我在错误处理中间件我的 Node 和 express 应用程序中没有收到 req.session？

Question

这是我得到的错误和未定义，当我在我的错误处理中间件中使用 console.log (req.session) 并访问 req.session.isLoggedIn 时

  cookie: {
    path: '/',
    _expires: null,
    originalMaxAge: null,
    httpOnly: true,
    secure: null,
    domain: null,
    sameSite: null
  },
  csrfSecret: 'TAmB7luZ3vUTFd0FWmsWoXHP',
  flash: {},
  isLoggedIn: true,
  user: {
    cart: { items: [] },
    _id: 5f1adb6163d0bc36506a6696,
    email: 'bella@gmail.com',
    password: '$2a$12$HCaoOhpMJiBEIw177tR4LuMV62a3zlnWFz4RQZYH4TPzit/vYRfn2',
    __v: 1
  }
}
undefined
TypeError: Cannot read property 'isLoggedIn' of undefined
    at D:\Node-Project\app.js:110:34
    at Layer.handle_error (D:\Node-Project\node_modules\express\lib\router\layer.js:71:5)
    at trim_prefix (D:\Node-Project\node_modules\express\lib\router\index.js:315:13)
    at D:\Node-Project\node_modules\express\lib\router\index.js:284:7
    at Function.process_params (D:\Node-Project\node_modules\express\lib\router\index.js:335:12)
    at next (D:\Node-Project\node_modules\express\lib\router\index.js:275:10)
    at Layer.handle_error (D:\Node-Project\node_modules\express\lib\router\layer.js:67:12)
    at trim_prefix (D:\Node-Project\node_modules\express\lib\router\index.js:315:13)
    at D:\Node-Project\node_modules\express\lib\router\index.js:284:7
    at Function.process_params (D:\Node-Project\node_modules\express\lib\router\index.js:335:12)
    at next (D:\Node-Project\node_modules\express\lib\router\index.js:275:10)
    at Layer.handle_error (D:\Node-Project\node_modules\express\lib\router\layer.js:67:12)
    at trim_prefix (D:\Node-Project\node_modules\express\lib\router\index.js:315:13)
    at D:\Node-Project\node_modules\express\lib\router\index.js:284:7
    at Function.process_params (D:\Node-Project\node_modules\express\lib\router\index.js:335:12)
    at next (D:\Node-Project\node_modules\express\lib\router\index.js:275:10)

Answer 1

In case of a POST request, req.session.isLoggedIn works only when the session is saved previously. Here, you have started the session and then completed it before assigning the value to isAuthenticated . Since, there is no session running during the assignment operation, it shows 'undefined'. You have the value of req.session.isLoggedIn in res.locals.isAuthenticated . So, replace req.session.isLoggedIn with res.locals.isAuthenticated and it will solve your problem as of now.