app.dynamicHelpers({
  __get: function(req){
    return req.query
  },
  __params: function(req){
    return req.params
  },
  __post: function(req){
    return req.body
  },
  __cookie: function(req){
    return req.cookies
  },
  __session: function(req){
    return req.session;
  },
  __siteurl: function(req){
    return 'http://'+req.headers.host+'/'
  }
});

@ljy0662 动态helper会因为请求的不同而改变 静态helper与请求无关