private AuthenticateResponse Authenticate(AuthenticateRequest authenticateRequest) { var user = users.SingleOrDefault(x => x.Username == authenticateRequest.Username && x.Password == authenticateRequest.Password); // return null if user not found if (user == null) { return(null); } // authentication successful so generate jwt token var token = AuthJWT.generateJwtToken(user); return(new AuthenticateResponse(user, token)); }