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Two way O365 Calendar sync

I am new to Flow and have just started tinkering with some flows.  There's a fairly basic O365 <-> O365 calendar sync widget that would be really useful for me, and I suspect would be for others.  I was able to find some some snippets of what I need here in the forums but several of the examples use older API versions that are significantly different than more recent ones.  Also, I need to be careful that my "newbi-ness" doesn't get me into trouble with an accidental sync loop storm that placess a million meetings on my calendars.


User Story:  I am a consultant that often works with two customers, who each will often double-book me or we need to go through scheduling message exchnages.  (Love Microsoft's FindTime add-in, BTW, it's a game-changer.)  The problem is that invites on account Foo may contain confidential information that is not appropriate to sync to account Bar, and vice-versa.  So Ideally, meetings on Foo sync to Bar as simply "not available" with no attachments, content, invitees, etc.  I call this the "obfuscation feature."


There are some examples that do one-way calendar syncs with the newer add-update-delete event model.  But they lack sync loop protection, do not incorporate obfuscation, and in some cases are a few years old and are based on older APIs.  The closest one has an intermediate process that includes sharepoint, that just adds complexity to my limited understanding.


I started out with a "when an event is added, updated or deleted trigger" leading to a switch (case statement for us older folks).  It appears now I don't have to get events any longer, I can go right into a create, update, or delete action.  So my mental pseudocode so far is:


New Event in Foo => create new event in Bar;

  1. See if event subject equals "Time blocked in Bar" - if so, this is a re-sync, bailout to prevent loop
  2. Set event start and stop times on new event from original event.  (Not sure how time zones would be handled but luckily Foo and Bar are in same zone...  But what about travel?)
  3. Set subject to "Time blocked in Foo" (which will be tested to prevent sync loop)
  4. Maybe set a category to color code it as a reminder it's from the other calndar
  5. Deal with recurrence.  (Oy, this is getting complicated for a newbie!)
  6. End

Similar intuition for update and delete.  Same code in both directions flipping Foo with Bar.


More puzzlement:

  1. So, do I need to deal with event IDs, as some samples have?
  2. Handling recurrence is a little unsettling.  (I need to report what looks like a bug in the Create event (v2) action too)


Any help would be appreciated, Thanks!

Community Champion
Community Champion

Hi @MaxR 


Indeed this is tricky but there are others trying to do the same.

Here are some already answered questions. Hope this helps you:


Hope this helps you.


If I have answered your question, please mark your post as Solved.
If you like my response, please give it a Thumbs Up.




Manuel, thanks so much for your follow up. In my younger days, this would have become one of those Asperger obsessions I have, where I would spend months creating a really elegant solution for no other reason than the satisfaction of having created an elegant solution--and all the learning that goes along with that. Fast forward to today, when I am doing management consulting and my coding experience is decades old, and it just becomes a rabbit hole best not pursued.


Getting the events to copy as-is, I accomplished in probably an hour of googling followed by trial and error. Having the event content blanked out took another hour or two. Then I started thinking about event deletion... Now I have to store lists, rely on enumeration... And if I am going to do that in SharePoint, I have to study up on that and configure an instance... Now I'll be 20 more hours minimum down the rabbit hole. Oh, and then dealing with recurring events... more hours...


I began to see that creating a generalized flow to support typical calendar scenarios was going to take me down a rabbit hole from which there would be no escape. The amount of time I spend having to invest to understand each API call, then do some trial and error testing, just becomes too high an investment. It's best left to someone who already has significant flow experience, or has a job where they can ROI the time investment in learning flows.


In the end, I manually sync my calendars by hand each week. It's cumbersome, but it would take me years of manually syncing to ever offset the amount of time I was starting to put into trying to create something elegant. And to the point others have brought up... This is a common enough use case that one would think there'd be a generalized toolkit from Microsoft for common email, contact, and calendar syncing between Microsoft platforms, like Exchange and O365.


To me, the logical way to accomplish this is not through a Sharepoint table, that seems unsustainable long-term as entries become orphaned, links broken, etc. Neither is a Get method that returns an entire enumerated array of instances--this becomes a cumbersome amount of data for someone with a busy, complex schedule. The only way I can see to make this sustainable is to fully contain the linking data within the data structure of the event. That is, both the local and the foreign event have stored within their own data structures the unique ID of the corresponding event. Both calendar entries know the foreign key of the remote event on the other server and can access it directly without enumeration or lookup. But again, researching the feasibility of user-defined data structures within the exchange/O365 stack is well past my time horizon.


Thanks again! -Max

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