Main.hs

{-# LANGUAGE DataKinds #-}
{-# LANGUAGE TypeOperators #-}
module Main where

import Business.Types
import Data.IORef
import Servant.API
import Servant.Server
import Network.Wai.Handler.Warp
import Control.Monad.Trans (liftIO)
import Control.Monad (void)
import Data.Proxy

type MyAPI =      "counter" :> Get  Counter
             :<|> "counter" :> Post Counter

main = do
  counter <- newIORef (Counter 0)
  run 7000 $ serve myAPI (server counter)
  where myAPI :: Proxy MyAPI
        myAPI = Proxy

server :: IORef Counter -> Server MyAPI
server ref = getCounter :<|> postCounter
  where
    getCounter  = liftIO $ readIORef ref
    postCounter = liftIO $ atomicModifyIORef ref
                           (\c -> (incrementCounter c,
                                   incrementCounter c))