node js introduction

Agenda

�  Introduction � Package Manager � Web Framework �  Testing � Callback Hell � Obfuscator � Build Tool

Introduction

What is Node.js �  Server Side JavaScript �  Based on Chrome’s V8 Engines �  Non Blocking I/O �  15,000+ Modules �  Active Community (IRC, Mailing Lists, Twitter,

Github) �  Mac, Linux and Windows (all first class

citizens) �  One Language for Frontend and Backend �  Node is a platform for JavaScript applications

which is not to be confused with a framework.

What is Node.js

Who's using Node.js

Why Node.js

� Apache v.s. Nginx

Blocking I/L $query = 'SELECT * FROM users WHERE id = ?'; $users = query($query, array($id)); print_r($users); $query = 'SELECT * FROM activities ORDER BY timestamp LIMIT 50'; $activities = query($query); print_r($activities); $query = 'SELECT count(points) as total, user_id FROM activities LIMIT 50'; $leader_board = query($query);

Non-Blocking I/J var query = 'SELECT * FROM users WHERE id = ?'; db.query(query, [userId], function (err, results) { console.log(results); }); var query = 'SELECT * FROM activities ORDER BY timestamp LIMIT 50'; db.query(query, function (err, results) { console.log(results); }); var query = 'SELECT count(points) as total, user_id FROM activities LIMIT 50'; db.query(query, function (err, results) { console.log(results); });

Why Node.js

Installing Node.js Mac OS X 1.  Go to http://nodejs.org and click install 2.  Install the downloaded package Windows 1.  Go to http://nodejs.org and click install 2.  Install the downloaded package Linux (and *nix variants) 1.  Go to http://nodejs.org and click install 2.  Decompress source and… ./configure … make … make

install ( for Ubuntu use Chris Lea’s PPA – ppa:chris-lea/node.js )

Hello World Create hello-world.js console.log(‘Hello World’);

On the command line run node hello-world.js

You should see Hello World

Basic HTTP Server var http = require('http'); var server = http.createServer(function (req, res) { res.writeHead(200); res.end('Hello World'); }); server.listen(4000);

Foreign Function Interface

�  node-ffi �  a Node.js addon for loading and calling

dynamic libraries using pure JavaScript. It can be used to create bindings to native libraries without writing any C++ code.

Package Manager

NPM

� Simple CLI tools � Register registry.npmjs.org � Web site npmjs.org �  Included in node.js since 0.6 � Git friendly

NPM Usage

�  npm search express �  npm info express �  npm install -g express �  npm update �  npm publish

NPM Usage �  npm install ./package.tgz �  npm install sax --save �  npm install node-tap --save-dev �  npm install dtrace-provider --save-optional �  npm install https://github.com/indexzero/forever/

tarball/v0.5.6

Module Metas

�  package.json { "name": "my-website", "version": "0.0.1", "dependencies": { "express": "2.4.7", "jade": ">= 0.0.1", "oauth": ">= 0.9.5" } }

Transitive dependencies

Virtual Environment �  nvm (starred 3884 on github)

�  Simple bash script to manage multiple active node.js versions

$ nvm install 0.10.29 $ nvm ls v0.10.29 current: v0.10.29 $ nvm use 0.10.29 Now using node v0.10.29 $ node --version v0.10.29

Virtual Environment �  nave (starred 645 on github)

�  Virtual Environments for Node �  run on various node.js builds

$ nave install latest $ nave ls src: 0.10.28 0.11.13 installed: 0.10.28 0.11.13 $ nave use 0.11.13 Already installed: 0.11.13 using 0.11.13 $ node --version v0.11.13

Web Framework

Express

� Express is a minimal and flexible node.js web application framework, providing a robust set of features for building single and multi-page, and hybrid web applications.

Express �  Generate an app $ npm install -g express-generator $ express --css stylus myapp create : myapp create : myapp/package.json create : myapp/app.js create : myapp/public create : myapp/public/javascripts create : myapp/public/images create : myapp/routes create : myapp/routes/index.js create : myapp/routes/users.js create : myapp/public/stylesheets create : myapp/public/stylesheets/style.styl create : myapp/views create : myapp/views/index.jade create : myapp/views/layout.jade create : myapp/views/error.jade create : myapp/bin create : myapp/bin/www install dependencies: $ cd myapp && npm install run the app: $ DEBUG=myapp ./bin/www

Express Middleware

� Middleware is any number of functions that are invoked by the Express.js routing layer before your final request handler is

Express Middleware var app = express(); app.use(function(req, res, next) { console.log('%s %s', req.method, req.url); next(); }); app.get('/', function(req, res, next) { res.send('Hello World!'); }); app.get('/help', function(req, res, next) { res.send('Nope.. nothing to see here'); });

