CODEWITHSUNDEEP
httpcookiesserver-side
Oleksandr Yanovets
Oleksandr Yanovets

Reputation: 4667

How to detect server-side whether cookies are disabled

How can I detect on the server (server-side) whether cookies in the browser are disabled? Is it possible?

Detailed explanation: I am processing an HTTP request on the server. I want to set a cookie via the Set-Cookie header. I need to know at that time whether the cookie will be set by the client browser or my request to set the cookie will be ignored.

Upvotes: 95

Views: 94417

Answers (14)

thomasrutter
thomasrutter

Reputation: 117333

The below answer was written a long time ago. Now, for better or worse, due to laws in various countries it has become either good practice - or a legal requirement - not to require cookies except where necessary, at least until the user has had a chance to consent to such mechanisms.

It's a good idea to only do this when the user is trying to do something that initiates a session, such as logging in, or adding something to their cart. Otherwise, depending on how you handle it, you're potentially blocking access to your entire site for users - or bots - that don't support cookies.

First, the server checks the login data as normal - if the login data is wrong the user receives that feedback as normal. If it's right, then the server immediately responds with a cookie and a redirect to a page which is designed to check for that cookie - which may just be the same URL but with some flag added to the query string. If that second page doesn't receive the cookie, then the user receives a message stating that they cannot log in because cookies are disabled on their browser.

If you're following the Post-Redirect-Get pattern for your login form already, then this setting and checking of the cookie does not add any additional requests - the cookie can be set during the existing redirect, and checked by the destination that loads after the redirect.

Now for why I only do a cookie test after a user-initiated action other than on every page load. I have seen sites implement a cookie test on every single page, not realising that this is going to have effects on things like search engines trying to crawl the site. That is, if a user has cookies enabled, then the test cookie is set once, so they only have to endure a redirect on the first page they request and from then on there are no redirects. However, for any browser or other user-agent, like a search engine, that doesn't return cookies, every single page could simply result in a redirect.

Another method of checking for cookie support is with Javascript - this way, no redirect is necessarily needed - you can write a cookie and read it back virtually immediately to see if it was stored and then retrieved. The downside to this is it runs in script on the client side - ie if you still want the message about whether cookies are supported to get back to the server, then you still have to organise that - such as with an Ajax call.

For my own application, I implement some protection for 'Login CSRF' attacks, a variant of CSRF attacks, by setting a cookie containing a random token on the login screen before the user logs in, and checking that token when the user submits their login details. Read more about Login CSRF from Google. A side effect of this is that the moment they do log in, I can check for the existence of that cookie - an extra redirect is not necessary.

Upvotes: 18

buycanna.io
buycanna.io

Reputation: 1204

NodeJS - Server Side - Cookie Check Redirect Middleware - Express Session/Cookie Parser

Dependencies

var express = require('express'),
    cookieParser = require('cookie-parser'),
    expressSession = require('express-session')

Middleware

return (req, res, next) => {
  if(req.query.cookie && req.cookies.cookies_enabled)
    return res.redirect('https://yourdomain.io' + req.path)
  if(typeof(req.cookies.cookies_enabled) === 'undefined' && typeof(req.query.cookie) === 'undefined') {
    return res.cookie('cookies_enabled', true, {
      path: '/',
      domain: '.yourdomain.io',
      maxAge: 900000, 
      httpOnly: true,
      secure: process.env.NODE_ENV ? true : false
    }).redirect(req.url + '?cookie=1')
  }
  if(typeof(req.cookies.cookies_enabled) === 'undefined') {
    var target_page = 'https://yourdomain.io' + (req.url ? req.url : '')
    res.send('You must enable cookies to view this site.<br/>Once enabled, click <a href="' + target_page + '">here</a>.')
    res.end()
    return
  }
  next()
}

Upvotes: 2

balexandre
balexandre

Reputation: 75073

You can use Javascript to accomplish that

Library:

function createCookie(name, value, days) {
    var expires;
    if (days) {
        var date = new Date();
        date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
        expires = "; expires=" + date.toGMTString();
    }
    else expires = "";
    document.cookie = name + "=" + value + expires + "; path=/";
}

function readCookie(name) {
    var nameEQ = name + "=";
    var ca = document.cookie.split(';');
    for (var i = 0; i < ca.length; i++) {
        var c = ca[i];
        while (c.charAt(0) == ' ') c = c.substring(1, c.length);
        if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length, c.length);
    }
    return null;
}

function eraseCookie(name) {
    createCookie(name, "", -1);
}

function areCookiesEnabled() {
    var r = false;
    createCookie("testing", "Hello", 1);
    if (readCookie("testing") != null) {
        r = true;
        eraseCookie("testing");
    }
    return r;
}

Code to run:

alert(areCookiesEnabled());

Remember

This only works if Javascript is enabled!

