Question

I am using polymorphic association.

I have 2 models articles and events which have has_many association with comments model using polymorphic association

Inside comments controller :

def index

  @commentable = find_commentable

  @comments = @commentable.comments

end

def find_commentable

  params.each do |name, value|

    if name =~ /(.+)_id$/

      return $1.classify.constantize.find(value)

    end

  end

  nil

end

Inside article and event model i wrote:

has_many :comments, :as => :commentable,:dependent => :destroy

Inside comments model:

belongs_to :commentable, :polymorphic => true

Inside routes :

resources :articles do
resources :comments

end

my problem is

1) When I enter http://localhost:3003/articles/8/comments it gives the following error:

undefined method `comments' for nil:NilClass

2) Also I dont want to use nested routes, I want to use simple routes. How can I achieve the same thing as this code is doing?

Answer 1

1. You’re receiving this error because @commentable is nil. Do you have an article with an ID of 8? Is find_commentable function is returning the commentable correctly? My guess is the answer to one of those two questions is “no.”

2. If you don’t want nested routes, you can just do resources :comments but you should be sure you pass in commentable_type and commentable_id as params to the controller; otherwise you won’t be able to look up the commentable class to get its comments.