I have this provider hosted app/addin with STS, high trust scheme. My question is, how can I authenticate a user from my provider hosted against an on-premise SharePoint ?
I want this because my app will be hosted open in the internet and I want to make sure that my users are authorized in the SharePoint server.
I thought about making a call against the api asking for the current logged user but this only works client-side.
Is there any way I can achieve this server-side ?