servant/servant-server/test/Servant/Server/UsingContextSpec/TestCombinators.hs
Andres Loeh b1a6d88845 Revise the Router type to allow proper sharing.
We've previously used functions in the Router type to provide
information for subrouters. But this accesses the Requests too
early, and breaks sharing of the router structure in general,
causing the Router or large parts of the Router to be recomputed
on every request.

We now do not use functions anymore, and properly compute all
static parts of the router first, and gain access to the request
only in Delayed.

This also turns the code used within Delayed into a proper monad
now called DelayedIO, making some of the code using it a bit
nicer.
2016-04-12 09:38:49 +02:00

71 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
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)
where
subProxy :: Proxy subApi
subProxy = Proxy
inject context f = f (getContextEntry context)
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