I have a website currently running Sinatra and a bunch of other technologies. I wanted to get progress bars running, but that's been a no go. So, a friend of mine whipped up a quick upload in Java, and I'm running that through scponly (chrooted) to make sure they can't do anything funny with changing directories and suchlike.

But how can I start the jnlp file from Sinatra? Is it as simply as making it a link and then letting it be downloaded by the user? This code suggests otherwise, but there are a lot of things in there I don't understand (probably because I'm not reading it in the context of the larger program there).