Question

目前我有一些代码可以为某些测试目的创建服务器和客户端。

服务器代码

import Network.Socket
import Network.Socket.ByteString as NSB
import Network.Socket.ByteString.Lazy as NSBL
import Data.ByteString.Lazy as BSL
import Data.ByteString as BS
import Data.HashMap as HM
import System.IO as IO

main = withSocketsDo $ do
  sock <- socket AF_INET Stream 0
  setSocketOption sock ReuseAddr 1
  bindSocket sock (SockAddrInet (fromInteger 8585) iNADDR_ANY)
  listen sock 100
  servLoop sock

servLoop sock = do
  client = accept sock
  IO.putStrLn "Got a connection"
  h <- SocketToHandle client ReadWriteMode
  hSetBuffering h NoBuffering
  req <- BSL.hGet h 1024
  IO.putStrLn "Got some contents:"
  IO.putStrLn $ show req

客户代码

import Network.Socket
import Network.BSD
import Control.Monad
import System.IO as IO
import Data.Text as T
import Data.ByteString.Lazy as BSL
import Data.MessagePack as MP

main = withSocketsDo $ do
  sock <- socket AF_INET Stream 0
  setSocketOption sock ReuseAddr 1
  addr <- liftM hostAddresses $ getHostByName "localhost"
  connect sock $ SockAddrInet (fromInteger 8585) (Prelude.head addr)
  handle <- socketToHandle sock ReadWriteMode
  replicateM_ 5 $ BSL.hPut handle $ MP.pack ("Hello host" :: Text)
  hFlush handle
  getLine
  replicateM_ 5 $ BSL.hPut handle $ MP.pack ("Hello host" :: Text)
  hFlush handle
  hClose handle

观察到的行为是，在客户端调用hClose句柄之前，不会发送消息。但是，我希望保持句柄处于打开状态，以便快速发送更多请求并接收响应。我是以正确的方式来做这件事的吗？如果是这样，有没有办法保持句柄打开但是读取和写入套接字？

Answer 1

do r1 <- BSL.hGet h 1 rRest <- BSL.hGetNonBlocking h 1024 return (r1 BS.append rRest)一直尝试读取，直到它有你所要求的字节数，即1024.你可能想要使用hGetNonBlocking。或类似的东西：

library(lubridate)

df1 <- data.frame(
  StartDate = as.Date(c("2015-07-01", "2015-06-01", "2015-07-15", "2015-08-01")),
  EndDate = as.Date(c("2015-09-30", "2015-10-31", "2016-01-31", "2015-12-31")),
  MonthlyRental = c(500, 600, 400, 800)
)

d <- c( as.Date("2015-07-31"),
        as.Date("2015-08-31"),
        as.Date("2015-09-30"),
        as.Date("2015-10-31"),
        as.Date("2015-11-30"),
        as.Date("2015-12-31"),
        as.Date("2016-01-31"),
        as.Date("2016-02-29")  )

RentPerDay <- outer( df1$"MonthlyRental", days_in_month(d), "/" )

countDays <- pmin( pmax( outer( d, df1$"StartDate", "-") + 1, 0 ), days_in_month(d) ) -
             pmin( pmax( outer( d, df1$"EndDate"  , "-"), 0 ), days_in_month(d) )

rentalIncome <- colSums( t(countDays) * RentPerDay )

在保持连接打开的同时从套接字读取

1 个答案: