Abandon Long Processes in PHP (But let them complete)

Question

I have an HTML form that submits to a PHP page which initiates a script. The script can take anywhere from 3 seconds to 30 seconds to run - the user doesn't need to be around for this script to complete.

Is it possible to initiate a PHP script, immediately print "Thanks" to the user (or whatever) and let them go on their merry way while your script continues to work?

In my particular case, I am sending form-data to a php script that then posts the data to numerous other locations. Waiting for all of the posts to succeed is not in my interest at the moment. I would just like to let the script run, allow the user to go and do whatever else they like, and that's it.

Answer 1

Place your long term work in another php script, for example

background.php:

sleep(10);
file_put_contents('foo.txt',mktime());

foreground.php

$unused_but_required = array();
proc_close(proc_open ("php background.php &", array(), $unused_but_required));
echo("Done);

You'll see "Done" immediately, and the file will get written 10 seconds later.

I think proc_close works because we've giving proc_open no pipes, and no file descriptors.

Answer 2

In the script you can set:

<?php
 ignore_user_abort(true);

That way the script will not terminate when the user leaves the page. However be very carefull when combining this whith

 set_time_limit(0);

Since then the script could execute forever.

Answer 3

You can use set_time_limit and ignore_user_abort , but generally speaking, I would recommend that you put the job in a queue and use an asynchronous script to process it. It's a much simpler and durable design.

Answer 4

You could try the flush and related output buffer functions to immediately send the whatever is in the buffer to the browser:

Answer 5

Theres an API wrapper around pcntl_fork() called php_fork .

But also, this question was on the Daily WTF ... don't pound a nail with a glass bottle.

Answer 6

I ended up with the following.

<?php

  // Ignore User-Requests to Abort
  ignore_user_abort(true);
  // Maximum Execution Time In Seconds
  set_time_limit(30);

  header("Content-Length: 0");
  flush();

  /*

    Loooooooong process

  */

?>