将sendAll消息发送给套接字客户端会导致：“`Exception: Network.Socket.sendBuf:无效参数(传输端点未连接)”

Question

当从套接字服务器调用Network.Socket.ByteString.sendAll (hackage docs - sendall) (发送到套接字客户端)时，我遇到了一个Network.Socket.ByteString.sendAll错误。

我不知道为什么会有这个错误？看来我只能用一种方式发送数据？

在使用netcat而不是Haskell客户端时，我也遇到了相同的错误：

echo 'test' | nc  -N -U /tmp2/test2.soc

客户的输出：

*Server Main> main
Hello, Haskell!2
"sent ping....."

来自服务器的输出：

*Server> serv
"begin"
"Running daemon"
"begin2"
<socket: 13>

"Got message:"
"ping"
"Sending pong...."
*** Exception: Network.Socket.sendBuf: invalid argument (Transport endpoint is not connected)

完整项目：https://github.com/chrissound/UnixSocketPingPongHaskellTest

完整源代码：

客户：

{-# Language OverloadedStrings #-}
module Main where

import Network.Socket hiding (send)
import Network.Socket.ByteString as NBS
import Control.Concurrent
import Control.Monad

main :: IO ()
main = do
  putStrLn "Hello, Haskell!2"
  withSocketsDo $ do
    soc <- socket AF_UNIX Stream 0
    connect (soc) (SockAddrUnix "/tmp2/test2.soc")
    forever $ do
      send soc ("ping")
      threadDelay $ 1 * 10^6
      print "sent ping....."
      threadDelay $ 1 * 10^6
      msg <- NBS.recv soc 400000
      print msg
      print "got reply to ping...."
    close soc

服务器：

{-# Language OverloadedStrings #-}
module Server where

import Network.Socket hiding (send)
import Network.Socket.ByteString as NBS
import Control.Concurrent
import Control.Monad

serv :: IO ()
serv = do
  print "begin"
  print "Running daemon"
  soc <- socket AF_UNIX Stream 0
  bind soc . SockAddrUnix $ "/tmp2/test2.soc"
  listen soc maxListenQueue
  accept soc >>= (\(x,y)-> do
    print "begin2"
    print x
    print y
    forever $ do
      msg <- NBS.recv x 400000
      print "Sending pong...."
      NBS.sendAll soc "ppong"
      print "alll done"

      threadDelay $ 3 * 10^6
      )

Answer 1

您正在侦听套接字上发送；您可能希望使用已接受的套接字来发送。

  listen soc maxListenQueue
  accept soc >>= (\(x,y)-> do
    ...
    NBS.sendAll soc "ppong"  -- should be   sendAll x "ppong"