Quick and dirty media player controller script

mediacontrol.py

#!/usr/bin/env python3
import dbus
import subprocess
import sys

class InvalidCommand(Exception):
	pass

class NoServiceAvailable(Exception):
	pass

class Controller():
	def __init__(self):
		self.commandMap = {
			"next": self.next,
			"previous": self.previous,
			"toggle": self.toggle
		}

	def route(self, command):
		if command not in self.commandMap.keys():
			raise InvalidCommand()
		self.commandMap[command]()

	def next(self):
		pass

	def previous(self):
		pass

	def toggle(self):
		pass


class Spotify(Controller):
	def __init__(self):
		Controller.__init__(self)
		try:
			session = dbus.SessionBus()
			self.client = session.get_object("org.mpris.MediaPlayer2.spotify", "/org/mpris/MediaPlayer2")
			self.available = True
		except dbus.exceptions.DBusException:
			self.available = False

	def isAvailable(self):
		return self.available

	def next(self):
		self.client.Next()

	def previous(self):
		self.client.Previous()

	def toggle(self):
		self.client.PlayPause()

class MPD(Controller):
	def __init__(self):
		Controller.__init__(self)

	def isAvailable(self):
		try:
			subprocess.call(["mpc"])
			return True
		except FileNotFoundError:
			return False

	def next(self):
		subprocess.call(["mpc", "next"])

	def previous(self):
		subprocess.call(["mpc", "prev"])

	def toggle(self):
		subprocess.call(["mpc", "toggle"])

def route(command):
	controllers = [Spotify(), MPD()]
	applicable = [c for c in controllers if c.isAvailable()]
	if len(applicable) > 0:
		applicable[0].route(command)
	else:
		raise NoServiceAvailable()

if __name__ == "__main__":
	if len(sys.argv) > 1:
		try:
			route(sys.argv[1])
		except InvalidCommand:
			sys.exit("Invalid command")
		except NoServiceAvailable:
			sys.exit("No service available")
	else:
		sys.exit("Invalid usage")