[PyQt] How to process QDBusPendingCallWatcher results?

[Phil Thompson]

On Sun, 12 Aug 2012 23:31:54 -0400, Evade Flow <evadeflow at gmail.com>
wrote:
> I'm working on an app that needs to invoke methods in
> various D-Bus services asynchronously, so I wrote this small program to
> test the basic machinery:
> 
> 
>    from PyQt4 import QtCore, QtDBus
> 
>    class DeviceInterface(QtDBus.QDBusAbstractInterface):
> 
>        def __init__(self, service, path, connection, parent=None):
>            super().__init__(service, path,
>                             'org.freedesktop.UDisks.Device',
>                             connection, parent)
> 
>        @QtCore.pyqtSlot(QtDBus.QDBusArgument)
>        def callFinishedSlot(self, arg):
>            print("Got result:", arg)
> 
> 
>    if __name__ == '__main__':
>        import sys
>        app = QtCore.QCoreApplication(sys.argv)
> 
>        dev = DeviceInterface('org.freedesktop.UDisks.Device',
>                              '/org/freedesktop/UDisks/Device/sda1',
>                              QtDBus.QDBusConnection.systemBus(), app)
> 
>        async = dev.asyncCall("FilesystemListOpenFiles");
>        watcher = QtDBus.QDBusPendingCallWatcher(async, dev)
>        watcher.finished.connect(dev.callFinishedSlot)
>        sys.exit(app.exec_())
> 
> 
> It seems to work(?) Anyway, it prints:
> 
>    Got result: <PyQt4.QtDBus.QDBusPendingCallWatcher object at
0xb740c77c>
> 
> The trouble is, I can't figure out how to get results out of the
> QDBusPendingCallWatcher object.  The C++ code I adapted the above
> example from does this:
> 
>     void MyClass.callFinishedSlot(QDBusPendingCallWatcher *call)
>     {
>         QDBusPendingReply<QString, QByteArray> reply = *call;
>         if (reply.isError()) {
>             showError();
>         } else {
>             QString text = reply.argumentAt<0>();
>             QByteArray data = reply.argumentAt<1>();
>             showReply(text, data);
>         }
>         call->deleteLater();
>     }
> 
> Can anyone suggest how I might convert the C++ slot syntax to something
> that will work with PyQt?  Thanks!

Try this...

    def callFinishedSlot(self, call):
        reply = QtDBus.QPyDBusPendingReply(call)

        if reply.isError():
            self.showError()
        else:
            text = reply.argumentAt(0)
            data = reply.argumentAt(1)

...etc.

Phil