module NofollowLinks


    #
    #
    def self.included(base)
        base.extend(ClassMethods)
    end
    
    
    #
    #
    def self.addNoFollow(text)
        tokenizer = HTML::Tokenizer.new(text)
          out = ''
          while token = tokenizer.next
              node = HTML::Node.parse(nil, 0, 0, token, false)
              if node.tag? and node.name.downcase == 'a'
                  node.attributes['rel'] = 'nofollow' unless node.attributes.nil?
              end
              out << node.to_s
          end
          out
    end
    
    module ClassMethods
      
        #
        #
        def nofollow_links(*attr_names)
            attr_names.each do |field|
                before_save do |record|
                    record[field] = NofollowLinks.addNoFollow(record[field]) if record[field].kind_of? String
                end
            end
        end  #end method
      
        
    end # end ClassMethod
end #end module