# File lib/openid/server.rb, line 447
      def encode_to_url(server_url)
        q = {
          'openid.mode' => @mode,
          'openid.identity' => @identity,
          'openid.return_to' => @return_to
        }

        q['openid.trust_root'] = @trust_root if @trust_root
        q['openid.assoc_handle'] = @assoc_handle if @assoc_handle

        # add other openid stuff into the query (extensions)
        @query.each do |k,v|
          if k.starts_with?('openid.') and not q.has_key?(k)
            q[k] = v
          end
        end

        return OpenID::Util.append_args(server_url, q)
      end