private void sendHeaders() {
final Response res = getResponse();
final String filename = "playlist." +extension;
res.addHeader( "Content-type", Files.getMimeType(filename) );
res.addHeader( "Content-Disposition", "inline; filename=\"" +filename+ "\"" );
res.addHeader( "Expires", "0" );
res.addHeader( "Cache-Control", "must-revalidate, post-check=0, pre-check=0" );
res.addHeader( "Pragma", "nocache" );