how to use express Session
<p>I am a express freshman, I have a problem with session now. this code I can't store seesion. req.session.user is undefined, maybe the quession was the session not store. what's wrong of my code, please tell me my wrong please thanks</p>

<pre><code>var express = require('express');
var bodyParser = require('body-parser');
var expressSession = require('express-session');
var cookieParser = require('cookie-parser');
var app = express();
app.use(cookieParser());
app.use(expressSession({
    secret: 'keyboard cat',
    resave: false,
    saveUninitialized: true,
    cookie: { secure: true }
}))
var auth = function(req, res, next) {
    console.log(req.session.user);  **this is undefined**
    if (req.session &amp;&amp; req.session.user === "amy" &amp;&amp; req.session.admin)
        return next();
    else
        return res.sendStatus(401);
};
app.get('/login', function (req, res) {
    if (!req.query.username || !req.query.password) {
        res.send('login failed');
    } else if(req.query.username === "amy" || req.query.password === "amyspassword") {
        req.session.user = "amy";
        req.session.admin = true;
        res.send(req.session.user);
    }
});
app.get('/logout', function (req, res) {
    req.session.destroy();
    res.send("logout success!");
});
app.get('/content', auth, function (req, res) {
    res.send("You can only see this after you've logged in.");
});
app.listen(3000);
</code></pre>