Need help in debugging the websocket connection

[var19]

So the issue is that sending a message is only working once, at the start. Any message after that isn't getting sent.

HTML

<form onsubmit="sendMsg()">
  <textarea id="msg"></textarea>
  <button type="submit"> Send</button>
</form>

JS

  var controller = new WebSocket('.......');
  controller.onmessage = function (event) {
      console.log(event.data);
  };
  
  function sendMsg() {
      const msg = document.getElementById('msg').value;
      controller.send(msg);
  }

Controller

instance WSApp MyController where
    initialState = MyController
    run = do
        msg :: Text <- receiveData
        sendTextData (msg)
        forever receiveDataMessage

After a lot of debugging, I found that, for some reason controller.send(msg) is only working the first time. Everything apart from that is working properly. Any ideas why this could be happening?

[mpscholten]

Any message after that isn't getting sent.

What's the error?

If you want the websocket to output the received message in a loop you need this:

instance WSApp MyController where
    initialState = MyController
    run = do
        forever do
            msg :: Text <- receiveData
            sendTextData (msg)

[var19]

Yes, this worked. Thank you.

However, the guide mentions using forever receiveDataMessage. Why does that not work?

[mpscholten]

Technically it should work. But practically it only keeps receiving data and then not doing anything with it. I'll update the docs to clarify this.

[var19]

Oh okay. That makes sense since there were no errors. It looked as if controller.send(msg) isn't working properly since the controller also stopped receiving data after the first message.