Continue PHP execution after sending HTTP response

How can I have PHP 5.2 (running as apache mod_php) send a complete HTTP response to the client, and then keep executing operations for one more minute?

The long story:

I have a PHP script that has to execute a few long database requests and send e-mail, which takes 45 to 60 seconds to run. This script is called by an application that I have no control over. I need the application to report any error messages received from the PHP script (mostly invalid parameter errors).

The application has a timeout delay shorter than 45 seconds (I do not know the exact value) and therefore registers every execution of the PHP script as an error. Therefore, I need PHP to send the complete HTTP response to the client as fast as possible (ideally, as soon as the input parameters have been validated), and then run the database and e-mail processing.

I'm running mod_php, so pcntl_fork is not available. I could work my way around this by saving the data to be processed to the database and run the actual process from cron, but I'm looking for a shorter solution.

Solution 1:

I had this snippet in my "special scripts" toolbox, but it got lost (clouds were not common back then), so I was searching for it and came up with this question, surprised to see that it's missing, I searched more and came back here to post it:

<?php
 ob_end_clean();
 header("Connection: close");
 ignore_user_abort(); // optional
 ob_start();
 echo ('Text the user will see');
 $size = ob_get_length();
 header("Content-Length: $size");
 ob_end_flush(); // Strange behaviour, will not work
 flush();            // Unless both are called !
 session_write_close(); // Added a line suggested in the comment
 // Do processing here 
 sleep(30);
 echo('Text user will never see');
?>

I actually use it in few places. And it totally makes sense there: a banklink is returning the request of a successful payment and I have to call a lot of services and process a lot of data when that happens. That sometimes takes more than 10 seconds, yet the banklink has fixed timeout period. So I acknowledge the banklink and show him the way out, and do my stuff when he is already gone.

Solution 2:

Have the script that handles the initial request create an entry in a processing queue, and then immediately return. Then, create a separate process (via cron maybe) that regularly runs whatever jobs are pending in the queue.