PHP Mobile Detection - php

Question

I have a problem with the Mobile Detection Script.
There are two scenarios:
First the script should detect if it's a mobile or not. If mobile, than redirect to another page (this works fine).
The second query should determine, if the person is on the root page or not. If it's not the root page, the layout should be the classic one. (no redirection)
But when I add this line there won't be anymore redirection, even if I open the root page on a mobile.
I also tried to destroy the session on the google_mobile.php (redirected page) and set the $_SESSION['layoutType'] = 'mobile', but anyway the session is set to classic when I open the root page.
Thanks for your help!
Here is the script:
session_start();
require_once 'Mobile_Detect.php';
function layoutTypes() {
return array('classic', 'mobile');
}
function initLayoutType() {
// Safety check.
if (!class_exists('Mobile_Detect'))
return 'classic';
$detect = new Mobile_Detect;
$isMobile = $detect->isMobile();
$layoutTypes = layoutTypes();
// Set the layout type.
if (isset($_GET['layoutType'])) {
$layoutType = $_GET['layoutType'];
} else {
if (empty($_SESSION['layoutType'])) {
$layoutType = ($isMobile ? 'mobile' : 'classic');
} else {
$layoutType = $_SESSION['layoutType'];
}
//check if it's the root page
if ($_SERVER['REQUEST_URI'] != "/")
$layoutType = 'classic';
}
// Fallback. If everything fails choose classic layout.
if (!in_array($layoutType, $layoutTypes))
$layoutType = 'classic';
// Store the layout type for future use.
$_SESSION['layoutType'] = $layoutType;
return $layoutType;
}
$layoutType = initLayoutType();
if ($_SESSION['layoutType'] == 'mobile') {
header("Location: www.example.com/google_mobile.php");
exit;
}

Answer 1

I've tested your code, it seems to work as you described. I'd guess it is a session issue.
session_destroy() does not clear your previous session state in the immediate session. That means your $_SESSION would still be "dirty" in a script even if session_destroy() is the first line in it. It's safer to clear cookies from your browser instead.
One other possible problem would be query string. You're checking the REQUEST_URI and it includes any query string on URI. "/?foo=bar" is certainly not "/". You may want to check SCRIPT_NAME (i.e. $_SERVER['SCRIPT_NAME'] == 'index.php) instead.