Calendar event repeat

[eebene]

Allow one to repeat an event on a specific date on of the month: e.g. repeat on second Thursday of the month similar to google calendar. See attached image

[cogk]

How to implement this feature?

• [x] new field: Event.rrule (Data)
• [ ] new doctype: Event Recurrence (why?)
  • [ ] rrule: Data -- encodes everything we want (more info)
  • [ ] event: Link[Event]
• [ ] new doctype: Event Exception Change the label of the event for one specific repetition
  • [ ] instance_id: Data -- unique identifier, most likely the index in the recurrence (e.g. 3^rd repetition)
  • [ ] overrides: Table[Event Exception Override] -- list of changes done to the event for this instance
• [ ] new doctype: Event Exception Override (not sure about this doctype… maybe just copy the original event and store it inside the Event Exception)
  • [ ] key: Data
  • [ ] value: Data
• [ ] make it generic, so that any doctype can benefit for recurrences, not just Event?

Personal experience

We have done a partial implementation for recurring events in Dokos, but bringing more features is a big task.

References

• https://dateutil.readthedocs.io/en/stable/rrule.html
• https://interviewready.io/blog/low-level-design-google-calendar-prototype-design-pattern
• https://frappeframework.com/docs/user/en/basics/doctypes/virtual-doctype
• https://developers.google.com/calendar/api/guides/recurringevents?hl=fr
• https://www.linkedin.com/pulse/tiny-system-design-google-calendar-like-app-recurring-rajesh-pillai