[Python] Script that automatically records tracks played by the linux spotify client.

spotify-recorder.py

from subprocess import run, PIPE, Popen
import shutil
import string

try:
    import psutil
except ModuleNotFoundError:
    print("psutil not found, please install it.\n$pip install psutil\n$python3 -m pip install psutil")
    exit(1)


def format_filename(s):
    """
    Shamelessly stolen from https://gist.github.com/seanh/93666
    """
    valid_chars = "-_.() %s%s" % (string.ascii_letters, string.digits)
    filename = ''.join(c for c in s if c in valid_chars)
    return filename.replace(' ', '_')


def wait_for_spotify():
    print("Waiting for Spotify to launch...")
    while True:
        pidlist = [p.info for p in psutil.process_iter(attrs=['pid', 'name']) if 'spotify' in p.info['name']]
        if pidlist:
            pid = pidlist[0]["pid"]
            print("Found Spotify, PID " + str(pid))
            return pid


def get_playing(pid):
    p = run(["wmctrl", "-l", "-p"], stdout=PIPE, encoding="UTF-8")
    for line in p.stdout.splitlines():
        args = line.split()
        if args and int(args[2]) == pid:
            title = " ".join(args[4:])
            return title if not title == "Spotify" else None


def get_monitor():
    print("Attempting to find PulseAudio Monitor...")
    pacmd = run(["pacmd", "list"], stdout=PIPE, encoding="UTF-8")
    for line in pacmd.stdout.splitlines():
        if ".monitor" in line:
            monitor = line[line.index("<") + 1 :line.index(">")]
            print("Found Monitor " + monitor)
            return monitor


def start_recording(monitor, title):
    print("Starting Recording...")
    return Popen(["parec", "-d", monitor, "--file-format=wav", format_filename(title + ".wav")])


def test_for_command(cmd):
    return shutil.which(cmd) is not None


print("Starting...")

print("Checking for pacat...")
if not test_for_command("pacat"):
    print("pacat is not installed, exiting...")
    exit(1)
print("Checking for wmctrl...")
if not test_for_command("wmctrl"):
    print("wmctrl is not installed, exiting...")
    exit(1)
print("OK\n")

monitor = get_monitor()
pid = wait_for_spotify()
print("Ready.\n")

old_title = None
rec = None
while True:
    try:
        title = get_playing(pid)

        if not old_title == title:
            if old_title:
                # The old track has ended
                print("Track '" + old_title + "' has ended, stopping Recording...")
                rec.terminate()
                rec = None

            if title:
                # A new track has started playing
                print("Now Playing: " + title)
                rec = start_recording(monitor, title)

        old_title = title
    except KeyboardInterrupt:
        print("Received KeyboardInterrupt, exiting...")
        exit(0)