Websocket delay in sending a message

Question

currently I am developing an webapp which will run on a tizen device (Samsung Gear S3). The purpose of that App is to send a message to a websocketserver (written in Python and running on my Computer) when swiping. When I swipe to the right I send a string1 and when I swipe left I send string2. The Problem is that it takes a while until the message arrives to the server (approx. 5 sec). This delay only happend when I run send the message the first time after a while. As far as I could observe that its 10 seconds. That means that I can send any message immidiataly within 10 seconds after the last. But when I Pause for more than 10 seconds there will be a delay of 5 sec.

So the qustion is whats the reason for that delay? Or how can I avoid this. It seems like there is a timeout, but How can I avoid this?

The code on client side (Tizen SmartWatch) is written in Javascript and jquery.

This is the clientsided Code I shorted a little. The HTML Part is not included.

<script>

var webSocketURL1 = "ws://";
var webSocketURL2 = "Computer10";
var webSocketURL3 = ":9998/echo";

function WS(String){

      var webSocketURL=webSocketURL1+webSocketURL2+webSocketURL3;
      var webSocket = new WebSocket(webSocketURL);
      webSocket.onopen = function (e) {
      console.log('connection open, readyState : ' + e.target.readyState);
      webSocket.send(String); 
    };

     function closeConnection() {
          if (webSocket.readyState === 1) {
              webSocket.close();
          }
      };
}
</script>

<script>
$(document).ready(function(){
  $("body").on("swiperight",function(){     
        WS("string1");
  });                       
});
</script> 

<script>
$(document).ready(function(){
  $("body").on("swipeleft",function(){      
        WS("string2");
    });                       
});
</script>

Md. Armaan-Ul-Islam · Accepted Answer · 2017-06-27 18:42:43Z

2

I would suggest to keep the var 'webSocket' declared globally, not inside function scope.

Check also in your python code again, Are you making any unnecessary/optional socket closing ? Try to get rid off them.

edited Jun 27, 2017 at 18:42

answered Jun 22, 2017 at 8:22

Md. Armaan-Ul-Islam

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2 Comments

Pluxyy Over a year ago

Thank you this solved the problem partially. Now I can send my message immidiately the first time. But if I dont send any message for about 10 seconds and then start again sending messages it takes like 5 seconds to send the message. I am just curious why it takes so long.

Md. Armaan-Ul-Islam Over a year ago

Edited @ Pluxyy

raj peer · Accepted Answer · 2017-06-22 07:41:26Z

here i have changed some part of code. please test it and let me know if any issue found

<script>
    var webSocketURL = 'ws://Computer10:9998/echo';
    var ws;

    function connect() {
      //alert('connect');
        ws = new WebSocket(webSocketURL, []);
        // Set the function to be called when a message is received.
        ws.onmessage = handleMessageReceived;
        // Set the function to be called when we have connected to the server.
        ws.onopen = handleConnected;
        // Set the function to be called when an error occurs.
        ws.onerror = handleError;

    }

    function handleMessageReceived(data) {
        // Simply call logMessage(), passing the received data.
        logMessage(data.data);
    }

    function handleConnected(data) {
        // Create a log message which explains what has happened and includes
        // the url we have connected too.
        var logMsg = 'Connected to server: ' + data.target.url;
        // Add the message to the log.
        logMessage(logMsg)
    }

    function handleError(err) {
        // Print the error to the console so we can debug it.
        console.log("Error: ", err);
    }

    function logMessage(msg) {
        // $apply() ensures that the elements on the page are updated
        // with the new message.
        $scope.$apply(function() {
            //Append out new message to our message log. The \n means new line.
            $scope.messageLog = $scope.messageLog + msg + "\n";
        });

    }

    $(document).ready(function(){
      $("body").on("swiperight",function(){     
            ws.send("string1");
      });                       
    });

    $(document).ready(function(){
      $("body").on("swipeleft",function(){      
            ws.send("string2");
        });                       
    });

    connect();
</script>

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