Correct way to handle Websocket

Question

I've a client to server Websocket connection which should be there for 40 seconds or so. Ideally it should be forever open.

The client continually sends data to server and vice-versa.

Right now I'm using this sequence:

var socket;
function senddata(data)
{

    if (!socket)
    {
        socket = new WebSocket(url);
        socket.onopen = function (evt) {

            socket.send(data);

            socket.onmessage = function (evt) {
                var obj = JSON.parse(evt.data);

                port.postMessage(obj);
            }

            socket.oneerror = function (evt) {
                socket.close();
                socket = null;
            }
           socket.onclose = function(evt){
               socket = null;
           }


        }
    }
    else
    {
        socket.send(data);
    }

}

Clearly as per current logic, in case of error, the current request data may not be sent at all.

To be frank it sometimes gives error that websocket is still in connecting state. This connection breaks often due to networking issues. In short it does not work perfectly well.

I've read a better design : How to wait for a WebSocket's readyState to change but does not cover all cases I need to handle.

Also I've Googled about this but could not get the correct procedure for this.

So what is the right way to send regular data through Websockets which handles well these issues like connection break etc?

Answer 1

An event you don't seem to cover is onclose. Which should work really well, since it's called whenever the connection terminates. This is more reliable than onerror, because not all connection disruptions result in an error.