GRAILS RAPID WEB APPLICATION DEVELOPMENT MADE EASY

RAPID WEB APPLICATION DEVELOPMENT MADE EASY

About: Sven Haiges Actionality Deutschland GmbH Senior Java Developer Diplom-Informatiker (FH), MBA My personal framework evolution: Struts, JSF, Spring MVC, GRAILS Since Juli 2006: Grails Podcast, Grails Screencasts

Actionality Deutschland GmbH

Senior Java Developer

Diplom-Informatiker (FH), MBA

My personal framework evolution: Struts, JSF, Spring MVC, GRAILS

Since Juli 2006: Grails Podcast, Grails Screencasts

Goals What is Grails & how do I create my first Grails app? What are the powerful cornerstones of Grails? Which features does Grails provide out of the box? Next Steps @ Home/Work

What is Grails & how do I create my first Grails app?

What are the powerful cornerstones of Grails?

Which features does Grails provide out of the box?

Next Steps @ Home/Work

Agenda Basics Foundations MVC Features Roadmap Your Next Steps

Grails Basics

Grails MVC Grails is an MVC Web Framework Inspired by Ruby on Rails Uses the powerful Groovy Scripting Language Convention Over Configuration Don't Repeat Yourself (DRY)

Grails is an MVC Web Framework

Inspired by Ruby on Rails

Uses the powerful Groovy Scripting Language

Convention Over Configuration

Don't Repeat Yourself (DRY)

Grails History & Team Started by Groovy enthusiasts: Guillaume LaForge, Steven Devijver and Graeme Rocher (current project lead) 0.1 was out March 29th, 2006 Current Team: Graeme Rocher, Marc Palmer, Dierk Koenig, Steven Devijer, Jason Rudolph, Sven Haiges... YOU!

Started by Groovy enthusiasts: Guillaume LaForge, Steven Devijver and Graeme Rocher (current project lead)

0.1 was out March 29th, 2006

Current Team: Graeme Rocher, Marc Palmer, Dierk Koenig, Steven Devijer, Jason Rudolph, Sven Haiges... YOU!

Using Grails Standalone Configuration details are hidden 0..100 in no time! Integrate with existing applications Still use the flexibility of Grails for existing DB-Schemas, HBM-Mappings, Spring Configuration, etc. Pimp your app!

Standalone

Configuration details are hidden

0..100 in no time!

Integrate with existing applications

Still use the flexibility of Grails for existing DB-Schemas, HBM-Mappings, Spring Configuration, etc.

Pimp your app!

Powerful Foundations Foundations Groovy: 1 st class integration with Java Platform and all Java Code you have ever written! Spring: IoC, Spring MVC, WebFlow, ... Hibernate: powerful p ersistence Layer SiteMesh: flexible layout framework

Foundations

Groovy: 1 st class integration with Java Platform and all Java Code you have ever written!

Spring: IoC, Spring MVC, WebFlow, ...

Hibernate: powerful p ersistence Layer

SiteMesh: flexible layout framework

Installing Grails No previous Groovy installation needed, just a Java VM 1.4+ (but does not hurt :-) grails.org/Installation Download, extract, set GRAILS_HOME, add bin to PATH, run it! Type „grails“ to verify it works

No previous Groovy installation needed, just a Java VM 1.4+ (but does not hurt :-)

grails.org/Installation

Download, extract, set GRAILS_HOME, add bin to PATH, run it!

Type „grails“ to verify it works

Your First Grails App „ grails create-app“ „ cd appName” „ grails run-app“ „ grails create-domain-class“, edit class „ grails generate-all“ „ grails run-app“

„ grails create-app“

„ cd appName”

„ grails run-app“

„ grails create-domain-class“, edit class

„ grails generate-all“

„ grails run-app“

Grails Foundations

Spring Spring Framework is used to hold everything together You can specify your own Spring Beans for injection into Controllers, Services, Jobs in spring/resources.xml Good to know: a Grails app is an Spring MVC app... Spring Webflow to be used in future

Spring Framework is used to hold everything together

You can specify your own Spring Beans for injection into Controllers, Services, Jobs in spring/resources.xml

Good to know: a Grails app is an Spring MVC app... Spring Webflow to be used in future

Hibernate Hibernate is the de facto standard for O/R Mapping Grails maps your Domain Classes automatically, even creates and exports the schema to the database 1:n & m:n supported! Great flexibility: use your own HBM files for legacy database schemas!

