Plugin Architecture:
OmniGrowl is designed to be highly customizable and modular. This is so one can have one stay-open background application to provide Growl notifications for applications that do not support Growl natively.
OmniGrowl can call custom AppleScripts at specified intervals according to their file names. OmniGrowl will install template scripts in:
~/Library/Scripts/Growl/OmniGrowl/Plugins/
Your own notification scripts can be called every 30 seconds, every 2.5 minutes, or at a certain minute every hour. (See the “OmniGrowl Plugin Template” script comments for details on usage.)
The "OmniGrowl Hacker Attempt" script can be called when a hack notification is displayed, for further action.
The "OmniGrowl Events” script will be called for Calendar (and iCal) event notifications.
The "OmniGrowl iTunes" script will be called for iTunes track change notifications.
See the corresponding template’s script comments for details.
Scripting Immediate Actions:
Many of the installed scripts are read-only for reasons of ease with XCode. If you want “roll your own” or do something else with the facilities, a zipped archive of these scripts is included in the OmniGrowl package in the Resources folder. Please note that OmniGrowl will overwrite any scripts with the same path name at every launch -- so if you do modify them you must name them something different (or place in a different folder). Templates are not read-only and can be edited, but since they will be overwritten, edited versions should be renamed.