Ruby / Rails-嵌套资源的AJAX分页-如何确定父资源？

Posts

Users

Comments

index

user_id

post_id

params[:user_id]

params[:post_id]

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

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