How to get the AD username and domain

I have SS hosted in IIS and I have my custom Auth provider derived from CredentialsAuthProvider which authenticate the user on AD. I also have the JWT Provider and getting a token.
All this works very well when the user passes its username, password and domain from our Angular app.
The thing is, our app needs an “Auto Login” feature. Using this, the user does not have to enter its username and domain (we don’t need the password). Before, when using WCF/IIS, the service was getting the user info from ServiceSecurityContext.Current.PrimaryIdentity.Name. Now, using a REST Api, this is not working and I don’t know how to get it…

Is this feasible keeping my current implementation?

In .NET Framework Apps the AspNetWindowsAuthProvider is the Auth Provider that authenticates against Windows Auth.

There’s also a IRequest.GetUser() extension method for retrieving the Windows Auth IPrincipal associated with an IRequest.