connected_devices.py

#!/usr/bin/env python3
import dbus
import dbus.mainloop.glib
from gi.repository import GLib

dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)
mainloop = GLib.MainLoop()


def interfaces_added(path, interfaces):
    if 'org.bluez.Device1' in interfaces:
        print('Device added at {}'.format(path))
        Device(path)

def get_iface_prop(iface, prop):
    response = {}
    bus = dbus.SystemBus()
    mng =  dbus.Interface(bus.get_object('org.bluez', '/'),
                          'org.freedesktop.DBus.ObjectManager')
    bus.add_signal_receiver(interfaces_added,
                            dbus_interface='org.freedesktop.DBus.ObjectManager',
                            signal_name='InterfacesAdded')
                            
    for path, ifaces in mng.GetManagedObjects().items():
        if iface in ifaces:
            response[path] = ifaces[iface][prop]
    return response

class Device:
    def __init__(self, device_path):
        self.bus = dbus.SystemBus()
        self.device_path = device_path
        self.device_obj = self.bus.get_object('org.bluez', device_path)
        device_props = dbus.Interface(self.device_obj, dbus.PROPERTIES_IFACE)
        device_props.connect_to_signal('PropertiesChanged', self.on_prop_changed)

    def on_prop_changed(self, iface, changed_props, invalidated_props):
        if 'org.bluez.Device1' in iface:
            if 'Connected' in changed_props:
                print('{0} is now {1}'.format(self.device_path, changed_props['Connected']))


if __name__ == '__main__':
    for k, v in get_iface_prop('org.bluez.Device1', 'Connected').items():
        print('{0} is {1}'.format(k, v))
        Device(k)

    mainloop.run()