Content-Disposition: - Sending Files for Downloading

PHP Tutorials - Herong's Tutorial Examples - Version 4.20, by Dr. Herong Yang

PHP Tutorials - Herong's Tutorial Examples

∟Controlling HTTP Response Header Lines in PHP Scripts

∟Content-Disposition: - Sending Files for Downloading

This section provides a tutorial example on how to insert the 'Content-Disposition:' header line in a HTTP response to tell the browser to prompt the user the download and save the response entity body as a file.

In the previous section, the requested file is delivered to the browser for opening immediately. HTTP does also support another header line called "Content-Disposition" which tells the browser to not open the file immediately, but prepare for downloading the entity body. The following script will show you how to do this:

<?php 
#  Download.php
#- Copyright (c) 2003-2019, HerongYang.com, All Rights Reserved.
#
   $ok = array_key_exists('QUERY_STRING', $_SERVER);
   if ($ok) {
      $p = $_SERVER['QUERY_STRING'];
      $ok = strlen($p)>0 && file_exists($p);
   }
   if ($ok) {
      if (strpos($p,".html")!=false) {
         header("Content-Type: text/html");
      } else if (strpos($p,".gif")!=false) {
         header("Content-Type: image/gif");
      } else if (strpos($p,".pdf")!=false) {
         header("Content-Type: application/pdf");
      } else if (strpos($p,".doc")!=false) {
         header("Content-Type: application/msword");
      } else {
         $ok = false;
      }
   }
   if ($ok) {
      header("Content-Length: ".filesize($p));
      header("Content-disposition: attachment; filename=".$p);
      readfile($p);
   } else {
      print("<html><body>Bad request.</body></html>");
   }
?>

In this page, another header line, "Content-Disposition", is added to the response, in which I am telling the client program that the entity data is an attachment, with file name specified.

Now try to use IE to request http://localhost/Download.php?hello.pdf, you will see IE prompting you to save the attachment instead of calling Adobe Reader to display the data.

Try to use IE to request http://localhost/Download.php?other_existing_file, you will see IE display the "Bad request" message. The script is working correctly.

Last update: 2019.

Table of Contents

About This Book

Introduction and Installation of PHP 7.3

PHP Script File Syntax

PHP Data Types and Data Literals

Variables, References, and Constants

Expressions, Operations and Type Conversions

Conditional Statements - "if" and "switch"

Loop Statements - "while", "for", and "do ... while"

Function Declaration, Arguments, and Return Values

Arrays - Ordered Maps