note ELISHEVA <p>Please be <i>very</i> careful with any URL that
can trigger memory or CPU intensive processes. The web-based
cron that I've seen comes in two flavors: <ul> <li>a provider
that lets you submit a schedule and sends a URL request at a
specified time.</li> <li>a script on your own website checks a
scheduling file each time someone makes a web-request. If it
finds any tasks scheduled before the present moment, it runs
them if they haven't been run already.</li> </ul> <p>If you go
with the first solution you must be <i>very</i> sure that only
that web-cron provider can trigger the script. Ideally this
should be done both on the web server level (via well configured
.htaccess files) and checks internal to your script. If you are
not very careful, you can open yourself up to DOS attacks. You
don't need to be a known target to be vulnerable. There are non-
so-nice crawlers and script kiddies out there that will canvas
random websites looking for vulnerable URLs and when they have
found them, they "play