How to change Cookies value at runtime [duplicate] - php

Question

I have the following PHP function:
function validateUser($username){
session_regenerate_id ();
$_SESSION['valid'] = 1;
$_SESSION['username'] = $username;
setcookie('username2',$username,time()+60*60*24*365);
header("Location: ../new.php");
}
And then I fetch the cookie:
echo $_COOKIE['username2']; exit();
(I only put exit() for debugging purposes)
Only problem, it's coming out blank. Any ideas?
UPDATE:
This is how the function is called:
if(mysql_num_rows($queryreg) != 0){
$row = mysql_fetch_array($queryreg,MYSQL_ASSOC);
$hash = hash('sha256', $row['salt'] . hash('sha256', $password));
if($hash == $row['password']) {
if($row['confirm'] == 1){
if(isset($remember)){
setcookie('username',$username,time()+60*60*24*365);
setcookie('password',$password,time()+60*60*24*365);
} else {
setcookie('username','',time()-3600);
setcookie('password','',time()-3600);
}
validateUser($username);
I didn't include all the if() statements to save some space.

Answer 1

try adding the path = /, so that the cookie works for the whole site not just the current directory (that has caught me out before)
example
setcookie('password',$password,time()+60*60*24*365, '/');
also make sure the cookie is the first thing being output
as advised in the php manual (this has caught me out before too)
Like other headers, cookies must be sent before any output from your
script (this is a protocol restriction).

Answer 2

Why you are having this problem
The problem comes from the fact that setcookie() doesn't set the cookies immediately, it sends the headers so the browser sets the cookies. This means that, for the current page load, setcookie() will no generate any $_COOKIE.
When the browser later on requests a page, it sends the cookies in the headers so the PHP can retrieve them in the form of $_COOKIE.
Simple, old solution
About solutions, the obvious one:
setcookie('username',$username,time()+60*60*24*365);
// 'Force' the cookie to exists
$_COOKIE['username'] = $username;
A better solution
I created a class, Cookie, that addresses the problems that setcookie() and $_COOKIE share:
// Class that abstracts both the $_COOKIE and setcookie()
class Cookie
{
// The array that stores the cookie
protected $data = array();
// Expiration time from now
protected $expire;
// Domain for the website
protected $domain;
// Default expiration is 28 days (28 * 3600 * 24 = 2419200).
// Parameters:
// $cookie: $_COOKIE variable
// $expire: expiration time for the cookie in seconds
// $domain: domain for the application `example.com`, `test.com`
public function __construct($cookie, $expire = 2419200, $domain = null)
{
// Set up the data of this cookie
$this->data = $cookie;
$this->expire = $expire;
if ($domain)
$this->domain = $domain;
else
{
$this->domain =
isset($_SERVER['HTTP_X_FORWARDED_HOST']) ?
$_SERVER['HTTP_X_FORWARDED_HOST'] :
isset($_SERVER['HTTP_HOST']) ?
$_SERVER['HTTP_HOST'] :
$_SERVER['SERVER_NAME'];
}
}
public function __get($name)
{
return (isset($this->data[$name])) ?
$this->data[$name] :
"";
}
public function __set($name, $value = null)
{
// Check whether the headers are already sent or not
if (headers_sent())
throw new Exception("Can't change cookie " . $name . " after sending headers.");
// Delete the cookie
if (!$value)
{
setcookie($name, null, time() - 10, '/', '.' . $this->domain, false, true);
unset($this->data[$name]);
unset($_COOKIE[$name]);
}
else
{
// Set the actual cookie
setcookie($name, $value, time() + $this->expire, '/', $this->domain, false, true);
$this->data[$name] = $value;
$_COOKIE[$name] = $value;
}
}
}
Then you can use it like this:
$Cookie = new Cookie($_COOKIE);
$User = $Cookie->user;
$LastVisit = $Cookie->last;
$Cookie->last = time();
And of course, you have to pass it around. Much better than having globals.

Answer 3

Here is the general syntax of setcookie
setcookie(name,value,expire,path,domain,secure);
Look at third argument, if you do not set it the script will take it to current working directory. So if you set a cookie without setting path at a.com/b/setcookie.php the cookie will not be available to a.com/checkcookie.php. What you are doing is setting cookie in a subfolder and the redirecting to a parent folder, look at ../, where it is not available hence the issue. How to avoid this? Normal procedure is to supply a path that is /, in your case supply / as fourth param. The fifth argument for your cookie will set it secure. http://www.php.net/setcookie has more explanation. This should fix your problem. Setting domain path to domain.com, will make the cookie available to everything under domain.com but not to something.domain.com. Set domain value to .domain.com, look at the dot preceding domain.com, will make it available across anything.domain.com. HTH!

