Getting started with WebSockets

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Remarks

This section provides an overview of what websocket is, and why a developer might want to use it.

It should also mention any large subjects within websocket, and link out to the related topics. Since the Documentation for websocket is new, you may need to create initial versions of those related topics.

Installation or Setup

Detailed instructions on getting web-socket set up or installed.

web-socket Client example

This is an example of a web-socket client in javascript.
It:

  1. Connects to a live demo server.
  2. Sends a message.
  3. Receives message(s).
  4. Disconnects after an interval.
var mySocket    = null;
var serverUrl   = 'wss://echo.websocket.org';  //  wss: is ws: but using SSL.
var oWebSocket  = window.WebSocket || window.MozWebSocket;
if (oWebSocket) {
    mySocket = new oWebSocket (serverUrl);
    if (mySocket) {
        console.log (mySocket);
        mySocket.onopen     = onSocketOpen;
        mySocket.onclose    = onSocketClose;
        mySocket.onmessage  = onSocketMessage;
        mySocket.onerror    = onSocketError;

        setTimeout (closeSocket, 5000);  //  Be polite and free socket when done.
    }
}

function onSocketOpen (evt) {
    console.log ("Socket is now open.");
    mySocket.send ("Hello from my first live web socket!");
}

function onSocketClose (evt) {
    console.log ("Socket is now closed.");
}

function onSocketMessage (evt) {
    console.log ("Recieved from socket: ", evt.data);
}

function onSocketError (evt) {
    console.log ("Error with/from socket!:");
    console.log (evt);
}

function closeSocket () {
    if (mySocket.readyState !== mySocket.CLOSED) {
        console.log ("Closing socket from our end (timer).");
        mySocket.close ();
    }
    else
        console.log ("Socket was already closed (timer).");
}
 

If you run that code in a console you get a result like:

WebSocket { url: "wss://echo.websocket.org/", readyState: 0, bufferedAmount: 0, onopen: null,
    onerror: null, onclose: null, extensions: "", protocol: "", onmessage: null,
    binaryType: "blob" 
}
2  //  <--- 2 was the socket ID in this instance.
Socket is now open. 
Recieved from socket:  Hello from my first live web socket! 
Closing socket from our end (timer). 
Socket is now closed.
 

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Sunday, January 1, 2017
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