I have not seen anyone else post example code for using Subsonic's REST API in AutoIt. I played around with this a couple of months ago and posted an example on the AutoIt forum and thought others might be interested.
https://www.autoitscript.com/forum/topic/169791-subsonic-jukebox-control/
My example script searches for a song in the Subsonic library, queues it in the jukebox playlist, starts it playing on the server, then stops it and clears the playlist.