php 遍历网站

<?php
function traverseWebsite($url, $depth = 0, $maxDepth = 3) {
    if ($depth > $maxDepth) return;

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
    $html = curl_exec($ch);
    curl_close($ch);

    $dom = new DOMDocument();
    @$dom->loadHTML($html);
    $links = $dom->getElementsByTagName('a');

    foreach ($links as $link) {
        $href = $link->getAttribute('href');
        if (strpos($href, 'http') === 0) {
            echo "Depth $depth: $href\n";
            traverseWebsite($href, $depth + 1, $maxDepth);
        }
    }
}

traverseWebsite('https://example.com');
?>