This flow provides a "fake" OAuth 2 implementation for use with the Google Actions API.
Exposes three endpoints:
- /google/oauth-auth - Main auth endpoint that Google will call to initialize an OAuth 2 handshake. Checks "client" and "client secret", and returns a login form.
- /google/oauth-login - Processes login form, verifies "auth key" provided and generates a new OAuth auth code that the caller (Google) can then exchange for a real OAuth 2 ticket via the last endpoint.
- /google/oauth-token - Allows the caller to exchange an "auth key" for a valid OAuth 2 token, or request a new token via refresh token.