servant/servant-examples/getting-started/GS1.hs
2015-05-09 18:11:03 +02:00

45 lines
1,002 B
Haskell

{-# LANGUAGE DataKinds #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE TypeOperators #-}
import Data.Aeson
import Data.Time.Calendar
import GHC.Generics
import Network.Wai.Handler.Warp (run)
import Servant
data User = User
{ name :: String
, age :: Int
, email :: String
, registration_date :: Day
} deriving (Eq, Show, Generic)
-- orphan ToJSON instance for Day. necessary to derive one for User
instance ToJSON Day where
-- display a day in YYYY-mm-dd format
toJSON d = toJSON (showGregorian d)
instance ToJSON User
type UserAPI = "users" :> Get '[JSON] [User]
users :: [User]
users =
[ User "Isaac Newton" 372 "isaac@newton.co.uk" (fromGregorian 1683 3 1)
, User "Albert Einstein" 136 "ae@mc2.org" (fromGregorian 1905 12 1)
]
userAPI :: Proxy UserAPI
userAPI = Proxy
server :: Server UserAPI
server = return users
runServer :: Int -> IO ()
runServer port = run port (serve userAPI server)
main :: IO ()
main = runServer 8081