<?php

    $file =$_GET['file'];
    if(file_exists($file)) {

      $fileExtension = substr($file, -3);
      if($fileExtension === "pdf"){
        $filenameIndex = strpos($file, "pdf/") + 4;
        $filename = basename($file);

      }
      elseif ($fileExtension === "mp3") {
        $filenameIndex = strpos($file, "mp3/") + 4;
        $filename = basename($file);
      }

      header('Content-Type: application/octet-stream');
      header('Content-Disposition: attachment; filename="'.$filename.'"');
      header('Content-length: '. filesize($file));
      header('X-Pad: avoid browser bug');
      header('Cache-Control: no-cache');
      header('Content-Transfer-Encoding: chunked');
      readfile($file);
      print file_get_contents($file);
      exit;
    }
    ?>