servant/servant-examples/wai-middleware/wai-middleware.hs
2016-01-21 17:58:50 +01:00

51 lines
1.3 KiB
Haskell

{-# LANGUAGE DataKinds #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE OverloadedStrings #-}
import Data.Aeson
import Data.Text
import GHC.Generics
import Network.Wai
import Network.Wai.Handler.Warp
import Network.Wai.Middleware.RequestLogger
import Servant
data Product = Product
{ name :: Text
, brand :: Text
, current_price_eur :: Double
, available :: Bool
} deriving (Eq, Show, Generic)
instance ToJSON Product
products :: [Product]
products = [p1, p2]
where p1 = Product "Haskell laptop sticker"
"GHC Industries"
2.50
True
p2 = Product "Foldable USB drive"
"Well-Typed"
13.99
False
type SimpleAPI = Get '[JSON] [Product]
simpleAPI :: Proxy SimpleAPI
simpleAPI = Proxy
server :: Server SimpleAPI
server = return products
-- logStdout :: Middleware
-- i.e, logStdout :: Application -> Application
-- serve :: Proxy api -> Config config -> Server api -> Application
-- so applying a middleware is really as simple as
-- applying a function to the result of 'serve'
app :: Application
app = logStdout (serve simpleAPI EmptyConfig server)
main :: IO ()
main = run 8080 app