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 #GetFile.php
# Copyright (c) 2005 by Dr. Herong Yang, http://www.herongyang.com/
#
$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, anther 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 prompting you to save the attachment. The script is working correctly.
