Init Hydra login flow from oathKeeper

[mathieu-gilloots]

Hello,
I would like to know if there is a way to init a hydra login flow from oathKepper ?
My use case :
I only use Hydra and OathKeeper.
I have a PHP Symfony application (called "accounts") with a login page that also handle login (form, ...) loginChallenge from hydra, ...
This php application own the Identity side (db, user model, ...).
I don't want to use Kratos.

I would like an authenticator in oathKeeper that redirect and init an Hydra Login flow when there is no Oauth2 / JWT Header.

For example :
1 / I go to one frontend microservice for the first time with no Session => Redirect to hydra Login flow (then to accounts login form with a login challenge).
2/ If there is a session, Oathkeeper add the Authorization Header to each request (mutator ?)

Do you have any idea ?
Thanks