Simple and lightweight Virtus analog.
Simple and lightweight Virtus analog without any dependencies. Documentation.
There are already a lot of good and flexible gems which solve a similar problem, allowing attributes
to be defined with their types, for example: virtus, fast_attributes
or attrio. However, the disadvantage of these gems is performance or API. So, the goal
of ShallowAttributes is to provide a simple solution which is similar to the Virtus API, simple, fast,
understandable and extendable.
Add this line to your application's Gemfile:
gem 'shallow_attributes'And then execute:
$ bundleOr install it yourself as:
$ gem install shallow_attributesYou can create classes extended with Virtus and define attributes:
class User
include ShallowAttributes
attribute :name, String
attribute :age, Integer
attribute :birthday, DateTime
end
class SuperUser "Anton"
user.age = '31' # => 31
user.age = nil # => nil
user.age.class # => Fixnum
user.birthday = 'November 18th, 1983' # => #
user.attributes # => { name: "Anton", age: 31, birthday: nil }
# mass-assignment
user.attributes = { name: 'Jane', age: 21 }
user.name # => "Jane"
user.age # => 21
super_user = SuperUser.new
user.age = nil # => 0ShallowAttributes doesn't make any assumptions about base classes. There is no need to define default attributes, or even mix ShallowAttributes into the base class:
require 'active_model'
class Form
extend ActiveModel::Naming
extend ActiveModel::Translation
include ActiveModel::Conversion
include ShallowAttributes
def persisted?
false
end
end
class SearchForm "Anton"…You can provide present: true option for any attribute that will prevent class from initialization
if this attribute was not provided:
class CreditCard
include ShallowAttributes
attribute :number, Integer, present: true
attribute :owner, String, present: true
end
card = CreditCard.new(number: 1239342)
# => ShallowAttributes::MissingAttributeError: Mandatory attribute "owner" was not providedclass City
include ShallowAttributes
attribute :name, String
attribute :size, Integer, default: 9000
end
class Address
include ShallowAttributes
attribute :street, String
attribute :zipcode, String, default: '111111'
attribute :city, City
end
class User
include ShallowAttributes
attribute :name, String
attribute :address, Address
end
user = User.new(address: {
street: 'Street 1/2',
zipcode: '12345',
city: {
name: 'NYC'
}
})
user.address.street # => "Street 1/2"
user.address.city.name # => "NYC"……ShallowAttributes performs coercions only when a value is being assigned. If you mutate the value later on using its own interfaces then coercion won't be triggered.
Here's an example:
class Book
include ShallowAttributes
attribute :title, String
end
class Library
include ShallowAttributes
attribute :books, Array, of: Book
end
library = Library.new
# This will coerce Hash to a Book instance
library.books = [ { :title => 'Introduction' } ]
# This WILL NOT COERCE the value because you mutate the books array with Array# 'Another Introduction' }class User
include ShallowAttributes
attribute :name, String
alias_method :_name=, :name=
def name=(new_name)
custom_name = nil
if new_name == "Godzilla"
custom_name = "Can't tell"
end
self._name = custom_name || new_name
end
end
user = User.new(name: "Frank")
user.name # => 'Frank'
user = User.new(name: "Godzilla")
user.name # => 'Can't tell'ShallowAttributes is fully compatible with ActiveModel.
require 'active_model'
class SearchForm
extend ActiveModel::Naming
extend ActiveModel::Translation
include ActiveModel::Conversion
include ShallowAttributes
attribute :name, String
attribute :service_ids, Array, of: Integer
attribute :archived, 'Boolean', default: false
def persisted?
false
end
def results
# ...
end
end
class SearchesController
require 'active_model'
class Children
include ShallowAttributes
include ActiveModel::Validations
attribute :scream, String
validates :scream, presence: true
end
user = User.new(scream: '')
user.valid? # => false
user.scream = 'hello world!'
user.valid? # => trueYou can use dry-types objects as a type for your attribute:
module Types
include Dry::Types.module
end
class User
include ShallowAttributes
attribute :name, Types::Coercible::String
attribute :age, Types::Coercible::Int
attribute :birthday, DateTime
end
user = User.new(name: nil, age: 0)
user.name # => ''
user.age # => 0ShallowAttributes is known to work correctly with the following rubies:
Also we run rbx-2 buld too.
Bug reports and pull requests are welcome on GitHub at https://github.com/davydovanton/shallow_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.
The gem is available as open source under the terms of the MIT License.
No open issues yet, or sync has not completed.