Express Middleware �  body-parser

�  body �  co-body �  raw-body

�  compression �  connect-timeout �  cookie-parser �  cookie-session �  csurf �  errorhandler �  express-session �  method-override �  morgan �  response-time �  serve-favicon �  serve-index �  serve-static �  vhost

Express I18N app.js var i18n = require('i18n'); app.use(i18n.init); app.use(function (req, res, next) { res.locals.__ = function () { return function (text, render) { return i18n.__.apply(req, arguments); }; }; next(); });

en.js { "Home": "Home", "About Us": "About Us", "Program": "Program", "Venue": "Venue", "Sponsors": "Sponsors" }

menu.hjs <li>{{#__}}Home{{/__}}</li> <li>{{#__}}About Us{{/__}}</li> <li>{{#__}}Program{{/__}}</li> <li>{{#__}}Venue{{/__}}</li> <li>{{#__}}Sponsors{{/__}}</li>

menu.html <li>Home</li> <li>About Us</li> <li>Program</li> <li>Venue</li> <li>Sponsors</li>

Express Authentication �  Passport

�  authentication middleware for Node.js.

app.post('/login', passport.authenticate('local'), function(req, res) { res.redirect('/users/' + req.user.username); }); app.use(function(req, res, next) { if (!req.session.userid) { return res.redirect(url); } next(); });

Template Engine

�  Jade � EJS � Hogan.js

Jade doctype html html(lang="en") head title= pageTitle script(type='text/javascript'). if (foo) { bar(1 + 5) } body h1 Jade - node template engine #container.col if youAreUsingJade p You are amazing else p Get on it! p. Jade is a terse and simple templating language with a strong focus on performance and powerful features.

<!DOCTYPE html> <html lang="en"> <head> <title>Jade</title> <script type="text/javascript"> if (foo) { bar(1 + 5) } </script> </head> <body> <h1>Jade - node template engine</h1> <div id="container" class="col"> <p>You are amazing</p> <p> Jade is a terse and simple templating language with a strong focus on performance and powerful features. </p> </div> </body> </html>

Jade var fn = jade.compile(jadeTemplate); var htmlOutput = fn({ data = {'title': 'Cleaning Supplies', 'supplies': ['mop', 'broom', 'duster']} });

h1= title ul each supply in supplies li= supply

<h1>Cleaning supplies</h1> <ul>

<li>mop</li> <li>broom</li> <li>duster</li>

</ul>

EJS data = {'title': 'Cleaning Supplies', 'supplies': ['mop', 'broom', 'duster']} var html = new EJS({url: 'cleaning.ejs'}).render(data);

<h1><%= title %></h1> <ul> <% for(var i=0; i<supplies.length; i++) {%>

<li><%= supplies[i] %></li> <% } %> </ul>



</ul>

Hogan.js data = {'title': 'Cleaning Supplies', 'supplies': ['mop', 'broom', 'duster']} var template = Hogan.compile(text); var output = template.render(data);

<h1>{{ title }}</h1> <ul> {{#supplies}}

<li>{{.}}</li> {{/supplies}} </ul>



</ul>

Redis Driver $ npm install redis hiredis var redis = require("redis"), client = redis.createClient(); // if you'd like to select database 3, instead of 0 (default), call // client.select(3, function() { /* ... */ }); client.on("error", function (err) { console.log("Error " + err); }); client.set("string key", "string val", redis.print); client.hset("hash key", "hashtest 1", "some value", redis.print); client.hset(["hash key", "hashtest 2", "some other value"], redis.print); client.hkeys("hash key", function (err, replies) { console.log(replies.length + " replies:"); replies.forEach(function (reply, i) { console.log(" " + i + ": " + reply); }); client.quit(); });

Redis Sentinel Driver $ npm install redis hiredis redis-sentinel var sentinel = require('redis-sentinel'); var endpoints = [ {host: '127.0.0.1', port: 26379}, {host: '127.0.0.1', port: 26380} ]; var opts = {}; var masterName = 'mymaster'; var redisClient = sentinel.createClient(endpoints, masterName, opts);

Mongo Driver $ npm install mongodb

var MongoClient = require('mongodb').MongoClient; MongoClient.connect('mongodb://192.168.68.234:27017/qcloud', function(err, db) { if(err) throw err; var collection = db.collection('device'); collection.find({'device_name':'alexnas'}).toArray(function(err, results) { console.dir(results); db.close(); }); });

Mongo Driver �  Mongoose

�  Mongoose provides a straight-forward, schema-based solution to modeling your application data and includes built-in type casting, validation, query building, business logic hooks and more, out of the box.

var mongoose = require('mongoose'); mongoose.connect('mongodb://192.168.68.234:27017/alex_test'); var Cat = mongoose.model('Cat', { name: String }); var kitty = new Cat({ name: 'Zildjian' }); kitty.save(function (err) { console.log('meow'); });

Testing

Debugging �  Node-inspector

�  Node Inspector is a debugger interface for Node.js applications that uses the Blink Developer Tools (formerly WebKit Web Inspector).

