Rails Trick & Tips : Rails delegate delegate, rails tips & tricks

April 15, 2013

Rails delegate

So checkout this page : http://devblog.avdi.org/2011/07/05/demeter-its-not-just-a-good-idea-its-the-law/

Here, adding some delegate to the user class :

    class Project < ActiveRecord::Base

      belongs_to :user
      belongs_to :owner, :class_name => 'User', :foreign_key => 'owner_id'

      delegate :username, :to => :owner, :prefix => true, :allow_nil => true
      delegate :username, :to => :user, :prefix => "author", :allow_nil => true

    end

And now in the show.html.haml , we can use (with possibly null value) :

  %p= @project.owner_username
  %p= @project.author_usermane