hello-world wai-warp server

Main.hs

module Main where

import Network.Wai.Handler.Warp (run)
import qualified Routes as R

main = do
  run 3000 R.routes

prj.cabal

name:          Project
version:       1.0.0
build-type:    Simple
cabal-version: >= 1.2
license:       MIT
author:        Author
homepage:      http://example.com
category:      Testing
synopsis:      synopsis

executable main
  main-is: Main.hs
  hs-source-dirs: src
  build-depends: base       >= 4   && < 5
               , conduit    >= 1   && < 1.1
               , http-types >= 0.8 && < 1
               , wai        >= 1.4 && < 1.5
               , warp       >= 1.3 && < 1.4
  

Routes.hs

{-# LANGUAGE OverloadedStrings #-}
module Routes where

import Network.Wai
import Network.HTTP.Types (ok200)
import Data.Conduit


routes :: Request -> ResourceT IO Response
routes req = return $ responseLBS ok200 [] "OK"