Upvotes: 41

Shoban
Shoban

Reputation: 23016

I dont think there are direct ways to check. The best way is to store a value in the cookie and try to read them and decide whether cookies are enabled or not.

Upvotes: 18

Zameer Khan
Zameer Khan

Reputation: 1196

The cookieEnabled property returns a Boolean value that specifies whether or not cookies are enabled in the browser

<script>
if (navigator.cookieEnabled) {
    // Cookies are enabled
}
else {
    // Cookies are disabled
}
</script>

Upvotes: 0

user3211045
user3211045

Reputation: 1

<?php   session_start();
if(SID!=null){
  echo "Please enable cookie";
}
?>

Upvotes: -1

user2511210
user2511210

Reputation: 93

check this code , it' will help you .

<?php
session_start();

function visitor_is_enable_cookie() {
    $cn = 'cookie_is_enabled';
    if (isset($_COOKIE[$cn]))
        return true;
    elseif (isset($_SESSION[$cn]) && $_SESSION[$cn] === false)
        return false;

    // saving cookie ... and after it we have to redirect to get this
    setcookie($cn, '1');
    // redirect to get the cookie
    if(!isset($_GET['nocookie']))
        header("location: ".$_SERVER['REQUEST_URI'].'?nocookie') ;

    // cookie isn't availble
    $_SESSION[$cn] = false;
    return false;
}

var_dump(visitor_is_enable_cookie());

Upvotes: 2

bren
bren

Reputation: 4334

Use navigator.CookieEnabled for cookies enabled(it will return true of false) and the Html tag noscript. By the way navigator.cookieEnabled is javascript so don't type it in as HTML

Upvotes: -3

Broote
Broote

Reputation: 845

I'm using a much more simplified version of "balexandre"'s answer above. It tries to set, and read a session cookie for the sole purpose of determining if cookies are enabled. And yes, this requires that JavaScript is enabled as well. So you may want a tag in there if you care to have one. 

<script>
// Cookie detection
document.cookie = "testing=cookies_enabled; path=/";
if(document.cookie.indexOf("testing=cookies_enabled") < 0)
{
    // however you want to handle if cookies are disabled
    alert("Cookies disabled");
}
</script>
<noscript>
    <!-- However you like handling your no JavaScript message -->
    <h1>This site requires JavaScript.</h1>
</noscript>

Upvotes: 1

user1018130
user1018130

Reputation: 195

I always used this:

navigator.cookieEnabled

According to w3schools "The cookieEnabled property is supported in all major browsers.".

However, this works for me when i am using forms, where i can instruct the browser to send the additional information.

Upvotes: 2

magritte
magritte

Reputation: 7636

If you only want to check if session cookies (cookies that exist for the lifetime of the session) are enabled, set your session mode to AutoDetect in your web.config file, then the Asp.Net framework will write a cookie to the client browser called AspxAutoDetectCookieSupport. You can then look for this cookie in the Request.Cookies collection to check if session cookies are enabled on the client.

E.g. in your web.config file set:

<sessionState cookieless="AutoDetect" />

Then check if cookies are enabled on the client with:

if (Request.Cookies["AspxAutoDetectCookieSupport"] != null)  { ... }

Sidenote: By default this is set to UseDeviceProfile, which will attempt to write cookies to the client so long as the client supports them, even if cookies are disabled. I find it slightly odd that this is the default option as it seems sort of pointless - sessions won't work with cookies disabled in the client browser with it set to UseDeviceProfile, and if you support cookieless mode for clients that don't support cookies, then why not use AutoDetect and support cookieless mode for clients that have them disabled...

Upvotes: 1

L. Cornelius Dol
L. Cornelius Dol

Reputation: 64026

Send a redirect response with the cookie set; when processing the (special) redirected URL test for the cookie - if it's there redirect to normal processing, otherwise redirect to an error state.

Note that this can only tell you the browser permitted the cookie to be set, but not for how long. My FF allows me to force all cookies to "session" mode, unless the site is specifically added to an exception list - such cookies will be discarded when FF shuts down regardless of the server specified expiry. And this is the mode I run FF in always.

Upvotes: 61

MSalters
MSalters

Reputation: 179779

The question whether cookies are "enabled" is too boolean. My browser (Opera) has a per-site cookie setting. Furthermore, that setting is not yes/no. The most useful form is in fact "session-only", ignoring the servers' expiry date. If you test it directly after setting, it will be there. Tomorrow, it won't.

Also, since it's a setting you can change, even testing whether cookies do remain only tells you about the setting when you tested. I might have decided to accept that one cookie, manually. If I keep being spammed, I can (and at times, will) just turn off cookies for that site.

Upvotes: 1

Joonas Pulakka
Joonas Pulakka

Reputation: 36577

Try to store something into a cookie, and then read it. If you don't get what you expect, then cookies are probably disabled.

Upvotes: 3

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