�  Node Inspector works in Chrome and Opera only.

$ npm install -g node-inspector $ node-debug app.js or $ node-inspector & $ node --debug app.js

Testing Framework

� Mocha � Mocha is a feature-rich JavaScript test

framework running on node.js and the browser, making asynchronous testing simple and fun.

� Nodeunit �  Simple syntax, powerful tools. Nodeunit

provides easy async unit testing for node.js and the browser.

Mocha var assert = require("assert"); describe('Test', function() { var foo; beforeEach(function() { console.log('setup'); foo = 'bar'; }); afterEach(function() { console.log('teardown'); }); it('#test1', function() { console.log('run test1'); assert.equal(foo, 'bar'); }); });

Nodeunit module.exports = { setUp: function (callback) { console.log('setup'); this.foo = 'bar'; callback(); }, tearDown: function (callback) { console.log('teardown'); callback(); }, test1: function (test) { console.log('run test1'); test.equals(this.foo, 'bar'); test.done(); } };

Callback Hell

Callback Hell doAsync1(function() { doAsync2(function() { doAsync3(function() { doAsync4(function() { }); }); }); });

Callback Hell �  An example from http://callbackhell.com/ fs.readdir(source, function(err, files) { if (err) { console.log('Error finding files: ' + err) } else { files.forEach(function(filename, fileIndex) { console.log(filename) gm(source + filename).size(function(err, values) { if (err) { console.log('Error identifying file size: ' + err) } else { console.log(filename + ' : ' + values) aspect = (values.width / values.height) widths.forEach( function(width, widthIndex) { height = Math.round(width / aspect) console.log('resizing ' + filename + 'to ' + height + 'x' + height) this.resize(width, height).write(destination + 'w' + width + '_' + filename, function(err) { if (err) console.log('Error writing file: ' + err) }) }.bind(this)) } }) }) } })

Avoiding Callback Hell

� Keep your code shallow � Break up your code into small

chunks(modularize) � Use a sequential library like async

async approach

� Async is a utility module which provides straight-forward, powerful functions for working with asynchronous JavaScript.

$ npm install async

async approach var async = require('async'); var db = require(’db'); function getUser (callback) { var query = 'SELECT * FROM users WHERE id = ?'; db.query(query, [userId], callback); } function getActivities (callback) { var query = 'SELECT * FROM activities ORDER BY timestamp LIMIT 50'; db.query(query, callback); } function getLeaderBoard (callback) { var query = 'SELECT count(points) as total, user_id FROM activities LIMIT 50'; db.query(query, callback); } var tasks = [getUser, getActivities, getLeaderBoard]; async.parallel(tasks, function (err, results) { var user = results[0][0]; var activities = results[1]; var leaderBoard = results[2]; });

promises approach

� A tool for making and composing asynchronous promises in JavaScript

$ npm install q

promises approach var q = require('q'); var fs = require('fs'); var request = require('request'); var readFile = q.denodeify(fs.readFile); var q_request = q.denodeify(request); readFile('url.txt', 'utf-8') .then(function(text) { return q_request(text); }) .then(function(result) { console.log(result[0].statusCode); }) .fail(function(err) { console.log('an error occurs : ' + err); });

generator approach

� Generators are lightweight co-routines for JavaScript.

� Available in Node >=0.11.2 or above

generator approach var co = require('co'); var thunkify = require('thunkify'); var request = require('request'); var get = thunkify(request.get); co(function *(){ var a = yield get('http://google.com'); var b = yield get('http://yahoo.com'); var c = yield get('http://cloudup.com'); console.log(a[0].statusCode); console.log(b[0].statusCode); console.log(c[0].statusCode); })() co(function *(){ var a = get('http://google.com'); var b = get('http://yahoo.com'); var c = get('http://cloudup.com'); var res = yield [a, b, c]; console.log(res); })()

Obfuscator

Obfuscator

� YUI Compressor � Google Closure Compiler � minifyjs �  uglify-js uglifyjs app.js -m -o app-min.js

�  node-obfuscator obfuscator --entry app.js app.js routes/index.js routes/user.js

Obfuscator

� Write your extension �  Implement encrypt/decrypt functions

require.extensions[".jse"] = function (m) { m.exports = MyNativeExtension.decrypt(fs.readFileSync(m.filename)); }; require("YourCode.jse");

Precompilation

� Nexe � Nexe is a command-line utility that compiles

your Node.js application into a single executable file.

Build Tool

Make

� GNU Make is a tool which controls the generation of executables and other non-source files of a program from the program's source files.

Grunt

�  JavaScript Task Runner � minification �  compilation �  unit testing � …….

�  Thousands of plugins

Questions?

node js introduction

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