Authenticating your client to Cloud Endpoints without a Google Account login

Question

I have been doing extensive research on how to authenticate your client (Android, iOS, web-app) with Cloud Endpoints without requiring your user to use their Google

Answer 1

I have implemented Endpoint Auth using a custom header "Authorization" and it works just fine. In my case this token is set after login but should work all the same with your app. Check your tests because the value should be there. The way to retrieve that header is indeed:

String Auth = req.getHeader("Authorization");

You could take it a step further and define your own implementations of an Authenticator and apply it to your secure API calls.