I have a SharePoint Framework on-premises solution where I want to call securely an external web api, also on-premises (the same).
This means that the logged on user identity should be passed to the external web api in the request. The external web api should be able to verify if the user's identity is genuine.
What authentication would I need to use on my web api?
I was thinking about a solution similar to a provider hosted app. But I do not know how to get and pass a token similar to the "AppContextToken", which then could be used to construct the SharePointContext.