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Network.Socket.ByteString | Portability | portable | Stability | experimental | Maintainer | johan.tibell@gmail.com |
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Description |
This module provides access to the BSD socket interface. This
module is generally more efficient than the String based network
functions in Network.Socket. For detailed documentation, consult
your favorite POSIX socket reference. All functions communicate
failures by converting the error number to System.IO.IOError.
This module is made to be imported with Network.Socket like so:
import Network.Socket hiding (send, sendTo, recv, recvFrom)
import Network.Socket.ByteString
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Synopsis |
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Send data to a socket
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:: Socket | Connected socket
| -> ByteString | Data to send
| -> IO Int | Number of bytes sent
| Send data to the socket. The socket must be connected to a
remote socket. Returns the number of bytes sent. Applications are
responsible for ensuring that all data has been sent.
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:: Socket | Connected socket
| -> ByteString | Data to send
| -> IO () | | Send data to the socket. The socket must be connected to a
remote socket. Unlike send, this function continues to send data
until either all data has been sent or an error occurs. On error,
an exception is raised, and there is no way to determine how much
data, if any, was successfully sent.
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:: Socket | Socket
| -> ByteString | Data to send
| -> SockAddr | Recipient address
| -> IO Int | Number of bytes sent
| Send data to the socket. The recipient can be specified
explicitly, so the socket need not be in a connected state.
Returns the number of bytes sent. Applications are responsible for
ensuring that all data has been sent.
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:: Socket | Socket
| -> ByteString | Data to send
| -> SockAddr | Recipient address
| -> IO () | | Send data to the socket. The recipient can be specified
explicitly, so the socket need not be in a connected state. Unlike
sendTo, this function continues to send data until either all
data has been sent or an error occurs. On error, an exception is
raised, and there is no way to determine how much data, if any, was
successfully sent.
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Vectored I/O
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Vectored I/O, also known as scatter/gather I/O, allows multiple
data segments to be sent using a single system call, without first
concatenating the segments. For example, given a list of
ByteStrings, xs,
sendMany sock xs
is equivalent to
sendAll sock (concat xs)
but potentially more efficient.
Vectored I/O are often useful when implementing network protocols
that, for example, group data into segments consisting of one or
more fixed-length headers followed by a variable-length body.
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:: Socket | Connected socket
| -> [ByteString] | Data to send
| -> IO () | | Send data to the socket. The socket must be in a connected
state. The data is sent as if the parts have been concatenated.
This function continues to send data until either all data has been
sent or an error occurs. On error, an exception is raised, and
there is no way to determine how much data, if any, was
successfully sent.
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:: Socket | Socket
| -> [ByteString] | Data to send
| -> SockAddr | Recipient address
| -> IO () | | Send data to the socket. The recipient can be specified
explicitly, so the socket need not be in a connected state. The
data is sent as if the parts have been concatenated. This function
continues to send data until either all data has been sent or an
error occurs. On error, an exception is raised, and there is no
way to determine how much data, if any, was successfully sent.
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Receive data from a socket
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:: Socket | Connected socket
| -> Int | Maximum number of bytes to receive
| -> IO ByteString | Data received
| Receive data from the socket. The socket must be in a connected
state. This function may return fewer bytes than specified. If
the message is longer than the specified length, it may be
discarded depending on the type of socket. This function may block
until a message arrives.
Considering hardware and network realities, the maximum number of bytes to
receive should be a small power of 2, e.g., 4096.
For TCP sockets, a zero length return value means the peer has
closed its half side of the connection.
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:: Socket | Socket
| -> Int | Maximum number of bytes to receive
| -> IO (ByteString, SockAddr) | Data received and sender address
| Receive data from the socket. The socket need not be in a
connected state. Returns (bytes, address) where bytes is a
ByteString representing the data received and address is a
SockAddr representing the address of the sending socket.
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Example
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Here are two minimal example programs using the TCP/IP protocol: a
server that echoes all data that it receives back (servicing only
one client) and a client using it.
-- Echo server program
module Main where
import Control.Monad (unless)
import Network.Socket hiding (recv)
import qualified Data.ByteString as S
import Network.Socket.ByteString (recv, sendAll)
main :: IO ()
main = withSocketsDo $
do addrinfos <- getAddrInfo
(Just (defaultHints {addrFlags = [AI_PASSIVE]}))
Nothing (Just "3000")
let serveraddr = head addrinfos
sock <- socket (addrFamily serveraddr) Stream defaultProtocol
bindSocket sock (addrAddress serveraddr)
listen sock 1
(conn, _) <- accept sock
talk conn
sClose conn
sClose sock
where
talk :: Socket -> IO ()
talk conn =
do msg <- recv conn 1024
unless (S.null msg) $ sendAll conn msg >> talk conn
-- Echo client program
module Main where
import Network.Socket hiding (recv)
import Network.Socket.ByteString (recv, sendAll)
import qualified Data.ByteString.Char8 as C
main :: IO ()
main = withSocketsDo $
do addrinfos <- getAddrInfo Nothing (Just "") (Just "3000")
let serveraddr = head addrinfos
sock <- socket (addrFamily serveraddr) Stream defaultProtocol
connect sock (addrAddress serveraddr)
sendAll sock $ C.pack "Hello, world!"
msg <- recv sock 1024
sClose sock
putStr "Received "
C.putStrLn msg
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