servant/servant-server/src/Servant/Server/Experimental/Auth.hs

72 lines
2.5 KiB
Haskell

{-# OPTIONS_GHC -fno-warn-orphans #-}
{-# LANGUAGE DeriveDataTypeable #-}
{-# LANGUAGE DeriveFunctor #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE UndecidableInstances #-}
module Servant.Server.Experimental.Auth where
import Control.Monad.Trans
(liftIO)
import Data.Proxy
(Proxy (Proxy))
import Data.Typeable
(Typeable)
import GHC.Generics
(Generic)
import Network.Wai
(Request)
import Servant
((:>))
import Servant.API.Experimental.Auth
import Servant.Server.Internal
(DelayedIO, Handler, HasContextEntry, HasServer (..),
addAuthCheck, delayedFailFatal, getContextEntry, runHandler,
withRequest)
-- * General Auth
-- | Specify the type of data returned after we've authenticated a request.
-- quite often this is some `User` datatype.
--
-- NOTE: THIS API IS EXPERIMENTAL AND SUBJECT TO CHANGE
type family AuthServerData a :: *
-- | Handlers for AuthProtected resources
--
-- NOTE: THIS API IS EXPERIMENTAL AND SUBJECT TO CHANGE
newtype AuthHandler r usr = AuthHandler
{ unAuthHandler :: r -> Handler usr }
deriving (Functor, Generic, Typeable)
-- | NOTE: THIS API IS EXPERIMENTAL AND SUBJECT TO CHANGE
mkAuthHandler :: (r -> Handler usr) -> AuthHandler r usr
mkAuthHandler = AuthHandler
-- | Known orphan instance.
instance ( HasServer api context
, HasContextEntry context (AuthHandler Request (AuthServerData (AuthProtect tag)))
)
=> HasServer (AuthProtect tag :> api) context where
type ServerT (AuthProtect tag :> api) m =
AuthServerData (AuthProtect tag) -> ServerT api m
hoistServerWithContext _ pc nt s = hoistServerWithContext (Proxy :: Proxy api) pc nt . s
route Proxy context subserver =
route (Proxy :: Proxy api) context (subserver `addAuthCheck` withRequest authCheck)
where
authHandler :: Request -> Handler (AuthServerData (AuthProtect tag))
authHandler = unAuthHandler (getContextEntry context)
authCheck :: Request -> DelayedIO (AuthServerData (AuthProtect tag))
authCheck = (>>= either delayedFailFatal return) . liftIO . runHandler . authHandler