You can use the Scheduler module in Xaraya to queue up jobs.

For example, Pubsub allows users to subscribe to events on your system; when an article (in a particular category) is changed or comments are added to a forum, subscribed users will be notified via email.

Or, you can schedule regular backups using Sitetools. And so on.

To run the jobs queued up in the Scheduler, you need a trigger. This trigger can be someone hitting the scheduler module on your site. You can setup a cron job to trigger the scheduler, say, once an hour.

Configure Scheduler Module

On the Scheduler Config screen choose "External Scheduler", and the IP address where your cron job will be running. Use the "Note: you are connected ..." to help decided.

Also note the url that the Trigger specifies, e.g. http://www.mysite.com/?module=scheduler

Test Trigger from Command Line

From the command line on that system, run

curl  "http://www.mysite.com/?module=scheduler"   

If it comes back (wading through the html) with something like

Starting jobs
pubsub admin processq succeeded : 
1 

then you're cool. Otherwise check the Source IP settings.

Make a Scheduler Theme

We dont need all the html, so I create a very simple theme (e.g. from the empty/ theme) named "scheduler", that all it has is a pages/default.xt that contains

<xar:module id="modulespace"  main="true" /> 

Then you can trigger with

curl  "http://www.mysite.com/?module=scheduler&theme=scheduler"  

Write a Shell Script

Once that's working put the curl command into a shell script, such as scheduler.sh

#!/bin/sh
/usr/local/bin/curl -v "http://www.mysite.com/?module=scheduler&theme=scheduler"; >>/home/xaraya/crondump.txt  

Note that I direct output to a file, at least until we're sure things are working. Make sure it's chmod 755

Create the Crontable

Next, create the crontable. Make a file like crontable.xaraya with something like

# hourly triggers for xaraya scheduler
0 * * * * sh /home/me/scheduler.sh 

And add it to cron with

crontab  crontable.xaraya 

Make sure its there with

crontab -l  

That's it, should be good to go.

Crontable Format

Wikipedia has a nice article: http://en.wikipedia.org/wiki/Cron

# append a message to file every minute, tests cron is working
* * * * * echo "hello from crontab" >>/home/me/crondump.txt 
 

# hourly triggers for xaraya scheduler
0 * * * * curl "http://www.mysite.org/?module=scheduler&theme=scheduler";  

# (Use to post in the top of your crontab)
# ----------------- minute (0 - 59)
# |  -------------- hour (0 - 23)
# |  |  ----------- day of month (1 - 31)
# |  |  |  -------- month (1 - 12)
# |  |  |  |  ----- day of week (0 - 7) (Sunday=0 or 7)
# |  |  |  |  |
# *  *  *  *  *  command to be executed