Initial commit

1 files changed, 30 insertions, 0 deletions

diff --git a/net/client.hs b/net/client.hs
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index 0000000..863df6e
--- /dev/null
+++ b/net/client.hs
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+{-# LANGUAGE OverloadedStrings #-}
+-- Echo client program
+module Main (main) where
+
+import qualified Control.Exception as E
+import qualified Data.ByteString.Char8 as C
+import Network.Socket
+import Network.Socket.ByteString (recv, sendAll)
+
+main :: IO ()
+main = runTCPClient "127.0.0.1" "3000" $ \s -> do
+    sendAll s "Hello, world!"
+    msg <- recv s 1024
+    putStr "Received: "
+    C.putStrLn msg
+
+-- from the "network-run" package.
+runTCPClient :: HostName -> ServiceName -> (Socket -> IO a) -> IO a
+runTCPClient host port client = withSocketsDo $ do
+    addr <- resolve
+    E.bracket (open addr) close client
+  where
+    resolve = do
+        let hints = defaultHints { addrSocketType = Stream }
+        head <$> getAddrInfo (Just hints) (Just host) (Just port)
+    open addr = do
+        sock <- socket (addrFamily addr) (addrSocketType addr) (addrProtocol addr)
+        connect sock $ addrAddress addr
+        return sock
+