Session variable not storing in node.js

Question

I searched and found a lot of similar problems with session variable being set to undefined, but none of the answers I found seemed applicable.

I have this function in my router file:

exports.loginHandler = function(req, res){
    username = req.body.username;
    password = req.body.password;
    readAccount(username, function(acct){
        if (acct.password = password){
            req.session.username = username;
            console.log(username+' logged in'+' pass: '+acct.password);
        };
    });
    res.redirect('/');
};

console.log executes just fine and both username and acct.password have the appropriate values. However, req.session.username just ends up being set to undefined.

Here's the readAccount function:

readAccount = function(user, callback){
    AM.login(user, function(acct){
        callback(acct);
    });
};

And here's AM.login:

exports.login = function(user, callback){
    accounts.findOne({username: user}, function(err, result){
    if (err) throw err;
    callback(result);
    })
}

I'm guessing session variables can't be set under conditions, since this type of error doesn't seem uncommon.

have you actually set up session state storage for your application? AFAIK it does not come baked in. — Brian Driscoll
– Brian Driscoll, Commented Jan 2, 2013 at 21:10
It does come baked in with express, or at least it did for me. The problem was that res.redirect was executing before the variable could be assigned. — user1816679
– user1816679, Commented Jan 2, 2013 at 21:51

Jonathan Lonowski · Accepted Answer · 2013-01-02 21:55:38Z

5

The issue is that you're redirecting, which ends the response and saves the session, before you've set the session.username property. This is because readAccount, by way of accounts.findOne, is asynchronous and won't finish before res.redirect() is called.

You can ensure their execution order by moving the res.redirect() into the readAccount callback:

exports.loginHandler = function(req, res){
    username = req.body.username;
    password = req.body.password;

    readAccount(username, function(acct){
        if (acct.password = password){
            req.session.username = username;
            console.log(username+' logged in'+' pass: '+acct.password);
        };

        res.redirect('/');
    });
};

Also, be careful with throw'ing errors in asynchronous operations. The callback will have a different call stack than the starting function (e.g. readAccount), which makes catching errors difficult. This is why many APIs for Node pass errors as arguments instead.

edited Jan 2, 2013 at 21:55

answered Jan 2, 2013 at 21:37

Jonathan Lonowski

124k35 gold badges203 silver badges202 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Saani Over a year ago

how to access this variable at other places?

Harnarinder Singh · Accepted Answer · 2017-06-23 06:35:04Z

0

Its short and easy method is write following line before sending response.

res.locals.session = req.session;

and your session will save the value of the varible.

answered Jun 23, 2017 at 6:35

Harnarinder Singh

1

Collectives™ on Stack Overflow

Session variable not storing in node.js

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related