Answer 4

Thought I would add another possible reason why a cookie may not be either setting or showing random functional behavior.
The following case may be applicable to some programmers having what appears to be an illusive cookie setting issue as a result of the incorrect usage of header_remove()
If you try to set a cookie before calling header_remove(), the cookie will never be created because you have also immediately destroyed the header that was set in order to create the cookie before it was buffered out to the client.
You may find when fiddling around that your cookie suddenly works for an unknown reason, so you need to understand the race-conditions around headers:
On first run you set a cookie and don't call header_remove() at all.
On a second run you do call header_remove()
You will find your cookie is now always set regardless of condition (2) and the number of times it is called because (1) happened first at least once.
The cookie will remain set until it either expires, is overwritten or unset()
The same will apply when modifying headers like a cookie value before the eventual call of header_remove(), you again will fail to set new values because they will be wiped before the response is buffered out to the user.
You need to set cookies and any other headers for that matter after a header_remove() not before.
Use header_remove() to cleanup ALL previously set headers in order to set new headers for a final output.
An example of scenario for such a case may be as follows:
Use header_remove() to alter a hierarchy of HTTP Response codes for a RESTFUL API where you are using axios with interceptors.
Your application sets a 400+ header error first, should the application error out at any point of execution.
Modify the header to a 200 when final desired execution point has been reached & a valid response is expected.
In such an event, it is likely you want to preserve all other previously set headers but clear out the HTTP Status (400?) code in order to set a new (200?) code for the final response.
If you try to set the header again in order to change the status code before removing the previously set header then you will get the "Headers already sent" error.
You can remove specific headers with header_remove, here is how to unset the status code and set a new code in stages:
// Set a default status code
http_response_code(500);
// Boot Logic runs - if fails here 500 is returned
// Authentication Logic - If unauthorized ?
header_remove('HTTP/1.0'); // Clear previous 500
http_response_code(401); // Set new status code
// else ?
// Return Data Logic - Success
header_remove('HTTP/1.0'); // Clear previous 500
http_response_code(200) // Set new status code

Answer 5

This requires that you place calls to this function prior to any output, including and tags as well as any whitespace.
this is how the structure looks
<?php
$cookie_name = "user";
$cookie_value = "Ahmed Moftah";
setcookie($cookie_name, $cookie_value, time() + (86400 * 30), "/"); // 86400 = 1 day
?>
<?php
if(!isset($_COOKIE[$cookie_name])) {
echo "Cookie named '" . $cookie_name . "' is not set!";
} else {
echo "Cookie '" . $cookie_name . "' is set!<br>";
echo "Value is: " . $_COOKIE[$cookie_name];
}
?>
<html>
<body>
</body>
</html>

Answer 6

It might be a cache problem. Try closing the browser and opening a new one with the localhost file path. I had the same issue and my page was cached so the cookies weren't working, even though I could put in new code and see a change on the page. Very weird... Cleaning your cache might help, try that first. Then try a new browser, then try to go to your localhost:8080 index and hit refresh to see when the last page was modified.
If that doesn't fix it, try restarting LAAMP or XAAMP or whatever you are using.

Answer 7

This happens with the session cookies are disabled.
You can navigate to your php.ini file(changes depending on server. Ubuntu 20.04's default is /etc/php/{X.x}/{apache2|[others]}/php.ini) and ensure that session.use_cookies=1
Restart your server and then try to set the cookie. They should immediately be available.

Answer 8

You probably have sent header hereby making it impossible to set header for cookie.
It might be a simple solution of ob_start() at the start of your page.

Answer 9

[Solution tested in XAMPP for PHP 8.0.19]
I modified the file php.ini and set session.auto_start=1. Keep in mind that i'm calling session_set_cookie_params([param => value]) just before session_start() every time this functions appears in my code, in every file.
session.auto_star: Initialize session on request startup.
http://php.net/session.auto-start
Still studying and analysing the reason and functionality of this, it was kind of a serendipity.
Probably not the most secure solution.

Answer 10

You can't get the $_COOKIE on the same request but you can get $_SESSION on the same request.
So the idea is
Set the $username in both the session & cookie.
Get the username from the session for the first time (if the same request)
Unset session
Always get the cookie from $_COOKIE from next request.
// Set Cookie
setcookie('username',$username,time()+60*60*24*365);
$_SESSION['username'] = $username;
//GET Cookies
if(!$_COOKIE['username']){
$username = $_SESSION['username'];
unset($_SESSION['username']);
}else{
$username = $_COOKIE['username'];
}