Session-only cookie for Express.js


Question

http://www.javascriptkit.com/javatutors/cookie.shtml

Session-only cookies, on the other hand, stores information in the browser memory, and is available for the duration of the browser session. In other words, the data stored inside a session cookie is available from the time of storage until the browser is closed. Moving from page to page during this time does not erase the data.

How can I achieve this using Express.js?

1
22
5/4/2015 10:45:29 AM

Accepted Answer

The following is what I wanted (sort of). When I close browser the information is gone.

var express = require('express');
var app = express.createServer();

var MemoryStore = require('connect/middleware/session/memory');
app.use(express.bodyDecoder());
app.use(express.cookieDecoder());

app.get('/remember', function(req, res) {
    res.cookie('rememberme', 'yes', { expires: new Date() - 1, httpOnly: true });
});

app.get('/', function(req, res){
    res.send('remember: ' + req.cookies.rememberme);
});

app.listen(4000, '127.0.0.1');
10
5/4/2015 10:46:20 AM

First off, that website is a horrible place to go.

Now on to the question.

What sessions actually are:

  • Data is stored on the server side.
  • A cookie is issued which contains an ID.
  • This ID gets send back to the server on every request, due to the fact that the browser sends the cookies.
  • Now the server can re-associate the ID in the cookie - commonly called Session ID or short SID - with the session data stored on the server.

Express.js has support for sessions built in.

What the example shows:

  • Setting up the Express.js middleware
  • Using a third-party store for saving the session data, in this case Redis (which IMO is overkill for your problem atm)

Installing Redis requires quite some work, but it's also possible to use Express.js's built-in memory store:

var express = require('express');
var app = express.createServer();

var MemoryStore = require('connect/middleware/session/memory');
app.use(express.bodyDecoder());
app.use(express.cookieDecoder());
app.use(express.session({ store: new MemoryStore({ reapInterval: 60000 * 10 }) }));

app.get('/', function(req, res){
    req.session.visitCount = req.session.visitCount ? req.session.visitCount + 1 : 1;
    res.send('You have visited this page ' + req.session.visitCount + ' times');
});

app.listen(4000);

This will simply keep track of how many times you visited the page, closed your browser and re-opend. The counts will still be there.

You can find more on the options of the MemoryStore, like maximum life time of a session, etc. here.


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