Scala Play Websocket - use one out actor to send both: Array[Byte] and String messages

I have Play websockets action:

def socket = WebSocket.acceptWithActor[String, Array[Byte]] { request => out =>     Props(new WebSocketInActor(out)) } 

Generally I need to send to browser large raw arrays of data. But sometimes I need to send some small string data. In browser I can detect is data in text format or raw ArrayBuffer. If I create actor that sends String, I can send string messages, If I create actor that sends with Array[Byte], I can send raw arrays. Both situations I don't need to change client code. So, how can I force Play to use both sending methods with one out actor?

1 Answers

Answers 1

Ah, those answers that comes just after you post question on SO. Looking through reference and sourcecode, I found that there is mixedFrame FrameFromatter: https://github.com/playframework/playframework/blob/2.4.x/framework/src/play/src/main/scala/play/api/mvc/WebSocket.scala#L75

So you just need to say that you will respond with Either[String, Array[Byte]] and if you want to send string use Left(somestring) or else use Right[somearray].

  class WebSocketInActor(out: ActorRef) extends Actor {     override def preStart() = {       println("User connected")       val s = "Hello"       out ! Left(s)       out ! Right(s.getBytes("utf8"))     }     override def postStop() = {       println("User discconnected")     }     def receive = {       case msg: String => {       }       case _ =>     }   }    def socket = WebSocket.acceptWithActor[String, Either[String, Array[Byte]]] { request => out =>     Props(new WebSocketInActor(out))   } 

UPDATE:

Or you can go one step further and create your own frame formatter

  sealed trait WSMessage   case class StringMessage(s: String) extends WSMessage   case class BinaryMessage(a: Array[Byte]) extends WSMessage   case class JsonMessage(js: JsValue) extends WSMessage    implicit object myFrameFormatter extends BasicFrameFormatter[WSMessage] {     private val textFrameClass = classOf[TextFrame]     private val binaryFrameClass = classOf[BinaryFrame]      def toFrame(message: WSMessage): BasicFrame = message match {       case StringMessage(s) => TextFrame(s)       case BinaryMessage(a) => BinaryFrame(a)       case JsonMessage(js) => TextFrame(Json.stringify(js))     }     def fromFrame(frame: BasicFrame): WSMessage = frame match {       case TextFrame(s) => StringMessage(s)       case BinaryFrame(a) => BinaryMessage(a)     }     def fromFrameDefined(clazz: Class[_]): Boolean = clazz match {       case `textFrameClass` => true       case `binaryFrameClass` => true       case _ => false // shouldn't be reachable     }   }    class WebSocketInActor(out: ActorRef) extends Actor {     override def preStart() = {       println("User connected")       val s = "Hello"       val a:Array[Byte] = Array(100, 50, 30).map(_.toByte)       out ! StringMessage(s)       out ! JsonMessage(Json.obj("txt" -> s, "array" -> a))       out ! BinaryMessage(a)     }     override def postStop() = {       println("User discconnected")     }     def receive = {       case msg: String => {       }       case _ =>     }   }    def socket = WebSocket.acceptWithActor[String, WSMessage] { request => out =>     Props(new WebSocketInActor(out))   } 

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