simple dbus python problem ... please help

[bob]

Hi,

I have this sample python script from the hal sources, but it doesn't work
for me. This is despite other example python scripts I have to help me are
working fine. The problem is that this script is the closet to what it is
I actually want to learn to do.

The error is:

Traceback (most recent call last):
  File "./dbus-3.py", line 6, in ?
    hal_service = bus.get_service ('org.freedesktop.Hal')
AttributeError: 'SystemBus' object has no attribute 'get_service'


The script is as follows:

#!/usr/bin/python

import dbus

bus = dbus.Bus (dbus.Bus.TYPE_SYSTEM)
hal_service = bus.get_service ('org.freedesktop.Hal')
hal_manager = hal_service.get_object ('/org/freedesktop/Hal/Manager',
                                      'org.freedesktop.Hal.Manager')

volume_udi_list = hal_manager.FindDeviceByCapability ('volume')
for udi in volume_udi_list:
    volume = hal_service.get_object (udi, 'org.freedesktop.Hal.Device')
    device_file = volume.GetProperty ('block.device')
    fstype = volume.GetProperty ('volume.fstype')
    storage_udi = volume.GetProperty ('block.storage_device')
    storage = hal_service.get_object (storage_udi, 'org.freedesktop.Hal.Device')
    drive_type = storage.GetProperty ('storage.drive_type')
    print 'udi=%s device_file=%s fstype=%s drive_type=%s'%(udi,
    device_file, fstype, drive_type)

Documentation on this stuff is extremely thin on the ground, so links to
any good resources other than those at freedesktop.org would be most
appreciated!

All I really want to do is have a nice routine to do the following:

1. check whether or not a user has a dvd drive.
2. check whether a disc is in it.
3. if there is a disc in the drive, check the various properties relating
to it.

Surely it cannot be that hard to get enough information to work out how to
do that!

Thanks for reading :)