当客户端尝试连接到断开连接的IP地址时，超时时间超过15秒......我们如何减少此超时？配置它的方法是什么？
我用来设置套接字连接的代码如下：
try
{
m_clientSocket = new Socket(
AddressFamily.InterNetwork,
SocketType.Stream,
ProtocolType.Tcp);
IPAddress ip = IPAddress.Parse(serverIp);
int iPortNo = System.Convert.ToInt16(serverPort);
IPEndPoint ipEnd = new IPEndPoint(ip, iPortNo);
m_clientSocket.Connect(ipEnd);
if (m_clientSocket.Connected)
{
lb_connectStatus.Text = "Connection Established";
WaitForServerData();
}
}
catch (SocketException se)
{
lb_connectStatus.Text = "Connection Failed";
MessageBox.Show(se.Message);
}
答案 0 :(得分：129)
Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
// Connect using a timeout (5 seconds)
IAsyncResult result = socket.BeginConnect( sIP, iPort, null, null );
bool success = result.AsyncWaitHandle.WaitOne( 5000, true );
if ( socket.Connected )
{
socket.EndConnect( result );
}
else
{
// NOTE, MUST CLOSE THE SOCKET
socket.Close();
throw new ApplicationException("Failed to connect server.");
}
//...
答案 1 :(得分：28)
我的看法：
public static class SocketExtensions
{
/// <summary>
/// Connects the specified socket.
/// </summary>
/// <param name="socket">The socket.</param>
/// <param name="endpoint">The IP endpoint.</param>
/// <param name="timeout">The timeout.</param>
public static void Connect(this Socket socket, EndPoint endpoint, TimeSpan timeout)
{
var result = socket.BeginConnect(endpoint, null, null);
bool success = result.AsyncWaitHandle.WaitOne(timeout, true);
if (success)
{
socket.EndConnect(result);
}
else
{
socket.Close();
throw new SocketException(10060); // Connection timed out.
}
}
}
答案 2 :(得分：22)
我刚写了一个扩展类，以便在连接中允许超时。完全像使用标准Connect()方法一样使用它，并使用名为timeout的额外参数。
using System;
using System.Net;
using System.Net.Sockets;
/// <summary>
/// Extensions to Socket class
/// </summary>
public static class SocketExtensions
{
/// <summary>
/// Connects the specified socket.
/// </summary>
/// <param name="socket">The socket.</param>
/// <param name="host">The host.</param>
/// <param name="port">The port.</param>
/// <param name="timeout">The timeout.</param>
public static void Connect(this Socket socket, string host, int port, TimeSpan timeout)
{
AsyncConnect(socket, (s, a, o) => s.BeginConnect(host, port, a, o), timeout);
}
/// <summary>
/// Connects the specified socket.
/// </summary>
/// <param name="socket">The socket.</param>
/// <param name="addresses">The addresses.</param>
/// <param name="port">The port.</param>
/// <param name="timeout">The timeout.</param>
public static void Connect(this Socket socket, IPAddress[] addresses, int port, TimeSpan timeout)
{
AsyncConnect(socket, (s, a, o) => s.BeginConnect(addresses, port, a, o), timeout);
}
/// <summary>
/// Asyncs the connect.
/// </summary>
/// <param name="socket">The socket.</param>
/// <param name="connect">The connect.</param>
/// <param name="timeout">The timeout.</param>
private static void AsyncConnect(Socket socket, Func<Socket, AsyncCallback, object, IAsyncResult> connect, TimeSpan timeout)
{
var asyncResult = connect(socket, null, null);
if (!asyncResult.AsyncWaitHandle.WaitOne(timeout))
{
try
{
socket.EndConnect(asyncResult);
}
catch (SocketException)
{ }
catch (ObjectDisposedException)
{ }
}
}
答案 3 :(得分：8)
我不用C＃编程，但是在C中，我们通过使套接字无阻塞然后将fd放在select / poll循环中来解决同样的问题，其中超时值等于我们愿意等待的时间量为了成功连接。
我为Visual C ++找到了this，并且那里的解释也倾向于我之前解释过的select / poll机制。
根据我的经验，您无法更改每个套接字的连接超时值。您可以更改它（通过调整OS参数）。
答案 4 :(得分：4)
我通过使用Socket.ConnectAsync方法而不是Socket.Connect方法解决了这个问题。 在调用Socket.ConnectAsync（SocketAsyncEventArgs）之后，启动一个计时器（timer_connection），如果时间到了，检查套接字连接是否已连接（如果（m_clientSocket.Connected）），如果没有，则弹出超时错误。
private void connect(string ipAdd,string port)
{
try
{
SocketAsyncEventArgs e=new SocketAsyncEventArgs();
m_clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPAddress ip = IPAddress.Parse(serverIp);
int iPortNo = System.Convert.ToInt16(serverPort);
IPEndPoint ipEnd = new IPEndPoint(ip, iPortNo);
//m_clientSocket.
