hacking with node.JS

#hacking withnode.JS
HarshaVashisht
http://www.harsharv.com
@harsharv
Picture Source: http://bethesignal.org/blog/2011/01/06/speaking-lca2011-html5-nodejs/

What is node.js?

Node is an exciting new platform developed byRyan Dahl.

It is a lot of sugar on v8

It allows JavaScript developers to create extremely high performance servers by leveraging Google's V8 JavaScript engine, and asynchronous I/O.

Never wait it the motto

Recap… What is Node.js?
Node is an exciting new platform developed by Ryan Dahl.
It allows JavaScript developers to create extremely high performance servers by leveraging Google's V8 JavaScript engine, and asynchronous I/O.
Node is a lot of Sugar written on V8
Never wait is the motto. Either to fetch a page from the web or fetch data from a DB.

let us look at…

DUCK! There will be code…
Lets see cod

LAMP STACK
1. Order
2. Waits for the food
to be cooked
3.Food is ready
4. Serve

Node JS
1. Order
2. Places the order
with the cook
3. Immediately moves on to take the order from the next table
4. Cook notifies that the food is
ready
5. Food is served

commonjs
CommonJS is a community driven effort to standardize packaging of JavaScript libraries, known as modules. Modules written which comply to this standard provide portability between other compliant frameworks such as narwhal, and in some cases even browsers.*
* Conditions Apply

Why node.js?

Global objects
Require
Module/ export
Process

Require
This is used to specify that a module is required.
Example:
var operation = require(“pow”)

Module/ exports
This is used to package JavaScript libraries and expose the functionality to be used else where.
Example:
exports.pow = function (a, b) {
…
}

process
The process object is a global object and can be accessed from anywhere.
It is an instance of EventEmitter.
Can be thought as an equivalent to Window object in the browser
Examples:
process.cwd()
process.exit(1)
process.argv
process.on('exit', function () {
...}
process.on('uncaughtException', function (err) {
…}

Simple http server
/* File Name: hello-server.js */
/* Include the http module. */
var http = require('http');
/* Create a server which accepts Request - req and returns Response - res */
http.createServer(function (req, res) {
/* Set the HTTP header for the response. */
res.writeHead(200, {'Content-Type': 'text/plain'});
/* End the HTTP response */
res.end('Hello Worldn');
}).listen(9000, "127.0.0.1");
/* Print a message to indicate that the server is running. */
console.log('Server running at http://127.0.0.1:9000/');

Modules lets right some

Calculate power of a number
exports.pow = function (a, b) {
/* Check if a number is passed. */
if (isNaN (a-0) || isNaN (b-0)) {
return null;
}
varans = 1;
for (vari = 1; i <= b; i++) {
ans *= a;
}
return ans;
}
Link: https://github.com/harsharv/OpenHackDay2011/blob/master/hello-server.js

twitter search module
https://github.com/harsharv/OpenHackDay2011/blob/master/twitter.js
https://github.com/harsharv/OpenHackDay2011/blob/master/mashup.js

Npm – node package manager
npm is the package manager for the Node JavaScript platform
It puts modules in place so that node can find them, and manages dependency conflicts intelligently.

More about npm
Install NPM
curl http://npmjs.org/install.sh | sh
Browse the packages of NPMhttp://search.npmjs.org/

Npm basic commands
npm search
npmls
npm install yui3
npm uninstall yui3

Yui3 and node.js

resources
http://nodejs.org/
http://npmjs.org/
http://www.yuiblog.com/blog/2010/04/05/running-yui-3-server-side-with-node-js/
http://developer.yahoo.com/yui/3/
http://github.com/davglass/nodejs-yui
http://github.com/davglass/yui-express
http://github.com/harsharv/OpenHackDay2011

Harsha R. Vashishtmail@harsharv.com
http://www.harsharv.comhttp://twitter.com/harsharv
http://www.facebook.com/harsharvhttp://www.slideshare.net/harsharv
http://github.com/harsharv/

hacking with node.JS

by Harsha Vashisht

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