how to set express's session timeout

[xiongjiabin]

I am writing a auth function using node.js and express, how to set the
session timeout after log in?

Here are my code.
//in log in part
if( isValidUser(user,pass)) {
req.session.valid = true;
req.session.user = user;
}


//other part that need to determine user log in or not
if(req.session.valid) {
......
}

My problem is after some seconds or some minutes, the
req.session.valid will be removed in the session object, where is the
problem?

Cheers,
Totty

[tjholowaychuk]

you can alter it with req.session.cookie.maxAge = milliseconds or
req.session.cookie.expires = Date