REST is a buzzword in the modern web development world. “Be RESTful”, “Keep up to the RESTful rules” is usually thought as one of the best practices we need to keep in mind.

We are all blessed as a Ruby & Rails developer, since Rails has already had REST baked within its heart, for example,

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# config/routes.rb

resources :photos

will generate 7 routes for us:

Awesome! we can also adjust which actions we want via editing the resources defined in the config/routes.rb:

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# config/routes.rb

resources :photos, :only => [:index, :show]

Now we have only two actions left for the PhotosController, and they are GET /photos and GET /photos/:id, any other requests except these two will result in an error. So far so, good, until one day, the boss came over and told you to add comment to the photos, we want the user to comment the photos, who doesn’t? OK, roll up the sleeves, and change the config/routes.rb to:

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# config/routes.rb

resources :photos, :only => [:new, :create] do
  member do
    post :comment
  end
end

that will give us a new routes POST /photos/:id/comment, and we add the corresponding action to the PhotosController:

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class PhotosController < ApplicationController
  before_filter :find_the_current_user
  before_filter :find_the_current_photo

  def comment
    comment = current_user.comments.new(params[:comment])
    comment.commentable = current_photo

    if comment.save
      redirect_to current_photo, notice: "new comment added!"
    else
      redirect_to current_photo, notice: "oops, xxit happens!"
    end
  end
end

After done with spec, and all green, we are happy to close the ticket and move on to next issue. Wait a minute, someone is whispering “Be RESTful”, sounds like we are doing something wrong, we are not RESTful enough! We all know the above code will work and do the job, the QA will happily accept your work and everything seems to be working flawlessly. Just one thing, we are not keeping up to RESTful rules, we are adding new action besides the 7 actions given to us, that’s not good enough. Let’s fix it:

• remove the action comment defined in the PhotosController
• edit the config/routes.rb and change it to:

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  resources :photos, :only => [:new, :create]
  resources :comments, :only => [:create]

• add a new CommentsController and it should have action create within it
• move the photos_controller#comment spec to comments_controller#create

that’s all, the refactor is all about moving things around, nothing more. But it’s important for two reasons:

• we keep the PhotosController only concerned photos, that’s SRP
• we make it clear that the comments related action should go to its own controller, we are telling the developer reading this code later after us that we have two resources defined in our app, one is photo, another is comment.

Yes, RESTful is all about resource.