req.session returns undefined in the next POST request after is defined

Question

I'm working with a back-end made with Node.js and front-end made with Angular. I use express-sessions for login, at first, it returns the correct req.session.usuario. But in the next POST request for checking if the user is logged in it returns undefined.

Here is the app.js of node

var express = require('express');
var path = require('path');
var logger = require('morgan');
var cors = require('cors');
var session = require('express-session');
var cookieParser = require('cookie-parser');


var indexRouter = require('./routes/index');
var authRouter = require('./routes/auth');
var usersRouter = require('./routes/users');
var instructorRouter = require('./routes/instructor');

var app = express();


app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(express.static(path.join(__dirname, 'public')));
app.use(cookieParser());
app.use(cors( {
  credentials: true,
  origin: 'http://localhost:4200'
}));
app.use(session({
    secret: "Shh, es un secreto",
    resave: false,
    saveUninitialized: true
    
}))

app.use('/', indexRouter);
app.use('/auth', authRouter);
// app.use('/usuario', authMiddleware.estaLogueado ,usersRouter);
app.use('/usuario', usersRouter);
app.use('/instructor', instructorRouter);

...

module.exports = app;

This is my function for the route in the auth.js

router.post('/login', (req, res, next) => {
    const username = req.body.username.toLowerCase();
    Usuario.findOne({
        where: {
            username: username
        }
    }).then((usuario) =>{
        if (usuario) {
            bcrypt.compare(req.body.password, usuario.password, function(errp, result) {
                if(result){
                    req.session.usuario = usuario.id; // Saves the session
                    console.log("La sesion " + req.session.usuario);
                    res.json({username: usuario.username, color: usuario.color});
                } else {
                    next(new Error("Contraseña incorrecta"));
                }
            });
        }else{
            next(new Error("Usuario invalido"));
        }
    }, err => {
        next(new Error("Usuario invalido: " + err));
    });
});

And this is the function that I use for checking if is logged in:

router.post('/logged', (req, res) => {
    console.log("intento: " + req.session.usuario) // here it shows undefined
    req.session.usuario ? res.json({loggedIn: true}) : res.json({loggedIn: false});
})

In Angular these are the two functions that I use, the first one is the login (which works) and the second one is the logged that returns false all the time:

login(user, pass)  {
    return this.http.post(server + '/auth/login', 
        {username: user, password: pass},
        {withCredentials: true}
    )
}

logged(){
    return this.http.post(server + '/auth/logged', {withCredentials: true})
}

In the actual component I do:

this.authservice.logged().subscribe( (data) => {
    this.loggedIn = data['loggedIn'];
    console.log(data['loggedIn']);
});

What is the problem here?

Answer 1

I finally got the answer! I was doing everything ok but the second request was actually not including the withCredentials json as options, it was passed as body so I added empty brackets to simulate the body and now it works like a charm!