D-Bus method not found at object path despite the fact that method exist - dbus

Question

I implement an app with this com.example.appname.desktop file as follows:
$ cat /usr/local/share/applications/com.example.appname.desktop
[Desktop Entry]
Version=1.0
Terminal=false
Type=Application
Name=appname
Exec=/opt/app/appname %u
DBusActivatable=true
Categories=Network;
MimeType=x-scheme-handler/itmm;
NoDisplay=false
$ cat /usr/share/dbus-1/services/com.example.appname.service
[D-BUS Service]
Name=com.example.appname
Exec=/opt/app/appname
Introspection XML looks like this:
$ qdbus com.example.appname /com/example/appname org.freedesktop.DBus.Introspectable.Introspect
<!DOCTYPE node PUBLIC "-//freedesktop//DTD D-BUS Object Introspection 1.0//EN"
"http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
<node>
<interface name="org.freedesktop.Application">
<method name="ActivateAction">
<arg name="action_name" type="s" direction="in"/>
<arg name="parameter" type="av" direction="in"/>
<arg name="platform_data" type="a{sv}" direction="in"/>
<annotation name="org.qtproject.QtDBus.QtTypeName.In2" value="QVariantMap"/>
</method>
<method name="Activate">
<arg name="platform_data" type="a{sv}" direction="in"/>
<annotation name="org.qtproject.QtDBus.QtTypeName.In0" value="QVariantMap"/>
</method>
<method name="Open">
<arg name="uris" type="as" direction="in"/>
<arg name="platform_data" type="a{sv}" direction="in"/>
<annotation name="org.qtproject.QtDBus.QtTypeName.In1" value="QVariantMap"/>
</method>
</interface>
<interface name="org.freedesktop.DBus.Properties">
<method name="Get">
<arg name="interface_name" type="s" direction="in"/>
<arg name="property_name" type="s" direction="in"/>
<arg name="value" type="v" direction="out"/>
</method>
----<snipped>-----
But when i try to launch the method it gives me an error:
$ gapplication launch com.example.appname
error sending Activate message to application: GDBus.Error:org.freedesktop.DBus.Error.UnknownMethod: No such method 'Activate' in interface 'org.freedesktop.Application' at object path '/com/example/appname' (signature 'a{sv}')
Is "annotation name=.." XML tag (see introspection XML) the reason this method is not found?
Browsing to itmm://192.168.1.1/query?version=1.0 via browser launches the application with command line parameter, but it is not launched via D-Bus service and thats what my requirement is. Is there a way to debug this via firefox or google chrome browsers?

Answer 1

I use QT's D-Bus binding to implement D-Bus service. My issue were
My class that implemented D-Bus interface was not inheriting QDBusAbstractAdaptor .
Methods to be exported were not marked as public slots
My original class looked like this below:
class DBusService : public Application
{
QOBJECT
Q_CLASSINFO("D-Bus Interface", "org.freedesktop.Application")
public:
void Activate(QMap<QString, QVariant> platform_data)
{
Q_UNUSED(platform_data);
}
void Open(QStringList uris, QMap<QString, QVariant> platform_data)
{
Q_UNUSED(platform_data);
if( ! uris.size() ) {
return;
}
QUrl url(uris[0]);
//use url
}
}
Following one works:
class DBusService : public QDBusAbstractAdaptor //<----- Inherit from this class
{
QOBJECT
Q_CLASSINFO("D-Bus Interface", "org.freedesktop.Application")
public slots: // <------ mark public slots
void Activate(QMap<QString, QVariant> platform_data)
{
Q_UNUSED(platform_data);
}
void Open(QStringList uris, QMap<QString, QVariant> platform_data)
{
Q_UNUSED(platform_data);
if( ! uris.size() ) {
return;
}
QUrl url(uris[0]);
qApp->MyCustomMethod(url);
}
}
D-Bus debugging tools
These tools helped me debugging D-Bus issues.
dbus-monitor - sniffs traffic on the bus
gapplication - lets you debug DBusActivatable services.