getRating
http://your-server/rest/getRating.view
{Parameter, Required, Comment}
{id, yes, A string which uniquely identifies the file (song) or folder (album/artist) to get the rating of.}
It seems setRating isn't even integrated into the web app so I can understand if this won't ever be done. Currently subsonic's only use for the setRating is on the album viewer, and you can only rate an album, not even an artist, or a song. I personally am developing my own playlist generator which relies HEAVILY on the user's ratings so being able to get/set this would be hugely welcomed. The star/unstar methods aren't enough for a rating, 1-5 stars is much more preferred than a boolean rating system.