Provided by: python3-sdbus_0.11.1-2build1_amd64 
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-Feet 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
# instrospection 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('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_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.
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.
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.
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_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_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.
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.
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
# instrospection 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.
Properties have following methods:
@sdbus.setter(set_function)
Defines the setter function. This makes the property read/write instead of
read-only.
See example on how to use.
@sdbus.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.
async sdbus.get_async()
Get the property value.
The property can also be directly await ed instead of calling this method.
async sdbus.set_async(new_value)
Set property value.
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
@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.
Signals have following methods:
sdbus.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
sdbus.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.
sdbus.emit(args)
Emit a new signal with args data.
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
@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()
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
sdbus.utils.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_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_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 andthe 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).
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_interface.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 Jinja2 to be installed.
WARNING:
Do NOT send the generator result to exec() function. Interface code MUST be inspected
before running.
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.
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.
bus: SdBus
Bus instance connected to isolated D-Bus environment.
It is also set as a default bus.
Usage 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'),
)
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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AUTHOR
igo95862
Apr 11, 2024 PYTHON-SDBUS(1)