Module: ActiveModel::Attributes::ClassMethods

Relationships & Source Files
Defined in:	activemodel/lib/active_model/attributes.rb

Instance Method Summary

#attribute(name, cast_type = nil, default: nil, **options)

Defines a model attribute.
#attribute_names

Returns an array of attribute names as strings.
#define_method_attribute=(name, owner:) private

Instance Method Details

#attribute(name, cast_type = nil, default: nil, **options)

Defines a model attribute. In addition to the attribute name, a cast type and default value may be specified, as well as any options supported by the given cast type.

class Person
  include ActiveModel::Attributes

  attribute :name, :string
  attribute :active, :boolean, default: true
end

person = Person.new
person.name = "Volmer"

person.name   # => "Volmer"
person.active # => true

[ GitHub ]

# File 'activemodel/lib/active_model/attributes.rb', line 59


def attribute(name, ...)
  super
  define_attribute_method(name)
end

#attribute_names

Returns an array of attribute names as strings.

class Person
  include ActiveModel::Attributes

  attribute :name, :string
  attribute :age, :integer
end

Person.attribute_names # => ["name", "age"]

[ GitHub ]

# File 'activemodel/lib/active_model/attributes.rb', line 74


def attribute_names
  attribute_types.keys
end

#define_method_attribute=(name, owner:) (private)

[ GitHub ]

# File 'activemodel/lib/active_model/attributes.rb', line 79


def define_method_attribute=(name, owner:)
  ActiveModel::AttributeMethods::AttrNames.define_attribute_accessor_method(
    owner, name, writer: true,
  ) do |temp_method_name, attr_name_expr|
    owner.define_cached_method("#{name}=", as: temp_method_name, namespace: :active_model) do |batch|
      batch <<
        "def #{temp_method_name}(value)" <<
        "  _write_attribute(#{attr_name_expr}, value)" <<
        "end"
    end
  end
end