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:

Mark the Book class with @Resource(uri = "/books").
Remove scaffold controller BookController.
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.

Try adding "/books"(resources:"book") into your urlmapping.groovy instead of @Resource on your domain see if that helps, You can use url-mappings-report to see which services are exposed. — Alidad
Alidad, I'd tried it - and it didn't work (returns 404 for valid requests). I guess, only @Resource generates needed controller in runtime. Moreover, the docs say that RESTy URL mapping in UrlMapping should be used in conjunction with @Resource - it's just another place to define mappings with some additional (like nest resources) features. — aka_sh
I'm currently (using 2.4.0) having the same issue, it's like the mappings are all wrong. :( — genuinefafa
The solution did not work for me with 2.4.4. If I remove static scaffold = true from the controller, the REST URLS all still give 404. Basically, @Resource seems to do nothing. — John Little
As per the post below by evanwong, this is working for me in 2.4.4 without the @Resource in the domain class but this in UrlMappings.groovy: "/books"(resources:"Book"). I have REST and scaffolded screens working together as desired. Also a big thanks to Alidad for the tip on the grails url-mappings-report command. — ed209

evanwong evanwong · Accepted Answer · 2014-01-06T20:33:12

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.

How to use scaffolding and RESTfulness together in Grails 2.3

6 Answers