Node.js Introduction

• History and Background
• Installation
• Features
  • Async non-blocked I/O
  • Event Driven
  • CommonJS
• Libraries and Framework

Node.js is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.

• Chrome's Javascript runtime is an open souce fastest javascript engine, called V8
• Node.js run on V8
• Create by Ray Daul in 2009

• libev(event loop)
• libeio(non-block thread pool)
• V8(Javascript engine)

• Windows Installer
• Editor
  • Sublime
  • Visual Studio

• Non-blocking I/O
• Event Driven
• CommonJS

• All I/Os are expensive
• Program is blocked by I/O operation
• Thread is used to make program paralle
• Thread context swtiching is expensive

var data = file.read('file.data');
//waiting for read to complete...
doSomething(data)

• Program returned immediately, continue execute
• Program has an event loop
• Program informed when data ready event emitted, through callback

file.read('file.data', function(data){
	doSomethingWithData(data);
}
doOtherThingWhileReadingData();

• Key feature of Node.js
• Support async Event like Ajax
• Derived from events.EventEmitter

var req = http.request(options, function (res) {
    console.log('STATUS: ' + res.statusCode);
    console.log('HEADERS: ' + JSON.stringify(res.headers));
    res.setEncoding('utf8');
    res.on('data', function (chunk) {
        console.log('BODY: ' + chunk);
    });
});

• Demo1: emit and handle events
• Demo2: custom events.EventEmitter

• CommonJs specified JS standard library
• Node.js implemented CommonJs specification

• Each js file is a module
• Variables outside the file cannot visible except their are global or exported
• Use module.exports to write modules
• Use require('fs') to import fs module

• Package is a group of a modules
• Package metadata is defined in package.json
• package.json in the root of a package dir

• find a package: search in npm.org
• install package: npm install package_name
• npm installed package in current dir: ./node_modules/
• npm install -g, install package to global node_modules dir

• Http Module
• Express
• Tower.js
• async
• socket.io

var http = require('http');
var server = http.createServer(function(request, response) {
    response.write('Hello, world!');
    response.end();
});
var port = 3500;
server.listen(port);
console.log("server listen on port: " + port);

• Routing
• Middleware
  • Logger
  • Body Parser
  • Method Override
  • Cookie Paser
  • Session
• Templating Engine
• Static Content

• Full stack web application framework
• based on Coffeescript
• more like Rail's framework

• Utils module to help avoid callback nessted
• Demo

• Used to make realtime apps
• Blurring the differences between the different transport mechanisms

• How to Node / Node Guid / The Node Beginner Book
• Express.js / Connect
• nowjs / Socket.IO
• Backbone.js & Underscore.js
• CoffeeScript

• Node history and background
• Node key features
  • non-blocking I/O
  • event driven
  • module and packages
• introduce some node module and packages