This post describes my experience organizing Rails controllers using only REST actions, an approach popularized by the mighty DHH and his cronies.

This article was published on 06/05/2019.

Premise

As demoed by DHH here and explained in depth here, organzing your Rails controllers with REST only actions, and then nesting sub controllers, you can make your application more consistent and approachable.

Example

Let’s say I have posts resource with your usual REST actions. Now I want to allow users to “correct” a post. One alternative is adding a correction route:

class PostsController < ApplicationController
  def correct
    # ...
  end
end

And in routes.rb, you would add the extra route. Something like:

resources :posts do
  get 'correct', controller: 'posts/correct'
end

The pattern DHH and friends describe encourages you to make a new controller for any non standard REST method. So we make a new file in app/controllers/posts/corrections_controller.rb:

module Posts
  class CorrectionsController < ApplicationController
    def index
    end
  end
end

Now, since it is a “nested” resource, we naturally want access to the parent resource (eg, the post). The simple way would be to just do @post = Post.find(params[:post_id]). However, there is a convention that comes along with this nested controllers approach to create a concern to set the post for us. In app/controllers/concerns/post_scoped.rb add:

module PostScoped
  extend ActiveSupport::Concern

  included do
    before_action :set_post
  end

  private

  def set_post
    @post = Post.find(params[:post_id])
  end
end

And in posts/corrections_controller.rb:

module Posts
  class CorrectionsController < ApplicationController
    include PostScoped

    def index
    end
  end
end

Now all the methods in the CorrectionsController have access to @post.

Lastly, routes.rb looks like this:

Rails.application.routes.draw do
  resources :posts do
    scope module: 'posts' do
      resources :corrections
    end
  end
end

Conclusion

I am excited to try this pattern out. It seems clean and scalable.

20190505 Organizing Rails Controllers with REST actions

Premise

Example

Conclusion