Node.js, developed by Ryan Dahl in 2009, is a high-performance, server-side JavaScript framework that utilizes an event-driven, non-blocking I/O model for efficient handling of thousands of concurrent connections. It is built on Google's V8 JavaScript engine and offers easy scalability for network applications. The document also discusses the asynchronous programming model, the use of npm for package management, and provides examples of basic file operations and HTTP server creation.

1. New Kid On The Block – Node.js
Joel Divekar
GM – Information Systems,
People Interactive (I) Pvt. Ltd.
Open Source Conference, Pune
23rd March, 2013

2. Node.js was developed by Ryan Dhal in 2009
and the project is managed by Joyent

3. Node.js is ...
Server side JavaScript
Event Driven
Asynchronous I/O
Single Threaded
Lightweight

4. 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

5. Node.js is similar to ...
EventMachine in Ruby
Twisted in Python

6. I/O
Blocking I/O
var fs = require('fs');
var file1 = fs.readFileSync('File1.txt', 'utf­8');
console.log(“Reading File1.txt”);
var file2 = readFileSync('File2.txt', 'utf­8');
console.log(“Reading File2.txt”);
Non-Blocking I/O
var fs = require('fs');
fs.readFileSync('File1.txt', 'utf­8', function(err,data){
console.log(“Reading File1.txt”)
});
fs.readFileSync('File2.txt', 'utf­8', function(err,data){
console.log(“Reading File2.txt”)
});

7. 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

8. Callback
//callback after 2 seconds
setTimeout(function(){
console.log(“World”);
}, 2000);
console.log(“Hello”);

9. 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

10. Node.js HTTP Server
var http = require("http");
http.createServer(function(req, res) {
req.on("end", function () {
res.writeHead(200, {'Content­Type' : 'text/plain'});
res.end('Your IP is ' + (req.headers['x­forwarded­for'] ||
req.connection.remoteAddress) + '!') });
}).listen(8080);
console.log("Server accepting request on http://127.0.0.1:8080");

11. Node.js HTTP Server
var http = require("http");
http.createServer(function(req, res) {
req.on("end", function () {
res.writeHead(200, {'Content­Type' : 'text/plain'});
res.end('Your IP is ' + (req.headers['x­forwarded­for'] ||
req.connection.remoteAddress) + '!') });
}).listen(8080);
console.log("Server accepting request on http://127.0.0.1:8080");

12. 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

13. Who is using Node.js ...

14. Thanks a lot for your time …
joel.divekar@gmail.com
www.linkedin.com/in/joeldivekar
joeldivekar.blogspot.com
www.slideshare.net/JoelDivekar