I have a question about Office365 REST API. Is there a way to obtain list of resources - meeting room calendars.
I can only get meetings that will take place in room if I know meeting room username.
https://outlook.office365.com/api/v1.0/users/room1@xxxx.onmicrosoft.com/calendars
Can I list all meeting rooms and obtain their calendars?
You can use the Azure AD Graph API to query the list of users. However, there is no field in the API that marks a user as being a conference room. Depending on how your organization creates and names rooms, maybe you can find a filter that will only return rooms.
After that, it's just a matter of implementing the client credential flow so you can access multiple mailboxes.
来源：https://stackoverflow.com/questions/29628035/office-365-rest-api-list-resources-meeting-rooms