How to use scaffolding and RESTfulness together in Grails 2.3

Question

Official Grails documentation says that

Version 2.0.x of the scaffolding plugin includes different scaffolding templates that are aligned with the new REST APIs introcued in Grails 2.3 and above. (taken from here http://grails.org/doc/latest/guide/scaffolding.html)

But I can't make (or I don't understand the concept) work RESTfulness together with scaffolding.

Let's start from scratch:

grails create-app myapp
cd myapp/
grails create-domain-class Book
grails create-scaffold-controller myapp.Book

Add a field to the domain class

class Book {
    String text

    static constraints = {
    }
}

and run the app with grails run-app. Surfing on the http://localhost:8080/myapp/ shows that scaffolding works great:

• http://localhost:8080/myapp/book/index page shows books list
• http://localhost:8080/myapp/book/show/1 page show details for the book with id = 1
• http://localhost:8080/myapp/book/create page creates a book
• and so force, good old scaffolding.

Let's see what about REST. Official docs say I should use URLs like http://localhost:8080/myapp/books/... for the REST but any attempt to access the app, like this curl -i -H "Accept: application/json" localhost:8080/myapp/books/1 returns 404 with bunch of HTML.

Ok, let's read docs carefully:

The easiest way to create a RESTful API in Grails is to expose a domain class as a REST resource. This can be done by adding the grails.rest.Resource transformation to any domain class

No problem, now the Book class heading is

import grails.rest.*

@Resource(uri='/books') class Book {

Now surfing on the http://localhost:8080/myapp/ shows that scaffolding is broken:

• http://localhost:8080/myapp/book/index page shows books list
• http://localhost:8080/myapp/book/create page shows xml output <?xml version="1.0" encoding="UTF-8"?><book><text /></book>
• and so force, bad new xml output.

I'd played with @Resource and "/books"(resources:"book") in URLMappings.groovy but hadn't found any working solution which makes possible scaffolding and RESTfulness work back-to-back. Indeed, I managed to make them work separately.

Update

I'd found the way how to achieve the desired goal. The way I found is:

1. Mark the Book class with @Resource(uri = "/books").
2. Remove scaffold controller BookController.
3. Create dedicated controller with scaffolding for the Book: class HumanBookController {static scaffold = Book}

Now scaffold GUI pages with URLs like http://localhost:8080/myapp/humanBook/index work pretty well. Either json requests are handled well with URLs like http://localhost:8080/myapp/books/1. But it's not elegant to have 2 controllers doing same things for common web and json.

Answer 1

You can do this:

import grails.rest.RestfulController

class BookController extends RestfulController {

    static responseFormats = ['html', 'json']

    BookController() {
        super(Book)
    }
}

And then in the UrlMappings.groovy:

 "/books"(resources:"book")
 "/$controller/$action?/$id?(.${format})?"{
    constraints {
        // apply constraints here
    }
  }

No need to add @Resource in the domain. You can now have /books/1.json or /books/1.html to point to the right places. You might still need to do grails generate-view Book to have the view generated. But although you need to generate the views for html, you keep only single controller and path.

Answer 2

I had the same problems as yours. That might be a trivial solution and not for every case, but try updating your Grails version. As for me: Grails 2.3.4 -> Grails 2.3.6 worked. Hope that help anyone.