如何在后台处理请求，然后报告结果？

I need to perform a time-consuming task when the user clicks a button. Basically, I'll be doing some processing on every post, sending requests to a remote server for many.

The user won't need the result immediately, so I can run it in the background. But I need to be able to tell the user whether the task has finished yet or not (and the result if finished) when they visit that page again. Additionally, I don't want them to be able to start another instance of the same task (by clicking the button) while the first one is still running.

Any way I can do all of the above?

EDIT: I am developing for WordPress. It was tagged, but I think I should have mentioned it in the question.

You need JavaScript to make Ajax Requests.

You need to learn at least the basics of JavaScript, then you can try one of Libraries ( e.g. jQuery ) or you can make one if you can.

This is the basic process I would go through

1. Create a session (stored in a cookie, long lasting)
2. Send the request to the sever (via ajax or form submission)
3. Server creates a job record in the database, eg jobs table = session_id | job_id | status
4. Page reloads and checks database for all jobs belonging to session_id, and displays them.
5. User goes away and comes back later
6. Page loads and checks database for all jobs belonging to session_id, and displays them.

Other ideas

• You could email the user when the job is finished.
• Long running jobs can be started via a daemon or cron job.
• Php scripts running from command line, don't have timeout issues, like webserver requests
• You could store job progress in the db table, if you wanted to go into that level of detail