Currently, authentication and response execution each unwrap ExceptT with separate runExceptT calls, which split the main request flow across nested pattern matching and Either handling. Control flow is complex and difficult to understand.
The goal of this change is to make request execution as sequential
monadic code with clear error handling.
To implement that, request handling is now run in ExceptT over WriterT (Last ByteString) IO monad stack. Auth role is written after authentication succeeds and further returned along the response. Thanks to it response observation generation is centralized at the end of request handling.
It was necessary to abstract monad stack in getAuthResult, lookupJwtCache, postgrestResponse, and withTiming to enable introduction of WriterT.
Also add a comment on `AuthResult` type to explain that
we can also access the claims in the db using GUCs.
Signed-off-by: Taimoor Zaeem <taimoorzaeem@gmail.com>
The logic to evaluate `JSPath` belongs to `JSPath.hs` module.
Hence, moving this logic from `Auth/Jwt.hs` to here.
Signed-off-by: Taimoor Zaeem <taimoorzaeem@gmail.com>
This change is an initial step to change JWT aud configuration to regular expression.
Exporting function
audMatchesCfg :: AppConfig -> Text -> Bool
from Config module allows changing the way how JWT aud is configured to be isolated and not affect code in Auth.JWT
Changes:
1. Refactoring and some cleanup of JWT handling code:
* Instead of caching AuthResult cache decoded claims (which signature was verified). Validating claims and determining role is done after cache lookup
* Cleaned up API so that usage of it is simplified: lookupJwtCache cache key >>= parseClaims configJwtAud time
* Handling of JwtCacheState initialization and updates of configuration is encapsulated in Auth.JwtCache module
2. Generic high performance (hopefully) scalable, dynamically resizeable cache implementation based on stm, stm-hamt and sieve algorithm. It also integrates with PostgREST measurements infrastructure providing usage stats (ie. hit ratio, evictions count)
This change introduces a PostgREST.Auth.Jwt module containing JWT validation functions.
The reason to extract them from Auth is to enable JwtCache module to reuse them without introducing module dependency cycle.
