January 4, 2011
storing multiple values of a variable in cookie and comparing
Question by John
How can i store multiple values for a variable in cookie using php, for example
$id = 1,2,4,5
Then how can i compare the stored values with a variable? for example, $new_id=4, i want to check if $new_id value exists in the stored values of $id in cookie.
Thanks for help and have a nice day.
Answer by tdammers
You can store arbitrary strings in cookie elements, so a serialized array should work. Example:
// To store:
$ids = array(1, 2, 3, 4);
setcookie('ids', serialize($ids));
// To retrieve:
$serialized = $_COOKIE['ids'];
$ids = unserialize($serialized);
// sanity check: $ids needs to be an array.
assert(is_array($ids));
// Now let's check:
if (in_array(4, $ids)) {
// Yes, it's here.
}
A few caveats though:
- The cookie is completely in the hands of the client, and cookie values should never be trusted. Treat them just like you would treat query string parameters or POST data.
- Cookies offer very limited storage (IIRC, the standard gives you 4096 bytes to work with).
With these in mind, it might be a better idea to store the array in $_SESSION instead – this will give you virtually unlimited storage, and the only way for the client application to fiddle with the values is through your code.
Answer by Starx
Store array in cookie and then compare them
