如何设置TCP sokcet连接的超时时间

Posted 2023-05-05

参考技术A 如果你确定,真的不需要等这么久,或者用户希望可以随时中上连接过程,那么一般是用 非阻塞模式来做的. 看看我的这段连接代码(节选),可以作为TCP连接的典范:

bool CRemoteLink::Connect()

OnDisconnected(); // 如果已经连接，则断开

if(!m_bUseProxy)


m_iConnStatus = SS_CONNECTING; // 正在连接状态
GNTRACE ("开始连接到远程服务器[%s][%ld]...\n", m_strip.c_str(), m_port);

// 建立套接字, 准备连接到服务器
m_socket = ::socket(AF_INET, SOCK_STREAM, 0);
if (socket < 0)
if(m_pCallBack)
m_pCallBack->OnSocketError(SE_CREATE, MSG_SE_CREATE);
return false;


// 设为异步操作方式
unsigned long on = 1;
if (::ioctlsocket(m_socket, FIONBIO, &on) < 0)
::closesocket(m_socket);
if(m_pCallBack)
m_pCallBack->OnSocketError(SE_CREATE, MSG_SE_CREATE);
return false;


sockaddr_in addr;
memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = inet_addr(m_strip.c_str());
addr.sin_port = htons(m_port);

int rt;
rt = ::connect(m_socket, (sockaddr *) &addr, sizeof(addr));
if (rt == 0)
OnConnected();
return true;


// ==================================================================
timeval to;

// 首先建立连接
fd_set wfds;
fd_set efds;
FD_ZERO(&wfds);
FD_ZERO(&efds);

// test shutdown event each 100ms.
to.tv_sec = 0;
// CONNECT_TIMEOUT;
to.tv_usec = 100000;

int it = 0;
while(!m_meShutdown.Wait(0) && !m_meConnStop.Wait(0))

FD_SET(m_socket, &wfds);
FD_SET(m_socket, &efds);
int n = select(m_socket + 1, NULL, &wfds, &efds, &to);

if (n > 0)
if(FD_ISSET(m_socket, &wfds))

OnConnected();
return true;

else

//int err = ::WSAGetLastError();
//const char* msg = GetLastErrorMessage(err);
GNTRACE ("CRemoteLink::Connect : connection attempt failed!\n");
if(m_pCallBack)
m_pCallBack->OnSocketError(SE_CONN, MSG_SE_CONN);
break;

else if (n < 0) // Select Error
int err = ::WSAGetLastError();
const char* msg = GetLastErrorMessage(err);
GNTRACE ("CRemoteLink::Connect : Select Error.[%d] - %s\n", err, msg);
if(m_pCallBack)
m_pCallBack->OnSocketError(err, msg);
break;

else

it += 100;
if(it > 30000) // 连接超时 -- (30S)

GNTRACE ("CRemoteLink::Connect : Time out.\n");
if(m_pCallBack)
m_pCallBack->OnSocketError(SE_TIMEOUT, MSG_SE_TIMEOUT);
break;



if(m_meConnStop.Wait(0))

GNTRACE("连接过程进行时被取消。\n");


else

// 通过代理服务器连接
转载

golang 关于处理TCP连接和设置超时的Golang示例。

package main

import (
	"fmt"
	"net"
	"time"
	"bufio"
)

func handleConnection(conn net.Conn) {
	fmt.Println("Handling new connection...")

	// Close connection when this function ends
	defer func() {
		fmt.Println("Closing connection...")
		conn.Close()
	}()

	timeoutDuration := 5 * time.Second
	bufReader := bufio.NewReader(conn)

	for {
		// Set a deadline for reading. Read operation will fail if no data
		// is received after deadline.
		conn.SetReadDeadline(time.Now().Add(timeoutDuration))

		// Read tokens delimited by newline
		bytes, err := bufReader.ReadBytes('\n')
		if err != nil {
			fmt.Println(err)
			return
		}

		fmt.Printf("%s", bytes)
	}
}

func main() {
	// Start listening to port 8888 for TCP connection
	listener, err:= net.Listen("tcp", ":8888")
	if err != nil {
		fmt.Println(err)
		return
	}

	defer func() {
		listener.Close()
		fmt.Println("Listener closed")
	}()

	for {
		// Get net.TCPConn object
		conn, err := listener.Accept()
		if err != nil {
			fmt.Println(err)
			break
		}

		go handleConnection(conn)
	}
}