php获取url的跳转最终地址

<?php
function getFinalUrl($url) {
    $headers = get_headers($url);
    if (is_array($headers)) {
        foreach ($headers as $header) {
            if (strpos($header, 'Location:') !== false) {
                $location = trim(substr(strstr($header, 'Location:'), 10));
                if (strpos($location, 'http') === 0) {
                    return getFinalUrl($location); // 递归调用以处理进一步的重定向
                } else {
                    return $url . $location; // 处理相对URL
                }
            }
        }
    }
    return $url; // 如果没有找到Location头，则返回原始URL
}

$initialUrl = 'http://example.com/some-redirect-url';
$finalUrl = getFinalUrl($initialUrl);
echo "The final URL is: " . $finalUrl;
?>

function getFinalUrl($url, $maxRedirects = 10) {
    if ($maxRedirects <= 0) {
        throw new Exception("Too many redirects");
    }
    // ... 其余代码不变 ...
}

if (strpos($location, 'http') !== 0) {
    $urlParts = parse_url($url);
    $finalUrl = $urlParts['scheme'] . '://' . $urlParts['host'] . $location;
    return getFinalUrl($finalUrl, $maxRedirects - 1);
}

if ($headers === false) {
    throw new Exception("Failed to retrieve headers for URL: " . $url);
}