Can closing the browser terminate the PHP script on the server?

Question

Say a user clicked a button, which resulted in a jquery ajax request being sent to my server.

The server begins a complicated process in response to the ajax request

Answer 1

PHP won't notice that the browser closed the connection unless it tries to output something (e.g. echo). If it fails to output something, the script will be terminated unless ignore_user_abort is On.

So the script will terminate only if the following conditions are met:

• the script attempts to output something (because the script won't notice that the user aborted the connection until then)
• AND php's ignore_user_abort setting is off (if the setting is off, php will terminate the script if fails to output something)

You can avoid the script from terminating by enabling ignore_user_abort.

You can use connection_aborted() at anytime to check is the browser aborted the request.

A script can terminate unexpectedly for other reasons (e.g. max execution time, exception, etc); so you should make use of transactions, so that half-finished changes are canceled if the script terminates abnormally.

Answer 2

The default behaviour for PHP is that your script will be aborted when the remote client disconnects, usually caused by a user closing their browser or hitting the stop button. It can also happen when someone closes a remote connection to a script run in CLI mode. The one exception to your script aborting is if you have registered a shutdown function using register_shutdown_function(). For a thorough explanation please see the Connection Handling page in PHP docs.

The point at which the script actually terminates is dependent upon when flush() is called, which essentially attempts to push current output all the way to the browser/client. At this point if the state of the connection is ABORTED then the script will terminate, unless we are ignoring user abort.

The important thing to note is that you can control whether this behaviour occurs or not, as you specify sometimes it is undesirable for this to happen. Using the ignore_user_abort() function or setting the associated directive in php.ini.

Answer 3

See: http://php.net/manual/en/function.ignore-user-abort.php. It depends on the ignore_user_abort setting and a few other conditions.

Answer 4

Unless it's launched as a background process i.e. with the & at the end... it will just terminate.

Closing browser a bit more to it... It will stop eventually, but will process for a little while before web server realises connection is gone.