Re: [Haskell-cafe] windows network programming

20 Jan 2011


      freenode figured this out. Pasting here for future reference.


import Control.Concurrent
import Network
import System.IO

main :: IO ()
main = withSocketsDo $ do
    m <- newEmptyMVar
    forkIO (waitAndPong m)
    ping m

-- The basic server
waitAndPong :: MVar () -> IO ()
waitAndPong m = do
    socket <- listenOn (PortNumber 8000)
    putMVar m ()
    (handle,_,_) <- accept socket
    hSetBuffering handle LineBuffering
    incoming <- hGetLine handle
    putStrLn ("> " ++ incoming)
    hPutStrLn handle "pong"

-- The basic client
ping :: MVar () -> IO ()
ping m = do
    _ <- takeMVar m
    handle <- connectTo "localhost" (PortNumber 8000)
    hSetBuffering handle LineBuffering
    hPutStrLn handle "ping"
    incoming <- hGetLine handle
    putStrLn ("< " ++ incoming)


On Thu, Jan 20, 2011 at 6:17 PM, Michael Litchard wrote:
...
I tried this as an example and got the following error when running.
net.exe: connect: failed (Connection refused (WSAECONNREFUSED))
Firewall is off, running as administrator
Windows is Windows 7 Enterprise.
Advice on what to do next is appreciated
On Tue, Nov 2, 2010 at 1:24 PM, Nils Schweinsberg  wrote:
...
Am 02.11.2010 19:57, schrieb Michael Litchard:
got any urls with examples?
...
Sure, see this short server-client-ping-pong application.
By the way, I noticed that you don't need withSocketsDo on windows 7, but
I guess it's there for a reason for older windows versions. :)
import Control.Concurrent
   import Network
   import System.IO
main :: IO ()
   main = withSocketsDo $ do
       forkIO waitAndPong
       ping
-- The basic server
   waitAndPong :: IO ()
   waitAndPong = do
       socket <- listenOn (PortNumber 1234)
       (handle,_,_) <- accept socket
       hSetBuffering handle LineBuffering
       incoming <- hGetLine handle
       putStrLn ("> " ++ incoming)
       hPutStrLn handle "pong"
-- The basic client
   ping :: IO ()
   ping = do
       handle <- connectTo "localhost" (PortNumber 1234)
       hSetBuffering handle LineBuffering
       hPutStrLn handle "ping"
       incoming <- hGetLine handle
       putStrLn ("< " ++ incoming)
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