PHP Daemon

Behemoth

Hi there,

what methods do you know to run a script or function at predefined intervals without someone triggering it by a browser ?

What I am looking for is a way to write some sort of daemon program, for example:
1. wake up every n minutes
2. check an email account
3. retrieve email & write content to database

I read the article about the mailbot but it uses CGI-php and I don't have access to sendmail on the server either.
cron would be an option but can you think of anything else ?

Thanks !

Daniel

FlipperPA

There is a program on just about all Unix flavors called crontab. What is does it runs a program at preset intervals - once per day, once per hour, once per minute, once per week, etc. The way I use crontab to run scripts is by editing my crontab (its actually a good practice to put crontabs under the root user, but if you don't have access, that's okay):

From the Unix command line:
crontab -e

This command will bring up the users crontab in an editor. Then you can do something like this:
0 2 /usr/scripts/backupcode.sh
0 4 * 0 /usr/local/bin/php /usr/scripts/compresslogs.php

The 5 "digits" or "*" before the command, left to right, represent:
MINUTE(0-59)
HOUR(0-23)
DAYOFMONTH(1-31)
MONTHOFYEAR(1-12)
DAYOFWEEK(0-6) Note 0 = Sun

If there is a "*" it will run on all of those days. So, in the above 2 examples, the top command will run at 2am every day, and the bottom will run at 4am every Sunday.

-Tim

Behemoth

well I already mentioned cron, I was thinking more in terms of putting the script in the background. perl has a Thread implementation which would allow that. I know there is nothing like that for PHP, but maybe a similar solution.

FlipperPA

I haven't been getting enough sleep lately. ;-)

I guess one way you could do it (this is a hack if I've ever seen one!):

set_time_limit(0);
while($x!=1) {
    [ do stuff here ]
    sleep(3600000); /* sleeps 1 hour */
}

Then run is using /usr/local/bin/php scriptname.php and it will just run forever.

viper21634

why not just include your script in the page on your site that gets run the most so it will run every time that page runs.

Behemoth

@ : good idea ! Yeah, something like that should do the job. If I find out something else, I will keep you informed.
@Flipper : evil hack ! 😉 But wouldn' t the script terminate if the
connection to the browser that called it broke ?

Weedpacket

Flipper's method would work, but it uses PHP in its CGI/command-line incarnation.

Personally, I'd go the cron route - seeing as cron's already running as a background process to handle exactly this sort of task.

FlipperPA

This is exactly for cron is built for - however, if you can't access cron for some reason, either method (sleep with cgi php, or in a page called frequently) would work.

If you don't have a cgi version of php compiled, its fairly simple (assuming you're just using a base install of php)... here are the install commands:

gunzip -c php-4.x.x.tar.gz | tar -xvf -
./configure
make
make install

That's it to make a cgi version, which you'd probably also want to use if you end up using cron. I started using cgi php for scripting so we're using 1 language rather than python or perl for scripting, and php for web!