The Mpd.Player genserver can be used to monitor the player's states. It contains the current playing song and the player status and listens to idles to update itself when it changes.

You can add the Player to you Application's supervisor or start manually like

Mpd.Player.start_link([])

Then you can play around with your mpd server and check it's current state with Mpd.Player.state/0

Events

When starting the process, you can give an on_update argument as a function. This function will be called on every player changes.

You could then use it with Phoenix's broadcast/subscribe:

Mpd.Player.start_link([on_update: fn state ->
  MyAppWeb.Endpoint.broadcast("mpd:update", state)
end)])