PHP output file on disk to browser

There is fpassthru() that should do exactly what you need. See the manual entry to read about the following example:

<?php

// open the file in a binary mode
$name = './img/ok.png';
$fp = fopen($name, 'rb');

// send the right headers
header("Content-Type: image/png");
header("Content-Length: " . filesize($name));

// dump the picture and stop the script
fpassthru($fp);
exit;

?>

See here for all of PHP's filesystem functions.

If it's a binary file you want to offer for download, you probably also want to send the right headers so the "Save as.." dialog pops up. See the 1st answer to this question for a good example on what headers to send.

I use this

  if (file_exists($file)) {


        header('Content-Description: File Transfer');
        header('Content-Type: application/octet-stream');
        header('Content-Disposition: attachment; filename='.basename($file));
        header('Content-Transfer-Encoding: binary');
        header('Expires: 0');
        header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
        header('Pragma: public');
        header('Content-Length: ' . filesize($file));

        ob_clean();
        flush();
        readfile($file);
        exit;

    } 

I use readfile() ( http://www.php.net/readfile )...

But you have to make sure you set the right "Content-Type" with header() so the browser knows what to do with the file.

You can also force the browser to download the file instead of trying to use a plug-in to display it (like for PDFs), I always found this to look a bit "hacky", but it is explained at the above link.

This should get you started: http://de.php.net/manual/en/function.readfile.php

Edit: If your web server supports it, using

header('X-Sendfile: ' . $filename);

where file name contains a local path like

/var/www/www.example.org/downloads/example.zip

is faster than readfile().

(usual security considerations for using header() apply)