Hibernate is the de facto standard for O/R Mapping

Grails maps your Domain Classes automatically, even creates and exports the schema to the database

1:n & m:n supported!

Great flexibility: use your own HBM files for legacy database schemas!

SiteMesh SiteMesh is a powerful Layout Framework and integrated into Grails grails-app/views/layout/main.gsp is the standard layout file This meta element in a head of a gsp file links it with the “main” layout: < meta name = &quot;layout&quot; content = &quot;main&quot; />

SiteMesh is a powerful Layout Framework and integrated into Grails

grails-app/views/layout/main.gsp is the standard layout file

This meta element in a head of a gsp file links it with the “main” layout: < meta name = &quot;layout&quot; content = &quot;main&quot; />

Grails Philosophy Reuse (see foundations) No “reinventing the wheel” Coding by Convention without being locked into a single solution! Domain-Centric, not DB-Centric DRY

Reuse (see foundations)

No “reinventing the wheel”

Coding by Convention

without being locked into a single solution!

Domain-Centric, not DB-Centric

DRY

Grails MVC

Model Above is a Domain Class .groovy files living in grails-app/domain Persistent id, version, equals, hashCode, toString is generated automatically, but can be overridden class Book { String title }

Above is a Domain Class

.groovy files living in grails-app/domain

Persistent

id, version, equals, hashCode, toString is generated automatically, but can be overridden

class Book {

String title

}

Model You will typically use this convenience target to create Domain Classes Will ask you for the name, make it uppercase if you forget > grails create-domain-class

You will typically use this convenience target to create Domain Classes

Will ask you for the name, make it uppercase if you forget

> grails create-domain-class

Model 1:1 mapping with Author Specify the “owning side” with this class Book { Author author String title } class Book { def belongsTo = Author Author author String title }

1:1 mapping with Author

Specify the “owning side” with this

class Book {

Author author

String title

}

class Book {

def belongsTo = Author

Author author

String title

}

Model 1:n mapping: Author has many Books Property “books” created automatically Same for adder method: class Author { def hasMany = [ books : Book ] String name } author.addBook(new Book(title:'Grails')) author.save()

1:n mapping: Author has many Books

Property “books” created automatically

Same for adder method:

class Author {

def hasMany = [ books : Book ]

String name

}

author.addBook(new Book(title:'Grails'))

author.save()

Model m:n possible, too! BelongsTo defines “owning side” class Book { def belongsTo = Author def hasMany = [authors:Author] } class Author { def hasMany = [books:Book] }

m:n possible, too!

BelongsTo defines “owning side”

class Book {

def belongsTo = Author

def hasMany = [authors:Author]

}

class Author {

def hasMany = [books:Book]

}

Model Constraints defined via constraints closure Affects generation of views, too! class User { String login String password String email Date age static constraints = { login(length:5..15,blank:false,unique:true) password(length:5..15,blank:false) email(email:true,blank:false) age(min:new Date(),nullable:false) } }

Constraints defined via constraints closure

Affects generation of views, too!

class User {

String login

String password

String email

Date age

static constraints = {

login(length:5..15,blank:false,unique:true)

password(length:5..15,blank:false)

email(email:true,blank:false)

age(min:new Date(),nullable:false)

}

}

Model Dynamic Finder Methods def results = Book.findByTitle(&quot;The Stand&quot;) results = Book.findByTitleLike(&quot;Harry Pot%&quot;) results = Book.findByReleaseDateBetween( firstDate, secondDate ) results = Book.findByReleaseDateGreaterThan( someDate ) You can also use Query by Example (QBE) the Hibernate Criteria Builder, or direct HQL queries!