e.RemoteEndPoint = ipEnd;
e.UserToken = m_clientSocket;
e.Completed+=new EventHandler<SocketAsyncEventArgs>(e_Completed);
m_clientSocket.ConnectAsync(e);
if (timer_connection != null)
{
timer_connection.Dispose();
}
else
{
timer_connection = new Timer();
}
timer_connection.Interval = 2000;
timer_connection.Tick+=new EventHandler(timer_connection_Tick);
timer_connection.Start();
}
catch (SocketException se)
{
lb_connectStatus.Text = "Connection Failed";
MessageBox.Show(se.Message);
}
}
private void e_Completed(object sender,SocketAsyncEventArgs e)
{
lb_connectStatus.Text = "Connection Established";
WaitForServerData();
}
private void timer_connection_Tick(object sender, EventArgs e)
{
if (!m_clientSocket.Connected)
{
MessageBox.Show("Connection Timeout");
//m_clientSocket = null;
timer_connection.Stop();
}
}
答案 5 :(得分：2)
在MSDN上查看此内容。您似乎无法使用Socket类中的已实现属性执行此操作。
MSDN上的海报实际上是solved his problem使用线程。他有一个主线程调用其他线程运行连接代码几秒钟，然后检查套接字的Connected属性：
我实际创建了另一种方法 连接插座...有主要的 线程睡眠2秒然后 检查连接方法（哪个 如果是，则在单独的线程中运行 插座连接好了 抛出异常“超时”和 就这样。再次感谢 repleies。
你想做什么，为什么不能在超时之前等待15-30秒呢？
答案 6 :(得分：2)
连接到Socket时遇到了同样的问题，我提出了以下解决方案，它对我来说很好。 `
private bool CheckConnectivityForProxyHost(string hostName, int port)
{
if (string.IsNullOrEmpty(hostName))
return false;
bool isUp = false;
Socket testSocket = null;
try
{
testSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPAddress ip = null;
if (testSocket != null && NetworkingCollaboratorBase.GetResolvedConnecionIPAddress(hostName, out ip))//Use a method to resolve your IP
{
IPEndPoint ipEndPoint = new IPEndPoint(ip, port);
isUp = false;
//time out 5 Sec
CallWithTimeout(ConnectToProxyServers, 5000, testSocket, ipEndPoint);
if (testSocket != null && testSocket.Connected)
{
isUp = true;
}
}
}
}
catch (Exception ex)
{
isUp = false;
}
finally
{
try
{
if (testSocket != null)
{
testSocket.Shutdown(SocketShutdown.Both);
}
}
catch (Exception ex)
{
}
finally
{
if (testSocket != null)
testSocket.Close();
}
}
return isUp;
}
private void CallWithTimeout(Action<Socket, IPEndPoint> action, int timeoutMilliseconds, Socket socket, IPEndPoint ipendPoint)
{
try
{
Action wrappedAction = () =>
{
action(socket, ipendPoint);
};
IAsyncResult result = wrappedAction.BeginInvoke(null, null);
if (result.AsyncWaitHandle.WaitOne(timeoutMilliseconds))
{
wrappedAction.EndInvoke(result);
}
}
catch (Exception ex)
{
}
}
private void ConnectToProxyServers(Socket testSocket, IPEndPoint ipEndPoint)
{
try
{
if (testSocket == null || ipEndPoint == null)
return;
testSocket.Connect(ipEndPoint);
}
catch (Exception ex)
{
}
}
答案 7 :(得分：1)
我使用Unity并且在socket中遇到了BeginConnect和其他异步方法的问题。
有些东西比我不理解，但之前的代码示例对我不起作用。
所以我编写了这段代码以使其工作。我在Android和PC的adhoc网络上测试它，也在我的计算机上本地测试。希望它可以提供帮助。
using System.Net.Sockets;
using System.Threading;
using System.Net;
using System;
using System.Diagnostics;
class ConnexionParameter : Guardian
{
public TcpClient client;
public string address;
public int port;
public Thread principale;
public Thread thisthread = null;
public int timeout;
private EventWaitHandle wh = new AutoResetEvent(false);
public ConnexionParameter(TcpClient client, string address, int port, int timeout, Thread principale)
{
this.client = client;
this.address = address;
this.port = port;
this.principale = principale;
this.timeout = timeout;
thisthread = new Thread(Connect);
}
public void Connect()
{
WatchDog.Start(timeout, this);
try
{
client.Connect(IPAddress.Parse(address), port);
}
catch (Exception)
{
UnityEngine.Debug.LogWarning("Unable to connect service (Training mode? Or not running?)");
}
OnTimeOver();
//principale.Resume();
}
public bool IsConnected = true;
public void OnTimeOver()
{
try
{
if (!client.Connected)
