PHP readfile() and large files

Question

When using readfile() -- using PHP on Apache -- is the file immediately read into Apache\'s output buffer and the PHP script execution completed, or does the PHP script exec

Answer 1

downloading files thru php isnt very efficient, using a redirect is the way to go. If you dont want to expose the location of the file, or the file isnt in a public location then look into internal redirects, here is a post that talks about it a bit, Can I tell Apache to do an internal redirect from PHP?

Answer 2

Under Apache, there is a nice elgant solution not involving php at all:

Just place an .htaccess config file into the folder containing the files to be offered for download with the following contents:

<Files *.*>
ForceType applicaton/octet-stream
</Files>

This tells the Apache to offer all files in this folder (and all its subfolders) for download, instead of directly displaying them in the browser.

Answer 3

Try using stream_copy_to_stream() instead. I find is has fewer problems than readfile().

set_time_limit(0);
$stdout = fopen('php://output', 'w');
$bfname = basename($fname);

header("Content-type: application/octet-stream");
header("Content-Disposition: attachment; filename=\"$bfname\"");

$filein = fopen($fname, 'r');
stream_copy_to_stream($filein, $stdout);

fclose($filein);
fclose($stdout);

Answer 4

a few things you can do (I am not reporting all the headers that you need to send that are probably the same ones that you currently have in your script):

set_time_limit(0);  //as already mention
readfile($filename);
exit(0);

or

passthru('/bin/cat '.$filename);
exit(0);

or

//When you enable mod_xsendfile in Apache
header("X-Sendfile: $filename");

or

//mainly to use for remove files
$handle = fopen($filename, "rb");
echo stream_get_contents($handle);
fclose($handle);

or

$handle = fopen($filename, "rb");
while (!feof($handle)){
    //I would suggest to do some checking
    //to see if the user is still downloading or if they closed the connection
    echo fread($handle, 8192);
}
fclose($handle);

Answer 5

You may still have PHP output buffering active while performing the readfile(). Check that with:

if (ob_get_level()) ob_end_clean();

or

while (ob_get_level()) ob_end_clean();

This way theonly remaining output Buffer should be apache's Output Buffer, see SendBufferSize for apache tweaks.

EDIT

You can also have a look at mod_xsendfile (an SO post on such usage, PHP + apache + x-sendfile), so that you simply tell the web server you have done the security check and that now he can deliver the file.

Answer 6

See below url

http://php.net/manual/en/function.readfile.php

<?php
$file = 'monkey.gif';

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');
    header('Pragma: public');
    header('Content-Length: ' . filesize($file));
    ob_clean();
    flush();
    readfile($file);
    exit;
}
?>