Exchange Online Meeting Room Statistics - Graph API

A few years ago I wrote an article named "Exchange Meeting Room Statistics" about a script to gather statistics regarding Exchange meeting room usage for MSExchange.org (now techgenix.com). For this script to work, we have to give ourselves FullAccess to the meeting rooms’ mailbox, add them into our Outlook profile, and then use an Outlook COM Object to connect to Outlook and gather this information. Far from ideal, especially when trying to analyse dozens of rooms!

A couple of years after, I wrote a new version that uses Exchange Web Services to gather the same information, plus some further stats. However, this script wasn't very reliable with Exchange Online as it would work in some environments, but not in other.

I have finally written this newer version, specifically targeted at Exchange Online only, this time using Graph API!

IMPORTANT:

• To analyze a particular meeting room, specify one or more primary SMTP addresses in the format: "room1@domain.com, room2@domain.com". Alternatively, analyze all meeting rooms by using the "-All" switch;
• You will need to have, or create, an 'app registration' in Azure and user digital certificate for authentication (you can update the script to use 'client secret' instead);
• The app registration will need the following API permissions to Graph API: 'User.Read.All', 'Calendars.Read', and 'Place.Read.All', all of type 'Application';
• Maximum range to search is 1825 days (5 years);
• You can enter the dates in the format "22/02/2020", "22/02/2020 15:00", or in ISO 8601 format such as "2020-02-22T15:00:00", or even "2020-02-22T15:00:00-08:00" to specify an offset to UTC (time zone).

The most basic way of running the script is as follows (more examples in the script itself):

.\Get-MeetingRoomStats_GraphAPI.ps1 -All -From "01/01/2020" -To "01/02/2020"

The script gathers and exports the following stats for each meeting room for the given date range:

• RoomName: the display name of the meeting room (when using -All). When using -RoomListSMTP, this will be the room's SMTP address;
• RoomSMTP: the SMTP address of the meeting room;
• From: the start of the date range to search the calendar;
• To: the end of the date range to search the calendar;
• totalMeetings: the total number of meetings;
• totalDuration: the total number of minutes for all meetings;
• totalAttendees: the total number of attendees invited across all meetings;
• totalUniqueOrganizers: the number of unique meeting organizers;
• totalUniqueAttendees: the number of unique attendees;
• totalReqAttendees: the total number of required attendees;
• totalOptAttendees: the total number of optional attendees;
• Top5Organizers: the email address of the top 5 meeting organizers, and how many meetings each scheduled;
• Top5Attendees: the email address of the top 5 meeting attendees, and how many meetings each attended;
• totalAllDay: the total number of 'all-day' meetings;
• totalAM: the total number of meetings that started in the morning (this excludes all-day meetings);
• totalPM: the total number of meetings that started in the afternoon;
• totalRecurring: the total number of recurring meetings;
• totalSingle: the total number of non-recurring meetings (single instance/occurrence).