c# – NetworkStream.Read的替代方案,表示远程主机已关闭连接?
作者:互联网
关于使用TcpClient类处理TCP / IP连接,是否有替代方法可以检查远程主机是否已关闭连接而不是等待NetworkStream.Read方法返回0?
解决方法:
您可以在TcpClient.Client上使用IOControlCode.KeepAliveValues来保证至少在指定的时间间隔内进行保持活动检查,然后检查TcpClient.Client.Connected属性.
如何使用它的一个例子:
struct tcp_keepalive
{
public int OnOff;
public int KeepAliveTime;
public int KeepAliveInterval;
public unsafe byte[] Buffer
{
get
{
var buf = new byte[sizeof(tcp_keepalive)];
fixed(void* p = &this) Marshal.Copy(new IntPtr(p), buf, 0, buf.Length);
return buf;
}
}
};
static void KeepAliveTest()
{
using(var c = new TcpClient())
{
c.Connect("www.google.com", 80);
var s = c.Client;
var ka = new tcp_keepalive();
ka.OnOff = 1; // enable
ka.KeepAliveTime = 1000 * 60; // 60 seconds of inactivity allowed
ka.KeepAliveInterval = 1000; // 1 second interval on keep-alive checks (default)
s.IOControl(IOControlCode.KeepAliveValues, ka.Buffer, null);
var ns = c.GetStream();
Console.WriteLine("Connected to " + s.RemoteEndPoint);
while(true)
{
SocketError se;
s.Blocking = false;
s.Receive(new byte[0], 0, 0, SocketFlags.Peek, out se);
s.Blocking = true;
if(!s.Connected)
{
// se==SocketError.ConnectionReset||SocketError.NetworkReset if the connection was closed because of a keep-alive check
Console.WriteLine("Socket disconnected: " + se);
break;
}
// do other stuff
if(ns.DataAvailable) ns.Read(new byte[100], 0, 100);
else Thread.Sleep(10);
}
}
}
标签:c,tcp,connection,tcpclient,networkstream 来源: https://codeday.me/bug/20190518/1130802.html