我在Windows 10上运行NetCore，我有两个程序-服务器和客户端都在本地运行。
执行顺序如下：
运行服务器-有一个处理客户端的循环
运行客户端-客户端执行其工作，过程终止
第二次运行客户端
此序列使用以下代码从服务器生成以下输出：
Waiting for client.
Reading message.
Incoming message: This message is longer than what
Sending message.
Closing connection.
Waiting for client.
Reading message.
Incoming message: This message is longer than what
Sending message.
Closing connection.
Waiting for client.
以及客户端的以下输出：
Connecting to server.
Sending message.
Reading message.
Incoming message: Thank you!
Connecting to server.
Sending message.
Reading message.
Unhandled Exception: System.AggregateException: One or more errors occurred. (Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.) ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host
换句话说，第二次运行客户端的尝试以异常结束。那是奇怪的部分。
这是我用于重现此问题的最小代码示例。
服务器代码：
public static async Task StartServerAsync()
{
TcpListener listener = new TcpListener(IPAddress.Any, 1234);
listener.Server.NoDelay = true;
listener.Server.LingerState = new LingerOption(true, 0);
listener.Start();
while (true)
{
Console.WriteLine("Waiting for client.");
using (TcpClient client = await listener.AcceptTcpClientAsync())
{
client.NoDelay = true;
client.LingerState = new LingerOption(true, 0);
Console.WriteLine("Reading message.");
using (NetworkStream stream = client.GetStream())
{
byte[] buffer = new byte[32];
int len = await stream.ReadAsync(buffer, 0, buffer.Length);
string incomingMessage = Encoding.UTF8.GetString(buffer, 0, len);
Console.WriteLine("Incoming message: {0}", incomingMessage);
Console.WriteLine("Sending message.");
byte[] message = Encoding.UTF8.GetBytes("Thank you!");
await stream.WriteAsync(message, 0, message.Length);
Console.WriteLine("Closing connection.");
}
}
}
}
客户代码：
public static async Task StartClientAsync()
{
using (TcpClient client = new TcpClient())
{
client.NoDelay = true;
client.LingerState = new LingerOption(true, 0);
Console.WriteLine("Connecting to server.");
await client.ConnectAsync("127.0.0.1", 1234);
Console.WriteLine("Sending message.");
using (NetworkStream stream = client.GetStream())
{
byte[] buffer = Encoding.UTF8.GetBytes("This message is longer than what the server is willing to read.");
await stream.WriteAsync(buffer, 0, buffer.Length);
Console.WriteLine("Reading message.");
int len = await stream.ReadAsync(buffer, 0, buffer.Length);
string message = Encoding.UTF8.GetString(buffer, 0, len);
Console.WriteLine("Incoming message: {0}", message);
}
}
}
奇怪的是，如果我们将客户的信息从
"This message is longer than what the server is willing to read."
至
"This message is short."
客户端的两个实例均完好无损，并产生相同的输出。
请注意，如果我省略了设置LingerState的所有三行，则没有区别。另外，如果我将LingerState设置为
new LingerState(true, 5)如果将NoDelay设置为false，也没有区别。换句话说，在任一侧将任何值设置为LingerState和NoDelay似乎都对崩溃没有任何影响。防止崩溃的唯一方法是从服务器端的客户端读取整个输入。
这很奇怪，我想知道是否有人可以解释这一点。我不确定它是否也适用于.NET Framework，仅在NetCore 1.0.0和Windows 10上进行了测试。
最佳答案
最终由.NET Core团队在GitHub上回答。
长答案-查看https://github.com/dotnet/corefx/issues/13114的最新评论
简短答案-
该行为是预期的，并且是设计使然。