git.iko.soy/servant
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servant/servant-examples/tutorial/T1.hs
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1{-# LANGUAGE DataKinds #-}
2{-# LANGUAGE TypeFamilies #-}
3{-# LANGUAGE DeriveGeneric #-}
4{-# LANGUAGE TypeOperators #-}
5module T1 where
7import Data.Aeson
8import Data.Time.Calendar
9import GHC.Generics
10import Network.Wai
11import Servant
13data User = User
14 { name :: String
15 , age :: Int
16 , email :: String
17 , registration_date :: Day
18 } deriving (Eq, Show, Generic)
20-- orphan ToJSON instance for Day. necessary to derive one for User
21instance ToJSON Day where
22 -- display a day in YYYY-mm-dd format
23 toJSON d = toJSON (showGregorian d)
25instance ToJSON User
27type UserAPI = "users" :> Get '[JSON] [User]
29users :: [User]
30users =
31 [ User "Isaac Newton" 372 "isaac@newton.co.uk" (fromGregorian 1683 3 1)
32 , User "Albert Einstein" 136 "ae@mc2.org" (fromGregorian 1905 12 1)
33 ]
35userAPI :: Proxy UserAPI
36userAPI = Proxy
38server :: Server UserAPI
39server = return users
41app :: Application
42app = serve userAPI server