Integration of WebSocket in nodejs application

The reactive aspect of nodejs applications is synonymous with the nodejs runtime itself. However, the real-time magic is attributed to the WebSocket addition. This article introduces how to integrate WebSocket support within an existing nodejs application.

In this article we will talk about:

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Show me the code

Express routes use socket.io instance to deliver messages of a socket/socket.io enabled application looks like following:

//module/socket.js - server or express app instance 
module.exports = function(server){
  var io = socket();
  io = io.listen(server);
  io.on('connect', fn); 
  io.on('disconnect',fn);
};
//OR
//module/socket.js 
var io = require('socket.io');
module.exports = function(server){
  //server will be provided by the calling application
  //server = require('http').createServer(app);
  io = io.listen(server);
  return io;
};

//module/routes.js - has all routes initializations
var route = require('express').Router();
module.exports = function(){
    route.all('',function(req, res, next){ 
    	res.send(); 
    	next();
 });
};

//in server.js 
var app = require('express').express(),
  server = require('http').createServer(app),
  sio = require('module/socket.js')(server);

//@link http://stackoverflow.com/a/25618636/132610
//Sharing session data between SocketIO and Express 
sio.use(function(socket, next) {
    sessionMiddleware(socket.request, socket.request.res, next);
});

//application app.js|server.js initialization, etc. 
require('module/routes')(server); ;

What can possibly go wrong?

When working in this kind of environment, we will find these two points to be of interest, if not challenging:

Conclusion

In this article, we revisited how to add real-time experience to a nodejs application. The use of WebSocket and Pub/Sub powered by a key/value data store was especially the main focus of this article. There are additional complimentary materials in the “Testing nodejs applications” book.

References

#snippets #nodejs #integration #WebSocket