Remove file after fpassthru, is there a callback? - php

Question

This could works perfectly in passing a zipped file back to the client. But the little snippet at the end unlinking the file doesn't seem to be working?
I am assuming that the fpassthru locks the file, so the unlink cannot do anything..
Is there a callback option available.. something to remove the file after the client has received it?
// we deliver a zip file
header("Content-Type: archive/zip");
// filename for the browser to save the zip file
header("Content-Disposition: attachment; filename=$guideName".".zip");
$filesize = filesize($zip_file);
header("Content-Length: $filesize");
// deliver the zip file
$fp = fopen($zip_file,'r');
echo fpassthru($fp);
// clean up the tmp zip file
unlink($zip_file);
exit();

Answer 1

While the file is opened, it's locked and cannot be deleted.
fclose($fp);
unlink($zip_file);
Also make sure the file is writable by the www-user / fpm script owner (=> chmod).
To debug this, I suggest a combination of error reporting, output buffers and mail:
ob_start();
error_reporting(E_ALL);
fclose($fp);
unlink($zip_file);
$debug = ob_get_contents();
mail('you#server', 'error in zip upload', var_export($debug, true));
Another sidenote is the concatenation here:
("Content-Disposition: attachment; filename=$guideName".".zip")
Properly:
("Content-Disposition: attachment; filename=" . $guideName . ".zip")
You could also use file_get_contents() which is basically the same as fopen, fpassthru, fclose in once:
header("Content-Length: $filesize");
// deliver the zip file
echo file_get_contents($zip_file);
// clean up the tmp zip file
unlink($zip_file);

Answer 2

You are ceating a file handle with the call to fopen, which is what will be locking the file. You need to ensure that you call fclose before unlink. E.g.
$fp = fopen($zip_file,'r');
echo fpassthru($fp);
fclose($fp);
unlink($zip_file);

Answer 3

First of all there is an error in your code which will most likely corrupt the file you are sending:
Return values
If an error occurs, fpassthru() returns FALSE. Otherwise, fpassthru()
returns the number of characters read from handle and passed through
to the output.
Therefore your code should look like:
// deliver the zip file
$fp = fopen($zip_file,'r');
fpassthru($fp);
Notice there is no echo before fpassthru.
A MUCH more reliable solution would be to run a separate script to clean the folder where these files are stored every x minutes/hours/days.
If the file is open and you delete it, it is still open and can be read from, but no longer accessible by file name. When script terminates and file handle is closed the space taken by the file will be freed.
The other possible way is using session shutdown handler.