Dbus Help - maemo.org

xur17 | # 1 | 2010-10-08, 18:47 | Report

I am trying to monitor a dbus signal, and make my n900 output some text when a specific signal is received.

I am using python. This is the signal that I am monitoring for (any presence change for a user on my jabber account). I got this using the dbus-monitor command:

Code:

signal sender=:1.496 -> dest=(null destination) serial=3979 path=/org/freedesktop/Telepathy/Connection/gabble/jabber/username_40gmail_2ecom_2fMaemo; interface=org.freedesktop.Telepathy.Connection.Interface.SimplePresence; member=PresencesChanged
   array [
      dict entry(
         uint32 209
         struct {
            uint32 2
            string "available"
            string "243"
         }
      )
   ]

Here is my code:

Code:

#! /usr/bin/python
import gobject, dbus
from dbus.mainloop.glib import DBusGMainLoop

def handle_presence():
    print "status changed"

if __name__ == '__main__':
	print "starting"
	DBusGMainLoop(set_as_default=True)
	bus = dbus.SystemBus()
	bus.add_signal_receiver(handle_presence, 'PresencesChanged', 'org.freedesktop.Telepathy.Connection.Interface.SimplePresence', None, '/org/freedesktop/Telepathy/Connection/gabble/jabber/username_40gmail_2ecom_2fMaemo')
	gobject.MainLoop().run()

As far as I can tell, this should work, but nothing is outputted.

kureyon | # 2 | 2010-10-08, 19:46 | Report

Have you used dbus-monitor to confirm that the events you expect are being triggered?

xur17 | # 3 | 2010-10-08, 19:51 | Report

Originally Posted by kureyon View Post

Have you used dbus-monitor to confirm that the events you expect are being triggered?

Yes, and they definitely are. I manually changed a user's presence that is on my buddy list while running dbus-monitor. I copied that exact line into this post, and made my script using it.

daperl | # 4 | 2010-10-08, 21:35 | Report

Change

bus = dbus.SystemBus()

to

bus = dbus.SessionBus()

and all should be good.

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xur17 | # 5 | 2010-10-08, 22:01 | Report

Originally Posted by daperl View Post

Change

bus = dbus.SystemBus()

to

bus = dbus.SessionBus()

and all should be good.

Thank you! I have been playing around with it for hours, and this fixed it for me!

xur17 | # 6 | 2010-10-08, 22:31 | Report

Do you know what type is passed to handle_presence?

nicolai | # 7 | 2010-10-08, 22:40 | Report

http://telepathy.freedesktop.org/spe...esencesChanged

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daperl | # 8 | 2010-10-08, 22:54 | Report

I changed your code to this:

Code:

def handle_presence(*args):
    print "status changed",args

and here's the output:

Code:

status changed (dbus.Dictionary({dbus.UInt32(1L): dbus.Struct((dbus.UInt32(2L), dbus.String(u'available'), dbus.String(u'')), signature=None)}, signature=dbus.Signature('u(uss)')),)

So, it looks like a one-value tuple with a dbus.Dictionary.

But I noticed that no events occur when the account is disabled, so maybe you also want to listen for this:

Code:

bus.add_signal_receiver(handle_presence, 'StatusChanged', 'org.freedesktop.Telepathy.Connection', None, '/org/freedesktop/Telepathy/Connection/gabble/jabber/username_40gmail_2ecom_2fMaemo')

Here's the output when I swap that with the other receiver call:

enabled:

Code:

status changed (dbus.UInt32(1L), dbus.UInt32(1L))
status changed (dbus.UInt32(0L), dbus.UInt32(1L))

disabled:

Code:

status changed (dbus.UInt32(2L), dbus.UInt32(1L))

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xur17 | # 9 | 2010-10-09, 00:13 | Report

What variable type is args?

I receive the following when I do print args:

Code:

(dbus.Dictionary({dbus.UInt32(3L): dbus.Struct((dbus.UInt32(4L), dbus.String(u'xa'), dbus.String(u"I'm away from my computer")), signature=None)}, signature=dbus.Signature('u(uss)')),)

It appears that it is a structure inside of a dictionary. How do I set a variable to the value of the status ("I'm away from my computer")?

daperl | # 10 | 2010-10-09, 01:17 | Report

I think all is answered by following nicolai's link and the dbus-python tutorial. According to the Data Types section, dbus.Dictionary is a sub-class of dict.

Remove the '*' from '*arg' and arg should just be a dbus.Dictionary.

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