php截取域名中间

<?php
function getDomainMiddlePart($url) {
    $pattern = '/(?<=:\/\/)[^\/]+(?=\/)/';
    preg_match($pattern, $url, $matches);
    if (!empty($matches)) {
        return $matches[0];
    }
    return null;
}

$url = "https://www.example.com/path/to/resource";
$middlePart = getDomainMiddlePart($url);
echo $middlePart; // 输出: example
?>

<?php
function isValidUrl($url) {
    return filter_var($url, FILTER_VALIDATE_URL);
}

$url = "https://www.example.com/path/to/resource";
if (isValidUrl($url)) {
    $middlePart = getDomainMiddlePart($url);
    echo $middlePart; // 输出: example
} else {
    echo "Invalid URL";
}
?>