PHP cookie value not being passed from one page to another - php

Question

This is in a page called headersessioncookie.php
<?php
session_start();
if ( ! isset ( $_SESSION['loggedin'] ) ) {
$_SESSION['loggedin'] = FALSE;
}
$expiry = time()+60*60*9000;
setcookie('cookie[loggedin]', '', $expiry, "", "", "", TRUE);
if ( ! isset ( $_COOKIE['cookie[loggedin]'] ) ) {
$_COOKIE['cookie[loggedin]'] = FALSE;
}
?>
This is in a page called test.php
<?php
require_once('headersessioncookie.php'); //start session and cookie
$_SESSION['loggedin'] = TRUE;
$_COOKIE['cookie[loggedin]'] = TRUE;
?>
When I run test.php and then run this page below called test1.php ...
<?php
require_once('headersessioncookie.php'); //start session and cookie
echo "sessionvalue" . $_SESSION['loggedin'] . '<br>';
echo "cookievalue" . $_COOKIE['cookie[loggedin]'] . '<br>';
?>
... I get
sessionvalue1
cookievalue
Why don't I get...
sessionvalue1
cookievalue1
...??

Answer 1

The superglobal variable $_COOKIE only contains the cookie values. If you modify this value won't affect to the cookie because you need to sent the headers to the browser to do so.
If you need to modify it you have to use the method setCookie because this will sent the headers with the new value.
Note Remember that the $_COOKIE only will be updated after use setCookie when you refresh the page.

Answer 2

So this should work:
File: headersessioncookie.php
<?php
//Session
session_start();
if ( !isset($_SESSION['loggedin']) )
$_SESSION['loggedin'] = FALSE;
//Cookie
$expiry = time()+60*60*9000;
if ( !isset($_COOKIE['cookieloggedin']) )
setcookie('cookieloggedin', '', $expiry, "", "", true);
?>
File: test.php
<?php
require_once('headersessioncookie.php'); //start session and cookie
$_SESSION['loggedin'] = TRUE;
setcookie('cookieloggedin', '1', $expiry, "", "", true);
?>
File: test1.php
<?php
require_once('headersessioncookie.php'); //start session and cookie
echo "sessionvalue" . $_SESSION['loggedin'] . '<br>';
echo "cookievalue" . $_COOKIE['cookieloggedin'] . '<br>';
?>
Please notice also:
-How to update a cookie: https://stackoverflow.com/a/6487597/3933332
-Is a Cookie Case Sensitive: https://stackoverflow.com/a/11312272/3933332

Answer 3

Answering my own question. Turns out there were 3 major problems with my code.
1) I was trying to set the cookie value by doing this:
$_COOKIE['cookie[loggedin]'] = FALSE;
Turns out one needs to use setcookie() to set the cookie value. Assigning a new value to $_COOKIE will change the value of that variable (within the scope of the same page), but it won't change the value inside the cookie (outside the scope of that page, calling $_COOKIE will yield the value stored in the cookie).
2) The following is incorrect
echo "cookievalue" . $_COOKIE['cookie[loggedin]'] . '<br>';
Instead it should be
echo "cookievalue" . $_COOKIE['cookie']['loggedin'] . '<br>';
3) Cookie necessarily has to be passed a string value. I was trying to pass a value = FALSE which is not a string. Instead, I could have correctly passed a value = 'FALSE'