magic_join model creation and rails 2 October 7th, 2008

If you are using Josh Susser’s clean magic_join solution to automagically create a join record an entry on a join table, you might well notice it doesn’t work with rails 2:

protected method `with_scope' called for #<Class:0x2109ddc>

Indeed the with_scope method is now protected.

In lieu of:

class Contributor < ActiveRecord::Base
  has_many :contributions, :dependent => :destroy
  has_many :books, :through => :contributions do
    def push_with_attributes(book, join_attrs)
      Contribution.with_scope(:create => join_attrs) { self << book }
    end
  end
end

Do:

class Contributor < ActiveRecord::Base
  has_many :contributions, :dependent => :destroy
  has_many :books, :through => :contributions do
    def push_with_attributes(book, join_attrs)
      Contribution.send(:with_scope, :create => join_attrs) { self << book }
    end
  end
end

/ Tags: Ruby on Rails, Design, Code Trackback