How to properly use express-session on firebase cloud functions - node.js

Question

Hello I am trying to use express sessions in my backend deployed to firebase cloud functions and I trying to use express-sessions to save data related to the current session. but this does not work, I save something using req.session.value = 5 and I try to get that value later and it is undefined.
this is my current express session config.
const session = require('express-session')
const config = require('./config')
const { v4: uuidv4 } = require('uuid');
admin.initializeApp();
const api = require("./api/index");
const app = express();
//app.use(cookieParser());
//app.set('trust proxy',1)
const sess = {
secret: config.secretKey,
genid: function(req){
return uuidv4();
},
resave: true,
saveUninitialized: true,
cookie: {
sameSite: false
}
}
if(app.get('env')==='production'){
app.set('trust proxy',1)
sess.cookie.secure = true;
}
app.use(session(sess));
app.use(cors());
app.use(express.json());
and I have a middleware that sets the value based in some conditions
// mymdileware
module.exports = (req, res,next)=>{
if(/* conditions */ ){
req.session.value = 5
next()
}
// other code here with a res.send()
})
and an endpoint to get the value of the session, and gets executed after the middleware
app.get("/someEndpontToReadSession", mymdileware,(req, res)=>{
if(req.session.value===5){
// do something and return something to the user
}
// other code here with a res.json()
})
the problem is when I read req.session.value it is undefined, even though I set it in the middleware.
this works locally but It does not work when I deployed to firebase functions.
Edit: I thought the problem was related to that I am not providing a store to the session config, so I added it.
but I am still facing this problem : /
const session = require('express-session')
const config = require('./config')
const { v4: uuidv4 } = require('uuid');
const {Firestore} = require('#google-cloud/firestore');
const {FirestoreStore} = require('#google-cloud/connect-firestore');
admin.initializeApp();
const api = require("./api/index");
const app = express();
//app.use(cookieParser());
//app.set('trust proxy',1)
const sess = {
secret: config.secretKey,
genid: function(req){
return uuidv4();
},
resave: false,
saveUninitialized: true,
cookie: {
sameSite: false
}
}
if(app.get('env')==='production'){
console.log('production : )');
app.set('trust proxy',1)
sess.store = new FirestoreStore({
dataset: new Firestore(),
kind: 'express-sessions'
})
sess.cookie.secure = true;
}
app.use(session(sess));

Answer 1

Firebase Cloud functions dont allow severals cookies Firebase Doc for their CDN cache , they allow just the cookie named __session so :
app.use(session({ name: "__session",
secret: process.env.SESSION_SECRET,
resave: false,
saveUninitialized: true,
cookie: {maxAge: 24 * 60 * 60 * 1000}, // 24 hours
store: sessionStorage}));