Is it possible to subscribe push notifications for Exchange room resource calendar

Question

We have an existing implementation that subscribes via EWS Managed API push notifications for a user's calendar in Office 365 Exchange Online.

PushSubscription pushSubscription = exchangeService.SubscribeToPushNotifications(
    new FolderId[] { WellKnownFolderName.Calendar },
    new Uri(callbackEndpoint), statusFrequency, null,
    EventType.Created, EventType.Deleted, EventType.Modified,
    EventType.Moved, EventType.Copied, EventType.FreeBusyChanged);

Other than the subscription not being able to last forever, it is otherwise fine; appointments scheduled on the calendar do send notifications to our web service.

Now instead of monitoring events from a user's mailbox perspective, we are wondering if it is possible to subscribe from the room resource mailbox perspective.

// Set room mailbox address.
exchangeService.ImpersonatedUserId = new ImpersonatedUserId(ConnectingIdType.SmtpAddress, roomAddress);

PushSubscription pushSubscription = exchangeService.SubscribeToPushNotifications(
    new FolderId[] { WellKnownFolderName.Calendar },
    new Uri(callbackEndpoint), statusFrequency, null,
    EventType.Created, EventType.Deleted, EventType.Modified,
    EventType.Moved, EventType.Copied, EventType.FreeBusyChanged);

Unfortunately it does not turn out to be so simple,

The request failed. The remote server returned an error: (457) https://autodiscover-s.outlook.com/owa/domain.onmicrosoft.com.

I cannot find any in-depth material explaining what error 457 truly is, and how to overcome this problem.

Additionally, I have not found anybody else attempting subscriptions to resource mailboxes. Is it because it is outright impossible, or simply nobody ever found a need to?

UPDATE

Tried using the EWSEditor tool to see what kinds of extra detail can be sniffed out; seems like impersonating a room mailbox requires some sort of special permission.

Exception details: Message: The account does not have permission to impersonate the requested user. Type: Microsoft.Exchange.WebServices.Data.ServiceResponseException Source: Microsoft.Exchange.WebServices ErrorCode: ErrorImpersonateUserDenied ErrorMessage: The account does not have permission to impersonate the requested user. Stack Trace: at Microsoft.Exchange.WebServices.Data.ServiceRequestBase.ProcessWebException(WebException webException) at Microsoft.Exchange.WebServices.Data.ServiceRequestBase.GetEwsHttpWebResponse(IEwsHttpWebRequest request) at Microsoft.Exchange.WebServices.Data.ServiceRequestBase.ValidateAndEmitRequest(IEwsHttpWebRequest& request) at Microsoft.Exchange.WebServices.Data.MultiResponseServiceRequest 1.Execute() at Microsoft.Exchange.WebServices.Data.ExchangeService.InternalConvertIds(IEnumerable 1 ids, IdFormat destinationFormat, ServiceErrorHandling errorHandling)
at Microsoft.Exchange.WebServices.Data.ExchangeService.ConvertIds(IEnumerable 1 ids, IdFormat destinationFormat) at EWSEditor.Common.Extensions.ExchangeServiceExtensions.TestExchangeService(ExchangeService service)

I tried assigning Full access for mailbox delegation in the Office 365 admin interface, but that did not appear to do any favours.

icelava icelava · Accepted Answer · 2015-01-20T12:01:27

Looks like the key to making this happen is enabling impersonation for a nominated service account.

http://blogs.msdn.com/b/pareshj/archive/2011/11/29/exchange-web-services-fail-using-impersonation-to-access-mailboxes.aspx

http://msdn.microsoft.com/en-us/library/bb204095.aspx

Once this is done for the organisation account and the nominated user account, interacting with EWS with the impersonated room mailbox, and subscribing, becomes possible.

Is it possible to subscribe push notifications for Exchange room resource calendar

1 Answers