Trying to use the DBus API with QtDBus - does the example work?

[devine-mlist ddevnet net]

I have hacked up the change-ipv4-address.cpp example in an attempt to 
make it so that the program takes an interface name such as "eth0" and 
changes the IP address instead of a UUID.
The problem is:
"Error: could not update connection: 
org.freedesktop.DBus.Error.UnknownMethod Method "Update" with signature 
"a{sa{sv}}" on interface 
"org.freedesktop.NetworkManager.Settings.Connection" doesn't exist"

This comes from a piece of code that I did not change and should work 
the same as the original - unless I have really misunderstood something.
Surfing around using the qdbus tool I noticed that I could not get to 
the Settings methods. I could only get 
org.freedesktop.NetworkManager.Device.* stuff.

qdbus --system org.freedesktop.NetworkManager 
/org/freedesktop/NetworkManager/Devices/0 
org.freedesktop.NetworkManager.[no Settings methods here!]


Example code: 
http://cgit.freedesktop.org/NetworkManager/NetworkManager/tree/examples/C/qt/change-ipv4-addresses.cpp


My code:
===================================

#include <QtDBus/QDBusConnection>
#include <QtDBus/QDBusInterface>
#include <QtDBus/QDBusMetaType>
#include <QtDBus/QDBusReply>
#include <QtCore/QList>
#include <QtCore/QMap>
#include <QtCore/QString>
#include <QtCore/QDebug>
#include <QtNetwork/QHostAddress>

#include "arpa/inet.h"

#include "NetworkManager.h"

typedef QMap<QString, QMap<QString, QVariant> > Connection;
Q_DECLARE_METATYPE(Connection)
Q_DECLARE_METATYPE(QList<uint>);
Q_DECLARE_METATYPE(QList<QList<uint> >);


QString ifaceNameToPath(const QString& iface_name){
        // Set up DBus interface to org.freedesktop.NetworkManager
        QDBusInterface interface(
                NM_DBUS_SERVICE,
                NM_DBUS_PATH,
                NM_DBUS_INTERFACE,
                QDBusConnection::systemBus());

        // Call GetDevicesByIpIface using iface_name
        QDBusReply<QDBusObjectPath> path = 
interface.call("GetDeviceByIpIface", iface_name);
        qDebug() << path.value().path();
        // return the path.
        return path.value().path();
}


void changeConnection(const QString& ifname)
{
    // Register types with D-Bus
    qDBusRegisterMetaType<Connection>();
    qDBusRegisterMetaType<QList<uint> >();
    qDBusRegisterMetaType<QList<QList<uint> > >();

    Connection connection;
    QString conPath;

    // Find connection by provided UUID
    conPath = ifaceNameToPath(ifname);
    qDebug() << "Derp conPath " << conPath << " ifname was " << ifname;
    if (!conPath.isEmpty()) {
        QList<QList<uint> > addresses;
        QList<uint> addr1, addr2;

        // Add some addresses
        addr1 << htonl(QHostAddress("192.168.1.105").toIPv4Address());
        addresses << addr1;

        // Set method to "Manual" and put addresses to the connection 
map
        connection["ipv4"]["method"] = "manual";
        connection["ipv4"]["addresses"] = 
QVariant::fromValue(addresses);

        QDBusInterface interface(
            NM_DBUS_SERVICE,
            conPath,
            NM_DBUS_IFACE_SETTINGS_CONNECTION,
            QDBusConnection::systemBus());

        // Call Update() D-Bus method to update connection
        QDBusReply<void> result = interface.call("Update", 
QVariant::fromValue(connection));
        if (result.isValid()) {
            qDebug() << QString("Connection successfully updated (path 
%1)").arg(conPath);
        } else {
           qDebug() << QString("Error: could not update connection: %1 
%2").arg(result.error().name()).arg(result.error().message());
        }
    } else {
            qDebug() << QString("Error: connection with name '%1' not 
found").arg(ifname);
    }
}

int main(int argc, char *argv[])
{
    if (argc != 2) {
        qDebug() << QString("Usage: %1 <UUID>").arg(argv[0]);
        return -1;
    }

    changeConnection(argv[1]);
}

--Daniel Devine