refactor: move role insertion in claims to PreQuery.hs

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>

src/PostgREST/Auth/Jwt.hs

@@ -16,7 +16,6 @@ module PostgREST.Auth.Jwt
   , parseClaims) where
 
 import qualified Data.Aeson                 as JSON
-import qualified Data.Aeson.KeyMap          as KM
 import qualified Data.ByteString            as BS
 import qualified Data.ByteString.Internal   as BS
 import qualified Data.ByteString.Lazy.Char8 as LBS
@@ -118,7 +117,7 @@ parseClaims cfg@AppConfig{configJwtRoleClaimKey, configDbAnonRole} time mclaims
   role <- liftEither . maybeToRight (JwtErr JwtTokenRequired) $
     unquoted <$> walkJSPath (Just $ JSON.Object mclaims) configJwtRoleClaimKey <|> configDbAnonRole
   pure AuthResult
-           { authClaims = mclaims & KM.insert "role" (JSON.toJSON $ decodeUtf8 role)
+           { authClaims = mclaims
            , authRole = role
            }
   where

src/PostgREST/Auth/Types.hs

@@ -6,7 +6,9 @@ import qualified Data.Aeson        as JSON
 import qualified Data.Aeson.KeyMap as KM
 import qualified Data.ByteString   as BS
 
--- | Parse result for JWT Claims
+-- |
+-- Parse and store result for JWT Claims. Can be accessed in
+-- db through GUCs (for RLS etc)
 data AuthResult = AuthResult
   { authClaims :: KM.KeyMap JSON.Value
   , authRole   :: BS.ByteString