servant/src/Servant/API/Capture.hs
2014-10-28 13:42:37 +08:00

50 lines
1.4 KiB
Haskell

{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE ScopedTypeVariables #-}
module Servant.API.Capture where
import Data.Proxy
import Data.Text
import GHC.TypeLits
import Network.Wai
import Servant.API.Sub
import Servant.Client
import Servant.Server
import Servant.Text
-- * Captures
data Capture sym a
captured :: FromText a => proxy (Capture sym a) -> Text -> Maybe a
captured _ = fromText
instance (KnownSymbol capture, FromText a, HasServer sublayout)
=> HasServer (Capture capture a :> sublayout) where
type Server (Capture capture a :> sublayout) =
a -> Server sublayout
route Proxy subserver globalPathInfo request respond = case pathInfo request of
(first : rest)
-> case captured captureProxy first of
Nothing -> respond Nothing
Just v -> route (Proxy :: Proxy sublayout) (subserver v) globalPathInfo request{
pathInfo = rest
} respond
_ -> respond Nothing
where captureProxy = Proxy :: Proxy (Capture capture a)
instance (KnownSymbol capture, ToText a, HasClient sublayout)
=> HasClient (Capture capture a :> sublayout) where
type Client (Capture capture a :> sublayout) =
a -> Client sublayout
clientWithRoute Proxy req val =
clientWithRoute (Proxy :: Proxy sublayout) $
appendToPath p req
where p = unpack (toText val)