knockoutwhistweb/app/assets/actor/KnockOutWebSocketActor.scala

@@ -0,0 +1,21 @@
+package actor
+
+import org.apache.pekko.actor.{Actor, ActorRef}
+import org.apache.pekko.http.scaladsl.model.ContentRange.Other
+
+
+class KnockOutWebSocketActor(
+                              out: ActorRef,
+                            ) extends Actor {
+    def receive: Receive = {
+      case msg: String =>
+        out ! s"Received your message: ${msg}"
+      case other: Other =>
+        println(s"Received unknown message: $other")
+    }
+
+    def sendJsonToClient(json: String): Unit = {
+      println("Received event from Controller")
+      out ! json
+    }
+}

knockoutwhistweb/app/controllers/WebsocketController.scala

@@ -0,0 +1,30 @@
+package controllers
+import actor.KnockOutWebSocketActor
+import org.apache.pekko.actor.{ActorRef, ActorSystem, Props}
+import org.apache.pekko.stream.Materializer
+import play.api.*
+import play.api.libs.streams.ActorFlow
+import play.api.mvc.*
+
+import javax.inject.*
+
+
+@Singleton
+class WebsocketController @Inject()(
+                                     cc: ControllerComponents,
+                                   )(implicit system: ActorSystem, mat: Materializer) extends AbstractController(cc) {
+
+  object KnockOutWebSocketActorFactory {
+    def create(out: ActorRef) = {
+      Props(new KnockOutWebSocketActor(out))
+    }
+  }
+  def socket() = WebSocket.accept[String, String] { request =>
+    ActorFlow.actorRef { out =>
+      println("Connect received")
+      KnockOutWebSocketActorFactory.create(out)
+    }
+  }
+
+
+}

knockoutwhistweb/conf/routes

@@ -39,3 +39,6 @@ POST   /game/:id/returnToLobby              controllers.IngameController.returnT
 
 # Polling
 GET    /polling/:gameId                     controllers.PollingController.polling(gameId: String)
+
+# Websocket
+GET     /websocket                          controllers.WebsocketController.socket()

knockoutwhistweb/public/javascripts/main.js

@@ -664,4 +664,23 @@ function sendPlayCardRequest(jsonObj, gameId, cardobject, dog) {
         })
     })
 }
+const ws = new WebSocket("ws://localhost:9000/websocket");
+ws.onopen = (event) => {
+    console.log("WebSocket connection established!");
+
+    ws.send("Client is now connected and ready.");
+};
+ws.onmessage = (event) => {
+    console.log("SERVER RESPONSE:", event.data);
+};
+ws.onerror = (error) => {
+    console.error("WebSocket Error:", error);
+};
+ws.onclose = (event) => {
+    if (event.wasClean) {
+        console.log(`Connection closed cleanly, code=${event.code} reason=${event.reason}`);
+    } else {
+        console.warn('Connection died unexpectedly.');
+    }
+};