Home > Programming > PHP codes to tell browsers to open the download dialog box for users to download a file instead of open into the Browsers

PHP codes to tell browsers to open the download dialog box for users to download a file instead of open into the Browsers

A fairly common question is, “How can I force a file to download to the user?” The answer is, you really cannot. You will need something on the server to send a Content-Disposition header to set the file as an attachment instead of being inline. You could do this with plain Apache configuration though.

<a href="download.php?file=path/<?=$row['file_name']?>">Download</a>

download.php:

<?php

$file = $_GET['file'];

download_file($file);

function download_file( $fullPath ){

  // Must be fresh start
  if( headers_sent() )
    die('Headers Sent');

  // Required for some browsers
  if(ini_get('zlib.output_compression'))
    ini_set('zlib.output_compression', 'Off');

  // File Exists?
  if( file_exists($fullPath) ){

    // Parse Info / Get Extension
    $fsize = filesize($fullPath);
    $path_parts = pathinfo($fullPath);
    $ext = strtolower($path_parts["extension"]);

    // Determine Content Type
    switch ($ext) {
      case "pdf": $ctype="application/pdf"; break;
      case "exe": $ctype="application/octet-stream"; break;
      case "zip": $ctype="application/zip"; break;
      case "doc": $ctype="application/msword"; break;
      case "xls": $ctype="application/vnd.ms-excel"; break;
      case "ppt": $ctype="application/vnd.ms-powerpoint"; break;
      case "gif": $ctype="image/gif"; break;
      case "png": $ctype="image/png"; break;
      case "jpeg":
      case "jpg": $ctype="image/jpg"; break;
      default: $ctype="application/force-download";
    }

    header("Pragma: public"); // required
    header("Expires: 0");
    header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
    header("Cache-Control: private",false); // required for certain browsers
    header("Content-Type: $ctype");
    header("Content-Disposition: attachment; filename=\"".basename($fullPath)."\";" );
    header("Content-Transfer-Encoding: binary");
    header("Content-Length: ".$fsize);
    ob_clean();
    flush();
    readfile( $fullPath );

  } else
    die('File Not Found');

}
?>

The way to force the browser not to handle the file internally is to change the headers (content-disposition prefereably, or content-type) so the browser will not try to handle the file internally. You can either do this by writing a script on the webserver that dynamically sets the headers (i.e. download.php) or by configuring the webserver to return different headers for the file you want to download.

Categories: Programming
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