跨多个页面存储PHP会话

Question

I have setup a PHP session to capture the CAMPAIGN and CLICKID variables that are passed to the site within a URL - i.e. domain.com/index.php?&clickid=test1&campaign=test1. I am achieving this using he code below :

<?php
session_start();
$_SESSION["campaign"] = $_GET['campaign'];
$_SESSION["clickid"] = $_GET['clickid'];
?>

I then pass this out to a third party in an external link, for example test.php?&clickid=&campaign=.

However what l cannot seem to do is share this SESSION across the domain. This script works if you land on page A and click the link, however what l want to be able to do is the user to click the link, visit page X and page Y, return to the page A and the variables still be stored.

Can anyone help ?

Answer 1

It appears you are overwritting your variables - if there are no get parameters.

You should only write to session if the parameters exist:

<?php
session_start();

if(isset($_GET['campaign'])){
    $_SESSION["campaign"] = $_GET['campaign'];
}
if(isset($_GET['clickid'])){
    $_SESSION["clickid"] = $_GET['clickid'];
}


?>