servant/servant-examples/tutorial/T7.hs
2016-01-21 17:55:02 +01:00

33 lines
849 B
Haskell

{-# LANGUAGE DataKinds #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
module T7 where
import Control.Monad.Trans.Except
import Control.Monad.Trans.Reader
import Network.Wai
import Servant
type ReaderAPI = "a" :> Get '[JSON] Int
:<|> "b" :> Get '[JSON] String
readerAPI :: Proxy ReaderAPI
readerAPI = Proxy
readerServerT :: ServerT ReaderAPI (Reader String)
readerServerT = a :<|> b
where a :: Reader String Int
a = return 1797
b :: Reader String String
b = ask
readerServer :: Server ReaderAPI
readerServer = enter readerToEither readerServerT
where readerToEither :: Reader String :~> ExceptT ServantErr IO
readerToEither = Nat $ \r -> return (runReader r "hi")
app :: Application
app = serve readerAPI EmptyConfig readerServer