"hello world" warp app

warp.hs

-- warp-2.1.5.2
-- ghc -O2 -threaded -rtsopts warp
-- ./warp +RTS -N -A1G
{-# LANGUAGE OverloadedStrings #-}
module Main where

import           Blaze.ByteString.Builder (copyByteString)
import           Data.Text (unpack)
import           Network.HTTP.Types.Status (status200)
import           Network.Wai
import           Network.Wai.Handler.Warp (run)

main :: IO ()
main = do
  putStrLn "starting simple HTTP"
  run 3001 app

app :: Application
app req = do
  --p $ show $ rawPathInfo req
  case map unpack (pathInfo req) of
    _ -> do
      s200

s200 :: IO Response
s200 = return
     $ responseBuilder status200 [("Content-Type", "text/plain")]
     $ copyByteString "PONG"