Exchange 2010/2013: Query the calendar of a room mailbox with EWS

Here again a small script from the Quick&Dirty corner. Querying the calendar of a room mailbox via EWS and Powershell. The script retrieves all calendar entries from the current time to 365 days in the future, or a maximum of 200 entries. The results are saved in the variable $results and can then be processed further.

$MailboxName = "Besprechungsraum@frankysweb.de"
$EWSPath = "C:\Program Files\Microsoft\Exchange\Web Services\2.2\Microsoft.Exchange.WebServices.dll"
Add-Type -Path $EWSPath
$version = [Microsoft.Exchange.WebServices.Data.ExchangeVersion]::Exchange2010_SP2
$service = new-object Microsoft.Exchange.WebServices.Data.ExchangeService($version)
$service.ImpersonatedUserId = new-object Microsoft.Exchange.WebServices.Data.ImpersonatedUserId([Microsoft.Exchange.WebServices.Data.ConnectingIdType]::SmtpAddress,$MailboxName);
$service.AutodiscoverUrl($mailboxName)
$calendar = [Microsoft.Exchange.WebServices.Data.Folder]::Bind($service,[Microsoft.Exchange.WebServices.Data.WellKnownFolderName]::Calendar)
$calendarView = new-object Microsoft.Exchange.WebServices.Data.CalendarView([System.DateTime]::Now, [System.DateTime]::Now.AddDays(365))
$calendarView.MaxItemsReturned = 200;
$calendarView.PropertySet = new-object Microsoft.Exchange.WebServices.Data.PropertySet([Microsoft.Exchange.WebServices.Data.BasePropertySet]::FirstClassProperties)
$results = $calendar.FindAppointments($calendarView)
$results | ft subject,start,end

In order to access a room mailbox via EWS, the user executing the script must have impersonation rights. The following command can be used to assign impersonation rights to a user:

New-ManagementRoleAssignment -Name impersonationAssignmentName -Role ApplicationImpersonation -User EWSServiceAccount

This gives the user "EWSServiceAccount" impersonation rights to all mailboxes, but this can also be further restricted:

New-ManagementScope -name meeting room -RecipientRestrictionFilter {Name -eq "meeting room"}
New-ManagementRoleAssignment -Name impersonationAssignmentName -Role ApplicationImpersonation -User EWSServiceAccount -CustomRecipientWriteScope meeting room 

The command above creates a new management area that only contains the "Meeting room" user. The impersonation rights therefore only apply to the EWSServiceAccount user for the "Meeting room" mailbox.