如何从URL下载文件到脚本的ftp？

I have a file, let's say sample.xml located at www.sample.com

I want a script, say, download.php located at www.download.com

download.php to download sample.xml and store it in download.com's ftp

I have this code but it downloads to the users local machine

$file_url = 'http://sample.com';

    header('Content-Type: application/octet-stream');
    header("Content-Transfer-Encoding: Binary"); 
    header("Content-disposition: attachment; filename='sample.xml'");

readfile($file_url);

Can someone advise a way to download straight to the hosts ftp?

$sample = file_get_contents('http://www.sample.com/sample.xml');
file_put_contents('sample.xml', $sample);

do it like this