url_for

# File actionpack/lib/action_controller/url_rewriter.rb, line 40
    def url_for(options)
      options = self.class.default_url_options.merge(options)
      
      url = ''
      unless options.delete :only_path
        url << (options.delete(:protocol) || 'http')
        url << '://'
        
        raise "Missing host to link to! Please provide :host parameter or set default_url_options[:host]" unless options[:host]
        url << options.delete(:host)
        url << ":#{options.delete(:port)}" if options.key?(:port)
      else
        # Delete the unused options to prevent their appearance in the query string
        [:protocol, :host, :port].each { |k| options.delete k }
      end
      url << Routing::Routes.generate(options, {})
      return url
    end