It will control spotify playback. Compile: gcc -Wall `pkg-config --cflags --libs gio-2.0` test-mediakeys.c -o test-mediakeys

test-mediakeys.c

/*
 * Copyright (C) 2017 La Ode Muh. Fadlun Akbar <[email protected]>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.

 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include <gio/gio.h>

static void
on_signal(GDBusProxy* proxy,
          __attribute__((unused)) gchar* sender_name,
          __attribute__((unused)) gchar* signal_name,
          GVariant* parameters,
          __attribute__((unused)) gpointer user_data)
{
    GDBusProxy* player_proxy = NULL;
    GVariant* player_dbus_ret = NULL;
    GError* error = NULL;
    gchar* player_control = NULL;

    player_proxy =
      g_dbus_proxy_new_for_bus_sync(G_BUS_TYPE_SESSION,
                                    G_DBUS_PROXY_FLAGS_NONE,
                                    NULL,
                                    "org.mpris.MediaPlayer2.spotify",
                                    "/org/mpris/MediaPlayer2",
                                    "org.mpris.MediaPlayer2.Player",
                                    NULL,
                                    &error);

    /* https://specifications.freedesktop.org/mpris-spec/latest/Player_Interface.html
       Next 	() 	→ 	nothing
       Previous () 	→ 	nothing
       Pause 	() 	→ 	nothing
       PlayPause() 	→ 	nothing
       Stop 	() 	→ 	nothing
       Play 	() 	→ 	nothing
    */
    g_variant_get(parameters, "(ss)", NULL, &player_control);
    if (g_strcmp0(player_control, "Play") == 0) {
        player_dbus_ret = g_dbus_proxy_call_sync(player_proxy,
                                                 "PlayPause",
                                                 NULL,
                                                 G_DBUS_CALL_FLAGS_NONE,
                                                 -1,
                                                 NULL,
                                                 &error);
    } else {
        player_dbus_ret = g_dbus_proxy_call_sync(player_proxy,
                                                 player_control,
                                                 NULL,
                                                 G_DBUS_CALL_FLAGS_NONE,
                                                 -1,
                                                 NULL,
                                                 &error);
    }
    if (player_dbus_ret != NULL) {
        g_variant_unref(player_dbus_ret);
    }

    g_free(player_control);
}

int
main(int argc, char* argv[])
{
    GMainLoop* loop = NULL;
    GDBusProxy* proxy = NULL;
    GError* error = NULL;

    loop = g_main_loop_new(NULL, FALSE);
    proxy = g_dbus_proxy_new_for_bus_sync(G_BUS_TYPE_SESSION,
                                          G_DBUS_PROXY_FLAGS_NONE,
                                          NULL,
                                          "org.gnome.SettingsDaemon",
                                          "/org/gnome/SettingsDaemon/MediaKeys",
                                          "org.gnome.SettingsDaemon.MediaKeys",
                                          NULL,
                                          &error);
    g_signal_connect(proxy, "g-signal", G_CALLBACK(on_signal), NULL);
    g_dbus_proxy_call(proxy,
                      "GrabMediaPlayerKeys",
                      g_variant_new("(su)", "ExampleMediaEvent", 0),
                      G_DBUS_CALL_FLAGS_NO_AUTO_START,
                      -1,
                      NULL,
                      NULL,
                      NULL);
    g_main_loop_run(loop);
    return 0;
}