Koine::Attributes

Strong attributes for ruby ruby objects.

Yes, there are so many alternative solutions already! Why then? Cause some times people need distractions at the airports.

Installation

Add this line to your application's Gemfile:

gem 'koine-attributes'

And then execute:

$ bundle

Or install it yourself as:

$ gem install koine-attributes

Usage

class Person
  include Koine::Attributes

  attributes do
    attribute :name, :string
    attribute :birthday, :date

    # or
    attribute :birthday, Koine::Attributes::Adapter::Date.new
  end
end

peson = Person.new
person.name = 'John Doe'
person.birtday = '2001-02-31' # Date Object can also be given

person.name # => 'John Doe'
person.birthday # => #<Date 2001-02-31>

person.attributes.to_h   # => {
                         #   name: 'John Doe',
                         #   birthday: #<Date 2001-02-31>
                         # }

Options:

attributes do
  attribute :name, Koine::Attributes::Adapters::Date.new.with_default_value('guest')

  # or
  attribute :name, :string, ->(adapter) { adapter.with_default_value('guest') }
end

Adapter's methods

• with_default_value(default, &block)
• with_nil_value(value = nil, &block)

Also, a constructor can be created by the API

class Person
  include Koine::Attributes

  attributes initializer: true do
    attribute :name, :string
    attribute :birthday, :date
  end
end

person = Person.new(name: 'John Doe', birthday: '2001-01-31')

# foo: attribute will raise error
person = Person.new(name: 'John Doe', birthday: '2001-01-31', foo: :bar)

You can disable strict mode

class Person
  include Koine::Attributes

  attributes initializer: { strict: false } do
    attribute :name, :string
    attribute :birthday, :date
  end
end

# foo will be ignored
person = Person.new(name: 'John Doe', birthday: '2001-01-31', foo: :bar)

class Product
  include Koine::Attributes

  attributes do
    attribute :price, MyCustom::Money.new
    attribute :available, :boolean, ->(attribues){ attributes.with_default_value(true) }
    attribute :available, Koine::Attributes::Drivers::Boolean.new.with_default_value(true)
    attribute :tags, array_of(:string)
    attribute :config, hash_of(:symbol, :string)

    # if you want to costumize the above
    attribute :config, hash_of(:symbol, :string) do |adapter|
      adapter.for_keys.with_nil_value
      adapter.for_values.with_nil_value
    end
  end
end

product = Product.new

product.available #  => true
product.available = 0
product.available #  => false

product.price = { currency: 'USD', value: 100 }

product.tags = ['new']

product.config = { short_url: 'http://config.url' }

# or
product.price = "100 USD"

class MyCustom::Money
  attr_accessor :attribute_name

  def default_value
    return 'some default_value'
  end

  def coerce(*values)
    Money.new(values.first, values.last)
  end
end

product = Product.new

product.available #  => true
product.available = 0
product.available #  => false

product.price = { currency: 'USD', value: 100 }

# or
product.price = "100 USD"

Value objects

class Location
  include Koine::Attributes

  attributes initializer: { freeze: true } do
    attribute :lat, :float
    attribute :lon, :float
  end
end

location = Location.new(lat: 1, lon: 2)
new_location = location.with_lon(3)

Standard types

- :any
- :array_of
- :boolean
- :date
- :float
- :hash_of
- :integer
- :string
  - empty_to_nil
  - trim_empty_spaces
- :symbol
- :time

Alternative solutions

• attributed_object
• virtus
• dry-struct

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/mjacobus/koine-attributes. 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.