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Echo server: Difference between revisions
add Haskell example
(→{{header|Common Lisp}}: note should have usocket) |
(add Haskell example) |
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Line 473:
(echo-server 12321)
</lang>
=={{header|Haskell}}==
<lang haskell>module Main where
import Network (withSocketsDo, accept, listenOn, sClose, PortID(PortNumber))
import Control.Monad (forever)
import System.IO (hGetLine, hPutStrLn, hFlush, hClose)
import System.IO.Error (isEOFError)
import Control.Concurrent (forkIO)
import Control.Exception (bracket)
-- For convenience in testing, ensure that the listen socket is closed if the main loop is aborted
withListenOn port body = bracket (listenOn port) sClose body
echo (handle, host, port) = catch doOneLine stop where
doOneLine = do line <- hGetLine handle
print (host, port, init line)
hPutStrLn handle line
hFlush handle
doOneLine
stop error = do putStrLn $ "Closed connection from " ++ show (host, port) ++ " due to " ++ show error
hClose handle
main = withSocketsDo $ do
withListenOn (PortNumber 12321) $ \listener ->
forever $ do
acc@(_, host, port) <- accept listener
putStrLn $ "Accepted connection from " ++ show (host, port)
forkIO (echo acc)</lang>
=={{header|Python}}==
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