Schedeled Tasks in PHP

Anon

My problem is I want to run automaticaly a php script at given date/time. Let's say: everyday at midnight (or another date/time I can add to the schedule).

Can you keep script alive on the server side without action from the visitor and will it not eat much of the resources...?
Because setting the maximum_execution_time to 0, and keep script running in the endless loop is not quite "clean" solution I think...

Is there any way to do it in PHP only?
Or Do I have to use some shell script which will invoke the php script?

Anon

The easiest way is to compile php as a cgi then place a script in your crontab. Look at the file /etc/crontab and type man crontab for more details.

Hope that helps.

Chris King

Anon

Right, cron daemon is what I need to run it from the shell...

However for curiosity only now: maybe there is some trick to do it in PHP?

Any ideas?

Anon

There should be some option to edit the messages...:/

I forget to thank you for your advice..

So Thanks! 🙂

Anon

One possible way is to use sleep()...the only question is, will it time-out/stop running after a long amount of time?

I'm not sure how server settings would effect sleep(), so that's not real dependable.

Actually however, I believe you can rig together some PHP daemons (this is just a theory of mine, so it would need testing).

Have any php script write the time/date into an otherwise empty text file.

In your daemon.php file, have your script open the file for reading and read the date.

If the date was older than what you specified (let's say you wanted it to do something every hour), it would execute a little loop, let's say all it would be is opening that time file with "w" and writing the new time/date.

Then, to be an actual daemon, have it sleep() for however long you need it to sleep. When it wakes up it examines the time, then sleeps for however long it needs to sleep to get up to 1 hour older than the time read, then it wakes up and checks again, and writes the date/time again.

The question is now, will the server allow a script to run for such a long time?

And also, how can you terminate the script like that? Wouldn't it just run infinately untill the server was reset?

If so, you should insert a little line into the daemon which reads the date, and if it says something like "TERMINATE", then it ends it's execution with exit.

So to terminate it, you'd simply open the text file yourself and change the time to "TERMINATE".

So, for you more experianced people, would that work?

I've been trying to make up an idea for a daemon and that's the closest I've come, if you don't have access to crontab.

Anon

Say you don't want to (or can't) recompile php. Get your cron job to contain a shell script which calls:

lynx --dump --show-source http://server/nightly.php3 > /dev/null

A sideways solution is to use randomness.
Say you don't have access to cron. Pick some popular page on your site and at the top, add a random number check. If you roll the dice correctly, then you go do your maintainence function. This way it doesn't hurt much, but it is happening periodically.

Generally the first way is better, though.

There's no point in any usable output from nightly.php3.