def parse(body)
        fields = {}
        for line in body.split('&')
          key, value = *line.scan( %r{^(\w+)\=(.*)$} ).flatten
          fields[key] = CGI.unescape(value)
        end

        {
          :approved => fields['trnApproved'],
          :id => fields['trnId'],
          :message_id => fields['messageId'],
          :message_text => fields['messageText'],
          :order_number => fields['trnOrderNumber'],
          :auth_code => fields['authCode'],
          :error_type => fields['errorType'],
          :error_fields => fields['errorFields'],
          :avs_processed => fields['avsProcessed'],
          :avs_id => fields['avsId'],
          :avs_result => fields['avsResult'],
          :avs_addr_match => fields['avsAddrMatch'],
          :avs_postal_match => fields['avsPostalMatch'],
          :avs_message => fields['avsMessage'],
          :response_type => fields['responseType'],
          :page_contents => fields['pageContents'],
        }.delete_if{|k, v| v.nil?}
      end