{
/*there is the trick. The abort method from thread doesn't
make the connection stop immediately(I think it's because it rise an exception
that make time to stop). Instead I close the socket while it's trying to
connect , that make the connection method return faster*/
IsConnected = false;
client.Close();
}
wh.Set();
}
catch(Exception)
{
UnityEngine.Debug.LogWarning("Connexion already closed, or forcing connexion thread to end. Ignore.");
}
}
public void Start()
{
thisthread.Start();
wh.WaitOne();
//principale.Suspend();
}
public bool Get()
{
Start();
return IsConnected;
}
}
public static class Connexion
{
public static bool Connect(this TcpClient client, string address, int port, int timeout)
{
ConnexionParameter cp = new ConnexionParameter(client, address, port, timeout, Thread.CurrentThread);
return cp.Get();
}
//http://stackoverflow.com/questions/19653588/timeout-at-acceptsocket
public static Socket AcceptSocket(this TcpListener tcpListener, int timeoutms, int pollInterval = 10)
{
TimeSpan timeout = TimeSpan.FromMilliseconds(timeoutms);
var stopWatch = new Stopwatch();
stopWatch.Start();
while (stopWatch.Elapsed < timeout)
{
if (tcpListener.Pending())
return tcpListener.AcceptSocket();
Thread.Sleep(pollInterval);
}
return null;
}
}
并且在C＃上有一个非常简单的监视器可以使它工作：
using System.Threading;
public interface Guardian
{
void OnTimeOver();
}
public class WatchDog {
int m_iMs;
Guardian m_guardian;
public WatchDog(int a_iMs, Guardian a_guardian)
{
m_iMs = a_iMs;
m_guardian = a_guardian;
Thread thread = new Thread(body);
thread.Start(this);
}
private void body(object o)
{
WatchDog watchdog = (WatchDog)o;
Thread.Sleep(watchdog.m_iMs);
watchdog.m_guardian.OnTimeOver();
}
public static void Start(int a_iMs, Guardian a_guardian)
{
new WatchDog(a_iMs, a_guardian);
}
}
答案 8 :(得分：1)
这就像FlappySock的答案，但我添加了回调，因为我不喜欢布局以及如何返回布尔值。在Nick Miller的回答评论中：
根据我的经验，如果可以达到终点，但端点上没有服务器能够接收连接，那么AsyncWaitHandle.WaitOne将发出信号，但套接字将保持未连接状态
所以对我而言，似乎依赖返回的内容可能很危险 - 我更喜欢使用socket.Connected。我设置了一个可以为空的布尔值并在回调函数中更新它。我还发现它在返回主函数之前总是没有完成报告结果 - 我也处理它，并让它等待结果使用超时：
private static bool? areWeConnected = null;
private static bool checkSocket(string svrAddress, int port)
{
IPEndPoint endPoint = new IPEndPoint(IPAddress.Parse(svrAddress), port);
Socket socket = new Socket(endPoint.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
int timeout = 5000; // int.Parse(ConfigurationManager.AppSettings["socketTimeout"].ToString());
int ctr = 0;
IAsyncResult ar = socket.BeginConnect(endPoint, Connect_Callback, socket);
ar.AsyncWaitHandle.WaitOne( timeout, true );
// Sometimes it returns here as null before it's done checking the connection
// No idea why, since .WaitOne() should block that, but it does happen
while (areWeConnected == null && ctr < timeout)
{
Thread.Sleep(100);
ctr += 100;
} // Given 100ms between checks, it allows 50 checks
// for a 5 second timeout before we give up and return false, below
if (areWeConnected == true)
{
return true;
}
else
{
return false;
}
}
private static void Connect_Callback(IAsyncResult ar)
{
areWeConnected = null;
try
{
Socket socket = (Socket)ar.AsyncState;
areWeConnected = socket.Connected;
socket.EndConnect(ar);
}
catch (Exception ex)
{
areWeConnected = false;
// log exception
}
}
答案 9 :(得分：1)
可能为时已晚，但是有一个基于Task.WaitAny（c＃5 +）的简洁解决方案：
public static bool ConnectWithTimeout(this Socket socket, string host, int port, int timeout)
{
bool connected = false;
Task result = socket.ConnectAsync(host, port);
int index = Task.WaitAny(new[] { result }, timeout);
connected = socket.Connected;
if (!connected) {
socket.Close();
}
return connected;
}
答案 10 :(得分：-8)
Socket类中应该有一个ReceiveTimeout属性。