Upgrade to WebSocket required on Play Scala app

[Isuru Samaraweera]

Hi,

I am trying to run a playframework 2.5 /scala twitter application based on web sockets on chrome browser.

When I run the app I am getting the text message in browser as 'Upgrade to WebSocket required'

Intended behavior is to display tweet in the browser.

Some sample codes are as below 

controller

def index = Action { implicit request =>

Ok(views.html.index("Tweets"))

}

index.scala.html

<div id="tweets"></div>

    <script type="text/javascript">

        function appendTweet(text) {

            var tweet = document.createElement("p");

            var message = document.createTextNode(text);

            tweet.appendChild(message);

            document.getElementById("tweets").appendChild(tweet);

        }

        function connect(attempt) {

            var connectionAttempt = attempt;

            var tweetSocket = new WebSocket("@routes.HomeController.tweets().webSocketURL()");

            tweetSocket.onmessage = function (event) {

                console.log(event);

                var data = JSON.parse(event.data);

                appendTweet(data.text);

            };

            tweetSocket.onopen = function() {

                connectionAttempt = 1;

                tweetSocket.send("subscribe");

            };

            tweetSocket.onclose = function() {

                if (connectionAttempt <= 3) {

                    appendTweet("WARNING: Connection with the server lost, attempting to reconnect. Attempt number " + connectionAttempt);

                    setTimeout(function() {

                        connect(connectionAttempt + 1);

                    }, 5000);

                } else {

                    alert("The connection with the server was lost. Please try again later. Sorry about that.");

                }

            };

        }

        connect(1);

    </script>

Please tell whats happening why its not working as expected.

Thanks,

Isuru

[Igmar Palsenberg]

Op maandag 24 april 2017 22:39:29 UTC+2 schreef Isuru Samaraweera:

Hi,

I am trying to run a playframework 2.5 /scala twitter application based on web sockets on chrome browser.

When I run the app I am getting the text message in browser as 'Upgrade to WebSocket required'

Intended behavior is to display tweet in the browser.

Some sample codes are as below 

controller

def index = Action { implicit request =>

Ok(views.html.index("Tweets"))

}

<snip>

 

Please tell whats happening why its not working as expected.

Your javascript code tries to open a websocket connection, but the controller above doesn't provide it. There is no automatic upgrade of a connection, and your controller must return a Websocket type. As a sidenote : All the usual things about the Result return type don't apply. 

Igmar

[Isuru Samaraweera]

Hi Igmar,

Here is my controller for tweets action as invoked in the java script.

   def tweets = WebSocket.accept[String, JsValue] { implicit request =>

    ActorFlow.actorRef(out => TwitterStreamer.props(out))

  }

And the twitterstreamer is like this

import akka.actor.{ Actor, ActorRef, Props }

import play.api.Logger

import play.api.libs.json.Json

class TwitterStreamer(out: ActorRef) extends Actor {

  def receive = {

    case "subscribe" =>

      Logger.info("Received subscription from a client")

      out ! Json.obj("text" -> "Hello, world!")

  }

}

object TwitterStreamer {

  def props(out: ActorRef) = Props(new TwitterStreamer(out))

}

Can you suggest what has gone wrong here?

Thanks

Isuru

[Isuru Samaraweera]

Still I am getting Upgrade to WebSocket required message o nthe browse when I call tweets action.

What can be the cause?

On Tuesday, April 25, 2017 at 2:09:29 AM UTC+5:30, Isuru Samaraweera wrote:

[Igmar Palsenberg]

Op woensdag 26 april 2017 10:13:19 UTC+2 schreef Isuru Samaraweera:

Still I am getting Upgrade to WebSocket required message o nthe browse when I call tweets action.

What can be the cause?

Is there a proxy / loadbalancer if front of that Play app ?

Igmar

[Isuru Samaraweera]

Hi,

I am running netty locally from activator.And browser also in the same machine.So no load balancer or proxy involved.

Thanks,

Isuru

On Tuesday, April 25, 2017 at 2:09:29 AM UTC+5:30, Isuru Samaraweera wrote:

[Isuru Samaraweera]

Hi Igmar,

Do you have any clue on this?

Thanks

On Tuesday, April 25, 2017 at 2:09:29 AM UTC+5:30, Isuru Samaraweera wrote:

[Isuru Samaraweera]

Hi Igmar,

Now web socket is fine..How ever corresponding actor is not invoked.

Here is the controller action.

   def tweets = WebSocket.accept[String, JsValue] { implicit request =>

     println("here")

    ActorFlow.actorRef(out => TwitterStreamer.props(out))

  }

'here; is printed and actor is not invoked.Here is the actor.

class TwitterStreamer(out: ActorRef) extends Actor {

   def receive = {

    case msg: String =>

      out ! ("I received your message: " + msg)

  }

    

}

object TwitterStreamer {

  def props(out: ActorRef) = Props(new TwitterStreamer(out))

}

Can you see why its not going in to the actor?

Thanks

Isuru

On Tuesday, April 25, 2017 at 2:09:29 AM UTC+5:30, Isuru Samaraweera wrote: