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module ActiveSupport::Configurable::ClassMethods

Public instance methods

config()

Source code GitHub 
# File activesupport/lib/active_support/configurable.rb, line 30
def config
  @_config ||= if respond_to?(:superclass) && superclass.respond_to?(:config)
    superclass.config.inheritable_copy
  else
    # create a new "anonymous" class that will host the compiled reader methods
    Class.new(Configuration).new
  end
end

configure()

Source code GitHub 
# File activesupport/lib/active_support/configurable.rb, line 39
def configure
  yield config
end

Private instance methods

config_accessor(*names, instance_reader: true, instance_writer: true, instance_accessor: true, default: nil)

Allows you to add shortcut so that you don’t have to refer to attribute through config. Also look at the example for config to contrast.

Defines both class and instance config accessors.

class User
  include ActiveSupport::Configurable
  config_accessor :allowed_access
end

User.allowed_access # => nil
User.allowed_access = false
User.allowed_access # => false

user = User.new
user.allowed_access # => false
user.allowed_access = true
user.allowed_access # => true

User.allowed_access # => false

The attribute name must be a valid method name in Ruby.

class User
  include ActiveSupport::Configurable
  config_accessor :"1_Badname"
end
# => NameError: invalid config attribute name

To omit the instance writer method, pass instance_writer: false. To omit the instance reader method, pass instance_reader: false.

class User
  include ActiveSupport::Configurable
  config_accessor :allowed_access, instance_reader: false, instance_writer: false
end

User.allowed_access = false
User.allowed_access # => false

User.new.allowed_access = true # => NoMethodError
User.new.allowed_access        # => NoMethodError

Or pass instance_accessor: false, to omit both instance methods.

class User
  include ActiveSupport::Configurable
  config_accessor :allowed_access, instance_accessor: false
end

User.allowed_access = false
User.allowed_access # => false

User.new.allowed_access = true # => NoMethodError
User.new.allowed_access        # => NoMethodError

Also you can pass default or a block to set up the attribute with a default value.

class User
  include ActiveSupport::Configurable
  config_accessor :allowed_access, default: false
  config_accessor :hair_colors do
    [:brown, :black, :blonde, :red]
  end
end

User.allowed_access # => false
User.hair_colors # => [:brown, :black, :blonde, :red]
Source code GitHub 
# File activesupport/lib/active_support/configurable.rb, line 111
def config_accessor(*names, instance_reader: true, instance_writer: true, instance_accessor: true, default: nil) # :doc:
  names.each do |name|
    raise NameError.new("invalid config attribute name") unless /\A[_A-Za-z]\w*\z/.match?(name)

    reader, reader_line = "def #{name}; config.#{name}; end", __LINE__
    writer, writer_line = "def #{name}=(value); config.#{name} = value; end", __LINE__

    singleton_class.class_eval reader, __FILE__, reader_line
    singleton_class.class_eval writer, __FILE__, writer_line

    if instance_accessor
      class_eval reader, __FILE__, reader_line if instance_reader
      class_eval writer, __FILE__, writer_line if instance_writer
    end

    send("#{name}=", block_given? ? yield : default)
  end
end

Definition files