Dynamic Finder Methods

def results = Book.findByTitle(&quot;The Stand&quot;)

results = Book.findByTitleLike(&quot;Harry Pot%&quot;)

results = Book.findByReleaseDateBetween( firstDate, secondDate )

results = Book.findByReleaseDateGreaterThan( someDate )

You can also use Query by Example (QBE) the Hibernate Criteria Builder, or direct HQL queries!

Model Database configuration is done in grails-app/conf directory DevelopmentDataSource.groovy ProductionDataSource.groovy TestDataSource.groovy If you hit “grails run-app” the dev datasource is the default

Database configuration is done in grails-app/conf directory

DevelopmentDataSource.groovy

ProductionDataSource.groovy

TestDataSource.groovy

If you hit “grails run-app” the dev datasource is the default

Model “grails war” creates your deployment war file with the production datasource class DevelopmentDataSource { boolean pooling = true // one of 'create', 'create-drop','update' //String dbCreate = &quot;create-drop&quot; String url = &quot;jdbc:postgresql://localhost:5432/act_dev&quot; String driverClassName = &quot;org.postgresql.Driver&quot; String username = &quot;dev&quot; String password = &quot;devpw&quot; def logSql = true //enable logging of SQL generated by Hibernate }

“grails war” creates your deployment war file with the production datasource

class DevelopmentDataSource {

boolean pooling = true

// one of 'create', 'create-drop','update'

//String dbCreate = &quot;create-drop&quot;

String url = &quot;jdbc:postgresql://localhost:5432/act_dev&quot;

String driverClassName = &quot;org.postgresql.Driver&quot;

String username = &quot;dev&quot;

String password = &quot;devpw&quot;

def logSql = true //enable logging of SQL generated by Hibernate

}

Model BootStrap files are picked up at startup and can be used to create initial (test) data class CompanyBootStrap { def init = { servletContext -> //Delete all data in the tables that we work on Company.executeUpdate( &quot;delete Company&quot; ) //now create the test data Company c1 = new Company(name: 'bmw' ) c1.addUser( new User(name: 'herbert' , admin: true , ...)) .save() } ...

BootStrap files are picked up at startup and can be used to create initial (test) data

class CompanyBootStrap {

def init = { servletContext ->

//Delete all data in the tables that we work on

Company.executeUpdate( &quot;delete Company&quot; )

//now create the test data

Company c1 = new Company(name: 'bmw' )

c1.addUser( new User(name: 'herbert' , admin: true , ...))

.save()

}

...

View Groovy Server Pages(GSP) or JavaServer Pages (JSP) TagLibs for both, but GSP is groovin' All views are in the grails-app/views directory Generate views for your domain class: “grails generate-views”

Groovy Server Pages(GSP) or JavaServer Pages (JSP)

TagLibs for both, but GSP is groovin'

All views are in the grails-app/views directory

Generate views for your domain class: “grails generate-views”

View Example GSP / uses “main” Layout < html > < head > < meta name = &quot;layout&quot; content = &quot;main&quot; /> < title > BlogEntry List </ title > </ head > < body > < div class = &quot;nav&quot; > < span class = &quot;menuButton&quot; > < g:link controller = &quot;authentication&quot; action = &quot;viewControllers&quot; > Home </ g:link ></ span > < span class = &quot;menuButton&quot; >< g:link action = &quot;create&quot; > New BlogEntry </ g:link ></ span > </ div > < div class = &quot;body&quot; > ... </ div > ...

Example GSP / uses “main” Layout

< html >

< head >

< meta name = &quot;layout&quot; content = &quot;main&quot; />

< title > BlogEntry List </ title >

</ head >

< body >

< div class = &quot;nav&quot; >

< span class = &quot;menuButton&quot; > < g:link controller = &quot;authentication&quot; action = &quot;viewControllers&quot; > Home </ g:link ></ span >

< span class = &quot;menuButton&quot; >< g:link action = &quot;create&quot; > New BlogEntry </ g:link ></ span >

</ div >

< div class = &quot;body&quot; >

...

