holinnn / orphan_record

Manage ActiveRecord orphan records

OrphanRecord¶ ↑

In some case you want to keep records that belongs to a deleted resource (ex: keep comments of a deleted user), but in this case you will have to manage the possibility that comment.user will return nil, so a lot of if/else in your views or helpers.

OrphanRecord makes it easy to return a default object instead of nil.

Installation¶ ↑

in your Gemfile

gem "orpahn_record", :git => "git://github.com/holinnn/orphan_record.git"

Create an orphan_record.en.yml in the I18n load path, it should looks like :

en:
  orhpan_record:
    adoptive_user:
      user_name: Account deleted

Usage¶ ↑

In your models:

class User < ActiveRecord::Base
  has_many :comments, :dependent => :nullify
end

class Comment < ActiveRecord::Base
  validates :user_id, :presence => true
  belongs_to :user
  can_be_abandoned_by :user
end

In your views :

OrphanRecord only redefine the url_for() helper it just return nil if the argument is an ActiveRecord object and if it returns true when #adopter? is called.

<%= link_to(user.user_name, url_for(user)) %>
# will produce :
# <a href='#'>Account deleted</a>

# if you don't want the <a></a> tag you can use the link_to_unless() helper
<%= link_to_unless(user.adopter? user.user_name, url_for(user) %>
# will produce :
# Account deleted

In the background it will create an AdoptiveUser class wich inherits from the User class and includes the Singleton module, it will redefine every methods present in the translation file, key/value will become method_name/returned_value

If you want to user a custom object instead of the Adoptive* classes you can use the :adopted_by option :

class Comment < ActiveRecord::Base
  validates :user_id, :presence => true
  belongs_to :user
  can_be_abandoned_by :user, :adopted_by => AnotherSingleton.instance
end

Important¶ ↑

You should not use OrphanRecord on relations that sometimes returns nil because it will always return the adoptive instance instead.