PHP：仅使用cURL写入文件

Due to hosting company restrictions we cannot use fopen() or file_put_contents(). So the question is, can I substitute the following code with cURL?

$fp = fopen("xyz/abc.pdf", "w");
if($fp)
{
    fwrite($fp, $contents);
    fclose($fp);
}

Additionally, the directory to which we are writing the file is outside of the web root (for security purposes).

Maybe help:

    function curl_download($Url, $saveTo)
    {
        $fp = fopen ($saveTo, 'w+');
         
        $ch = curl_init($Url);
         
        curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/5.0");
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_TIMEOUT, 1000);
        curl_setopt($ch, CURLOPT_FILE, $fp);

        curl_exec($ch);

        $result = curl_close($ch);
         
        return $result;
    }

    curl_download('http://code.freetuts.net/upload/tut/images/2015/03/25/345/selector-la-gi-tim-hieu-css-selector-can-ban.gif', './');