gistfile1.scala

  before() {
    contentType = "image/gif"
    response.setHeader("Cache-Control", "no-cache, no-store, must-revalidate")
    response.setHeader("Pragma", "no-cache")
    response.setHeader("Expires", "0")
  }

  get("/request_code/:id.gif") {
    val id = params("id")

    logger.info(s"/tracking/request_code ${id}")
    new java.io.File("transparent.gif")
  }
  
  
  // > 2014-02-25 17:13:43 INFO  TrackingApiServlet:57 - Tracking response for /request_code foo
  // [warn] /tracking/request_code/foo.gif
  //
  // (! 641)-> ls src/main/webapp/transparent.gif 
  // src/main/webapp/transparent.gif