</ div >

...

View Dynamic Tag Libraries Tags are fun again! “grails create-taglib” A plain *TagLib.groovy file in grails-app/taglib As with GSPs & Controllers: no server restart!

Dynamic Tag Libraries

Tags are fun again!

“grails create-taglib”

A plain *TagLib.groovy file in grails-app/taglib

As with GSPs & Controllers: no server restart!

View TagLib example (“simple” tag) class MyTagLib { includeJs = { attrs -> out << &quot;<script src='scripts/ ${attrs['script']} .js' />&quot; } } OutputStream is available via “out” All attributes are in the attrs map Usage of GStrings keeps tags readable

TagLib example (“simple” tag)

class MyTagLib {

includeJs = { attrs ->

out << &quot;<script src='scripts/ ${attrs['script']} .js' />&quot;

}

}

OutputStream is available via “out”

All attributes are in the attrs map

Usage of GStrings keeps tags readable

View Logical and iterative tags just as easy. You can even call tags as “methods” within GSP – here used as normal tag: <g:hasErrors bean=&quot;${book}&quot; field=&quot;title&quot;> <span class='label error'>There were errors on the book title</span> </g:hasErrors> Or as method: <span id=&quot;title&quot; class=&quot;label ${hasErrors(bean:book,field:'title','errors')}&quot;>Title</span>

Logical and iterative tags just as easy.

You can even call tags as “methods” within GSP – here used as normal tag:

<g:hasErrors bean=&quot;${book}&quot; field=&quot;title&quot;>

<span class='label error'>There were errors on the book title</span>

</g:hasErrors>

Or as method:

<span id=&quot;title&quot; class=&quot;label ${hasErrors(bean:book,field:'title','errors')}&quot;>Title</span>

View Creating markup from tags is a piece of cake: def dialog = { attrs, body -> mkp { div('class':'dialog') { body() } } } Above example uses a Groovy MarkupBuilder

Creating markup from tags is a piece of cake:

def dialog = { attrs, body ->

mkp {

div('class':'dialog') {

body()

}

}

}

Above example uses a Groovy MarkupBuilder

Controller All controllers are mapped to the Grails dispatcher servlet Create a new controller via: “grails create-controller” Or generate the controller based on an existing Domain Class: “grails generate-controller”

All controllers are mapped to the Grails dispatcher servlet

Create a new controller via: “grails create-controller”

Or generate the controller based on an existing Domain Class: “grails generate-controller”

Controller Default Mapping Convention http://.../appName/controller/action/id Some properties automatically available flash – map stores messages for next request log - a Log4J logger instance params – map with all request parameters request/response/servletContext etc.

Default Mapping Convention http://.../appName/controller/action/id

Some properties automatically available

flash – map stores messages for next request

log - a Log4J logger instance

params – map with all request parameters

request/response/servletContext etc.

Controller Example generated controller: class AdvertisementController { def index = { redirect(action:list,params:params) } def list = { [ advertisementList: Advertisement.list( params ) ] } def show = { [ advertisement : Advertisement.get( params.id ) ] } ...

Example generated controller:

class AdvertisementController {

def index = { redirect(action:list,params:params) }

def list = {

[ advertisementList: Advertisement.list( params ) ]

}

def show = {

[ advertisement : Advertisement.get( params.id ) ]

}

...

