Minimum Wai + Warp Application Server. Compiled with GHC 7.4, Wai 1.1, Warp 1.1 versions.

WaiApp1.hs

{-# LANGUAGE OverloadedStrings #-}

-- | Hello world Wai+Warp applicaion server. Used GHC 7.4, Wai 1.1, Warp 1.1 versions.                                            
module Main where

import Network.HTTP.Types (status200)
import Network.Wai (Application,responseLBS)
import Network.Wai.Handler.Warp (run)

-- | Hello word Wai application.                                                                                                  
app :: Application
app _ = return $ responseLBS status200 [("Content-Type", "text/plain")] "Hello, Web!"

-- | Start Warp server on port 8080.                                                                                              
main :: IO ()
main = do
  putStrLn $ "http://localhost:8080/"
  run 8080 app