nextcloud/apps/bookmarks/bookmarksHelper.php

<?php

// Source: http://www.php.net/manual/de/function.curl-setopt.php#102121
// This works around a safe_mode/open_basedir restriction
function curl_exec_follow(/*resource*/ $ch, /*int*/ &$maxredirect = null) {
	$mr = $maxredirect === null ? 5 : intval($maxredirect);
	if (ini_get('open_basedir') == '' && ini_get('safe_mode' == 'Off')) {
		curl_setopt($ch, CURLOPT_FOLLOWLOCATION, $mr > 0);
		curl_setopt($ch, CURLOPT_MAXREDIRS, $mr);
	} else {
		curl_setopt($ch, CURLOPT_FOLLOWLOCATION, false);
		if ($mr > 0) {
			$newurl = curl_getinfo($ch, CURLINFO_EFFECTIVE_URL);

			$rch = curl_copy_handle($ch);
			curl_setopt($rch, CURLOPT_HEADER, true);
			curl_setopt($rch, CURLOPT_NOBODY, true);
			curl_setopt($rch, CURLOPT_FORBID_REUSE, false);
			curl_setopt($rch, CURLOPT_RETURNTRANSFER, true);
			do {
				curl_setopt($rch, CURLOPT_URL, $newurl);
				$header = curl_exec($rch);
				if (curl_errno($rch)) {
					$code = 0;
				} else {
					$code = curl_getinfo($rch, CURLINFO_HTTP_CODE);
					if ($code == 301 || $code == 302) {
						preg_match('/Location:(.*?)\n/', $header, $matches);
						$newurl = trim(array_pop($matches));
					} else {
						$code = 0;
					}
				}
			} while ($code && --$mr);
			curl_close($rch);
			if (!$mr) {
				if ($maxredirect === null) {
					trigger_error('Too many redirects. When following redirects, libcurl hit the maximum amount.', E_USER_WARNING);
				} else {
					$maxredirect = 0;
				}
				return false;
			}
			curl_setopt($ch, CURLOPT_URL, $newurl);
		}
	}
	return curl_exec($ch);
}

function getURLMetadata($url) {
	//allow only http(s) and (s)ftp
	$protocols = '/^[hs]{0,1}[tf]{0,1}tp[s]{0,1}\:\/\//i';
	//if not (allowed) protocol is given, assume http
	if(preg_match($protocols, $url) == 0) {
		$url = 'http://' . $url;
	} 
	$metadata['url'] = $url;

	if (!function_exists('curl_init')){
		return $metadata;
	}
	$ch = curl_init();
	curl_setopt($ch, CURLOPT_URL, $url);
	curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
	$page = curl_exec_follow($ch);
	curl_close($ch);

	@preg_match( "/<title>(.*)<\/title>/si", $page, $match );
	$metadata['title'] = htmlspecialchars_decode(@$match[1]); 

	return $metadata;
}