PHP download file: show progress in browser - php

Question

User on my site can download files. Sometimes these files are pretty large and I would like users to see download progress bar at their browsers.
I use the following code to give user a file:
header('Content-Type: text/xml');
header('Content-Disposition: attachment; filename='.$fileName);
header('Pragma: no-cache');
header('Content-Transfer-Encoding: binary');
header('Pragma: public');
header('Content-Length: '.filesize($fullFileName));
header("Content-Description: File Transfer");
$fileHandler = fopen($fullFileName, 'r');
while(!feof($fileHandler)){
echo fread($fileHandler, 2048);
}
fclose($fileHandler);
When I run this script browser(FireFox) freezes for some time, I can see loading colour circle and only after save/open dialog file appears. When I click on "save" button, file almost immediately is downloaded to my computer(while file is quite large - 50 Mb).
I want to have downloading system like on this site. Dialog for save/opean appears immediately when you click on any links. And after you can see downloading progress in your browser.
Are there any special headers to display progress bar in browser? How I should change my code?

Answer 1

I use the code below, and in Firefox it does give me the download time and progress:
// send headers first
header('Content-type: application/octet-stream');
header('Content-Transfer-Encoding: binary');
header('Content-disposition: attachment; filename='.$FileName);
header("Content-Length: ".filesize($Path));
// then use an easy way to flush and end all output buffers
while (#ob_end_flush());
// flush file
readfile($Path);
It should work if you specify Content-Length correctly. The only thing I find mildly weird in your code is the Content-Type: text/xml header. Note that I use Content-type: application/octet-stream.