How can PHP developers handle cases where the HTTP_REFERER variable returns empty or inaccurate data for tracking purposes?

When the HTTP_REFERER variable returns empty or inaccurate data, PHP developers can use alternative methods to track user referrals. One common approach is to use cookies or session variables to store referral information when the HTTP_REFERER is not available. Another option is to include a tracking parameter in URLs that lead to the site, allowing developers to track referrals directly from the URL itself.

// Check if HTTP_REFERER is empty or inaccurate
if(empty($_SERVER['HTTP_REFERER']) || !filter_var($_SERVER['HTTP_REFERER'], FILTER_VALIDATE_URL)) {
    // Use cookies or session variables to store referral information
    $_SESSION['referral'] = "Unknown";
} else {
    // Extract referral information from HTTP_REFERER
    $referral = $_SERVER['HTTP_REFERER'];
    // Process the referral information as needed
}