Question

In Rails, when I need:

/comments

and

/posts/1/comments

How do I best organize CommentsController? E.g. let the routes share the index actions, or work with 2 controllers?

Answer 1

You can work with only one controller.

I would go with a before_filter to check if the post_id param is present:

class CommentsController < ApplicationController
  before_filter :find_post, only: [:index]

  def index
    if @post.present?
      ## Some stuff
    else
      ## Other stuff
    end
  end

  private

    def find_post
      @post = Post.find(params[:post_id]) unless params[:post_id].nil?
    end
end

And have in your routes (with the constraints of your choice) :

resources :posts do
  resources :comments
end
resources :comments