Syncing EKRecurrenceRules with Cloud Service RFC 2445 iCalendar specification RRULE

Question

I'm trying to create a cloud based service which stores recurring Events. I have chosen to do this using the icalendar RRULE standards (RFC2445) and use a database schema as below exposed via cloud based service.

EventID
EventName
EventDescripton
Start
End
RecurrenceRule  <-- Store RFC 2445 iCalendar specification RRULE (recurrence)
Active
Deleted
DateCreated
DateLastUpdated

I beleive that the EKRecurrenceRules are RFC 2445 compliant, however by storing the string representation of the RRULE or description of the EKRecurrenceRule makes for a more cross platform compliant architecture.

I am able to create a EKRecurrenceRule on the client side easily and extract the RRULE from the EKRecurrenceRule description property. However, my question is how to convert that description property back to an EKRecurrenceRule object on the client when extracted from the cloud service? It seems stupid Apple would expose a property to extract the compliant RRULE but not provide any way to convert an RRULE to a native object.

I'd like to avoid storing individual components of the EKRecurrence rule if possible.

Answer 1

you might be able to use this library: https://github.com/FabienDiTore/ios-rrule_parser

to create an EKRecurrenceRule. If you do, please let me know.

Answer 2

...extract the RRULE from the EKRecurrenceRule description property

This seems fraught with peril. The documentation for -[id<NSObject> description] only guarantees that it returns "a string that describes the contents of the receiver" - EKRecurrenceRule's implementation might not give a proper RRULE in the future, or might change just barely enough that "extracting" the RRULE won't work. (This is probably why Apple doesn't provide anything to convert an RRULE back to an EKRecurrenceRule - they didn't mean for you to be able to extract and work with the RRULE in the first place.)

It seems to me that a better solution would be to find or write a library or EKRecurrenceRule category that provides a proper - (NSString *)rrule accessor and perhaps a corresponding - (id)initWithRRule:(NSString *)rrule initializer. That way, you can avoid relying on undocumented behavior and be confident that you can convert between RRULEs and EKRecurrenceRule instances in the way that you want.