Vüqar Süleymanov

Java Developer at Cybernet

RESTful

• What is Web Services?

• About RESTful

• RESTful with Groovy & Grails

Web Service is online API which we call from code.

Web Service

What is Web Sevices?

Difference between java local api and online api.

Client App

Library

Library

Library

Web Services

Web Service

Web Service

Client

Post to your wallApps

Games

http://www.twitter.com http://api.twitter.com

HTML XML / JSON

Web Service Types

REST Web Services

SOAP Web Services

Client Server

HTTP request

HTTP response

HTTP exchange

Client Web Service

Data<html…>

…</html>

HTTP exchange

Protocol

Client Web Service

Message format

SOAPSimple Object Access Protocol

Protocol

ClientSOAP

Web Service

SOAP protocol

ClientREST

Web Service

XMLJSONText…

What is RESTful Web Sevices?

• RESTful services was first introduced in the year 2000 by Roy Fielding at the university of California. But RESTful was popular only the last few years.

• Many developers found SOAP hard to use. For example, working with SOAP in JavaScript means writing a ton of code to perform extremely simple tasks because you must create the required XML structure absolutely every time.

• REST provides a lighter weight alternative. Instead of using XML to make a request, REST relies on a simple URL in many cases.

• Resource based URIs

• HTTP methods

• HTTP status codes

• Message headers

What we need?

RESTful with Groovy on Grails

Different approaches

• Using just @Resource.

• With uri attribute.

• With explicit UrlMappings

• Using Controller

package com.grailsbaki

import grails.rest.Resource

@Resourceclass Job {

String name

static constraints = {

}}

package com.grailsbaki

import grails.rest.Resource

@Resource(uri=‘/category’)class Category {

String name

static hasMany = [jobs: Job]

static constraints = { }}

<?xml version="1.0" encoding="UTF-8"?><list> <category id="1"> <jobs /> <name>Information Technology</name> </category> <category id="2"> <jobs /> <name>Sales &amp; Marketing</name> </category> <category id="3"> <jobs /> <name>Banking &amp; Finance</name> </category></list>

http://localhost:8080/RESTfulOnGrails/category

<?xml version="1.0" encoding="UTF-8"?><list> <category id="1"> <jobs /> <name>Information Technology</name> </category> <category id="2"> <jobs /> <name>Sales &amp; Marketing</name> </category> <category id="3"> <jobs /> <name>Banking &amp; Finance</name> </category></list>

http://localhost:8080/RESTfulOnGrails/categories

package com.grailsbaki

import grails.rest.Resource

@Resource(uri=‘/category’, formats=[‘json’], readOnly = true)class Category {

String name

static hasMany = [jobs: Job]

static constraints = { }} [

{ "class": "com.grailsbaku.Category", "id": 1, "jobs": [], "name": "Information Technology" }, { "class": "com.grailsbaku.Category", "id": 2, "jobs": [], "name": "Sales & Marketing" }, { "class": "com.grailsbaku.Category", "id": 3, "jobs": [], "name": "Banking & Finance" }]

grails> url-mappings-report

"/categories" (resources: "category"){ "/jobs" (resources: "job")}

UrlMapping

http://localhost:8080/RESTfulOnGrails/categories/1/jobs<?xml version="1.0" encoding="UTF-8"?><list> <job id="1"> <name>Java Developer</name> </job> <job id="2"> <name>C# Developer</name> </job> <job id="3"> <name>Php Developer</name> </job></list>

Using Controller

def save(params) {new Person(name: params.name, surname: params.surname).save(flush: true)

}

def update() {print("update method")

}

def delete() {print("delete method")

}

def list() {def people = Person.list()respond people, [formats:['xml','json']]

request.withFormat { json { render people as JSON }

}}

static allowedMethods = [save:'POST',delete:['POST', 'DELETE'], update:'POST', list:'GET']

POSTMAN

The End