Groovy Web Services

Groovy Web Services

RESTful Web Services

Addressable Resources

GET --> find

POST --> insert

PUT --> update

DELETE --> delete

vs

URL based: "GETful"

params tell the story (rather than path)

Example: Google Chart API

http://chart.apis.google.com/chart?

plus lots of parameters

http://chart.apis.google.com/chart?&cht=bhs&chs=800x360&chd=t:10,15,25,40,65,100,-15,-30,-60,-90,5,10&chm=tInitial+publication,000000,0,0,12|tFavorable+mention+in+GroovyMag,000000,0,1,12|tJolt+award+nomination,000000,0,2,12|tWitty+repartee+on+Letterman,000000,0,3,12|tProduct+placement+in+Harry+Potter+movie,000000,0,4,12|tOprah%27s+Book+Club,000000,0,5,12|tDrunken+rant+on+Larry+King+Live,000000,0,6,12|tBug+found+in+book+source+code,000000,0,7,12|tInformercial+with+ShamWow+guy,000000,0,8,12|tScandalous+YouTube+video%28s%29,000000,0,9,12|tTearful+apology+on+The+View,000000,0,10,12|tO%27Reilly+%27Behind+the+Text%27+Special,000000,0,11,12&chds=-95,140&chtt=Anticipated+Impact+on+%22Making+Java+Groovy%22+Book+Sales&chco=0000ff|0000ff|0000ff|0000ff|0000ff|0000ff|ff0000|ff0000|ff0000|ff0000|0000ff|0000ff

Amazon Product API

Build URL with Groovy

def queryStrng = params.collect { k,v -> "$k=$v" }.join('&')

def url = "${baseUrl}?${queryString}"

Parse XML Results

def response = new XmlSlurper().parse(url)

def item = response.Items.Item

book.title = item.ItemAttributes.Title

Jersey

Annotations for REST

+ WADL

Part of Java EE 6

Grails

"/product/$id"(controller:"product", parseRequest:true){

action = [GET:"show", PUT:"update", DELETE:"delete", POST:"save"]

}

import grails.converters.*

class ProductController {

def show = {

if(params.id && Product.exists(params.id)) {

def p = Product.findByName(params.id)

render p as XML

} else {

def all = Product.list()

render all as XML

}

}

}

import grails.converters.*

class BookController {

def books

def list = {

this.books = Book.list()

withFormat {

html bookList:books

js { render "alert('hello')" }

xml { render books as XML }

}

}

}

JAX-WS Web Services

apt

wsimport

Example: ISBN Service

wsimport -keep -p mjg <wsdl_url>

wsgen

Example: Potter's Potions, Ltd.

@WebService

public interface Wizard {

@WebMethod

@WebResult(name="potion")

Potion brewPotion(@WebParam(name="ingredients")

Ingredient[] elements);

@WebMethod

@WebResult(name="when")

Date sendOwl(@WebParam(name="message")

String message);

}

so much for interface / implemenation split

Enter Groovy @Delegate

HTTPBuilder

GroovyWS

Content Negotiation

URL Mappings

Groovy SIB

Groovy @Delegate

Methods forward to delegate

Annoying wsgen Issue

@WebService(endpointInterface="Wizard")

class Granger implements Wizard {

Potion brewPotion(Ingredient[] elements) {

return new Potion(name:'polyjuice',

effect:'change appearance');

}

Date sendOwl(String message) {

return new Date()

}

}

@WebService(endpointInterface="Wizard")

class HogwartsWizard implements Wizard {

@Delegate Wizard wizard

}

Converters

Working from SIB puts SIB class name in WSDL for service and port

Publish Service

RESTful Tools

Wizard wiz = new HogwartsWizard(

wizard:new Granger())

Endpoint.publish('http://.../potions', wiz)

println 'Ready to receive requests...'

Java SIB

JAX-RS (JSR 311)

"Jersey"

Restlets

Grails

Implementations

Potions Client

@WebService(endpointInterface="Wizard")

public class Weasley implements Wizard {

public Potion brewPotion(Ingredient[] elements) {

Potion p = new Potion();

p.setName("veritiserum");

p.setEffect("makes you tell the truth");

return p;

}

public Date sendOwl(String message) {

return new Date();

}

}

wsgen works from SIBs

(Service Implementation Beans)

def url = 'http://chart.apis.google.com/chart?'

def data = ['Initial publication':10,'Favorable mention in GroovyMag':15,

'Jolt award nomination':25,'Witty repartee on Letterman':40,

'Product placement in Harry Potter movie':65,"Oprah's Book Club":100,

'Drunken rant on Larry King Live':-15,'Bug found in book source code':-30,

'Informercial with ShamWow guy':-60,'Scandalous YouTube video(s)':-90,

'Tearful apology on The View':5,"O'Reilly 'Behind the Text' Special":10

]

