deep_cloning.rb

module Mongoid
  module DeepCloning
    def deep_clone(attrs = {}, obj = nil)
      returning obj || self.class.new do |o|
        o.write_attributes(@attributes.merge(attrs).except("_id", "versions").except(*o.class.associations.keys))
        yield o if block_given?
        o.save
        @attributes.each_pair do |key, value|
          next unless proxy = self.associations[key]
          case proxy.association
          when Mongoid::Associations::EmbedsMany
            value.each do |v|
              v.deep_clone({}, o.send(key).build)
            end
          when Mongoid::Associations::EmbedsOne
            value.deep_clone({}, o.send(:"build_#{key}"))
          else
            o.send :"#{key}=", value
          end
        end
      end
    end
  end
end