I’m looking for some ideas to do the following. I need a PHP script to perform certain action for quite a long time. This is an extension for a CMS and this can’t be anything else but PHP. It also can’t be a command line script because it should be used by common people that will have only the standard means of the CMS. One of the options is having a cron job (most simple hostings have it) that will trigger the script often so that instead of working for a long time it could perform the action step by step preserving its state from one launch to the next one. This is not perfect but I can’t see of any other solutions. If the script will be redirecting to itself server will interrupt it. What other options can suit?
Thanks everyone in advance!
What you’re talking about is a daemon or long running program that waits for calls by client programs, performs and action, provides a response then keeps on waiting for more calls.
You might be familiar w/ these in the form of Apache & MySQL 😉 Anyway PHP is generally OK in this regard, it does have the ability to function over raw sockets as well as fork sub-processes to handle multiple requests simultaneously.
Having said that PHP daemons are a tool where YMMV. Some folks will say they work great, other folks like me will say they have issues w/ interprocess communication and leaking memory even amidst plethora unset() calls.
Anyway you likely won’t be able to deploy a daemon of any type on a shared hosting environment. You’ll need to get a better server package or stick with a Cron based solution.
Here’s a link about writing a PHP daemon.
Also, one more note. Daemons do crash from time to time and therefore you may still need to store state about whats going on, just in case someone trips over the power cord to your shared server 🙂