我正处于编写新的 Windows 服务应用程序的设计阶段，该应用程序接受 TCP/IP 连接以进行长时间运行的连接(即，这不像 HTTP 那样有许多短连接，而是客户端连接并保持连接数小时或数天甚至数周)。
我正在寻找设计网络架构的最佳方式的想法。我将需要为该服务至少启动一个线程。我正在考虑使用异步 API(BeginRecieve 等)，因为我不知道在任何给定时间(可能是数百个)我将连接多少个客户端。我绝对不想为每个连接启动一个线程。
数据将主要从我的服务器流出到客户端，但有时会从客户端发送一些命令。这主要是一个监控应用程序，我的服务器定期向客户端发送状态数据。
使其尽可能可扩展的最佳方法是什么？基本工作流程？
明确地说，我正在寻找基于 .NET 的解决方案(如果可能，C#，但任何 .NET 语言都可以使用)。
我需要一个解决方案的工作示例，作为指向我可以下载的内容的指针或内嵌的简短示例。并且它必须是基于 .NET 和 Windows 的(任何 .NET 语言都是可以接受的)。

最佳答案

我以前写过类似的东西。我多年前的研究表明，使用异步套接字编写自己的套接字实现是最好的选择。这意味着客户没有真正做任何事情实际上需要相对较少的资源。发生的任何事情都由 .NET 线程池处理。
我把它写成一个管理服务器所有连接的类。
我只是使用一个列表来保存所有客户端连接，但是如果您需要更快地查找更大的列表，您可以随心所欲地编写它。

private List<xConnection> _sockets;

private System.Net.Sockets.Socket _serverSocket;

public bool Start()
{
  System.Net.IPHostEntry localhost = System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName());
  System.Net.IPEndPoint serverEndPoint;
  try
  {
     serverEndPoint = new System.Net.IPEndPoint(localhost.AddressList[0], _port);
  }
  catch (System.ArgumentOutOfRangeException e)
  {
    throw new ArgumentOutOfRangeException("Port number entered would seem to be invalid, should be between 1024 and 65000", e);
  }
  try
  {
    _serverSocket = new System.Net.Sockets.Socket(serverEndPoint.Address.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
   }
   catch (System.Net.Sockets.SocketException e)
   {
      throw new ApplicationException("Could not create socket, check to make sure not duplicating port", e);
    }
    try
    {
      _serverSocket.Bind(serverEndPoint);
      _serverSocket.Listen(_backlog);
    }
    catch (Exception e)
    {
       throw new ApplicationException("An error occurred while binding socket. Check inner exception", e);
    }
    try
    {
       //warning, only call this once, this is a bug in .net 2.0 that breaks if
       // you're running multiple asynch accepts, this bug may be fixed, but
       // it was a major pain in the rear previously, so make sure there is only one
       //BeginAccept running
       _serverSocket.BeginAccept(new AsyncCallback(acceptCallback), _serverSocket);
    }
    catch (Exception e)
    {
       throw new ApplicationException("An error occurred starting listeners. Check inner exception", e);
    }
    return true;
 }

    private void acceptCallback(IAsyncResult result)
    {
       xConnection conn = new xConnection();
       try
       {
         //Finish accepting the connection
         System.Net.Sockets.Socket s = (System.Net.Sockets.Socket)result.AsyncState;
         conn = new xConnection();
         conn.socket = s.EndAccept(result);
         conn.buffer = new byte[_bufferSize];
         lock (_sockets)
         {
           _sockets.Add(conn);
         }
         //Queue receiving of data from the connection
         conn.socket.BeginReceive(conn.buffer, 0, conn.buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveCallback), conn);
         //Queue the accept of the next incoming connection
         _serverSocket.BeginAccept(new AsyncCallback(acceptCallback), _serverSocket);
       }
       catch (SocketException e)
       {
         if (conn.socket != null)
         {
           conn.socket.Close();
           lock (_sockets)
           {
             _sockets.Remove(conn);
           }
         }
         //Queue the next accept, think this should be here, stop attacks based on killing the waiting listeners
         _serverSocket.BeginAccept(new AsyncCallback(acceptCallback), _serverSocket);
       }
       catch (Exception e)
       {
         if (conn.socket != null)
         {
           conn.socket.Close();
           lock (_sockets)
           {
             _sockets.Remove(conn);
           }
         }
         //Queue the next accept, think this should be here, stop attacks based on killing the waiting listeners
         _serverSocket.BeginAccept(new AsyncCallback(acceptCallback), _serverSocket);
       }
     }

private void ReceiveCallback(IAsyncResult result)
{
  //get our connection from the callback
  xConnection conn = (xConnection)result.AsyncState;
  //catch any errors, we'd better not have any
  try
  {
    //Grab our buffer and count the number of bytes receives
    int bytesRead = conn.socket.EndReceive(result);
    //make sure we've read something, if we haven't it supposadly means that the client disconnected
    if (bytesRead > 0)
    {
      //put whatever you want to do when you receive data here

      //Queue the next receive
      conn.socket.BeginReceive(conn.buffer, 0, conn.buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveCallback), conn);
     }
     else
     {
       //Callback run but no data, close the connection
       //supposadly means a disconnect
       //and we still have to close the socket, even though we throw the event later
       conn.socket.Close();
       lock (_sockets)
       {
         _sockets.Remove(conn);
       }
     }
   }
   catch (SocketException e)
   {
     //Something went terribly wrong
     //which shouldn't have happened
     if (conn.socket != null)
     {
       conn.socket.Close();
       lock (_sockets)
       {
         _sockets.Remove(conn);
       }
     }
   }
 }

//put whatever you want to do when you receive data here

//Queue the next receive
conn.socket.BeginReceive(conn.buffer, 0, conn.buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveCallback), conn);

public bool Send(byte[] message, xConnection conn)
{
  if (conn != null && conn.socket.Connected)
  {
    lock (conn.socket)
    {
    //we use a blocking mode send, no async on the outgoing
    //since this is primarily a multithreaded application, shouldn't cause problems to send in blocking mode
       conn.socket.Send(bytes, bytes.Length, SocketFlags.None);
     }
   }
   else
     return false;
   return true;
 }

public class xConnection : xBase
{
  public byte[] buffer;
  public System.Net.Sockets.Socket socket;
}

using System.Net.Sockets;

关于c# - 如何编写可扩展的基于 TCP/IP 的服务器，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/869744/