A Zope 2 catalog index with support for indexing of recurring events, following the icalendar standard. It is a drop-in replacement for the Zope2 DateIndex and will produce the same results for non-recurring dates.
The DateRecurringIndex accepts following parameters:
- Required. The name of the field or object attribute to be indexed.
- Required. The name of the object attribute, which returns the icalendar rrule (recurrence rule) string.
- Optional. The name of the objects attribute, which returns the date, until the recurrence should happen. The recurrence definition can also contain an UNTIL component. If both are defined, the recurrence calculation stops whenever the first until-date is met. If not given at all, there is a MAXCOUNT ceiling constant, defined in plone.event.recurrence, which defines the maximum number of occurences.
Datetime.DateTime vs. datetime.datetime
Inside Zope2 everybody uses DateTime.DateTime or iow the Zope-DateTime. At time of writing Zope-DateTime (around 1998) there was no good date/time implementation in python. But these days we have a better implementation. Even if the pythons datetime implementation has its problems, together with pytz for timezone handling it is very mature.
So, why is it covered here? Just because dst-handling over recurring events works only if the start and until values are non-naive python datetimes. Just keep it in mind when using this index: If you use recurring dates and you want dst-adjust make sure your implementation returns a python datetime. And also keep in mind: If youre i.e. in Austria with CET timezone, add a recurring date: it will look fine to you, every day at 11:00am, doesnt matter if DST or not, your event happens. If you go international and your event is shown in a different timezone - or in the same in a country without DST at all - it might differ and is not always at the the time.