Rails - May 2006 - Overwriting setters for associated objects

Hi all,

I''m trying to overwrite a setter method, but am running into some 
difficulties. This is normally really easy when overwriting a setter for 
a table column, but in this case it is the setter for an associated 
object.

Here''s a hypothetical example:


  class User < ActiveRecord::Base
    has_many :posts
  end

  class Post < ActiveRecord::Base
    belongs_to :user

    def user=(new_user)
      self[:user] = new_user
      self[:user_id] = new_user.id

      # do other stuff (not relevant here)
    end
  end


Unfortunately `self[]` only works when modifying table column values, so 
`self[:user] = new_user` doesn''t do anything. The only solution I have 
at the moment is this...


  def user=(new_user)
    self[:user_id] = new_user.id
    self.reload

    # do other stuff
  end


... which isn''t ideal, since `self.reload` will have to hit the 
database.

Is there any easier way to update an associated object from within a 
model?

Thanks in advance,
Anthony.

-- 
Posted via http://www.ruby-forum.com/.

an idea would be to use alias_method

so in your example

  alias_method ''ar_user='', ''user=''
  def user=(new_user)
    # some custom logic here
    ar_user = new_user
  end

hope this helps.

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Posted via http://www.ruby-forum.com/.