I am using Exchange web services (Exchange server 2010) to synchronize user's outlook calendar with my application.I implemented EWS Push Notifications to call back my application whenever events are created ,modified ,deleted by out look users. I achieved this by subscribing user's email credentials with EWS.
Client application should send OK responses to server whenever it get callbacks from the server .If there are no OK responses from client application for some time the particular subscription will be automatically unsubscribed.
If client is unreachable for some time due to any unexpected reason i need to subscribe only unsubscribed users instead of subscribing all the users.
My issue now is how to get unsubscribed users/Or subscriptions Id's from EWS?I couldn't find anything helpful regarding this in MSDN documentation.
Any one knows?
MSDN Reference enter link description here
I believe the only way to do this is to make use of the StatusEvent
(I call it the heartbeat). When you subscribe, you set a parameter to indicate how often EWS is to POST to your Push HTTP listener. (I use 3 minutes--YMMV.) So after 3 minutes (plus a little extra to be sure), if you don't hear from EWS, either by a StatusEvent or some other "real" event for a subscription, then you should re-subscribe for that user.