php execute a background process

Question

I need to execute a directory copy upon a user action, but the directories are quite large, so I would like to be able to perform such an action without the user being aware of the time it takes for the copy to complete.

Any suggestions would be much appreciated.

Answer 1

PHP scripting is not like other desktop application developing language. In desktop application languages we can set daemon threads to run a background process but in PHP a process is occuring when user request for a page. However It is possible to set a background job using server's cron job functionality which php script runs.

Answer 2

If you need to just do something in background without the PHP page waiting for it to complete, you could use another (background) PHP script that is "invoked" with wget command. This background PHP script will be executed with privileges, of course, as any other PHP script on your system.

Here is an example on Windows using wget from gnuwin32 packages.

The background code (file test-proc-bg.php) as an exmple ...

sleep(5);   // some delay
file_put_contents('test.txt', date('Y-m-d/H:i:s.u')); // writes time in a file

The foreground script, the one invoking ...

$proc_command = "wget.exe http://localhost/test-proc-bg.php -q -O - -b";
$proc = popen($proc_command, "r");
pclose($proc);

You must use the popen/pclose for this to work properly.

The wget options:

-q    keeps wget quiet.
-O -  outputs to stdout.
-b    works on background

Answer 3

You might want to try to append this to your command

>/dev/null 2>/dev/null &

eg.

shell_exec('service named reload >/dev/null 2>/dev/null &');

Answer 4

You might try a queuing system like Resque. You then can generate a job, that processes the information and quite fast return with the "processing" image. With this approach you won't know when it is finished though.

This solution is intended for larger scale applications, where you don't want your front machines to do the heavy lifting, so they can process user requests. Therefore it might or might not work with physical data like files and folders, but for processing more complicated logic or other asynchronous tasks (ie new registrations mails) it is nice to have and very scalable.

Answer 5

I know it is a 100 year old post, but anyway, thought it might be useful to someone. You can put an invisible image somewhere on the page pointing to the url that needs to run in the background, like this:

<img src="run-in-background.php" border="0" alt="" width="1" height="1" />

Answer 6

Can you arrange to fork off a separate process, and then run your copy in the background? It's been a while since I did any PHP, but the function pcntl-fork looks promising.