16 Scaffolding - Reference Documentation
Authors: Graeme Rocher, Peter Ledbrook, Marc Palmer, Jeff Brown, Luke Daley, Burt Beckwith
Version: 2.0.4
16 Scaffolding
Scaffolding lets you auto-generate a whole application for a given domain class including:- The necessary views
- Controller actions for create/read/update/delete (CRUD) operations
Dynamic Scaffolding
The simplest way to get started with scaffolding is to enable it with thescaffold property. Set the scaffold property in the controller to true for the Book domain class:class BookController {
static scaffold = true
}BookController follows the same naming convention as the Book domain class. To scaffold a specific domain class we could reference the class directly in the scaffold property:class SomeController {
static scaffold = Author
}- list
- show
- edit
- delete
- create
- save
- update
http://localhost:8080/app/book in a browser.If you prefer to keep your domain model in Java and mapped with Hibernate you can still use scaffolding, simply import the domain class and set its name as the scaffold argument.You can add new actions to a scaffolded controller, for example:class BookController { static scaffold = Book def changeAuthor() {
def b = Book.get(params.id)
b.author = Author.get(params["author.id"])
b.save() // redirect to a scaffolded action
redirect(action:show)
}
}class BookController { static scaffold = Book // overrides scaffolded action to return both authors and books
def list() {
[bookInstanceList: Book.list(),
bookInstanceTotal: Book.count(),
authorInstanceList: Author.list()]
} def show() {
def book = Book.get(params.id)
log.error(book)
[bookInstance : book]
}
}By default, the size of text areas in scaffolded views is defined in the CSS, so adding 'rows' and 'cols' attributes will have no effect.Also, the standard scaffold views expect model variables of the form<propertyName>InstanceListfor collections and<propertyName>Instancefor single instances. It's tempting to use properties like 'books' and 'book', but those won't work.
Customizing the Generated Views
The views adapt to Validation constraints. For example you can change the order that fields appear in the views simply by re-ordering the constraints in the builder:def constraints = {
title()
releaseDate()
}inList constraint:def constraints = {
title()
category(inList: ["Fiction", "Non-fiction", "Biography"])
releaseDate()
}range constraint on a number:def constraints = {
age(range:18..65)
}def constraints = {
name(size:0..30)
}Static Scaffolding
Grails also supports "static" scaffolding.The above scaffolding features are useful but in real world situations it's likely that you will want to customize the logic and views. Grails lets you generate a controller and the views used to create the above interface from the command line. To generate a controller type:grails generate-controller Book
grails generate-views Book
grails generate-all Book
grails generate-all com.bookstore.Book