Subscribing to new mail event of multiple impersonated user through one ExchangeService object

Question

I am able to subscribe to push notifications by specifying impersonating users' credentials and then specifying impersonated user's email in ExchangeService.ImpersonatedUserId property.

However want to know how can I handle new email events on multiple email ids that are impersonated by one email id, since there is no collection as such on ExchangeService to specify multiple Impersonation Ids. In fact I think we can handle only one email id by using single ExchangeService object. And to subscribe to multiple user mail events, even through impersonation, I have to create multiple instances of ExchangeService. And also multiple callback listeners too. This is what I want confirmation about:

Q. Do I need to create multiple instances of ExchangeService and callback listeners to handle new mail event on multiple user id with impersonation?

Q. Without impersonation?

Q. Also want to know given credentials of impersonating user, can I retrieve list of all users impersonated by that user.

Answer 1

Q. Do I need to create multiple instances of ExchangeService and callback listeners to handle new mail event on multiple user id with impersonation?

Ans. In Exchange 2013 we do have the option of grouping see here . In 2010 the only way is to use a separate Instances for every user you are impersonating.

Q. Without impersonation?

Ans. To use single user account to subscribe to events on folders of different users, user account your using for authentication must be granted Access to the Folders your subscribing to (either on the Folder using Add-MailboxFolderPermission or Outlook delegation) or on the Mailbox using Add-MailboxPermission. A single ExchangeService instance can have only single user account credentials associated with it.

As a side note: There are throttling limitations around the total number of subscriptions one particular user can make see here.

Q. Also want to know given credentials of impersonating user, can I retrieve list of all users impersonated by that user.

Ans. There is no cmdlets or EWS operations that can tell you this, however if you having logging enabled then you should be able to track the user of impersonation though the logs on IIS and the EWS.log see here.

Answer 2

Looks like you got this answered on the Exchange Development Forum: http://social.msdn.microsoft.com/Forums/exchange/en-US/4b9ed4a6-2664-4c4d-9b10-c5a03e72ae56/subscribing-to-new-mail-event-of-multiple-impersonated-user-through-one-exchangeservice-object?forum=exchangesvrdevelopment.