Revath S Kumar

Building a simple http server is pretty easy in nodejs, we can use createServer method in http module for this. The createServer method will take a function as argument and return the object of http.Server.

var server = require('http').createServer(function(req, res) {


});

The createServer callback will be executed when ever a request is received, and a object of request and response will be passes to it.

You can also listen to request event on server.

var http = require('http');
var server = http.createServer();

server.on('request', function(req, res){
  
});

Next in order to accept connection you need to bind it to a port. You can use listen method for it.

server.listen(port);

You can either pass a callback, or can bind to listening event to do something soon after a server is bound to the port.

server.on('listening', function(){
  console.log('Listening to ', port);
}); 

You can also set the port using the environment variable.

For error handling you can you error event.

server.on('error', function(err){
  
});

An error object will be passed to the callback on error. Now the code for the simple server will be

// server.js
var http    = require('http');
var server  = http.createServer();
var port    = process.env.PORT || 9001;

server.listen(port);

server.on('request', function(req, res){
  req.write('<h1>Hello World :: </h1>');

  res.end();
});

server.on('listening', function(){
  console.log('Listening to ', port);
});

server.on('error', function(err){
  console.log(err);
});

Now when you run node server.js the application will run on port 9001 and you can request localhost:9001 on you browser to see the result.

You can also bind other events like connection which is emitted when a new connection is made and close which will emit when server closes. The close event is emitted only when all the connections are ended.

Hope that helps.