python-adbus

D-Bus Binding for Python utilizing the Python's asyncio module.

Links

• Documentation
• Project Page
• Issues

Dependencies

1. Python >= 3.7
2. libsystemd >= 232 (don’t need systemd, just libsystemd which is a separate package)
3. Cython >= 0.25.2

Building / Installing

• To build in place for development python ./setup.py build_ext --inplace
• The html documents are stored in gh-pages branch, so that GitHub will serve them as a GitHub Pages. To build them: 1. check out the gh-pages branch into ../python-adbus/html 2. cd into docs 3. sphinx-apidoc -o source/ ../adbus 4. make html

Unit-Tests

NOTE: Some test-cases require the busctl tool from systemd.

• To run a specific unit-test from the root directory (eg.):

python -m unittest tests.test\_sdbus\_method.Test.test\_method\_single\_str

• To run a specific unit-test module from the root directory (eg.):

python -m unittest tests.test\_sdbus\_method

• To run all unit-tests from the root directory:

tox

Server Examples

Object Example

This is an example of an object, which can be connected to a service.

import adbus
import typing

class ExampleClass(adbus.server.Object):

    signal1: int = adbus.server.Signal()
    signal2: typing.List[int] = adbus.server.Signal()

    property1: str = adbus.server.Property('none', read_only=True, hidden=True)
    property2: typing.List[int] = adbus.server.Property(['rr', 'ff'], deprecated=True)

    def __init__(self, service):
        super().__init__(service, path='/xxx/yyy', interface='yyy.xxx')

    @adbus.server.method(name='test', hidden=True)
    def test_method(self, r: int, gg: str) -> int:
        return r + 10

    def do_something(self):
        self.signal1.emit(14)

Setting Multiple Properties

It's possible to set multiple properties at the same time, this will defer the property update signal, and send one signal for all property changes. It's good practice to use this when changing multiple properties, it will reduce traffic on the D-Bus.

NOTE: Must be running in a loop.

Client Examples

Accessing Remote Interface via a Proxy

It's possible to map a remote interface to a local instantiated class using a Proxy.

If the even loop isn't running no signals will caught, and properties will not cache (i.e. will read on every access instead of tracking the property changes signals)

The proxy opbject must be saved for as long as you want to activily receive signals. If the proxy object is garbage collected it will no longer receive signals and it won't forward them to a watcher.

service = adbus.Service(bus='session')
proxy = adbus.client.Proxy(service, 'com.example.xxx', '/com/example/Service1',
    interface='com.example.service.unit')

async def proxy_examples():
  await proxy.update() # initialize the proxy

  # == Access Properties
  await proxy.remote_propertyX.set(45)
  print(await proxy.remote_propertyY.get())

  # == or
  await proxy.remote_propertyX(45)
  print(await proxy.remote_propertyY())

  # == Access Methods
  asyncio.ensure_future(proxy.remote_method_foo("some info")) # don't wait for result
  x = await proxy.remote_method_bar(100, 12, -45) # wait for result

  # == Add a Coroutine to a Signal
  async def local_method(signal_data: int):
    print(signal_data)
  proxy.remote_signal.add(local_method)

  # == or
  proxy.remote_signal(local_method)

  # == Remove a Coroutine to a Signal
  proxy.remote_signal.remove(local_method)

  # == or (if already added)
  proxy.remote_signal(local_method)

  # == Access a method using a different interface name
  proxy['com.example.service.serve'].remote_method_800(b"data")

  # == Create a new proxy from a node in the proxy
  proxy_new = await proxy('Test')

  # == Loop through all nodes in a proxy
  sum_cnt = 0
  async for node in proxy:
      try:
          sum_cnt += await node.count
      except AttributeError:
          pass

  # == set multiple properties in one message (if linked to an adbus based server)
  async with proxy as p:
      p.property1 = "some data"
      p.property2 = [1,2,3,4,5]

loop = asyncio.get_event_loop()
loop.run_until_complete(proxy_examples())
loop.close()

Style Guide

For a consistent style all code is updated using yapf with the following options:

yapf --recursive --verbose --in-place --no-local-style

--style="{dedent_closing_brackets: True, continuation_indent_width: 8, split_complex_comprehension: True}" <filename>