Minimal POP3 client in Haskell

pop3.hs

module Main where

import Network.Socket hiding (send, sendTo, recv, recvFrom)
import Network.Socket.ByteString (send, recv)
import qualified Data.ByteString.Char8 as B8


main :: IO()
main = client' 110



client' :: Int -> IO ()
client' = client "mail.gandi.net"

client :: String -> Int -> IO ()
client host port = withSocketsDo $ do
                addrInfo <- getAddrInfo Nothing (Just host) (Just $ show port)
                print addrInfo
                let serverAddr = head addrInfo
                sock <- socket (addrFamily serverAddr) Stream defaultProtocol
                connect sock (addrAddress serverAddr)
                msgSender sock
                sClose sock


recv' sock = do rMsg <- recv sock 100000000
                putStrLn $ "IN : " ++ (B8.unpack rMsg)
                return rMsg

send' sock m = do putStrLn $ "OUT: " ++ m
                  send sock $ (B8.append (B8.pack m) (B8.pack "\n"))


msgSender :: Socket -> IO ()
msgSender sock = do
  recv' sock
  send' sock "USER admin@call-cc.be"
  recv' sock
  send' sock "PASS bleep"
  recv' sock
  send' sock "stat"
  recv' sock
  send' sock "list"
  recv' sock
  send' sock "retr 1"
  recv' sock
  return ()