Ruby / Rails - AJAX 嵌套资源的分页 - 如何确定父资源？

Question

My model has Posts , Users , and Comments . Users can leave Comments on/about Posts. Every Comment belongs to a User and a Post. Therefore, the Comment model has a user_id field and a post_id field.

When viewing a Post , I want to paginate through that Post's comments.
When viewing a User , I want to paginate through that User's comments.
I want to paginate using AJAX (via the Kaminari gem).

I have my nested routes set up for both.

On the Post, the URL being hit is http://localhost:3000/posts/{:id}/comments?page={page_number}
On the User, the URL being hit is http://localhost:3000/users/{:id}/comments?page={page_number}

Both URLs are hitting the index action of the Comments controller.

My question is this: inside the index action, how do I determine if the {:id} provided is a user_id or a post_id so I can retrieve the desired comments.

Answer 1

Check for params[:user_id] and params[:post_id] in your Comments controller:

if params[:user_id]
  #call came from /users/ url
elsif params[:post_id]
  #call came from /posts/ url
else
  #call came from some other url
end

Answer 2

I like the Ryan Bates' way

class CommentsController
  before_action :load_commentable

  def index
    @comments = @commentable.comments.page(params[:page])
  end

  private

    def load_commentable
      klass = [Post, User].detect { |c| params["#{c.name.underscore}_id"] }
      @commentable = klass.find(params["#{klass.name.underscore}_id"])
    end
end