Create unique random attributes in ActiveRecord

random_attributes.rb

module RandomAttributes
  def self.included(controller)
    controller.send :extend, ClassMethods
    controller.send :include, InstanceMethods
  end

  module ClassMethods
    def random_attribute(attr_sym, key_length = 10)
      cattr_accessor :random_attributes
      validates_presence_of attr_sym
      validates_uniqueness_of attr_sym
      self.random_attributes = ((random_attributes || []) << {:attr_sym => attr_sym, :key_length => key_length})
    end
  end

  module InstanceMethods
    def save(perform_validation = true)
      self.class.random_attributes.each do |r|
        validate_random_attribute(r[:attr_sym], r[:key_length])
      end
      super(perform_validation)
    end

    def save!
      self.class.random_attributes.each do |r|
        validate_random_attribute(r[:attr_sym], r[:key_length])
      end
      super
    end
  end

  protected

  def validate_random_attribute(attr_sym, key_length = 10)
    set_sym = "#{attr_sym}=".to_sym
    while !self.valid? && self.errors.on(attr_sym)
      self.send(set_sym, random_string(key_length))
    end
  end

  def random_string(length = 10)
    srand
    Array.new(length){ rand(36).to_s(36) }.to_s
  end
end