PHP header download corrupts some files

[ScopeXL]

Hello,

 

I am trying to build a script that downloads a file from a specific location using a PHP header, though some of the files download as 0 bytes and are corrupted when extracted (if a .zip). Am I doing something wrong with these headers?

 

if (file_exists("downloads/file.zip"))
{
error_reporting(E_ALL);
        header('Content-Encoding: none');
header('Accept-Ranges: bytes');
header("Content-Type: application/zip");
header("Content-Disposition: attachment; filename=\"file.zip\"");
header("Pragma: no-cache");
header("Expires: 0");
header("Cache-Control: must-revalidate, post-check=0, pre-check=0"); 
header("Content-Length: ".filesize("downloads/file.zip");
ob_clean();
flush();
readfile("downloads/file.zip");
exit;
}

 

Some files work, some are corrupted. I cannot wrap my head around whats causing this. I tried downloading the files straight from FTP and they are not corrupted so I'm fairly sure its the header. Any help would be appreciated. Thank you.

[mcjwb]

There are a few postings on the php manual page, http://uk.php.net/manual/en/function.readfile.php, about corrupt files that may help you. In particular, setting error_reporting to 0.

 

Otherwise you could try opeining the corrupted file in a text editor and seeing if there is a readable error message in there.

 

One other thing to note is the file size. Do the files that get corrupted have large/similar file sizes? If so you will need to send/download the file in chunks - there is a function on the php manual page that will do this for you.

 

If none of the above helps, is there any other information/observations you can provide that may help dianose the problem?

[ScopeXL]

Ah, I was unaware their was a limit to what readfile() could handle. Thank you. For those with the same problem, I fixed with:

 

$filename = '/path/to/file.ext';
if (filesize($filename) > 4194304)
{
// Forcibly end any output buffering going on.
if (function_exists('ob_get_level'))
{
	while (@ob_get_level() > 0)
		@ob_end_clean();
}
else
{
	@ob_end_clean();
}
	$fp = fopen($filename, 'rb');
while (!feof($fp))
{
	echo fread($fp, 8192);
	flush();
}
fclose($fp);
}
else
{
readfile($filename);
}

 

Thanks again mcjwb.