Server.hs

module Main where

import Control.Monad (forever)
import Network.HTTP.Types (status200)
import qualified Network.WebSockets             as WS
import qualified Network.Wai                    as Wai
import qualified Network.Wai.Handler.Warp       as Warp
import qualified Network.Wai.Handler.WebSockets as WaiWS

import Echo

main :: IO ()
main = do
  putStrLn "started echo on port 9160"
  Warp.run 9160 $
    WaiWS.websocketsOr WS.defaultConnectionOptions wsapp backapp

wsapp :: WS.ServerApp
wsapp pending = WS.acceptRequest pending >>= talk

backapp :: Wai.Application
backapp _ respond = respond $
  Wai.responseLBS status200 [("Content-Type", "text/plain")] "Hello World"

talk :: WS.Connection -> IO ()
talk conn = forever $ do
  msg <- WS.receiveData conn
  WS.sendTextData conn $ echo msg