Controller You can also use dynamic scaffolding: class BookController { def scaffold = Book } list/show/edit/delete/create/save/ update “dynamically” available You can still override actions “grails generate-all” creates all views and all controller actions for a domain class

You can also use dynamic scaffolding:

class BookController {

def scaffold = Book

}

list/show/edit/delete/create/save/ update “dynamically” available

You can still override actions

“grails generate-all” creates all views and all controller actions for a domain class

Controller Grails Services can be used to encapsulate business logic Services may be injected into Controllers “grails create-service” creates a new service in grails-app/services

Grails Services can be used to encapsulate business logic

Services may be injected into Controllers

“grails create-service” creates a new service in grails-app/services

Controller Example Service class CountryService { def String sayHello(String name) { return &quot;hello ${name}&quot; } } Used within a controller class GreetingController { CountryService countryService def helloAction = { render(countryService.sayHello(params.name)) } }

Example Service

class CountryService {

def String sayHello(String name) {

return &quot;hello ${name}&quot;

}

}

Used within a controller

class GreetingController {

CountryService countryService

def helloAction = {

render(countryService.sayHello(params.name))

}

}

About Scaffolding... Use it to get up to speed, have something to show and work on You will not scaffold your complete web application Learn from the generated code, tweak it to fit your individual needs

Use it to get up to speed, have something to show and work on

You will not scaffold your complete web application

Learn from the generated code, tweak it to fit your individual needs

Grails Features

Auto Reloading In development mode, Grails synchronizes the current application with the server Controllers, GSPs, Tag Libraries, Domain Classes, Services, etc. This is essential for an iterative and incremental development. Call it “agile” if you like!

In development mode, Grails synchronizes the current application with the server

Controllers, GSPs, Tag Libraries, Domain Classes, Services, etc.

This is essential for an iterative and incremental development.

Call it “agile” if you like!

Spring Integration You can put additional Spring configuration in the /spring directory and use it to configure your beans Automatic DI is available even for these beans (not just Services) Easily integrate existing (Java) functionality that was configured with Spring

You can put additional Spring configuration in the /spring directory and use it to configure your beans

Automatic DI is available even for these beans (not just Services)

Easily integrate existing (Java) functionality that was configured with Spring

Hibernate Integration You can specify your own HBM files for your domain classes. (You can even use your existing Java classes if you like) Working with legacy database schemas is getting really simple Still use all benefits like dynamic finder methods

You can specify your own HBM files for your domain classes. (You can even use your existing Java classes if you like)

Working with legacy database schemas is getting really simple

Still use all benefits like dynamic finder methods

Eclipse “Integration” Grails creates an Eclipse Project file automatically, just run File > Import > Existing Project You'll have to tweak some file names if you use the development snapshot versions Be sure to install the Groovy Plugin: groovy.codehaus.org/Eclipse+Plugin

Grails creates an Eclipse Project file automatically, just run File > Import > Existing Project

You'll have to tweak some file names if you use the development snapshot versions

Be sure to install the Groovy Plugin: groovy.codehaus.org/Eclipse+Plugin

AJAX Grails supports AJAX with different AJAX toolkits, currently Prototype, Dojo and Yahoo Special AJAX tags can be used for asynchronous calls and form submission <div id=&quot;message&quot;></div> <g:remoteLink action=&quot;delete&quot; id=&quot;1&quot; update=&quot;message&quot;>Delete Book</g:remoteLink>

Grails supports AJAX with different AJAX toolkits, currently Prototype, Dojo and Yahoo

Special AJAX tags can be used for asynchronous calls and form submission

<div id=&quot;message&quot;></div>

<g:remoteLink action=&quot;delete&quot; id=&quot;1&quot; update=&quot;message&quot;>Delete Book</g:remoteLink>

AJAX On the server side, Grails supports AJAX via the render() Method, which makes AJAX responses really easy: def time = { render(contentType:'text/xml') { time(new Date()) } } Render() supports MarkupBuilders for XML, HTML, JSON, OpenRico

On the server side, Grails supports AJAX via the render() Method, which makes AJAX responses really easy:

def time = {

render(contentType:'text/xml') {

time(new Date())

}

}

Render() supports MarkupBuilders for XML, HTML, JSON, OpenRico

Job Scheduling Grails makes using Quartz even easier, just create this (in grails-app/jobs): class MyJob { def cronExpression = &quot;0,15,30,45 * * * * ?&quot; //every 15 seconds def execute(){ println &quot;Running job!&quot; } }

