我刚刚开始使用C＃进行套接字编程，现在我对这个问题感到有些困惑。 如何在不为每个客户端创建线程的情况下在单个服务器上处理多个客户端？
当有10个客户端时，每个客户端的一个线程工作正常，但如果客户端数量达到1000个客户端，则为每个客户端创建一个线程是否可取？如果有任何其他方法可以这样做，有人可以打电话给我？
答案 0 :(得分：27)
尝试使用异步服务器。 以下示例程序创建一个接收来自客户端的连接请求的服务器。服务器使用异步套接字构建，因此在等待来自客户端的连接时不会暂停服务器应用程序的执行。应用程序从客户端接收字符串，在控制台上显示字符串，然后将字符串回送给客户端。来自客户端的字符串必须包含字符串“”以表示消息的结尾。
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
// State object for reading client data asynchronously
public class StateObject {
// Client socket.
public Socket workSocket = null;
// Size of receive buffer.
public const int BufferSize = 1024;
// Receive buffer.
public byte[] buffer = new byte[BufferSize];
// Received data string.
public StringBuilder sb = new StringBuilder();
}
public class AsynchronousSocketListener {
// Thread signal.
public static ManualResetEvent allDone = new ManualResetEvent(false);
public AsynchronousSocketListener() {
}
public static void StartListening() {
// Data buffer for incoming data.
byte[] bytes = new Byte[1024];
// Establish the local endpoint for the socket.
// The DNS name of the computer
// running the listener is "host.contoso.com".
IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName());
IPAddress ipAddress = ipHostInfo.AddressList[0];
IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 11000);
// Create a TCP/IP socket.
Socket listener = new Socket(AddressFamily.InterNetwork,
SocketType.Stream, ProtocolType.Tcp );
// Bind the socket to the local endpoint and listen for incoming connections.
try {
listener.Bind(localEndPoint);
listener.Listen(100);
while (true) {
// Set the event to nonsignaled state.
allDone.Reset();
// Start an asynchronous socket to listen for connections.
Console.WriteLine("Waiting for a connection...");
listener.BeginAccept(
new AsyncCallback(AcceptCallback),
listener );
// Wait until a connection is made before continuing.
allDone.WaitOne();
}
} catch (Exception e) {
Console.WriteLine(e.ToString());
}
Console.WriteLine("\nPress ENTER to continue...");
Console.Read();
}
public static void AcceptCallback(IAsyncResult ar) {
// Signal the main thread to continue.
allDone.Set();
// Get the socket that handles the client request.
Socket listener = (Socket) ar.AsyncState;
Socket handler = listener.EndAccept(ar);
// Create the state object.
StateObject state = new StateObject();
state.workSocket = handler;
handler.BeginReceive( state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
}
public static void ReadCallback(IAsyncResult ar) {
String content = String.Empty;
// Retrieve the state object and the handler socket
// from the asynchronous state object.
StateObject state = (StateObject) ar.AsyncState;
Socket handler = state.workSocket;
// Read data from the client socket.
int bytesRead = handler.EndReceive(ar);
if (bytesRead > 0) {
// There might be more data, so store the data received so far.
state.sb.Append(Encoding.ASCII.GetString(
state.buffer,0,bytesRead));
// Check for end-of-file tag. If it is not there, read
// more data.
content = state.sb.ToString();
if (content.IndexOf("<EOF>") > -1) {
// All the data has been read from the
// client. Display it on the console.
Console.WriteLine("Read {0} bytes from socket. \n Data : {1}",
content.Length, content );
// Echo the data back to the client.
Send(handler, content);
} else {
// Not all data received. Get more.
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
}
}
}
private static void Send(Socket handler, String data) {
// Convert the string data to byte data using ASCII encoding.
byte[] byteData = Encoding.ASCII.GetBytes(data);
// Begin sending the data to the remote device.
handler.BeginSend(byteData, 0, byteData.Length, 0,
new AsyncCallback(SendCallback), handler);
}
private static void SendCallback(IAsyncResult ar) {
try {
// Retrieve the socket from the state object.
Socket handler = (Socket) ar.AsyncState;
// Complete sending the data to the remote device.
int bytesSent = handler.EndSend(ar);
Console.WriteLine("Sent {0} bytes to client.", bytesSent);
handler.Shutdown(SocketShutdown.Both);
handler.Close();
} catch (Exception e) {
Console.WriteLine(e.ToString());
}
}
public static int Main(String[] args) {
StartListening();
return 0;
}
}
那将是最好的解决方案。
答案 1 :(得分：1)
线程可以很好地工作，但很少能够很好地扩展到许多客户端。有两种简单的方法和许多更复杂的方法来处理它，这里有一些伪代码，用于说明通常如何构建更容易的方法来为您提供概述。
选择（）
这是一个调用来检查哪些套接字有新的客户端或数据等待它们，典型的程序看起来像这样。
server = socket(), bind(), listen()
while(run)
status = select(server)
if has new client
newclient = server.accept()
handle add client
if has new data
read and handle data
这意味着不需要线程来处理多个客户端，但是如果处理数据需要很长时间，那么它就不能很好地扩展，那么在完成之前你就不会读取新数据或接受新客户端。
异步套接字
这是另一种处理套接字的方法，它是一种抽象的选择。您只需为常见事件设置回调，让框架执行不那么繁重的工作。
function handleNewClient() { do stuff and then beginReceive(handleNewData) }
function handleNewData() { do stuff and then beginReceive(handleNewData) }
server = create, bind, listen etc
server.beginAddNewClientHandler(handleNewClient)
server.start()
如果您的数据处理需要很长时间，我认为这应该可以更好地扩展。你将做什么样的数据处理？
答案 2 :(得分：0)
This可能是一个很好的起点。如果你想避免1个线程＆lt; - ＆gt; 1个客户;那么你应该使用.NET中提供的异步套接字工具。这里使用的核心对象是SocketAsyncEventArgs。