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pythondbus

Inspect a received D-Bus signal on its handler

I'm building a general-purpose DBus proxy receiver that a user can leverage to configure generic signal listeners and proxy them to another service.

Therefore, I need to be able to listen to all the bus signals:

from dbus import SessionBus

def handler(*args, **kwargs):
  print(args, kwargs)

# ...

bus = SessionBus()
bus.add_signal_receiver(handler, signal_name=None, dbus_interface=None, path=None)

The problem with this approach is that I have no way from the handler's args and kwargs to tell which interface/signal name/path are associated with the signal:

args=(dbus.String(':1.22395'), dbus.String(''), dbus.String(':1.22395')) kwargs={}

Is there an easy way to inspect DBus to get more information about the received signal? I guess that it should exist (dbus-monitor --monitor does more or less the same thing that I'm trying to do), but I couldn't find any references online.

Solution

  • Look at the sender_keyword, destination_keyword, etc. keyword arguments of add_signal_receiver().

    You may want to consider using pydbus, or some other more modern D-Bus binding. dbus-python is old and not very Pythonic. It’s not very actively maintained, and certainly not actively developed.