I'm currently using a combination of the Office365 REST APIs and EWS SOAP APIs to create/fetch/edit calendar events in my application. I've been using impersonation to act on behalf of an event's organizer and attendees.
When updating a meeting I'm not sure of the best correlation between an organizer's meeting ItemId and an attendee's meeting ItemId.
For example:
-> The app impersonates user A and creates an event on their calendar with a room resource(attendee) set as the meeting location.
-> One event and a copy of the event is now created on user A's calendar and the room's calendar. Each has a different ItemId.
Is there any way to retrieve the room meeting ID via the user's meeting ID or vice versa?
The best bet I found was using one of the extended MAPI properties of the EWS meeting called CleanGlobalObjectID
that would supposedly be shared between the two items. This method would require multiple FindItems/GetItem calls just to get the shared event so I'm not sure if it's the best route.
Refs: