181e51d · servant · git.iko.soy

git.iko.soy/servant

Add `MonadFail` instance for `Handler` wrt #1545

181e51dJulian Ospald5 years ago

servant-server/CHANGELOG.md+5

@@ -3,6 +3,11 @@

4Package versions follow the [Package Versioning Policy](https://pvp.haskell.org/): in A.B.C, bumps to either A or B represent major versions.

6+Unreleased

7+----------

9+- Add `MonadFail` instance for `Handler` wrt [#1545](https://github.com/haskell-servant/servant/issues/1545)

10+

60.19

110.19

7----

12----

servant-server/src/Servant/Server/Internal/Handler.hs+7−2

@@ -13,17 +13,19 @@ import Control.Monad.Base

13import Control.Monad.Catch

14 (MonadCatch, MonadMask, MonadThrow)

15import Control.Monad.Error.Class

16− (MonadError)

16+ (MonadError, throwError)

17import Control.Monad.IO.Class

18 (MonadIO)

19import Control.Monad.Trans.Control

20 (MonadBaseControl (..))

21import Control.Monad.Trans.Except

22 (ExceptT, runExceptT)

23+import Data.String

24+ (fromString)

23import GHC.Generics

25import GHC.Generics

24 (Generic)

26 (Generic)

25import Servant.Server.Internal.ServerError

27import Servant.Server.Internal.ServerError

26− (ServerError)

28+ (ServerError, errBody, err500)

28newtype Handler a = Handler { runHandler' :: ExceptT ServerError IO a }

30newtype Handler a = Handler { runHandler' :: ExceptT ServerError IO a }

29 deriving

31 deriving

@@ -32,6 +34,9 @@ newtype Handler a = Handler { runHandler' :: ExceptT ServerError IO a }

32 , MonadThrow, MonadCatch, MonadMask

34 , MonadThrow, MonadCatch, MonadMask

33 )

35 )

37+instance MonadFail Handler where

38+ fail str = throwError err500 { errBody = fromString str }

39+

35instance MonadBase IO Handler where

40instance MonadBase IO Handler where

36 liftBase = Handler . liftBase

41 liftBase = Handler . liftBase