Comparison of Comet, SSE and WebSocket server to client communication with Playframework 2.0 in Scala

ServerEventsComparison.scala

  /**
   * Handles the comet event stream.
   */
  def cometStream = Action {
    AsyncResult {
      implicit val timeout = Timeout(5.seconds)
      val actor=Akka.system.actorOf(Props[EventListener])
      // Actor is listening for event on the eventStream
      Akka.system.eventStream.subscribe(actor,classOf[ChangeEvent])
      // For each event, stream the data to client
      (actor ? "start").mapTo[Enumerator[JsValue]].asPromise.map { chunks =>
        Ok.stream((chunks) &> Comet( callback = "parent.onEvent"))
      }
    }
  }

  /**
   * Handles the SSE event stream.
   */
   def eventSourceStream = Action {
    AsyncResult
    {
      implicit val timeout = Timeout(5.seconds)
      val actor=Akka.system.actorOf(Props[EventListener])
      // Actor is listening for event on the eventStream
      Akka.system.eventStream.subscribe(actor,classOf[ChangeEvent])
      // For each event, stream the data to client
      (actor ? "start").mapTo[Enumerator[JsValue]].asPromise.map { chunks =>
        Ok.feed(chunks &> EventSource()).as("text/event-stream")
      }
    }
  }

  /**
   * Handles the websocket event stream.
   */
  def listenEvents() = WebSocket.async[JsValue] { request  =>
    implicit val timeout = Timeout(5.seconds)
    val actor=Akka.system.actorOf(Props[EventListener])
    // Actor is listening for event on the eventStream
    Akka.system.eventStream.subscribe(actor,classOf[ChangeEvent])
      // For each event, stream the data to client
    val iteratee = Iteratee.foreach[JsValue] {event => println(event)}
    (actor ? "start").mapTo[Enumerator[JsValue]].asPromise.map {
      chunks =>
        (iteratee,chunks)
    }
  }

}

Why do you used Akka to contruct your stream.

I had a SSE dev but it's fail on undetermined situation (ie. AWS micro, broadcast, ...).

Could you please give me some help ?

  val (broadcast, _) = Concurrent.broadcast ({
    Enumerator.generateM[JsValue](getUrl(URL_STATUS)) &> Enumeratee.mapM[JsValue] {
      t => Promise.timeout(t, Random.nextInt(30) + 30, TimeUnit.SECONDS)
    }
  })

  def stream = Action {
    Ok.feed(broadcast &> EventSource()).as("text/event-stream")
  }