Read, Delete, Anonymize: Possibly long operations?

[allendav]

A plugin might have a lot of data to gather during a call to its read_userdata method. With database writing in the mix, delete_userdata and especially anonymize_userdata could take even longer than that. For example, in the case where a user has hundreds of comments on a site.

PHP has a default timeout of 60 seconds, and long pauses without progress are not the best UX. Some API clients might demand responses faster than 60 seconds even.

Let's come with a pattern that allows plugins to process userdata in batches and advise callers of progress/completion.

[vyskoczilova]

What about cron? Just plan it there, split it to smaller batches and let it doo the job. This technique I have used here: https://github.com/vyskoczilova/persoo-for-woocommerce (have a look inside the persoo-for-woocommerce/includes/class-persoo-xml-helpers.php around line 90 and in persoo-for-woocommerce/persoo-for-woocommerce.php around line 104 for scheduling the cron).

[allendav]

@vyskoczilova wrote:

What about cron? Just plan it there, split it to smaller batches and let it doo the job.

Yup! We would need to do something like that. We should also consider the final UX - which I imagine would include some sort of JavaScript polling and a progress indicator. The polling could kick-off processing of the next "small batch" much like wp_cron could.

The advantage to wp_cron would be that I would not need to leave the JS UI open to get the "long operation" to ultimately complete.