Dual

Dual is a gem that helps you clone object in Ruby. It is not tight to any particular web framework and should work with ease with any PORO.

Installation

Add this line to your application's Gemfile:

gem 'dual'

And then execute:

$ bundle

Or install it yourself as:

$ gem install dual

Usage

class Order
  attr_accessor :name, :type, :address

  include Dual

  dual do
    # Exclude a certain attribute from the cloned object
    exclude :type

    # Include a new attribute in the cloned object
    include :email, value: 'test@test.com'

    # Add a guard clause for both include and exclude statements
    include :date, value: Date.today, if: :delivery_incoming?
    
    # Perform any kind of finalizing actions on the created object
    # The callable object(any object that responds to `call`) receives
    # the dual object
    finalize -> (copied_order) { EventNotifier.call(copied_order) }
  end

  def delivery_incoming?
    delivery.today?
  end
end

order = Order.last
dual_order = order.dual_copy

If you are using Sequel you can also use dual to manipulate associations, supported ones are: one_to_one, one_to_many, many_to_one

  class User < Sequel::Model
    one_to_many :orders
    include Dual

    dual do
      add_association :orders
    end
  end

This will create association objects that do not point to the original associations. A simple example would be:

user = User.create
order = Order.create(address: 'some street')
user.add_order(order)

# Duplicate the user, along with the orders association
dupped_user = user.dual_copy
dupped_order = dupped_user.orders.first
# Change the order address
dupped_order.address = 'new street'

order.address == dupped_order.address
=> false

You can also remove certain associations:

  dual do
    remove_association :orders
  end

user = User.create
order = Order.create(address: 'some street')
user.add_order(order)

# Duplicate the user, excluding the orders association
dupped_user = user.dual_copy
dupped_user.orders
=> []

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/wizardone/dual. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Dual project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.