这个插件让我们给使用它的当前class添加一个使用MD5生成的token

class Invitation < ActiveRecord::Base
  include TokenGenerator
  before_create :set_token
end

class ImperialInvitation < ActiveRecord::Base
  include TokenGenerator
  before_create :set_token

  private
    def set_token
      self.token = generate_token { |token| complies_to_imperial_standards?(token) }
    end
end

源码也很简单，token_generator.rb:

module TokenGenerator
  def generate_token(size = 12, &validity)
    begin
      token = Digest::MD5.hexdigest("#{inspect}#{Time.now}").first(size)
    end while !validity.call(token) if block_given?

    token
  end

  def set_token
    self.token = generate_token { |token| self.class.find_by_token(token).nil? }
  end
end