Sending correct file size with PHP download script

Question

I created a file download script in PHP, it works, but web browsers report the file as \"Unknown Length\". My code is as follows:

function downloadFile($fil         


        

Answer 1

I had this same problem, and I fixed it by sending the Content-Length header before the Content-Disposition.

header('Content-Type: video/mp4');
header("Content-Transfer-Encoding: Binary"); 
header("Content-Length: ".filesize($file_url));
header("Content-disposition: attachment; filename=\"" . basename($file_url) . "\""); 
readfile($file_url);

Answer 2

Try not flushing the cache before readfile() function. My code is almost identical to yours otherwise, and works fine.

Answer 3

Originally from http://paul.luminos.nl/update/471:

The CrimsonBase website verifies downloads by passing them through a robust PHP script similar to the one published by Andrew Johnson in his article about PHP-controlled file downloads.

Andrew makes a very important comment at the end of the article:

"If you compress files with Zlib, mod_deflate and so on the Content-Length header won't be accurate so you'll end up seeing "Unknown size" and "Unknown time remaining" when downloading files."

I would like to stress this: if your browser doesn't appear to be obeying the headers generated by your PHP script—especially Content-Length—it is fairly likely that Apache's mod_deflate extension is enabled.

You can easily disable it for a single script using the following line in an applicable .htaccess file:

SetEnvIfNoCase Request_URI ^/download\.php no-gzip dont-vary

where download.php is here assumed to be in the download script located in the server's root directory path (e.g. www.crimsonbase.com/download.php). (That's because the regular expression is ^/download\.php.)