PHPで実際のファイルのダウンロードアドレスを隠す方法

function download_document($filename,$path="",$mimetype="application/octet-stream")
{
 header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
 header("Content-Disposition: attachment; filename = $filename");
 header("Content-Length: " . filesize($pathto . $filename));
 header("Content-Type: $mimetype");
 echo file_get_contents($pathto . $filename);
}

<?php
$file = "1.txt";// 文件的真实地址（支持url,不过不建议用url）
if (file_exists($file)) {
  header(&#39;Content-Description: File Transfer&#39;);
  header(&#39;Content-Type: application/octet-stream&#39;);
  header(&#39;Content-Disposition: attachment; filename=&#39;.basename($file));
  header(&#39;Content-Transfer-Encoding: binary&#39;);
  header(&#39;Expires: 0&#39;);
  header(&#39;Cache-Control: must-revalidate, post-check=0, pre-check=0&#39;);
  header(&#39;Pragma: public&#39;);
  header(&#39;Content-Length: &#39; . filesize($file));
  ob_clean();
  flush();
  readfile($file);
  exit;
}
?>