amazonka-s3-encryption-2.0: src/Amazonka/S3/Encryption/Decrypt.hs

-- |
-- Module      : Amazonka.S3.Encryption.Decrypt
-- Copyright   : (c) 2013-2023 Brendan Hay
-- License     : Mozilla Public License, v. 2.0.
-- Maintainer  : Brendan Hay <brendan.g.hay+amazonka.com>
-- Stability   : provisional
-- Portability : non-portable (GHC extensions)
module Amazonka.S3.Encryption.Decrypt where

import qualified Amazonka as AWS
import Amazonka.Core
import Amazonka.Prelude
import qualified Amazonka.S3 as S3
import Amazonka.S3.Encryption.Envelope
import Amazonka.S3.Encryption.Instructions
import Amazonka.S3.Encryption.Types
import qualified Amazonka.S3.Lens as S3
import Control.Lens ((%~), (^.))
import qualified Control.Monad.Except as Except
import qualified Network.HTTP.Client as Client

decrypted :: S3.GetObject -> (Decrypt S3.GetObject, GetInstructions)
decrypted x = (Decrypt x, getInstructions x)

newtype Decrypt a = Decrypt a

newtype Decrypted a = Decrypted
  { runDecrypted :: forall m. MonadResource m => Key -> AWS.Env -> Maybe Envelope -> m a
  }

instance AWSRequest (Decrypt S3.GetObject) where
  type AWSResponse (Decrypt S3.GetObject) = Decrypted S3.GetObjectResponse

  request overrides (Decrypt x) = coerce (request overrides x)

  response l s p r =
    Except.runExceptT $ do
      rs <- Except.ExceptT (response l s (proxy p) r)

      let body = Client.responseBody rs
          decrypt =
            Decrypted $ \key env m -> do
              encrypted <-
                case m of
                  Nothing -> fromMetadata key env (body ^. S3.getObjectResponse_metadata)
                  Just e -> pure e

              pure (body & S3.getObjectResponse_body %~ bodyDecrypt encrypted)

      pure (decrypt <$ rs)

proxy :: forall a. Proxy (Decrypt a) -> Proxy a
proxy = const Proxy