servant/servant-server/test/Servant/Server/UsingContextSpec/TestCombinators.hs
2016-03-19 10:08:48 +01:00

72 lines
2.2 KiB
Haskell

{-# LANGUAGE DataKinds #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE UndecidableInstances #-}
-- | These are custom combinators for Servant.Server.UsingContextSpec.
--
-- (For writing your own combinators you need to import Internal modules, for
-- just *using* combinators that require a Context, you don't. This module is
-- separate from Servant.Server.UsingContextSpec to test that the module imports
-- work out this way.)
module Servant.Server.UsingContextSpec.TestCombinators where
import GHC.TypeLits
import Servant
import Servant.Server.Internal.RoutingApplication
data ExtractFromContext
instance (HasContextEntry context String, HasServer subApi context) =>
HasServer (ExtractFromContext :> subApi) context where
type ServerT (ExtractFromContext :> subApi) m =
String -> ServerT subApi m
route Proxy context delayed =
route subProxy context (fmap (inject context) delayed :: Delayed (Server subApi))
where
subProxy :: Proxy subApi
subProxy = Proxy
inject ctx f = f (getContextEntry ctx)
data InjectIntoContext
instance (HasServer subApi (String ': context)) =>
HasServer (InjectIntoContext :> subApi) context where
type ServerT (InjectIntoContext :> subApi) m =
ServerT subApi m
route Proxy context delayed =
route subProxy newContext delayed
where
subProxy :: Proxy subApi
subProxy = Proxy
newContext = ("injected" :: String) :. context
data NamedContextWithBirdface (name :: Symbol) (subContext :: [*])
instance (HasContextEntry context (NamedContext name subContext), HasServer subApi subContext) =>
HasServer (NamedContextWithBirdface name subContext :> subApi) context where
type ServerT (NamedContextWithBirdface name subContext :> subApi) m =
ServerT subApi m
route Proxy context delayed =
route subProxy subContext delayed
where
subProxy :: Proxy subApi
subProxy = Proxy
subContext :: Context subContext
subContext = descendIntoNamedContext (Proxy :: Proxy name) context