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Active Model Attribute Methods

ActiveModel::AttributeMethods provides a way to add prefixes and suffixes to your methods as well as handling the creation of ActiveRecord::Base-like class methods such as table_name.

The requirements to implement ActiveModel::AttributeMethods are to:

  • include ActiveModel::AttributeMethods in your class.

  • Call each of its method you want to add, such as attribute_method_suffix or attribute_method_prefix.

  • Call define_attribute_methods after the other methods are called.

  • Define the various generic _attribute methods that you have declared.

  • Define an attributes method, see below.

A minimal implementation could be:

class Person
  include ActiveModel::AttributeMethods

  attribute_method_affix  prefix: 'reset_', suffix: '_to_default!'
  attribute_method_suffix '_contrived?'
  attribute_method_prefix 'clear_'
  define_attribute_methods :name

  attr_accessor :name

  def attributes
    {'name' => @name}
  end

  private

  def attribute_contrived?(attr)
    true
  end

  def clear_attribute(attr)
    send("#{attr}=", nil)
  end

  def reset_attribute_to_default!(attr)
    send("#{attr}=", 'Default Name')
  end
end

Note that whenever you include ActiveModel::AttributeMethods in your class, it requires you to implement an attributes method which returns a hash with each attribute name in your model as hash key and the attribute value as hash value.

Hash keys must be strings.

Constants

CALL_COMPILABLE_REGEXP = /\A[a-zA-Z_]\w*[!?]?\z/

NAME_COMPILABLE_REGEXP = /\A[a-zA-Z_]\w*[!?=]?\z/

Attributes

Show files where this module is defined (1 file)
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