// For bar chart, format is;

// label,label_color,data_set,point_index,label_size

// Would use a collect here instead, but need an index

def transformed = []

data.keySet().eachWithIndex { val, i ->

transformed << "t${URLEncoder.encode(val,'UTF-8')},000000,0,$i,12"

}

// Blue for positive, red for negative

def colors = data.values().collect() {

(it < 0 ? 'ff0000' : '0000ff')

}.join('|')

def title = 'Anticipated Impact on "Making Java Groovy" Book Sales'

def map = [

'cht' : 'bhs',

'chs' : '800x360',

'chd' : 't:'+ data.values().join(','),

'chm' : transformed.join('|'),

'chds': '-95,140',

'chtt': URLEncoder.encode(title,'UTF-8'),

'chco': colors

]

map.each { key, value ->

url += "&${key}=${value}"

}

println url

Wizard w = new HogwartsWizardService().getHogwartsWizardPort()

def ingredients = []

ingredients << new Ingredient(name:'Sopophorous bean',amount:1)

Potion p = w.brewPotion(ingredients)

println "$p.name: $p.effect"

base?k1=v1&k2=v2...

http://.../product/42

Java SEI

wsgen

Groovy SEI + POJOs

Groovy + POJOs

Looks almost identical

but Java Potions and Ingredients

Groovy SEI

POJO, not POGO

Use @WebMethod

or all public methods exposed

including invokeMethod(), etc

@WebService

interface Wizard {

@WebMethod

@WebResult(name="potion")

Potion brewPotion(@WebParam(name="ingredients")

Ingredient[] elements);

@WebMethod

@WebResult(name="when")

Date sendOwl(@WebParam(name="message")

String message);

}

JAX-WS --> JAXB

--> POGO properties

--> getMetaClass()

--> problems

generates WSDL

(and artifacts)

from bytecodes

POGO

Still Want POGOs?

Use field access rather than properties

@XmlAccessorType(XmlAccessType.FIELD)

class Potion {

String name

String effect

}

Special @XMLAccessor annotation

JAX-WS Tools

wsimport

Groovy Client + JAX-WS Stubs

Parse XML Data

WSDL --> Java

generates Java stubs from WSDL

Holy code generation, Batman

http://webservices.daehosting.com/services/isbnservice.wso?WSDL

Do-It-Yourself WS

Java --> WSDL

def getGame(away,home,year) {

def box = new XmlParser.parse(...)

def awayName = box.@away_fname

...

// add extracted data to a POGO

}

wsimport <options> <wsdl_loc>

Built into Java SE 6

ISBNServiceSOAPType service =

new ISBNService().getISBNServiceSOAP()

boolean ok = service.isValidISBN10("0978739299")

Invoke with Groovy (or Java)

Generate XML with MarkupBuilder

JAX-WS 2.0, including JAXB 2.0

apt

JAX-WS 2.1+ available from Metro

Parse or Slurp XML

annotation processing tool

Ken Kousen

works with Java source only

Baseball Data

No Groovy

Kousen IT, Inc.

ken.kousen@kousenit.com

http://www.kousenit.com

JAX-WS

Online XML game data

http://gd2.mlb.com/components/game/mlb

boxscores for all games on year, month, day

Data in XML format

Making Java Groovy

blog: http://kousenit.wordpress.com

WSDL

twitter: @kenkousen

O'Reilly, 2010 (?)

ISBN 0978739299

Top Down

Server

Skeleton

Client stubs

SIB/SEI

Bottom Up

Generate XML Response

Handlers

Intercept SOAP Messages

builder.games {

games.each { g ->

game(

outcome:"$g.away $g.aScore, ...",

lat:g.stadium.latitude,

lng:g.stadium.longitude

)

}

}

Process using SOAP with Attachments API for Java (SAAJ)

thyme

parsley

rosemary

SAAJ

Related Groovy Projects

Ugly, awkward in Java

Simple, elegant in Groovy

Uses for Handlers

Cross-cutting concerns

Conclusions

(Do-it-yourself AOP)

Logging, security, encryption, routing, etc.

or, app-specific concerns...

• XML always easier with Groovy
• Freely intermix with Java
• JAX-WS tools work with Groovy

GroovyWS

HTTPBuilder

Publish and access web services

Built on Apache HttpClient library

Uses Apache CXF

Automatic parsing based on content type

Uses Groovy builder syntax

Note: both version 0.5

docs are a bit "thin"

caveat emptor