This is a soft delete mixin for ActiveRecord 3.x. All you need to do is add a `deleted_at` column to the ActiveRecord models you mix this into.

soft_delete.rb

module SoftDelete
  extend ActiveSupport::Concern
  
  included do
    define_model_callbacks :soft_delete
    define_model_callbacks :recover
    default_scope where(:deleted_at => nil)
    class_eval do
      class << self
        alias_method :with_deleted, :unscoped
      end
    end
  end
  
  module ClassMethods
    def only_deleted
      unscoped.where("#{table_name}.deleted_at IS NOT NULL")
    end
  end
  
  def soft_delete
    run_callbacks :soft_delete do
      update_attribute(:deleted_at, Time.current)
    end
  end
  
  def recover
    run_callbacks :recover do
      update_attribute(:deleted_at, nil)
    end
  end
end

Brian's response

It's adding all the standard callback functionality so that the run_callbacks calls inside of soft_delete and recover function properly. It allows you to define callbacks for those lifecycle events the same way you do for destroy and save and create and validate.

http://api.rubyonrails.org/classes/ActiveModel/Callbacks.html
https://github.com/goncalossilva/acts_as_paranoid