require 'active_support/concern' require 'active_support/ordered_options' require 'active_support/core_ext/array/extract_options' module ActiveSupport # Configurable provides a config method to store and retrieve # configuration options as an OrderedHash. module Configurable extend ActiveSupport::Concern class Configuration < ActiveSupport::InheritableOptions def compile_methods! self.class.compile_methods!(keys) end # Compiles reader methods so we don't have to go through method_missing. def self.compile_methods!(keys) keys.reject { |m| method_defined?(m) }.each do |key| class_eval <<-RUBY, __FILE__, __LINE__ + 1 def #{key}; _get(#{key.inspect}); end RUBY end end end module ClassMethods 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 def configure yield config end # 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 opt out of the instance writer method, pass instance_writer: false. # To opt out of 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 opt out 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 a block to set up the attribute with a default value. # # class User # include ActiveSupport::Configurable # config_accessor :hair_colors do # [:brown, :black, :blonde, :red] # end # end # # User.hair_colors # => [:brown, :black, :blonde, :red] def config_accessor(*names) options = names.extract_options! names.each do |name| raise NameError.new('invalid config attribute name') unless name =~ /\A[_A-Za-z]\w*\z/ 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 unless options[:instance_accessor] == false class_eval reader, __FILE__, reader_line unless options[:instance_reader] == false class_eval writer, __FILE__, writer_line unless options[:instance_writer] == false end send("#{name}=", yield) if block_given? end end private :config_accessor end # Reads and writes attributes from a configuration OrderedHash. # # require 'active_support/configurable' # # class User # include ActiveSupport::Configurable # end # # user = User.new # # user.config.allowed_access = true # user.config.level = 1 # # user.config.allowed_access # => true # user.config.level # => 1 def config @_config ||= self.class.config.inheritable_copy end end end