module to make accidentally deleting records really hard

trashable.rb

module Trashable

  module ClassMethods

    def dependent_associations
      reflect_on_all_associations.select do |association|
        [:destroy, :delete_all].include?(association.options[:dependent])
      end
    end

    def trashable_associations
      dependent_associations.select do |association|
        association.klass.trashable?
      end
    end

    def deleted
      unscoped.where(arel_table[:deleted_at].not_eq(nil))
    end

  end

  def self.included(base)
    base.class_eval <<-EOS, __FILE__, __LINE__ + 1
      alias_method :destroy_for_real, :destroy
      alias_method :delete_for_real, :delete

      def destroy
        run_callbacks(:destroy) do
          update_column(:deleted_at, Time.zone.now)
        end
      end

      def delete
        destroy
      end

      def restore
        update_attribute(:deleted_at, nil)
        restore_associations
      end

      def restore_associations
        self.class.trashable_associations.each do |reflection|
          reflection_scope(reflection).each(&:restore)
        end
      end

      def reflection_scope(reflection)
        scope = reflection.klass.deleted
        scope.merge(association(reflection.name).association_scope)
      end

      default_scope { where(deleted_at: nil) }
    EOS

    base.send :extend, ClassMethods
  end

end

module ActiveRecord

  class Base

    def self.trashable?
      included_modules.include?(Trashable)
    end

  end

end