Grails makes using Quartz even easier, just create this (in grails-app/jobs):

class MyJob {

def cronExpression = &quot;0,15,30,45 * * * * ?&quot; //every 15 seconds

def execute(){

println &quot;Running job!&quot;

}

}

Unit & Functional Testing Both unit and functional testing supported Functional Testing uses Canoo Webtest “grails test-app” runs the unit tests “grails run-webtest” Generate a webtest with “grails generate-webtest”

Both unit and functional testing supported

Functional Testing uses Canoo Webtest

“grails test-app” runs the unit tests

“grails run-webtest”

Generate a webtest with

“grails generate-webtest”

Grails Roadmap

The Sandbox New Controllers Page Flows Constraints for DB-Schema creation Laszlo on Grails Mail / Messaging Integration Test DataSets Plugin-System

New Controllers

Page Flows

Constraints for DB-Schema creation

Laszlo on Grails

Mail / Messaging Integration

Test DataSets

Plugin-System

Roadmap 0.3 Spring 2 Web Services Service Classes M:N Mapping for GORM 0.4 DWR Support for Service Classes Pluggable Persistence Layer

0.3

Spring 2

Web Services Service Classes

M:N Mapping for GORM

0.4

DWR Support for Service Classes

Pluggable Persistence Layer

Roadmap 0.5 XML-RPC for Service Classes Generation of Domain Model from DB Schema 0.6 Scaffolding of User Authentication Code Grails is user-centric, you define what really happens. Vote in Jira: http://jira.codehaus.org/browse/GRAILS

0.5

XML-RPC for Service Classes

Generation of Domain Model from DB Schema

0.6

Scaffolding of User Authentication Code

Grails is user-centric, you define what really happens. Vote in Jira: http://jira.codehaus.org/browse/GRAILS

Your Next Steps

Learn more Download, Install, create your first app with the Quickstart Guide http://www.grails.org/Quick+Start Check out the Tutorials Section http://www.grails.org/Tutorials

Download, Install, create your first app with the Quickstart Guide http://www.grails.org/Quick+Start

Check out the Tutorials Section http://www.grails.org/Tutorials

Learn more Read & Work through the user guide http://www.grails.org/User+Guide Get onto the Grails user mailing list http://www.grails.org/Mailing+lists Remember: Grails is open source... The more you contribute, the more you get out in terms of learning, jobs, contacts...

Read & Work through the user guide http://www.grails.org/User+Guide

Get onto the Grails user mailing list http://www.grails.org/Mailing+lists

Remember: Grails is open source...

The more you contribute, the more you get out in terms of learning, jobs, contacts...

Watch Currently two screencasts available Scaffolding Directory Structure http://www.grails.org/Grails+Screencasts

Currently two screencasts available

Scaffolding

Directory Structure

http://www.grails.org/Grails+Screencasts

Listen Grails Podcast Weekly Show Grails News Grails Features Interviews Agile Development http://hansamann.podspot.de/rss

Grails Podcast

Weekly Show

Grails News

Grails Features

Interviews

Agile Development

http://hansamann.podspot.de/rss

Read Out soon! By Graeme Rocher, Grails Project Lead ISBN: 1-59059-758-3

Out soon!

By Graeme Rocher, Grails Project Lead

ISBN: 1-59059-758-3

Contribute Be part of the community Contribute a Tag! grails.org/Contribute+a+Tag Blog about Grails! Now! Answer questions on the Grails Users List! and...

Be part of the community

Contribute a Tag! grails.org/Contribute+a+Tag

Blog about Grails! Now!

Answer questions on the Grails Users List!

and...

Groovy & Grails Shop Buy your girlfriend one of those sexy Groovy GStrings http://tinyurl.com/y3zmos New!

Buy your girlfriend one of those sexy Groovy GStrings

http://tinyurl.com/y3zmos

GRAILS RAPID WEB APP DEVELOPMENT MADE EASY Questions? www.grails.org www.svenhaiges.de

RAPID WEB APP DEVELOPMENT MADE EASY

Questions?

www.grails.org www.svenhaiges.de