Contents

require "ar_default_values/version"
require 'active_support'
require 'active_record'

#
# = ActiveRecord::DefaultValue
# initialize with default_values
#
# == sample
# you can specify default values with hash:
#
#  class Book < ActiveRecord::Base
#    default_values rating: 'r18', type: 'comic'
#  end
#
#  book = Book.new
#  book.rating # => "r18"
#  book.type # => "comic"
#  book.title # => nil
#
# you can use instance values with lambda:
#  class Book < ActiveRecord::Base
#    default_values type: 'comic', released_at: lambda { Time.now }
#  end
#
# or with block:
#  class Book < ActiveRecord::Base
#    default_values type: 'comic' do
#      t = Time.now
#      {released_at: t, edition_updated_at: t}
#    end
#  end
#
#  book1 = Book.new
#  # wait 10 sec
#  book2 = Book.new
#  book1.release_at == book2.release_at # => false
#  book1.released_at == book1.edition_updated_at # => true
#
module DefaultValues
  extend ActiveSupport::Concern

  module ClassMethods
    def default_values(defaults = {}, &block)
      define_method(:initialize_with_default_values) do |*attributes, &inner_block|
        defaults = defaults.merge(block.call) if block_given?
        defaults = Hash[defaults.each_pair.map{ |key, value| [key, value.kind_of?(Proc) ? value.call : value]}]

        initialize_without_default_values(*attributes, &inner_block)

        defaults.each_pair do |key, value|
          write_attribute(key, value) unless attribute_present?(key)
        end
      end

      alias_method_chain :initialize, :default_values
    end
  end
end

ActiveRecord::Base.send(:include, DefaultValues)

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
ar_default_values-0.4.0	lib/ar_default_values.rb