cookie-session

Simple cookie-based session middleware.

A user session can be stored in two main ways with cookies: on the server or on the client. This module stores the session data on the client within a cookie, while a module like express-session stores only a session identifier on the client within a cookie and stores the session data on the server, typically in a database.

The following points can help you choose which to use:

• cookie-session does not require any database / resources on the server side, though the total session data cannot exceed the browser's max cookie size.
• cookie-session can simplify certain load-balanced scenarios.
• cookie-session can be used to store a "light" session and include an identifier to look up a database-backed secondary store to reduce database lookups.

Semantics

This module provides "guest" sessions, meaning any visitor will have a session, authenticated or not. If a session is new a Set-Cookie will be produced regardless of populating the session.

Install

$ npm install cookie-session

API

var cookieSession = require('cookie-session')

cookieSession(options)

Create a new cookie session middleware with the provided options.

Options

Cookie session accepts these properties in the options object.

name

The name of the cookie to set, defaults to express:sess.

keys

The list of keys to use to sign & verify cookie values. Set cookies are always signed with keys[0], while the other keys are valid for verification, allowing for key rotation.

secret

A string which will be used as single key if keys is not provided.

Cookie Options

Other options are passed to cookies.get() and cookies.set() allowing you to control security, domain, path, and signing among other settings.

The options can also contain any of the follow (for the full list, see cookies module documentation:

• maxAge: a number representing the milliseconds from Date.now() for expiry
• expires: a Date object indicating the cookie's expiration date (expires at the end of session by default).
• path: a string indicating the path of the cookie (/ by default).
• domain: a string indicating the domain of the cookie (no default).
• secure: a boolean indicating whether the cookie is only to be sent over HTTPS (false by default for HTTP, true by default for HTTPS).
• secureProxy: a boolean indicating whether the cookie is only to be sent over HTTPS (use this if you handle SSL not in your node process).
• httpOnly: a boolean indicating whether the cookie is only to be sent over HTTP(S), and not made available to client JavaScript (true by default).
• signed: a boolean indicating whether the cookie is to be signed (false by default). If this is true, another cookie of the same name with the .sig suffix appended will also be sent, with a 27-byte url-safe base64 SHA1 value representing the hash of cookie-name=cookie-value against the first Keygrip key. This signature key is used to detect tampering the next time a cookie is received.
• overwrite: a boolean indicating whether to overwrite previously set cookies of the same name (true by default). If this is true, all cookies set during the same request with the same name (regardless of path or domain) are filtered out of the Set-Cookie header when setting this cookie.

req.session

Represents the session for the given request.

.isNew

Is true if the session is new.

.populated

Determine if the session has been populated with data or is empty.

req.sessionOptions

Represents the session options for the current request. These options are a shallow clone of what was provided at middleware construction and can be altered to change cookie setting behavior on a per-request basis.

Destroying a session

To destroy a session simply set it to null:

req.session = null

Example

Simple view counter example

var cookieSession = require('cookie-session')
var express = require('express')

var app = express()

app.set('trust proxy', 1) // trust first proxy

app.use(cookieSession({
  name: 'session',
  keys: ['key1', 'key2']
}))

app.use(function (req, res, next) {
  var n = req.session.views || 0
  req.session.views = n++
  res.end(n + ' views')
})

app.listen(3000)

Per-user sticky max age

var cookieSession = require('cookie-session')
var express = require('express')

var app = express()

app.set('trust proxy', 1) // trust first proxy

app.use(cookieSession({
  name: 'session',
  keys: ['key1', 'key2']
}))

// This allows you to set req.session.maxAge to let certain sessions
// have a different value than the default.
app.use(function (req, res, next) {
  req.sessionOptions.maxAge = req.session.maxAge || req.sessionOptions.maxAge
})

// ... your logic here ...

License

MIT