DBus method calls with arguments

[StMartin81]

Hello,

I'm trying to replicate the following command using qdbus:

$ dbus-send --system --type=method_call --print-reply=literal --dest=org.bluez /org/bluez/hci1 org.freedesktop.DBus.Properties.Set string:org.bluez.Adapter1 string:Powered variant:boolean:true

Here are my two attempts which both didn't work:

#define BLUEZ_DBUS_SERVICE "org.bluez"
#define BLUEZ_DBUS_PATH "/org/bluez/hci1"
QDBusConnection bus = QDBusConnection::systemBus();
if (!bus.isConnected())
{
    qFatal("Cannot connect to the D-Bus session bus.");
    return;
}
QDBusMessage message = QDBusMessage::createMethodCall(BLUEZ_DBUS_SERVICE,
                                                      BLUEZ_DBUS_PATH,
                                                      "org.freedesktop.DBus.Properties",
                                                      "Set");
QList<QVariant> args;
args.append("org.bluez.Adapter1");
args.append("Powered");
args.append(true);
message.setArguments(args);
QDBusPendingReply<QVariantMap> reply = QDBusConnection::systemBus().asyncCall(message);
reply.waitForFinished();

and this is my second attempt:

QDBusConnection bus = QDBusConnection::systemBus();
if (!bus.isConnected())
{
    qFatal("Cannot connect to the D-Bus session bus.");
    return;
}
QDBusInterface dbus_iface(BLUEZ_DBUS_SERVICE,
                          BLUEZ_DBUS_PATH,
                          "org.freedesktop.DBus.Properties",
                          bus);
 dbus_iface.call("Set",
                 QString("org.freedesktop.DBus.Properties"),
                 QString("Powered"),
                 true);

If I try this:

message = QDBusMessage::createMethodCall(BLUEZ_DBUS_SERVICE,
                                         BLUEZ_DBUS_PATH,
                                         "org.freedesktop.DBus.Properties",
                                         "Get");
args.append("org.bluez.Adapter1");
args.append("Powered");
reply = QDBusConnection::systemBus().asyncCall(message);
reply.waitForFinished();
QVariantMap map = reply.value();
qDebug() << "Return value: " << map.begin().value();

I get the following output:

Return value:  QVariant(Invalid)

Can anybody tell me what I am doing wrong here?

Regards
Martin

[StMartin81]

I got it working. Problem was that instead of bool I had to use QVariant of QDBusVariant type. So the two functions look like this now:

These are the defines I've used:

#define BLUEZ_DBUS_SERVICE "org.bluez"
#define BLUEZ_DBUS_PATH "/org/bluez/hci0"
#define BLUEZ_DBUS_IF "org.bluez.Adapter1"

And here is the first implementationÖ

QDBusConnection bus = QDBusConnection::systemBus();
if (!bus.isConnected())
{
    qFatal("Cannot connect to the D-Bus session bus.");
    return;
}
QDBusMessage message = QDBusMessage::createMethodCall(BLUEZ_DBUS_SERVICE,
                                                      BLUEZ_DBUS_PATH,
                                                      "org.freedesktop.DBus.Properties",
                                                      "Set");
QList<QVariant> arguments;
arguments << BLUEZ_DBUS_IF
          << "Powered"
          << QVariant::fromValue(QDBusVariant(true));
message.setArguments(arguments);
QDBusPendingReply<QVariantMap> reply = bus.asyncCall(message);
reply.waitForFinished();

and here is the second possibility to implement the method call:

QDBusConnection bus = QDBusConnection::systemBus();
if (!bus.isConnected())
{
    qFatal("Cannot connect to the D-Bus session bus.");
    return;
}
QDBusInterface dbus_iface(BLUEZ_DBUS_SERVICE,
                          BLUEZ_DBUS_PATH,
                          "org.freedesktop.DBus.Properties",
                          bus);
if ( dbus_iface.isValid() ) {
    QDBusPendingReply<QVariantMap> reply = dbus_iface.asyncCall("Set",
                                                                BLUEZ_DBUS_IF,
                                                                "Powered",
                                                                QVariant::fromValue(QDBusVariant(true)));
    reply.waitForFinished();
    reply.error().message();
}

In case anybody wants to do the same thing there is also the possibility to set the "Powered" property directly:

QDBusInterface ifc(
            BLUEZ_DBUS_SERVICE,
            BLUEZ_DBUS_PATH,
            BLUEZ_DBUS_IF,
            QDBusConnection::systemBus());
if ( ifc.isValid() ) {
    ifc.setProperty("Powered", true);
}