Question

I have several classes associated as following:

class User < ActiveRecord::Base
   has_many :posts, :dependent => :destroy

class Group < ActiveRecord::Base
   has_many :posts, :dependent => :destroy

class Post < ActiveRecord::Base
   belongs_to :user
   belongs_to :groups

Now, I want to delete Users, Groups, and Posts by setting their ‘active’ field to false and leave them in database. Initially, I was hoping that destroying a user or a group will cause destruction of their posts (delete action would set the flag to false), However as far as I understood, in such cases Ruby just breaks the corresponding association without destroying the posts. I am wondering whether it can be done nicely, or I just have to write a separate function and call it instead of regular delete?

Answer 1

Rather than deleting records from the database, we can retire them with just a little bit of code and configuration.

1. Create a new directory under your app/ directory called “concerns”.

2. Create a new file in this directory called “retireable.rb”.

3. Copy and paste the following code into it:

   module Retireable
     extend ActiveSupport::Concern
   
     included do
       default_scope   :conditions => { :retired => false }
       scope :retired, :conditions => { :retired => true }
     end
   
     def destroy
       retire
     end
     def destroy!
       raise StandardError, "Cannot destroy!"
     end
   
     def retire
       update_attribute :retired,    true
       update_attribute :retired_at, Time.now
     end
     def retired?
       retired
     end
   end
   

4) Each of your models which need this functionality must:

4a) Have the ‘retired‘ boolean field and ‘retired_at‘ datetime field in the database schema.

4b) include Retireable must be within the class definition for that model; i.e.

    class User < ActiveRecord::Base
      include Retireable
      ...

5) In your ‘config/application.rb‘, add the following line:

    config.autoload_paths << "#{Rails.root}/app/concerns"

Now calls to instance.destroy (eg. @user.destroy, @group.destroy) will be handled by retireable, therefore not deleted from the database and not breaking the association.

Hope that helps!