Opinionated JWT authentication library for Http4s: https://http4s-jwt-auth.profunktor.dev/
Happy to add a function
def jwtDecodeAs[F[_]: ApplicativeError[*[_], Throwable], A: Decoder](
jwtToken: JwtToken,
jwtAuth: JwtAuth
): F[A] = ???If that's helpful. Contributions welcome :)
Hey there 👋 I've been trying to implement the JWT middleware (after learning about it in the PFPv2 book gvolpe 🙌) for a Firebase-based app which uses an asymmetric JWT.
I don't seem to be able to figure out an elegant solution on how to make the middleware obtain a new public key when the current one expires (the caching is not the issue).
If it's not possible through some clever wrapping of the middleware or similar, could another constructor that passes JwtAuth by-name work here?
JwtAuth instance needs to be a different one every time you get a new public key? If so, you need to keep track of the state. Using a Ref this is quite easy but I would suggest hiding the implementation details behind an interface. E.g. trait AuthKeyHandler[F[_]]:
def get: F[JwtAuth]
def refresh: F[JwtAuth] // or F[Unit] depending on your use case
object AuthKeyHandler:
def make[F[_]: Monad: Ref.Make](
initial: JwtAuth
): F[AuthKeyHandler[F]] =
Ref.of[F, JwtAuth](initial).map { ref => new:
def get: F[JwtAuth] = ref.get
def refresh: F[JwtAuth] = getPublicKey >>= ref.set
}Awesome, thanks! I ended up doing something very similar at the end (I was paying attention while reading your book afterall!).
That “AuthKeyHandler” in my case had to hide quite a lot having to also deal with Google’s insanity that they return a map of certificates that need to be converted into public keys which also expire every 6 hours 🥲