C#多用戶TCP服務器

嘗試創建異步 tcp 服務器。以前我可以用開始/結束模式很好地完成這一點，并像這樣處理多個客戶端：

class Server
{
    IPEndPoint ipep;
    TcpListener listener;
    bool Running;
    List<Client> clients;

    public Server(string host)
    {
        IPAddress ip = IPAddress.Parse(host);
        ipep = new(ip, 21);
        Running = false;
        clients = new();
    }

    public void Start()
    {
        listener = new(ipep);
        listener.Start();
        Running = true;
        while (Running)
            listener.BeginAcceptTcpClient(Accept, null);
    }

    public void Accept(IAsyncResult ar)
    {
        Client client = new(listener.EndAcceptTcpClient(ar));
        clients.Add(client);
        client.WaitCommands();
    }
}

class Client
{
    TcpClient client;
    NetworkStream stream;

    public Client(TcpClient client)
    {
        this.client = client;
        stream = client.GetStream();
    }

    public void WaitCommands()
    {
        stream.BeginRead(/*some buffer stuff*/, Receive, null);
    }

    public void Receive(IAsyncResult ar)
    {
        stream.EndRead(ar);
        stream.BeginRead(/*again buffer stuff*/, Receive, null);
    }
}

互聯網上有很多這樣的例子。但是 MSDN 似乎建議改用異步方法，所以我想轉換為它。這是我所擁有的：

class Server
{
    IPEndPoint ipep;
    TcpListener listener;
    bool Running;
    List<Client> clients;

    public Server(string host)
    {
        IPAddress ip = IPAddress.Parse(host);
        ipep = new(ip, 21);
        Running = false;
        clients = new();
    }

    public async Task Start()
    {
        listener = new(ipep);
        listener.Start();
        Running = true;
        while (Running)
        {
            Client c = await listener.AcceptTcpClientAsync();
            clients.Add(c);
            await c.WaitCommands();
        }
    }
}

class Client
{
    TcpClient client;
    NetworkStream stream;

    public Client(TcpClient client)
    {
        this.client = client;
        stream = client.GetStream();
    }

    public async Task WaitCommands()
    {
        while (true)
        {
            await stream.ReadAsync(/*buffer stuff*/);
        }
    }
}

并且顯然會await c.WaitCommands();阻止其他客戶端，因為應用程式卡在 while (true) 回圈中并且永遠不會再次到達 await Accept。我發現了一些可以解決 _ = Task.Run(async () => await client.WaitCommands());問題的方法。但據我所知，它從執行緒池中獲取執行緒，與開始/結束方法不同（或者我錯了？這也是問題）。

所以問題是

1. 如何開始從客戶端讀取并接受第二個示例中的另一個？
2. 我走對了路嗎？或者對于大多數用戶計數規模應該使用什么方法（即也許我應該為每個客戶端使用一些執行緒）？

uj5u.com熱心網友回復：

像這樣的東西：

using System.Net;
using System.Net.Sockets;

var svr = new Server("127.0.0.1");
await svr.Run();
Console.WriteLine("Goodby, World!");

class Server
{
    IPEndPoint ipep;
    TcpListener listener;
    bool Running;
    List<Client> clients;
    private CancellationTokenSource cts;

    public Server(string host)
    {
        IPAddress ip = IPAddress.Parse(host);
        ipep = new(ip, 1121);
        Running = false;
        clients = new();

        this.cts = new CancellationTokenSource();
    }

    public void Stop()
    {
        Running = false;
        cts.Cancel();
    }
    public async Task Run()
    {
        listener = new(ipep);
        listener.Start();
        Running = true;
        while (Running)
        {
            var c = await listener.AcceptTcpClientAsync(cts.Token);
            var client = new Client(c);
            clients.Add(client);
            var clientTask = client.Run(); //don't await
            clientTask.ContinueWith(t => clients.Remove(client));
        }
    }
}

class Client
{
    TcpClient client;
    NetworkStream stream;

    public Client(TcpClient client)
    {
        this.client = client;
        stream = client.GetStream();
        
    }

    public async Task Run()
    {
        var r = new StreamReader(stream);
        var w = new StreamWriter(stream);
        while (true)
        {
            await w.WriteLineAsync("You are standing in an open field west of a white house, with a boarded front door. There is a small mailbox here.");
            await w.WriteAsync(">");
            await w.FlushAsync();

            var l = await r.ReadLineAsync();
            await w.WriteLineAsync("Invalid command "   l);
        }
    }
}

你可以用它來測驗

c:\> telnet localhost 1121

標籤：C＃ 异步 通讯协议 网络流

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