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. Lets say that process takes 5 minutes to finish.

In the meantime the user gets bored and closes his browser window.

Will the script on the server continue its processing until it finishes on its normal time, or will it stop?

Same thing if the user visits a url, e.g example.com/process.php?data=xxx. This starts process.php which begins to process the data, and will take 5 mins to finish processing.

Will this processing always continue on, or if the user closes the browser, will it stop?

(I’m asking because I’m concerned about the process being left half finished and resulting in corrupt data).

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.