Express session store and reapInterval - session

Question

I have a question about express session store memory with setting the reapInterval value. I have an example code, which will output the values of a memorystore every 5 seconds. If i now set a reapinterval of 5000, it should clean up expired session every 5 seconds right? So my example looks like this:
/**
* Module dependencies.
*/
var express = require('express');
var app = module.exports = express.createServer();
var MemStore = require('express/node_modules/connect/lib/middleware/session/memory');
var store = new MemStore({reapInterval: 5000});
// Configuration
app.configure(function(){
app.set('views', __dirname + '/views');
app.set('view engine', 'jade');
app.use(express.bodyParser());
app.use(express.methodOverride());
app.use(express.cookieParser());
app.use(express.session({secret: 'your secret here', store: store, cookie: {maxAge: 30000}}));
app.use(app.router);
app.use(express.static(__dirname + '/public'));
});
setInterval(function(){
console.log(new Date());
console.log(store);
}, 5000);
app.configure('development', function(){
app.use(express.errorHandler({ dumpExceptions: true, showStack: true }));
});
app.configure('production', function(){
app.use(express.errorHandler());
});
// Routes
app.get('/', function(req, res){
res.render('index', {
title: 'Express'
});
});
app.listen(3000);
console.log("Express server listening on port %d in %s mode", app.address().port, app.settings.env);
And now the problem is, that if I revisit the page after 30 seconds, I get a new SID, but the old session in memorystore is still there... should it not be checked every 5 seconds and deleted?
Thx for your help!

Answer 1

So the first problem is a misunderstanding here. reapInterval does not do anything. MemoryStore clears cookies based on the expire time of session cookie. So there is in fact a bug in Connects MemoryStore. The way I see it the broken flow goes like this.
Set cookie to expire in X.
Get session data, has X gone by? No, ok.
(cookie expires)
Get session data, session doesn't exist, generate new one.
X has gone by but the session ID is missing because the browser expired it already.
There is a discussion regarding this here.
https://github.com/senchalabs/connect/issues/328
And a juicy quote
"short cookie sessions would be screwed I guess" --visionmedia