req.session未定义，req.session.user_id不起作用

我正在使用Express和node通过https进行会话管理。我想使用express创建一个会话，以便在重定向到公用文件夹中的静态文件之前进行身份验证和会话。以前我在使用express.session和https时遇到了麻烦， 但是通过在express.session中将路径包含为/ public来解决了问题，但是现在我的req.session显示为未定义，但是在浏览器中存在connect.sid cookie

app.js是：

var express = require('express')TypeError: Cannot set property 'user_id' of undefined at /opt/expressjs/app.js:59:24 at callbacks;
var http = require('http');
var https = require('https');
var fs = require('fs');
var mongo = require('mongodb');
var monk = require('monk');
var db = monk('localhost:27017/svgtest1');
var options = {
  key: fs.readFileSync('privatekey.pem'),
  cert: fs.readFileSync('certificate.pem')
};

var app = express();

app.use(express.static(__dirname + '/public'));
app.use(express.urlencoded());
app.use(express.json());
app.use(express.cookieParser());
app.use(express.session({cookie: {  path: '/public/',httpOnly: false , maxAge: 24*60*60*1000}, secret: '1234567890QWERT'}));

//middle ware to check auth
function checkAuth(req, res, next) {
  if (!req.session.user_id) {
    res.send('You are not authorized to view this page');
  } else {
    next();
  }
}


app.get('/', function(req, res) {
  console.log('First page called');
  res.redirect('loginform.html');
  console.log('redirected');
  res.end();
});

app.post('/login', function(req, res) {
  console.log('login called');
  var usrfield = req.body.usrfield;
  var passfield = req.body.passfield;

    console.log(req.session);


// Play with the username and password

        if (usrfield == 'kk' && passfield == '123') {
             req.session.user_id = 'xyz';
        res.redirect('svg-edit.html');
      } else {
        res.send('Bad user/pass');
      }


        console.log(usrfield);
        console.log(passfield);
        res.end();
    });

客户端 ：

    
            
            

    

    


    

        


            
LabelMe Dev
 
            

            


             Please Enter the Username
            

            


            
            

            

            


             Please Enter the Password
            

            

            
            

            

            


            
 

            
        
    
     
    

问题是console.log(req.session);给undefined，因此req.session.user_id = 'xyz';也无法正常工作并出现错误'TypeError: Cannot set property 'user_id' of undefined at /opt/expressjs/app.js:59:24 at callbacks'。我经历了很多问题，但无法弄清楚。

我的网站是静态的，所有* .html都位于公共目录中