[schooltool-dev] Fwd: Detecting changes to objects

[Tom Hoffman]

The current delimma of stAgent is how to know when person objects are
created/changed/modified. Paul Carduner told me to subcribe to
IObjectModifiedEvent objects, however I only receive event relating to
PersonContainer objects (among others) with the following

  <subscriber
    for="zope.lifecycleevent.interfaces.IObjectModifiedEvent"
    handler=".handler.someFunction"
  />

However I found I could narrow the search down to just Person objects
by adding their interface in the front of the for="". The following
calls the handler function whenever a Person object is created

  <subscriber
    for="schooltool.person.interfaces.IPerson
           zope.lifecycleevent.interfaces.IObjectCreatedEvent"
    handler=".handler.someFunction"
  />

Now the problem remains to detect changes and deletions of Person
objects. Whenever either of those occur, I get an IObjectModifiedEvent
for PersonContainer, however I have no way of knowing how its objects
were changed, only that one of them was. The following does not raise
any events at all

  <subscriber
     for="schooltool.person.interfaces.IPerson
            zope.lifecycleevent.interfaces.IObjectModifiedEvent"
     handler=".handler.someFunction"
   />

Right now, all I can think of is to keep track of the usernames of all
Person objects and check that against the usernames whenever an event
is called to find deleted people. Do any of you have any suggestions?