code: function(port) {
        var port = port || this.conf.port || 80;
        var server = this.app.listen(port, function() {
          console.log("WeChat server for %s starts...", self.url);
        });
        server.on('error', function(err) {
          console.log(err);
        });
      }
docs: /*
  Start wechat server
  
  *port*, which port to listen to, optinal. If not set, will look up
  conf.port and if still not set, 80 by default.