node.js如何在中间件中从redis数据库中获取数据

我正在做一个中间件模块，它将从redis中提取数据，并将数据放到req.my_会话中

这是在app.use（）内部调用的函数

---

我认为这个问题是因为async in-loop，您可以尝试以下方法

  function parse_cookies(req){
      if(req.headers.cookie != null){
        var result = req.headers.cookie.match(new RegExp('m:[^=]*=[^; ]*', 'ig'));
        if(result != null){
          var promises = [];
          for(var i = 0; i < result.length; i++){
            var result1 = result[i].split('=');
            promises.push(getFromRd(req, result1));

          }

          return Promise.all(promises)
                 .then(() => {
                      return next()
                 })
                 .catch((e) => {
                      return next({error: e})
                 })
        }
      }
    } // parse_cookies


  function getFromRd(req, result1) {
         req.my_session[result1[0].substr(2)] = result1[1];
         // get from redis value
         return client.get('sess:'+result1[1], function(err, reply) {
                if (err) {
                    throw Error(' failed to find ' + 'sess:' + result1[1])
                }
                // reply is null when the key is missing
                console.log(reply);
                let li = i;
                req.my_session[result1[0].substr(2)] = reply;
                console.log('li = ' + li);
                console.log('result1.lenght= ' + result.length);
                return {success:true}
            });
  }

函数解析\u cookies（请求）{
if（req.headers.cookie！=null）{
var result=req.headers.cookie.match（新的RegExp（'m:[^=]*=[^；]*'，'ig'）；
如果（结果！=null）{
var承诺=[]；
对于（变量i=0；i{
返回下一个（）
})
.catch（（e）=>{
返回下一个（{错误：e}）
})
}
}
}//解析cookies
函数getFromRd（请求，结果1）{
请求我的会话[result1[0].substr（2）]=result1[1]；
//从redis值中获取
返回client.get（'sess:'+result1[1]，函数（err，reply）{
如果（错误）{
抛出错误（'未能找到'+'sess:'+result1[1]）
}
//当密钥丢失时，reply为null
控制台日志（应答）；
设li=i；
请求我的会话[result1[0].substr（2）]=回复；
console.log（'li='+li）；
log（'result1.lenght='+result.length'）；
返回{success:true}
});
}

problem it's get data from database in my middleware, I can't because redis has callback function

    client.get("missingkey", function(err, reply) {
    // reply is null when the key is missing
    console.log(reply);
});

  function parse_cookies(req){
      if(req.headers.cookie != null){
        var result = req.headers.cookie.match(new RegExp('m:[^=]*=[^; ]*', 'ig'));
        if(result != null){
          var promises = [];
          for(var i = 0; i < result.length; i++){
            var result1 = result[i].split('=');
            promises.push(getFromRd(req, result1));

          }

          return Promise.all(promises)
                 .then(() => {
                      return next()
                 })
                 .catch((e) => {
                      return next({error: e})
                 })
        }
      }
    } // parse_cookies


  function getFromRd(req, result1) {
         req.my_session[result1[0].substr(2)] = result1[1];
         // get from redis value
         return client.get('sess:'+result1[1], function(err, reply) {
                if (err) {
                    throw Error(' failed to find ' + 'sess:' + result1[1])
                }
                // reply is null when the key is missing
                console.log(reply);
                let li = i;
                req.my_session[result1[0].substr(2)] = reply;
                console.log('li = ' + li);
                console.log('result1.lenght= ' + result.length);
                return {success:true}
            });
  }