Google calendar api v3: update all future events in recurring series limited by count

1
votes

My question: how do I update "this and all future" instances in a recurring event which is limited by count so that the total number of events stays consistent?

What is the problem:

Trying to modify recurring event and I follow the below guide:

https://developers.google.com/calendar/recurringevents

Basically to update all future recurring events using a target event, the doc says one need to do two calls:

  1. update existing event to make so it ends before the target event date
  2. create a new recurring event with the same fields except of those need changes.

That works fine until there is an event that is limited by the number of occurrences.

Let's say there is a recurring event limited by 10 occurrences and target event is 5th event. Now I need to split the original so that the first 4 events goes to the original one (so I update COUNT from 10 to 4) and then I create a new recurring event that holds the rest 6 events (so COUNT is 6 in this case)

My first observation is that this is not how the split events are displayed in google calendar - if I test that manually, the both events still show 10 occurrences but the second one doesn't produce any extra events (I'd expect 14 events from developer perspective, yet there are 10 as any user would expect). That implies there is a different approach here? Is it?

Also if I end up counting manually the number of events, there are still issues with cases like deleting one of the events first (let's say, the 4th event) - now how do I know that I need to show 6 instances in the new one and not 7?

Those thoughts make me think there is a better approach, but I can't find any other alternatives. Any advice on that?

UPDATE

It seems like google does it differently: for example after changing a title for "this and future" events in calendar view, it doesn't seem to produce two different recurring events since if you try to delete "all" events, that will remove all of them completely (rather than deleting only one chunk, either before or after the target event)

It seems like they are creating a bunch of exceptions or maybe "recurring exception" or something to do that. Can't find any examples on how to do that as of now thought.

2
google-calendar-api
How about using UNTIL instead of COUNT? So you can update all the events up to a certain date, and then create the rest from there. – Jescanellas
thanks @Jescanellas. I guess that might solve it from technical perspective. Just need to fetch all the instances to get the end date (in case of a big COUNT this might be another corner case). Though I think from UX point that would be unexpected - if user sets 10 events they would expect to stick to that type rather than switching it to a date (if they need to add more events for example, they just change the original count). Google still handles that nicely. Updated my question with more observations - maybe that might shed some additional light. – vir us
I understand and agree with your approach. Would you mind sharing a simple snippet of how you are updating the 1 to 4 event, and then 5 to 10? Do you get the 5th event with a previous call to the instances? Thanks. – Jescanellas
thanks @Jescanellas. This is actually what I'm trying to figure out - how do I code that. But to give you some more context, I always have the next 5 instances from "now" and the master instance. So as I was following the tutorial above, I supposed to use one of those instances as the target event with the "events.update" and "events.insert" methods from the googleapi nodejs library. But digging a bit deeper revealed this problem from my question. Not sure if that helps, so please let me know if I can provide any additional details on that. – vir us
To update specific events in a recurring event you need to update the individual instance by specifying the event instance ID. This is just the event ID concatenated with a datetime stamp (you can see this when making an events: instances request for your eventID; if your event ID is xxxxxxxxxxxx then an instance ID would be something like xxxxxxxxxxxx__20200603T170000Z). This is how the instances are updated with the UI but there's no direct update-instances endpoint so to update multiple instances in one request you'd need to use batching – Rafa Guillermo

2 Answers

0
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Can't find any good solution for this after a few days of research and while I need to move forward I ended up with a sort of "compromise" between "good enough UX for my case" and "breaking best practice".

So I ended up updating each event individually which goes against google's warning as shown below but I limited the max count by 50. This is not necessary what others want to do, but this is good enough for the real world use case in my app.

Warning: Do not modify instances individually when you want to modify the entire recurring event, or "this and following" instances. This creates lots of exceptions that clutter the calendar, slowing down access and sending a high number of change notifications to users.

And if user needs to schedule more than that, the user is asked to use "end date" instead.

Again, not ideal by any means so if anyone knows how to handle that correctly or knows how google handles that, you are very welcome to share it! (meh... and I need that for outlook too now...)

UPDATE: just got an idea: as an improvement, one can edit either "all future events" or alternatively the master event + "all previous events" depending on the index of the target event. In this case one can limit the number of requests by 2 (so in case of 50 events I'll need to do 25 requests maximum)

So if user wants to change the title from "Hello" to "Goodby" and if the user picked event number 5 in the series of 50 events to change all future events, we can change the master event to "Goodby" which will change the title of all events, and then update the first 4 events to the original "Hello".

0
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Obligatory summary of comments and chat:

Updating events:

To update specific events in a recurring event you need to update the individual instance by specifying the event instance ID.

This is just the event ID concatenated with a datetime stamp (you can see this when making an Events: instances request for your eventID; if your event ID is xxxxxxxxxxxx then an instance ID would be something like xxxxxxxxxxxx__20200603T170000Z).

Unfortunately there's no direct update-instances endpoint so to update multiple instances in one request you'd need to use batching

The API doesn't have a dedicated method for updating recurring events regardless of the recurrence type, and I presume this is the reason the documentation says to edit the previous recurring event by cutting it down and inserting a new one, as per Google's warning:

Do not modify instances individually when you want to modify the entire recurring event, or "this and following" instances. This creates lots of exceptions that clutter the calendar, slowing down access and sending a high number of change notifications to users.

Batching:

Making a batch update on event instances does keep count consistency. If you edit instances in a batch and then use the 'this and all future events' option when deleting one of the instances of the recurring event they do all get deleted as they're still a part of the recurrance. There is no new event being created in either scenario, the event instances are being changed.

If you play around with Events: instances and use Events: update to change only some instances of an event, then you can see that they all stay part of the same recurrence chain and there is no count change.

For arbitrary large counts, even if you have a recurring event with 9999999 instances, each event still has an ID which you can retrieve from Events: instances. It's stored as a single event for event use, but the IDs of the instances are the identifiers which are different.

Honestly, it's not great that you have to edit each one manually; for large counts like 9999999 it's basically infeasible because you'll have to make a batch request for each set of 100 instances you want to change, but it's the only option available via the API at the moment.

Feature Request:

You can however let Google know that this is a feature that is important for the Calendar API and that you would like to request they implement it. Google's Issue Tracker is a place for developers to report issues and make feature requests for their development services, I'd urge you to make a feature request there, the Calendar API feature request form can be found here.