nodejs session part 2 given in Vertis tech talk.

1. Introduction to
Web Applications
Budhram Gurung
By -
Code used for this session can be found : https://github.com/budh-ram/express_demo_app

2. node.js
Created by
Ryan Dahl
in 2009

3. Background
node.js runs on V8. It is a set of bindings to the V8
JavaScript VM.
V8 is an open source JavaScript engine developed by
Google. Its written in C++ and is used in Google Chrome
Browser.
Latest version is v0.10.18
Is Open Source. It runs well on Linux/Unix systems, can also
run on Windows systems.

4. Installation
node.js official site:
http://nodejs.org/download/
Url: https://github.com/joyent/node/wiki
/Installing-Node.js-via-package-manager
sudo apt-get update
sudo apt-get install python-software-properties python g++ make
sudo add-apt-repository ppa:chris-lea/node.js
sudo apt-get update
sudo apt-get install nodejs=0.10.18-1chl1~precise1
On winodws, you can use node.js installer.

5. node.js can be used to build
Network applications.

6. HTTP Request
Using http.request(options, callback)
Otions: host, hostname, port, method, path etc
var options = {
hostname: 'www.google.co.in',
path: '/',
method: 'GET'
};
var req = http.request(options, function(res) {
res.on('data', function (chunk) {
console.log('BODY: ' + chunk);
});
});
req.end();
Example:

7. How to GET
?
Using http.get(options, callback)
Example:
http.get("http://www.google.com/index.html", function(res) {
console.log("Got response: " + res.statusCode);
}).on('error', function(e) {
console.log("Got error: " + e.message);
});

8. Simple http Server
http.createServer(function(request, response){ ... });
http.createServer([requestListener])
Returns a new web server object.
The requestListener is a function which is automatically
added to the 'request' event.
Class: http.Server
This is an EventEmitter with the following events:
Event: 'request'
function (request, response) { }
Emitted each time there is a request.

9. Alternate Syntax
var server = http.createServer();
server.on('request', function(request, response){ ... });
Event: 'close'
server.on('close', function(){ ... });

10. Simple server example...

11. node.js also has frameworks...

12. Express
Sinatra inspired web development framework
for Node.js
It is insanely fast, flexible, and simple.
Easy route URLs to callbacks
Environment based configuration
Middleware via connect – bodyParser, cookieparser etc
Install as:
npm install express
Or
sudo npm install -g express

13. REST url in Express
Let assumes there is 'user' resource.
// List
app.get('/users', function(req, res) {
});
// Create
app.post('/users', function(req, res) {
});
// Read
app.get('/users/:id', function(req, res) {
});
// Update
app.put('/users/:id', function(req, res) {
});
// Delete
app.del('/users/:id', function(req, res) {
});

14. Express simple example
var express = require('express');
var app = express();
app.get('/', function(req, res){
res.send('hello world');
});
app.listen(3000);

15. Express App
Simple express App

16. Express App
Simple express App
REST urls

17. Express App
Simple express App
REST urls
Organize your App

18. Express App
Simple express App
REST urls
Organize your App
Error handling using Error Handler
Middlewares

19. Express App
Simple express App
REST urls
Organize your App
Error handling using Error Handler
Middlewares
Logger

20. Express App
Simple express App
REST urls
Organize your App
Error handling using Error Handler
Middlewares
Logger
Template Engine - EJS

21. Express App
Simple express App
REST urls
Organize your App
Error handling using Error Handler
Middlewares
Logger
Template Engine – EJS
Adding Twitter Bootstrap

22. Express Middleware

23. Express Middleware
bodyParser():
Request body parsing middleware supporting
JSON,
urlencoded, and
multipart requests.
Usage:
app.use(express.bodyParser());

24. Express Middleware
cookieParser():
Parses the Cookie header field and populates
'req.cookies' with an object keyed by the
cookie names.
Usage:
app.use(express.cookieParser());
or
app.use(express.cookieParser('some secret'));

25. Express Middleware
errorHandler():
Development error handler, providing stack traces
and error message responses for requests
accepting text, html, or json.
Usage:
app.use(express.errorHandler());

26. Express Middleware
methodOverride():
To simulate DELETE and PUT.
Use when _method post parameter set to 'delete' or
'put'.
Usage:
app.use(express.methodOverride());
Client side code:
<form> ...
<input type="hidden" name="_method"
value="put" />
</form>

27. Express Middleware
session():
Setup session store with the given options.
Usage:
app.use(express.session());
Example:
app.use(express.cookieParser());
app.use(express.session({ secret: 'keyboard cat', key:
'sid', cookie: { secure: true }})

28. Express App Generation
Command to generate express app:
express --sessions --css stylus --ejs myapp
It generates an application with EJS, Stylus,
and session.
EJS: Embedded JavaScript template engine
- EJS cleans the HTML out of
your JavaScript with client side templates.
- Similar to ERB in ruby.

29. Express generation
Demo...

30.  Yahoo! : iPad App Livestand uses Yahoo! Manhattan
framework which is based on Node.js.
 LinkedIn : LinkedIn uses a combination of Node.js and
MongoDB for its mobile platform. iOS and Android apps
are based on it.
 eBay : Uses Node.js along with ql.io to help application
developers in improving eBay’s end user experience.
 Dow Jones : The WSJ Social front-end is written
completely in Node.js, using Express.js, and many other
modules.
Complete list can be found at:
https://github.com/joyent/node/wiki/Projects,-
Applications,-and-Companies-Using-Node
Who is using Node.js?