simple module for permalinks for models in rails

gistfile1.txt

#This is a module for anything that can belong to a page - namely, MCOs

module Utilities 
  module Page

    def self.included(base)
      base.extend(ClassMethods)
      base.class_eval do 
        include InstanceMethods
      end
      class << base
        attr_accessor :permalink_field
      end
    end
    
    module ClassMethods

      def has_permalink(permalink_field)
        before_save :prepare_permalink
        self.permalink_field = permalink_field
      end

    end

    module InstanceMethods

      #Replace any character that is not an alphanumeric with an underscore
      REPLACE_CHARS = /[^a-zA-Z0-9]/

      def prepare_permalink
        base_string = self.send(self.class.permalink_field)
        base_string = base_string.downcase.gsub(REPLACE_CHARS,"_").squeeze("_")
        self[:permalink] = base_string
      end

    end

  end
end