Can I access the id of the parent object inside a named_scope when fetching associated objects with the 'others' method?

associations, named-scope, ruby-on-rails

Solution

Sounds like what you're actually after is an association extension: http://guides.rubyonrails.org/association_basics.html#association-extensions

In particular, `proxy_owner`, which will be the @article in question

eg:

class Article < ActiveRecord::Base
  has_many :posts do
    def sample_extension
      puts "Proxy Owner #{proxy_owner}"
    end
  end
end

@article.posts.sample_extension

Problem

Let's say you have two models: `articles` and `comments`. ``` class Article < ActiveRecord::Base has_many :comments end ``` You know you can fetch associated comments to an article like this: ``` article = Article.first article.comments # => SELECT * FROM "comments" WHERE ("comments".article_id = 123) ``` Is there a way to explicitly access the `article_id` (123) within a named_scope? I need this for a complex named_scope that joins another table. Basically the named_scope will depend on to be called from the associated parent object to make sense (`article.comments.my_named_scope` and not `Comments.my_named_scope`). I don't want to pass the id as a parameter for the named_scope. So, instead of passing the `article_id` to the named scope with `... lambda { |article| ...}` and access the id with `"... #{article.id} ..."`, I want to somehow access this `article_id` that the `others` method uses, which I get from the `has_many` association.

Original source