So for now I committed a manually adjusted vapi for gudev. This now makes it easy to write code that queries and listens to udev in Vala.

Small example:

using GUdev;

void
print_device(GUdev.Device d)
{
    stdout.printf("%s → %s\n", d.get_device_file(), d.get_sysfs_path());
    foreach (string s in d.get_device_file_symlinks())
        stdout.printf("  link: %s\n", s);
}

void
on_uevent(GUdev.Client client, string action, GUdev.Device dev)
{
    stdout.printf("[%s] ", action);
    print_device(dev);
}

int main(string[] args)
{
    var uc = new GUdev.Client({"usb"});

    print_device(uc.query_by_device_file(args[1]));

    stdout.printf("---- all block devices ---\n");
    GLib.List devs = uc.query_by_subsystem("block");
    foreach (GUdev.Device d in devs)
        print_device(d);

    stdout.printf("---- usb events ---\n");
    uc.uevent.connect(on_uevent);
    new GLib.MainLoop().run();
    return 0;
}

Build with valac --pkg gudev-1.0 udev.vala, and perhaps specify --vapidir if you keep the gudev-1.0.vapi file somewhere locally.

Update: I reverted the commit upstream for now, since Vala 0.8 already ships a gudev vapi. I must have overlooked that when I played with vapigen.. In the long run it’s probably better to generate vapis in the projects themselves to avoid API skew, but as long as the vapi can’t be generated automatically it does not make sense to have it in udev. Above code was updated for the vala provided one (which is lacking a return type specification for query_by_subsystem()).

And indeed I wasn’t disappointed. It’s not as convenient as Python, but really not far from it, and it’s faaaast!

Today I finally got back to this and wrote my first D-Bus example in vala which does a call to DeviceKit-disks:

using DBus;

int main(string[] args)
{
    Connection con = Bus.get(BusType.SYSTEM);

    dynamic DBus.Object dk = con.get_object(
            "org.freedesktop.DeviceKit.Disks",
	    "/org/freedesktop/DeviceKit/Disks",
	    "org.freedesktop.DeviceKit.Disks");

    ObjectPath[] devs = dk.EnumerateDevices();
    foreach (ObjectPath o in devs)
	stdout.printf("%s\n", o);

    return 0;
}

Compile and run it with

valac --pkg dbus-glib-1 dbus-dk.vala && ./dbus-dk

and voila!