def get_user_xrds_url(xrds, claimed_id)
      types_to_match = ['http://www.iana.org/assignments/relation/describedby']
      services = OpenID::Yadis::apply_filter(claimed_id, xrds)
      services.each do | service |
        if service.match_types(types_to_match)
          template = REXML::XPath.first(service.service_element, '//openid:URITemplate', NAMESPACES)
          authority = REXML::XPath.first(service.service_element, '//openid:NextAuthority', NAMESPACES)
          url = template.text.gsub('{%uri}', CGI::escape(claimed_id))
          return [url, authority.text]
        end
      end
    end
def get_user_xrds_url(xrds, claimed_id)
      types_to_match = ['http://www.iana.org/assignments/relation/describedby']
      services = OpenID::Yadis::apply_filter(claimed_id, xrds)
      services.each do | service |
        if service.match_types(types_to_match)
          template = REXML::XPath.first(service.service_element, '//openid:URITemplate', NAMESPACES)
          authority = REXML::XPath.first(service.service_element, '//openid:NextAuthority', NAMESPACES)
          url = template.text.gsub('{%uri}', CGI::escape(claimed_id))
          return [url, authority.text]
        end
      end
    end
Process the URITemplate in the XRDS to derive the location of the claimed id's XRDS