code: function(req, params) {
      if(!params) {
        params = URL.parse(req.url, true).query;
      }
      var cconfig = this.config.client;
      var next = params.next || cconfig.default_redirection_url;
      var url = cconfig.base_url + next;
      return url;
    }
docs: Returns value of next url query parameter if present, default otherwise.
  The next query parameter should not contain the domain, the result will.