Abandon Long Processes in PHP (But let them complete)

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.

From stackoverflow

• 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.

  Jonathan Sampson : Could you be a bit more descriptive in your answer?

  thomasrutter : Could you explain how it works? Looks like it tries to close the process immediately after it opens. According to proc_close documentation, it will wait for the process to terminate - isn't this what we wanted to avoid?

  Gabriel Sosa : I use this method to do threading and works really well

  Daniel Von Fange : Updated with more sample code.

  Jonathan Sampson : Daniel, how would you pass the $_POST/$_GET values to the background.php script?

  Daniel Von Fange : You could write them into a database table, and pass it the id as a argument, or you could serialize() the $_REQUEST and pass it as an argument (make sure to have it escaped)

  Bob Somers : I'd say you should avoid passing parameters to the script over the command line at all costs. All it takes is one poorly sanitized input and you've seriously compromised your system.

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

• 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.

• 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.

• 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.

• 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
  
    */
  
  ?>