Simple program that prints the current playing song from Rhythmbox.

now_playing.d

import std.conv;
import std.file;
import std.stdio;
import std.string;
import std.process;

import core.time;
import core.thread;
import core.sys.posix.unistd; // getlogin

void create_working_dir() {
    string dir = "/tmp/rb";
    if (!exists(dir)) {
        string user = fromStringz(getlogin()).idup;
        executeShell(format("doas -u %s mkdir -p %s", user, dir));
    }
}

void kill_get_song_loop(string pid_file) {
    if (exists(pid_file)) {
        auto f = File(pid_file, "r");
        string pid = strip(f.readln());
        executeShell(format("kill %s", pid));
        remove(pid_file);
    }
}

void print_song(string playing_file) {
    if (exists(playing_file)) {
        auto f = File(playing_file, "r");
        string song = strip(f.readln());
        writeln(song);
        return;
    }

    writeln("...");
}

void spawn_get_song_loop() {
    string pid_file = "/tmp/rb/pid";
    string playing_file = "/tmp/rb/playing";
    bool rb_running = false;

    auto processes = executeShell("pgrep rhythmbox | xargs printf '%d,'");
    string[] pids = chop(strip(processes.output)).split(",");
    foreach (pid; pids) {
        uint p = to!uint(pid);
        if (p != 0) rb_running = true;
        break;
    }

    if (rb_running && !exists(pid_file)) {
        auto pid = spawnProcess("rb_get_song");
        auto fo = File(pid_file, "w");
        fo.write(pid.processID.to!string);
        fo.flush();
        Thread.sleep(5.seconds);
    }
    else if (!rb_running) {
        if (exists(playing_file)) {
            remove(playing_file);
        }

        kill_get_song_loop(pid_file);
    }

    print_song(playing_file);
}

int main() {
    create_working_dir();
    spawn_get_song_loop();
    return 0;
}

rb_get_song

#!/usr/bin/env python3
# This Python program will get the current song from Rhythmbox.
# It should be invoked as a process by now_playing.
import dbus
import dbus.mainloop.glib
from gi.repository import GLib

playing_file = '/tmp/rb/playing'
_artist = ''

def dump_playing_file():
    with open(playing_file, 'w') as f:
        f.write('...')

if __name__ == "__main__":
    dump_playing_file()

    dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)
    bus = dbus.SessionBus()
    player = bus.get_object("org.mpris.MediaPlayer2.rhythmbox", "/org/mpris/MediaPlayer2")
    iface = dbus.Interface(player, "org.freedesktop.DBus.Properties")

    def on_metadata_changed(interface, changed_props, invalidated_props):
        if "Metadata" in changed_props:
            meta = changed_props["Metadata"]
            artist = meta.get(dbus.String("xesam:artist"), "")
            title = meta.get(dbus.String("xesam:title"), "")

            global _artist
            _artist = str(artist).split(".String('")[1]
            _artist = _artist.split("'")[0]

        try:
            if _artist != "":
                with open(playing_file, 'w') as f:
                    f.write(f'{_artist} - {title}')
        except:
            pass

    iface.connect_to_signal("PropertiesChanged", on_metadata_changed)
    GLib.MainLoop().run()

This program will be rewritten to support any player (including Chromium browsers for YouTube) which supports MPRIS.