Application.scala

case class Operation(id: String, amount: Int, access: String)

object Application extends Controller {

  val format = Json.format[Operation]

  def userFeed(role: String, lower: Int, high: Int) = Action {

    val enumerator: Enumerator[Array[Byte]] = WS.url("http://host:port/stream").withTimeout(-1).getStream

    val secure: Enumeratee[Operation, Operation] = Enumeratee.collect[Operation] {
      case e@Operation(_, _, "private") if role == "MANAGER" => e
      case e@Operation(_, _, "public") => e
    }

    val inBounds = Enumeratee.collect[Operation] {
      case e@Operation(_, amount, _) if amount > lower && amount < high => e
    }

    Ok.feed(
      enumerator &>
      Enumeratee.map[Array[Byte]](Json.parse) &>
      Enumeratee.map[JsValue](format.reads) &>
      Enumeratee.collect[JsResult[Operation]] { case JsSuccess(value, _) => value } &>
      secure &>
      inBounds &>
      Enumeratee.map[Operation](format.writes) &>
      EventSource()
    ).as("text/event-stream")
  }
}

routes

GET     /stream                    controllers.Streams.stream

Streams.scala

object Streams extends Controller {

  def stream = Action {
    val operations: Enumerator[JsValue] = Enumerator.generateM[JsValue] {
      Promise.timeout(
        Some( Json.obj(
          "id" -> UUID.randomUUID().toString(),
          "amount" -> Random.nextInt(1000),
          "access" -> if (Random.nextBoolean) "public" else "private"
        ) ), 
        500
      )
    }
    Ok.chunked( operations )  
  }
}