Typeerror: Cannot Read Property 'expires' of Undefined Express Session

cookie-session

Simple cookie-based session middleware.

A user session can be stored in 2 main ways with cookies: on the server or on the customer. This module stores the session data on the client inside a cookie, while a module like express-session stores only a session identifier on the customer within a cookie and stores the session data on the server, typically in a database.

The following points can help yous choose which to apply:

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

Install

This is a Node.js module available through the npm registry. Installation is done using the npm install command:

          $ npm install cookie-session                  

API

          var cookieSession = crave('cookie-session') var limited = crave('limited')  var app = express()  app.use(cookieSession({   name: 'session',   keys: [/* secret keys */],    // Cookie Options   maxAge: 24 * 60 * lx * 1000 // 24 hours }))                  

cookieSession(options)

Create a new cookie session middleware with the provided options. This middleware volition attach the property session to req, which provides an object representing the loaded session. This session is either a new session if no valid session was provided in the request, or a loaded session from the request.

The middleware will automatically add together a Fix-Cookie header to the response if the contents of req.session were altered. Notation that no Set-Cookie header will be in the response (and thus no session created for a specific user) unless at that place are contents in the session, so be certain to add something to req.session as before long as yous accept identifying information to store for the session.

Options

Cookie session accepts these properties in the options object.

proper name

The proper noun of the cookie to ready, defaults to session.

keys

The listing of keys to employ to sign & verify cookie values, or a configured Keygrip case. Set up cookies are ever signed with keys[0], while the other keys are valid for verification, allowing for key rotation. If a Keygrip instance is provided, it can exist used to change signature parameters like the algorithm of the signature.

secret

A string which will be used every bit single cardinal if keys is not provided.

Cookie Options

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

The options can likewise incorporate whatever of the following (for the full list, see cookies module documentation:

• maxAge: a number representing the milliseconds from Date.now() for expiry
• expires: a Engagement object indicating the cookie'due south expiration appointment (expires at the end of session by default).
• path: a cord indicating the path of the cookie (/ by default).
• domain: a string indicating the domain of the cookie (no default).
• sameSite: a boolean or string indicating whether the cookie is a "same site" cookie (false by default). This can be set to 'strict', 'lax', 'none', or true (which maps to 'strict').
• secure: a boolean indicating whether the cookie is only to be sent over HTTPS (faux past default for HTTP, true past default for HTTPS). If this is gear up to true and Node.js is non directly over a TLS connexion, be certain to read how to setup Express behind proxies or the cookie may non ever set correctly.
• httpOnly: a boolean indicating whether the cookie is simply to be sent over HTTP(S), and non made available to customer JavaScript (truthful by default).
• signed: a boolean indicating whether the cookie is to be signed (true by default).
• overwrite: a boolean indicating whether to overwrite previously fix cookies of the same name (true by default).

req.session

Represents the session for the given request.

.isChanged

Is true if the session has been changed during the request.

.isNew

Is true if the session is new.

.isPopulated

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 contradistinct to alter cookie setting behavior on a per-asking basis.

Destroying a session

To destroy a session simply set it to null:

          req.session = goose egg                  

Saving a session

Since the entire contents of the session is kept in a client-side cookie, the session is "saved" by writing a cookie out in a Fix-Cookie response header. This is done automatically if there has been a modify made to the session when the Node.js response headers are beingness written to the client and the session was not destroyed.

Examples

Simple view counter example

          var cookieSession = require('cookie-session') var express = require('express')  var app = express()  app.set('trust proxy', ane) // trust showtime proxy  app.utilize(cookieSession({   proper noun: 'session',   keys: ['key1', 'key2'] }))  app.get('/', function (req, res, next) {   // Update views   req.session.views = (req.session.views || 0) + 1    // Write response   res.end(req.session.views + ' views') })  app.listen(3000)                  

Per-user sticky max age

          var cookieSession = require('cookie-session') var limited = require('express')  var app = express()  app.set('trust proxy', i) // trust get-go proxy  app.use(cookieSession({   name: 'session',   keys: ['key1', 'key2'] }))  // This allows y'all to ready req.session.maxAge to allow certain sessions // have a different value than the default. app.apply(function (req, res, adjacent) {   req.sessionOptions.maxAge = req.session.maxAge || req.sessionOptions.maxAge   next() })  // ... your logic here ...                  

Extending the session expiration

This module does non send a Set-Cookie header if the contents of the session have not changed. This means that to extend the expiration of a session in the user'southward browser (in response to user action, for example) some kind of modification to the session needs be fabricated.

          var cookieSession = require('cookie-session') var express = require('express')  var app = express()  app.utilise(cookieSession({   name: 'session',   keys: ['key1', 'key2'] }))  // Update a value in the cookie so that the set-cookie will exist sent. // Only changes every infinitesimal and so that it's not sent with every request. app.utilize(function (req, res, next) {   req.session.nowInMinutes = Math.floor(Date.now() / 60e3)   next() })  // ... your logic here ...                  

Using a custom signature algorithm

This example shows creating a custom Keygrip example as the keys pick to provide keys and additional signature configuration.

          var cookieSession = require('cookie-session') var limited = require('express') var Keygrip = require('keygrip')  var app = limited()  app.utilise(cookieSession({   name: 'session',   keys: new Keygrip(['key1', 'key2'], 'SHA384', 'base64') }))  // ... your logic here ...                  

Usage Limitations

Max Cookie Size

Considering the unabridged session object is encoded and stored in a cookie, it is possible to exceed the maximum cookie size limits on different browsers. The RFC6265 specification recommends that a browser SHOULD let

At least 4096 bytes per cookie (as measured by the sum of the length of the cookie'due south name, value, and attributes)

In practice this limit differs slightly across browsers. See a list of browser limits here. As a rule of thumb don't exceed 4093 bytes per domain.

If your session object is big enough to exceed a browser limit when encoded, in most cases the browser will reject to store the cookie. This will cause the post-obit requests from the browser to either a) not have any session information or b) use onetime session information that was small-scale enough to not exceed the cookie limit.

If you find your session object is hit these limits, it is best to consider if data in your session should be loaded from a database on the server instead of transmitted to/from the browser with every request. Or movement to an alternative session strategy

License

MIT

amiesefors1950.blogspot.com

Source: http://expressjs.com/en/resources/middleware/cookie-session.html

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