Can't save express session in NodeJs

问题

I'm trying to save the userName of a user in express session. It saves the variable in session but it returns undefined on next request to the route. However, the problem is with POST route only.

With GET request, I can save session variable and it doesn't get destroyed on further requests. I think I must be doing something wrong. I tried save() method for POST but still it saves only first time and next time it is vanished.

Here's the code:

app.use(session({
  secret: 'some secret',
  resave: true,
  saveUninitialized: true,
  cookie: {
    maxAge: 36000000,
    httpOnly: false
  },
}));

FOLLOWING GET ROUTE WORKS.

app.get("/test", function(req, res, next){
    if(!req.session.name){
        req.session.name = "vikas kumar";
    } else {
        console.log(req.session.name);
    }
    res.end();
});

app.use(function (req, res, next) {
  var userName = req.session.userName;
  // console.log(req.session.userName);
  if(userName && userName != 'undefined'){
    res.send({status: "success", value: userName});
  } else {
    if(req.path == '/checkIfLoggedIn'){
        res.send({status: "error", message: "Session ended."});
    } else {
        next('route');
    }
  }
});

FOLLOWING ROUTE SAVES SESSION ONLY ONCE.

app.post('/getProfile', function (req, res, next) {
    console.log("Session", req.session.userName, req.session.name);
    if(typeof req.session.userName != 'undefined'){
        var userName = req.session.userName;
    } else {
        var userName = req.body.userName;
    }
   connectionPool.getConnection(function (err, connection) {
        if (err) {
            res.send({status: "error", message: err});
        } else {
        connection.query("SELECT * FROM cs_chat.users WHERE username=?", [userName], function (err, rows, fields) {
            if(rows.length==1){
                // console.log(">>>", req.session.userName);
                req.session.userName = userName;
                req.session.save();
                // console.log("<<<", req.session.userName);
                next();
            }else{
                res.send({status: "error", message: "Sorry, you're not registered."});
            }
            connection.release();

        });

        }
    });
}, function (req, res) {
    connectionPool.getConnection(function (err, connection) {
        if (err) {
            res.send({status: "error", message: err});
        } else {
            req.session.username = req.body.userName;
            req.session.save();
        connection.query("SELECT usr.username, usr.name, tsn.sender, CASE WHEN tsn.unseen is not null THEN tsn.unseen ELSE 0 END as unseen, tsn.receiver FROM users usr LEFT JOIN (SELECT sender, receiver, SUM(CASE WHEN seen = 0 THEN 1 ELSE 0 END) AS unseen FROM messages WHERE receiver = ? GROUP BY sender , receiver) tsn ON usr.username = tsn.sender where usr.username!=?", [req.body.userName, req.body.userName], function (err, rows, fields) {
            if(rows.length>0){
                res.send({status: "success", values: rows});
            }else{
                res.send({status: "success", values: []});
            }
            connection.release();
        });

        }
    });
});

Am I doing something wrong?

回答1:

Since it is Javascript you should be checking quality with === instead of == and for better response time releasing the connection and then again connecting to it, is simply unnecessary, when you have the connection to connectionPool just query from it twice and then release the connection.

Here is the sample modified app.post().. request, this should work:

    app.post('/getProfile', function (req, res, next) {
    console.log("Session", req.session.userName, req.session.name);
    var userName = (req.session.userName !== undefined) ? req.session.userName : req.body.userName;

    connectionPool.getConnection(function (err, connection) {
        if (err) {
            res.send({ status: "error", message: err });
        } else {
            connection.query("SELECT * FROM cs_chat.users WHERE username=?", [userName], function (err, rows, fields) {
                if (rows.length === 1) {
                    req.session.userName = userName;
                    req.session.save();
                } else {
                    res.send({ status: "error", message: "Sorry, you're not registered." });
                }
            });
            connection.query("SELECT usr.username, usr.name, tsn.sender, CASE WHEN tsn.unseen is not null THEN tsn.unseen ELSE 0 END as unseen, tsn.receiver FROM users usr LEFT JOIN (SELECT sender, receiver, SUM(CASE WHEN seen = 0 THEN 1 ELSE 0 END) AS unseen FROM messages WHERE receiver = ? GROUP BY sender , receiver) tsn ON usr.username = tsn.sender where usr.username!=?",
                [req.body.userName, req.body.userName],
                function (err, rows, fields) {
                    if (rows.length > 0) {
                        res.send({ status: "success", values: rows });
                    } else {
                        res.send({ status: "success", values: [] });
                    }
                });
            connection.release();
        }
    });
});

来源：https://stackoverflow.com/questions/44712538/cant-save-express-session-in-nodejs