php通过已知字符串截取url域名

<?php
function extractDomain($url) {
    // 正则表达式匹配域名
    $pattern = '/^(?:https?:\/\/)?(?:[^@\n]+@)?(?:www\.)?([^:\/\n]+)/';
    preg_match($pattern, $url, $matches);
    return isset($matches[1]) ? $matches[1] : null;
}

// 测试字符串
$url = "https://www.example.com/path/to/resource?query=param";

// 提取域名
$domain = extractDomain($url);

// 输出结果
echo "Extracted Domain: " . $domain; // 输出: Extracted Domain: www.example.com
?>

$url = urldecode($url);

function extractDomainWithoutWWW($url) {
    $pattern = '/^(?:https?:\/\/)?(?:[^@\n]+@)?(?:www\.)?([^:\/\n]+)/';
    preg_match($pattern, $url, $matches);
    $domain = isset($matches[1]) ? $matches[1] : null;
    return strpos($domain, 'www.') === 0 ? substr($domain, 4) : $domain;
}