I know this isn't a terribly helpful reply without more detail, but if you're going to hack your own script together, and you're using the Linux native version

I know this isn't a terribly helpful reply without more detail, but if you're going to hack your own script together, and you're using the Linux native version of the Spotify client, you ought to be able to get all of your playlist information out using dmesg. (The Linux client is quite nice!)