Nested Restful Scaffold

What is NestedRestfulScaffold

NestedRestfulScaffold is a gem built by BadrIT (www.badrit.com) for easily generating controller, views, model and routes of nested resources.

Why NestedRestfulScaffold

The story begins when I was working on a project at BadrIT (www.badrit.com) using Ruby on Rails. We needed to generate simple scaffold controller, views, models and routes for many nested resources. There were a huge number of resources and nested resources and sometimes the length of nesting was more than two. The problem I faced that I need to create them with rails scaffold generator then I need to update all generated controllers, views and models.

I need to update routes.rb to handle nested paths like /libraries/1/books
In the controller I need to be sure I am accessing the correct resource in the nested chain.
All ActiveRecord calls in the controller must be scoped.
Views will have a lot of work to support nested forms and links.
Create the Active Record associations in my models.

This was a big overhead to do all of that with all resources, so I decided to create a generator to do all that work for me.

How to install

To install QuickMagick just type at your command line:

gem install nested_restful_scaffold

… and it’s done. You don’t have to install any libraries or compile code from source.

How to use

Usage: ./script/generate nested_restful_scaffold ModelName [field:type, field:type, resource1,resource2,…:resources]

Lets start with an example of library resource and each library has books and each book has pages.

Library Resource

Use the following command to create library resource ./script/generate nested_restful_scaffold library name:string address:text It will use rails scaffold generator because there isn’t any nested resources included in the previous command.

Book & Page Resources

Use the following command to create library resource ./script/generate nested_restful_scaffold book name:string description:text library:references library:resources ./script/generate nested_restful_scaffold page contents:text book:references library,book:resources

As it is shown, we used library:resources for books resources and library,book:resources for pages resources. They will do the same job of rails scaffold generator in addition to the following: N.B. i will explain the result of the pages generation and it will be the same for book resources.

It updated the routes.rb file with libraries, books and pages routing to be as the following: map.resources :libraries do |library|
```
library.resources :books do |book|
book.resources :pages
```
end end

If you run rake routes, we can see the pages routes as the following:

library_book_pages GET    /libraries/:library_id/books/:book_id/pages                  {:controller=>"pages", :action=>"index"}
   formatted_library_book_pages GET    /libraries/:library_id/books/:book_id/pages.:format          {:controller=>"pages", :action=>"index"}
                                POST   /libraries/:library_id/books/:book_id/pages                  {:controller=>"pages", :action=>"create"}
                                POST   /libraries/:library_id/books/:book_id/pages.:format          {:controller=>"pages", :action=>"create"}
          new_library_book_page GET    /libraries/:library_id/books/:book_id/pages/new              {:controller=>"pages", :action=>"new"}
formatted_new_library_book_page GET    /libraries/:library_id/books/:book_id/pages/new.:format      {:controller=>"pages", :action=>"new"}
         edit_library_book_page GET    /libraries/:library_id/books/:book_id/pages/:id/edit         {:controller=>"pages", :action=>"edit"}

formatted_edit_library_book_page GET /libraries/:library_id/books/:book_id/pages/:id/edit.:format :action=>“edit”

          library_book_page GET    /libraries/:library_id/books/:book_id/pages/:id              {:controller=>"pages", :action=>"show"}
formatted_library_book_page GET    /libraries/:library_id/books/:book_id/pages/:id.:format      {:controller=>"pages", :action=>"show"}
                            PUT    /libraries/:library_id/books/:book_id/pages/:id              {:controller=>"pages", :action=>"update"}
                            PUT    /libraries/:library_id/books/:book_id/pages/:id.:format      {:controller=>"pages", :action=>"update"}
                            DELETE /libraries/:library_id/books/:book_id/pages/:id              {:controller=>"pages", :action=>"destroy"}
                            DELETE /libraries/:library_id/books/:book_id/pages/:id.:format      {:controller=>"pages", :action=>"destroy"}

Pages controller has new method book to get its parent resource protected def book
```
@book ||= Library.find(params[:library_id]).books.find(params[:book_id])
```
end
All ActiveRecord calls for page resource will be through its book to be well scoped. @pages = book.pages

The most bunch of work in in views files

<td><%= link_to 'Show', library_book_page_path(page.book.library,page.book,page) %></td>
<td><%= link_to 'Edit', edit_library_book_page_path(page.book.library,page.book,page) %></td>
<td><%= link_to 'Destroy', library_book_page_path(page.book.library,page.book,page), :confirm => 'Are you sure?', :method => :delete %></td>

and two links at the end of the html page to new page and to return to books page

<%= link_to 'New page', new_library_book_page_path %>
<%= link_to 'Return to books', library_books_path %>

In book.rb model file, there will be new line added to define association has_many :pages and in page.rb model file, also there will be new line added belongs_to :book

Conclusion

NestedRestfulScaffold is very easy to install, very easy to use and allows you to generate all that work for you. It will be very suitable for you if you are building a RESTful API or application with nested resources. It will reduce the overhead of updating controller, views, models and routes.

For more information on nested resources check: adam.blog.heroku.com/past/2007/12/20/nested_resources_in_rails_2 www.akitaonrails.com/2007/12/12/rolling-with-rails-2-0-the-first-full-tutorial