To convert the Spotify DJ from a little fun personal hack to something real it was clear that I needed some "consumer grade" way to install the DJing client on the machines of would be DJs.
"Some way" turned out to be Adobe AIR. Adobe AIR can be used with Flash, Flex or just plain old web skills - html and Javascript.
No matter which route you go you end up compiling a one file deliverable that installs as a real desktop application on the system.
I have had no exposure to Adobe AIR prior to today - but armed with online tutorials I started out at around 6 PM and at around 11 PM I was done - with time for UI tweaking and a little webserver work required to make the app work.
Adobe AIR quite simply brings web speed to the desktop. And its a pleasure to work with too. The runtime is a browser, so everything just works. I like JQuery - and of course I can just plug that in.
I haven't done things "properly" - haven't signed properly, haven't used the upgrading framework and so on, but the fact that I can make a useful UI that interacts with the file system and a web server in 4-5 hours is astounding. And it deploys as a 65k file.
[UPDATE: Morten tells me the config is the same on a mac, so I rewrote the script so it should also run on a Mac with perl installed]
[UPDATE II: The player is here! I can now remote DJ with Spotify!]
Inspired by Morten's suggestion for a DJing feature in Spotify and by the source code for Scrobblify, the Last.fm hack for Spotify, I decided to have a go at making just the feature Morten requested as a hack.
I started looking at the config-files for Spotify, found a file that is continuously updated with the track currently playing. It took a little figuring out to convert the internal hexadecimal ID to the Base62 encoded IDs used in the URLs but I figured it out and here it is - the very first rudimentary Spotify Auto-DJ for Windows.
I am running a version of this perl script which subscribes to file change notifications for the config file with the "now playing" track ID and then submits the latest track to this web server.
You can always find the current track I'm playing here or listen right away here. The web player automatically loads new tracks when I start listening to them.