A dbus.mainloop.NativeMainLoop instance is required [Was: Re: dbus-python: support for Windows and OS X]

[Lukas Hetzenecker]

I was able to compile dbus and dbus-python on Windows without any problems, 
but now I get strange error messages when I try to create a D-Bus service:

Windows XP; dbus 1.4.1-2 
 
C:\Python27\Lib\site-packages\dbus>C:\Python27\python.exe 
Python 2.7.1 (r271:86832, Nov 27 2010, 18:30:46) [MSC v.1500 32 bit (Intel)] 
on win32 
 
>>> import sys 
>>> import dbus 
>>> import dbus.service 
>>> import dbus.mainloop.qt 
>>> from PyQt4 import QtCore 
>>> 
>>> app = QtCore.QCoreApplication(sys.argv) 
>>> mainloop = dbus.mainloop.qt.DBusQtMainLoop(set_as_default=True) 
>>> sb = dbus.SessionBus() 
>>> name = dbus.service.BusName("net.sourceforge.series60remote", sb) 
 
>>> obj = dbus.service.Object.__init__(dbus.service.Object(), sb, 
'/Series60Remote') 
Traceback (most recent call last): 
  File "<stdin>", line 1, in <module> 
  File "C:\Python27\lib\site-packages\dbus\service.py", line 480, in __init__ 
    self.add_to_connection(conn, object_path) 
  File "C:\Python27\lib\site-packages\dbus\service.py", line 571, in 
add_to_connection 
    self._fallback) 
RuntimeError: To make asynchronous calls, receive signals or export objects, 
D-Bus connections must be attached to a main loop by passing mainloop=... to 
the constructor or calling dbus.set_default_main_loop(...) 

But when I try to call dbus.set_default_main_loop I get this error:

>>> dbus.set_default_main_loop(mainloop) 
Traceback (most recent call last): 
  File "<stdin>", line 1, in <module> 
TypeError: A dbus.mainloop.NativeMainLoop instance is required 
 

which is really odd, because mainloop is an instance of 
dbus.mainloop.NativeMainLoop:

>>> isinstance(mainloop, NativeMainLoop) 
True 
 
>>> dbus.version 
(0, 83, 2) 


The same code works on a Linux system without any problems:

Fedora 14; dbus 1.4.0-2 
 
Python 2.7 (r27:82500, Sep 16 2010, 18:02:00) 
[GCC 4.5.1 20100907 (Red Hat 4.5.1-3)] on linux2 
>>> import sys 
>>> import dbus 
>>> import dbus.service 
>>> import dbus.mainloop.qt 
>>> from PyQt4 import QtCore 
>>> app = QtCore.QCoreApplication(sys.argv) 
>>> mainloop = dbus.mainloop.qt.DBusQtMainLoop(set_as_default=True) 
>>> sb = dbus.SessionBus() 
>>> name = dbus.service.BusName("net.sourceforge.series60remote", sb) 
>>> obj = dbus.service.Object.__init__(dbus.service.Object(), sb, 
'/Series60Remote') 
 
>>> dbus.version 
(0, 83, 0) 


Does anybody know what causes this odd behaviour?

Thanks,
Lukas


Am Donnerstag, 27. Januar 2011, 23:13:26 schrieb Ralf Habacker:
> Am 26.01.2011 10:56, schrieb Lukas Hetzenecker:
> > Hello,
> > 
> > I'm the developer of the cross-platform application Series60-Remote,
> > which is written in Python. I would like to use an inter-process
> > communication framework and D-Bus seems to be a great choice.
> > Are there already python bindings which support also Windows (and OS X)?
> > 
> > I used the binary package for the D-Bus server of the KDE-Windows
> > project and this seems to work correctly. But I can't get the python
> > bindings to work. I followed the instructions of the deluge project
> > [1], but they seem to be outdated (they switched to an other IPC
> > framework in January 2010).
> > 
> > Is there anybody who has used dbus-python already on Windows or has an
> > installation howto?
> 
> In the KDE on windows buildsystem there is a build-from-source-package
> for dbus-python (it works at least for msvc release builds), see
> http://websvn.kde.org/trunk/kdesupport/emerge/portage/testing/dbus-python/
> 
> Regards
>   Ralf
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