Introduction to REST API with Node.js

Introduction to buildREST API with

WhatisNode.js ?
«Aplatform built onChrome's JavaScript runtime for easily building fast, scalable network applications.» http://nodejs.org/
Node.js isneithera server nora web framework

About Node.js
•Createdby Ryan Dahl in 2009
•Development and maintenance sponsored byJoyent
•LicenceMIT
•Last release : 0.10.31
•Based on Google V8 Engine
•+99 000 packages

Successstories
Rails to Node
« Servers were cut to 3 from 30 »
« Running up to 20x faster in some scenarios »
« Frontend and backend mobile teams could be combined […] »
Java to Node
« Built almost twice as fast with fewer people »
« Double the requests per second »
« 35% decrease in the average response time »

Architecture
•Single Threaded
•Event Loop
•Non-blockingI/O
•Javascript(Event DrivenLanguage)

Inside Node.js
Standard JavaScript with
•Buffer
•C/C++ Addons
•Child Processes
•Cluster
•Console
•Crypto
•Debugger
•DNS
•Domain
•Events
•File System
•Globals
•HTTP
•HTTPS
•Modules
•Net
•OS
•Path
•Process
•Punycode
•QueryStrings
•Readline
•REPL
•Stream
•String Decoder
•Timers
•TLS/SSL
•TTY
•UDP/Datagram
•URL
•Utilities
•VM
•ZLIB
… but withoutDOM manipulation

File package.json
Project informations
•Name
•Version
•Dependencies
•Licence
•Main file
•Etc...

NPM (NodePackagedModules)
•Findpackages : https://www.npmjs.org/
•Help : npm-l
•Createpackage.json: npminit
•Install package :
•npminstallexpress
•npminstallmongosse--save
•npminstall-g mocha
•npm installgrunt--save-dev
•Update project from package.json
•npm install
•npm update

Hello Node.js
console.log("Hello World !");
hello.js
> nodehello.js
Hello World !

Loadmodule
•Coremodule : var http = require('http');
•Project file module : var mymodule= require(‘./module’); // ./module.js or ./module/index.js var mymodule= require(‘../module.js’); var mymodule= require(‘/package.json’);
•Packagedmodule (in node_modulesdirectory): var express = require(‘express’);

Createmodule 1/2
var PI = Math.PI;
exports.area= function(r) {
return PI * r * r;
};
var circle= require('./circle.js');
console.log('The area of a circle of radius 4 is '+ circle.area(4));
circle.js

Createmodule 2/2
var PI = Math.PI;
module.exports= function(r) {
return PI * r * r;
};
var circleArea= require('./circle-area.js');
console.log('The area of a circle of radius 4 is '+ circleArea(4));
circle-area.js

Node.js
Talk is cheapShow me the code

Express introduction
«Fast, unopinionated, minimalist web framework forNode.js» http://expressjs.com

Express sample
var express = require('express');
var app= express();
app.get('/', function(req, res) {
res.send('Hello World!');
});
app.post('/:name', function (req, res) {
res.send('Hello !'+req.param('name'));
});
app.listen(3000);

Express middleware
Middleware can:
•Execute any code.
•Make changes to the request and the response objects.
•End the request-response cycle.
•Call the next middleware in the stack.
var app= express();
var cookieParser= require('cookie-parser');
app.use(express.static(__dirname+ '/public'));
app.use(cookieParser());
…

Express middleware modules
Module
Description
morgan
HTTP request logger middleware for node.js
express.static
Serve static content from the "public" directory (js, css, html, image, video, …)
body-parser
Parserequestbody and populatereq.body(ie: parsejsonbody)
cookie-parser
Parse cookie header and populate req.cookieswith an object keyed by the cookie names
cookie-session
Provide "guest" sessions, meaning any visitor will have a session, authenticated or not.
express-session
Providegenericsession functionality within-memorystorage by default
method-override
Lets you use HTTP verbs such as PUT or DELETE in places where the client doesn't support it.
csurf
Node.js CSRF protection middleware.
…

Express router
var router = express.Router();
router.get('/', function(req, res) {
res.send('Hello World!');
});
router.post('/:name', function(req, res) {
res.send('Hello !'+req.param('name'));
});
var app= express();
app.use('/api/', router);

Express

Mongooseintroduction
«Elegantmongodbobjectmodelingfornode.js » http://mongoosejs.com/

Mongooseconnect
var mongoose= require('mongoose');
mongoose.connect('mongodb://localhost/test');
mongoose.connection.on('error', console.log);
mongoose.connection.once('open', functioncallback (){ });
mongoose.connection.on('disconnected', functioncallback (){ });

Mongooseschema1/2
/* Article Schema*/
var ArticleSchema= new Schema({
title: {type : String, trim : true},
body: {type : String, trim: true},
user: {type : Schema.ObjectId, ref: 'User'},
comments: [{
body: { type : String, default : '' },
user: { type : Schema.ObjectId, ref: 'User' },
createdAt: { type : Date, default : Date.now}
}],
createdAt: {type : Date, default : Date.now}
});
/* Validations */
ArticleSchema.path('title').required(true, 'Article title cannot be blank');
ArticleSchema.path('body').required(true, 'Article body cannot be blank');
/* Save the Schema*/
mongoose.model('Article', ArticleSchema);

Mongooseschema2/2
Othersschemafeatures:
•Validator
•Virtual property
•Middleware
•Population
•…

Mongooseinstance & save
/* Getthe model */
var Article = mongoose.model('Article');
/* Createa new instance */
var article = new Article({
title: 'Introduction to Mongoose',
body : 'This is an article about Mongoose'
});
/* Save the instance */
article.save(function(err){
if(err) return console.log("not saved !");
console.log("saved");
});

Mongoosequery
var Article = mongoose.model('Article');
// A query
Article
.where('user').equals(myUserId)
.where('tile', /mongoose/i)
.select('titlebody createdAt')
.sort('-createdAt')
.limit(10)
.exec (function (err, data){ /* do anything */ });
// The samequery
Article.find({
user : myUserId,
title: /mongoose/i
},
'titlebody createdAt',
{
sort : '-createdAt',
limit: 10
},
function (err, data){ /* do anything */ }
);

Mongoose

Othersmodules
•Web frameworksExpress, Koa, Sails, Hapi, Restify, …
•Server toolsSocket.io, Passport, …
•LoggersWinston, Bunyan, …
•ToolsAsync, Q, Lodash, Moment, Cheerio, …
•TestingNight Watch, Supertest, Mocha, Jasmine, Sinon, Chai, …

Introduction to REST API with Node.js

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