

            @dbus_method_async('s', method_name='GetConnectionUnixProcessID')
            async def get_connection_pid(self, service_name: str) -> int:
                """Get process ID that owns a specified name.

                :param service_name: Service name to query.
                :return: PID of name owner
                :raises DbusNameHasNoOwnerError: Nobody owns that name
                """
                raise NotImplementedError

D-Bus properties and signals will be annotated with type taken from the stub function.

            @dbus_property_async('as')
            def features(self) -> List[str]:
                """List of D-Bus daemon features.

                Features include:

                * 'AppArmor' - Messages filtered by AppArmor on this bus.
                * 'HeaderFiltering' - Messages are filtered if they have incorrect \
                                      header fields.
                * 'SELinux' - Messages filtered by SELinux on this bus.
                * 'SystemdActivation' - services activated by systemd if their \
                                       .service file specifies a D-Bus name.
                """
                raise NotImplementedError

No parameters are supported at the moment for properties and signals.

  Unit testing

Python-sdbus provides several utilities to enable unit testing.

    class sdbus.unittest.IsolatedDbusTestCase
        Extension of unittest.IsolatedAsyncioTestCase from standard library.

        Creates an isolated instance of session D-Bus. The D-Bus will be closed and cleaned up after tests are finished.

        Requires dbus-daemon executable be installed.

        Example:

                from sdbus import DbusInterfaceCommonAsync, dbus_method_async
                from sdbus.unittest import IsolatedDbusTestCase

                class TestInterface(DbusInterfaceCommonAsync,
                                    interface_name='org.test.test',
                                    ):

                    @dbus_method_async("s", "s")
                    async def upper(self, string: str) -> str:
                        """Uppercase the input"""
                        return string.upper()

                def initialize_object() -> Tuple[TestInterface, TestInterface]:
                    test_object = TestInterface()
                    test_object.export_to_dbus('/')

                    test_object_connection = TestInterface.new_proxy(
                    "org.example.test", '/')

                    return test_object, test_object_connection

                class TestProxy(IsolatedDbusTestCase):
                    async def asyncSetUp(self) -> None:
                        await super().asyncSetUp()
                        await self.bus.request_name_async("org.example.test", 0)

                    async def test_method_kwargs(self) -> None:
                        test_object, test_object_connection = initialize_object()

                        self.assertEqual(
                            'TEST',
                            await test_object_connection.upper('test'),
                        )

        bus: SdBus
            Bus instance connected to isolated D-Bus environment.

            It is also set as a default bus.

        assertDbusSignalEmits(signal, timeout=1)
            Assert that a given signal was emitted at least once within the given timeout.

            Parameters

                •   signal -- D-Bus signal object. Can be a signal from either local or proxy object.

                •   timeout (Union[int, float]) -- Maximum wait time until first captured signal.

        Should be used as an async context manager. The context manager exits as soon as first signal is captured.

        The object returned by context manager has following attributes:

            output: List[Any]
                List of captured data.

        Example:

                    async with self.assertDbusSignalEmits(test_object.test_signal) as signal_record:
                        test_object.test_signal.emit("test")

                    self.assertEqual(["test"], signal_record.output)

        New in version 0.12.0.

  API Index

  Common:

get_default_bus()

request_default_bus_name_async()

set_default_bus()

decode_object_path()

encode_object_path()

sd_bus_open_system()

sd_bus_open_user()

DbusDeprecatedFlag

DbusHiddenFlag

DbusNoReplyFlag

DbusPropertyConstFlag

DbusPropertyEmitsChangeFlag

DbusPropertyEmitsInvalidationFlag

DbusPropertyExplicitFlag

DbusSensitiveFlag

DbusUnprivilegedFlag

  Asyncio:

DbusInterfaceCommonAsync

dbus_method_async()

dbus_method_async_override()

dbus_property_async()

dbus_property_async_override()

dbus_signal_async()

  Blocking:

DbusInterfaceCommon

dbus_method()

dbus_property()

  Exceptions:

exceptions.DbusAccessDeniedError

exceptions.DbusAccessDeniedError

exceptions.DbusAddressInUseError

exceptions.DbusAuthFailedError

exceptions.DbusBadAddressError

exceptions.DbusDisconnectedError

exceptions.DbusFailedError

exceptions.DbusFileExistsError

exceptions.DbusFileNotFoundError

exceptions.DbusInconsistentMessageError

exceptions.DbusInteractiveAuthorizationRequiredError

exceptions.DbusInvalidArgsError

exceptions.DbusInvalidFileContentError

exceptions.DbusInvalidSignatureError

exceptions.DbusIOError

exceptions.DbusLimitsExceededError

exceptions.DbusMatchRuleInvalidError

exceptions.DbusMatchRuleNotFound

exceptions.DbusNameHasNoOwnerError

exceptions.DbusNoMemoryError

exceptions.DbusNoNetworkError

exceptions.DbusNoReplyError

exceptions.DbusNoServerError

exceptions.DbusNotSupportedError

exceptions.DbusPropertyReadOnlyError

exceptions.DbusServiceUnknownError

exceptions.DbusTimeoutError

exceptions.DbusUnixProcessIdUnknownError

exceptions.DbusUnknownInterfaceError

exceptions.DbusUnknownMethodError

exceptions.DbusUnknownObjectError

exceptions.DbusUnknownPropertyError

exceptions.SdBusBaseError

exceptions.SdBusLibraryError

exceptions.SdBusUnmappedMessageError

exceptions.map_exception_to_dbus_error()

exceptions.SdBusRequestNameError

exceptions.SdBusRequestNameInQueueError

exceptions.SdBusRequestNameExistsError

exceptions.SdBusRequestNameAlreadyOwnerError

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