Links:

• Documentation:
  https://docs.firefly-iii.org/how-to/firefly-iii/advanced/authentication/#remote-user-authentication
• Potential Project that can help with this:
  https://github.com/oauth2-proxy/oauth2-proxy
• Use OIDC Connect:
  https://oauth2-proxy.github.io/oauth2-proxy/configuration/providers/openid_connect
• And config:
  https://oauth2-proxy.github.io/oauth2-proxy/configuration/overview/#config-file
  • X-Forwarded-Email as header that got exposed from this proxy.
  • Make sure this option on oauth2-proxy set to true: --pass-basic-auth.
  • On Firefly: AUTHENTICATION_GUARD_EMAIL="X-Forwarded-Email“.
  • --scope should also be matched with one from Zitadel.