New Kid On The Block – Node.js

Joel DivekarGM – Information Systems,People Interactive (I) Pvt. Ltd.Open Source Conference, Pune23rd March, 2013

Node.js was developed by Ryan Dhal in 2009

and the project is managed by Joyent

Node.js is ...

Server side JavaScript

Event Driven

Asynchronous I/O

Single Threaded

Lightweight

Node.js ...

High performance network application framework and can

easily handle thousands of concurrent connections with

minimum CPU / Memory Utilisation

Built on top of Google's V8 JavaScript engine used in

Chrome

Easy to build scalable network servers

Node.js is similar to ...

EventMachine in Ruby

Twisted in Python

I/O

Blocking I/O

var fs = require('fs');

var file1 = fs.readFileSync('File1.txt', 'utf-8');

console.log(“Reading File1.txt”);

var file2 = readFileSync('File2.txt', 'utf-8');

console.log(“Reading File2.txt”);

Non-Blocking I/O

var fs = require('fs');

fs.readFileSync('File1.txt', 'utf-8', function(err,data){

console.log(“Reading File1.txt”)

});

fs.readFileSync('File2.txt', 'utf-8', function(err,data){

console.log(“Reading File2.txt”)

});

I/O

Blocking I/O

Reading File1.txt took 10 ms

Reading File2.txt took 6 ms

Total time 16 ms

Non-Blocking I/O

Reading File1.txt took 10 ms

Reading File2.txt took 6 ms

Total time 10 ms

Callback

//callback after 2 seconds

setTimeout(function(){

console.log(“World”);

}, 2000);

console.log(“Hello”);

Node REPL

REPL : Read - Eval - Print - Loop$ node

> a=[1,2,"3",'four',];

[ 1, 2, '3', 'four' ]

> a.forEach(function (v) {

... console.log(v);

... });

1

2

3

four

Undefined

> .exit

Node.js HTTP Server

var http = require("http");

http.createServer(function(req, res) {

req.on("end", function () {

res.writeHead(200, {'Content-Type' : 'text/plain'});

res.end('Your IP is ' + (req.headers['x-forwarded-for'] || req.connection.remoteAddress) + '!') });

}).listen(8080);

console.log("Server accepting request on http://127.0.0.1:8080");

Node.js HTTP Server

var http = require("http");

http.createServer(function(req, res) {

req.on("end", function () {

res.writeHead(200, {'Content-Type' : 'text/plain'});

res.end('Your IP is ' + (req.headers['x-forwarded-for'] || req.connection.remoteAddress) + '!') });

}).listen(8080);

console.log("Server accepting request on http://127.0.0.1:8080");

npm

npm is package manager for node.js, similar to RubyGems & Python easy_install

npm install <module_name>

Modules

Express – MVC framework

Socket.IO – Websocket Library

Who is using Node.js ...

Thanks a lot for your time …

joel.divekar@gmail.comwww.linkedin.com/in/joeldivekar

joeldivekar.blogspot.comwww.slideshare.net/JoelDivekar