Implementing Shoutcast

Now you're ready to implement the Shoutcast server. Since the Shoutcast protocol is loosely based on HTTP, you can implement the server as a function within AllegroServe. However, since you need to interact with some of the low-level features of AllegroServe, you can't use the define-url-function macro from Chapter 26. Instead, you need to write a regular function that looks like this:

(defun shoutcast (request entity)
  (with-http-response
      (request entity :content-type "audio/MP3" :timeout *timeout-seconds*)
    (prepare-icy-response request *metadata-interval*)
    (let ((wants-metadata-p (header-slot-value request :icy-metadata)))
      (with-http-body (request entity)
        (play-songs
         (request-socket request)
         (find-song-source *song-source-type* request)
         (if wants-metadata-p *metadata-interval*))))))