如何通过转义键停止无尽的服务器线程

Question

我正在尝试用 c# 编写一个 webSocket 服务器。服务器作为作业运行：

using Unity.Jobs;
using UnityEngine;

public class ServerStartup : MonoBehaviour
{
    WebSocketServerJob server = new WebSocketServerJob();
    JobHandle jobHandle;

    // Start is called before the first frame update
    void Start()
    {
        Debug.Log("Starting up the websocket server...");

        jobHandle = server.Schedule();
        
        Debug.Log("...the server should be running in it's own thread now :-)");
    }

    private void Update()
    {
        if (Input.GetKey(KeyCode.Escape))
        {
            Debug.Log("Escape key detected...stopping server!");
            server.StopSwitch = true;
            Debug.Log("Waiting for server tread to complete!");
            jobHandle.Complete();
            Debug.Log("Server tread complete...quitting app!");
            Application.Quit();
        }
    }


}

服务器作业目前是一个无休止的作业，但我希望它在我按 Escape 时结束。然而，仅仅从外部取消它（使用 Abort 或类似的）并不好，因为我首先想关闭套接字并清理。所以线程应该从外部得到某种通知它即将终止。


        //
// csc wsserver.cs
// wsserver.exe

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Text.RegularExpressions;
using Unity.Jobs;
using UnityEngine;


public struct WebSocketServerJob : IJob
{
    bool stopSwitch;

    public bool StopSwitch
    {
        set { stopSwitch = value; }
    }

    public void Execute()
    {
        StopSwitch = false;
        string ip = "127.0.0.1";
        int port = 80;
        var server = new TcpListener(IPAddress.Parse(ip), port);

        server.Start();
        Debug.Log("Server has started on " + ip + ":" + port + " Waiting for a connection...");

        TcpClient client = server.AcceptTcpClient();
        Debug.Log("ServerMsg: A client connected.");

        NetworkStream stream = client.GetStream();

        // enter to an infinite cycle to be able to handle every change in stream
        while (!stopSwitch)
        {
            while (!stream.DataAvailable) ;
            while (client.Available < 3) ; // match against "get"

            byte[] bytes = new byte[client.Available];
            stream.Read(bytes, 0, client.Available);
            string s = Encoding.UTF8.GetString(bytes);

            if (Regex.IsMatch(s, "^GET", RegexOptions.IgnoreCase))
            {
                Debug.Log("=====Handshaking from client=====\n" + s);

                // 1. Obtain the value of the "Sec-WebSocket-Key" request header without any leading or trailing whitespace
                // 2. Concatenate it with "258EAFA5-E914-47DA-95CA-C5AB0DC85B11" (a special GUID specified by RFC 6455)
                // 3. Compute SHA-1 and Base64 hash of the new value
                // 4. Write the hash back as the value of "Sec-WebSocket-Accept" response header in an HTTP response
                string swk = Regex.Match(s, "Sec-WebSocket-Key: (.*)").Groups[1].Value.Trim();
                string swka = swk + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
                byte[] swkaSha1 = System.Security.Cryptography.SHA1.Create().ComputeHash(Encoding.UTF8.GetBytes(swka));
                string swkaSha1Base64 = Convert.ToBase64String(swkaSha1);

                // HTTP/1.1 defines the sequence CR LF as the end-of-line marker
                byte[] response = Encoding.UTF8.GetBytes(
                    "HTTP/1.1 101 Switching Protocols\r\n" +
                    "Connection: Upgrade\r\n" +
                    "Upgrade: websocket\r\n" +
                    "Sec-WebSocket-Accept: " + swkaSha1Base64 + "\r\n\r\n");

                stream.Write(response, 0, response.Length);
            }
            else
            {
                bool fin = (bytes[0] & 0b10000000) != 0,
                    mask = (bytes[1] & 0b10000000) != 0; // must be true, "All messages from the client to the server have this bit set"

                int opcode = bytes[0] & 0b00001111, // expecting 1 - text message
                    msglen = bytes[1] - 128, // & 0111 1111
                    offset = 2;

                if (msglen == 126)
                {
                    // was ToUInt16(bytes, offset) but the result is incorrect
                    msglen = BitConverter.ToUInt16(new byte[] { bytes[3], bytes[2] }, 0);
                    offset = 4;
                }
                else if (msglen == 127)
                {
                    Debug.Log("TODO: msglen == 127, needs qword to store msglen");
                    // i don't really know the byte order, please edit this
                    // msglen = BitConverter.ToUInt64(new byte[] { bytes[5], bytes[4], bytes[3], bytes[2], bytes[9], bytes[8], bytes[7], bytes[6] }, 0);
                    // offset = 10;
                }

                if (msglen == 0)
                    Debug.Log("msglen == 0");
                else if (mask)
                {
                    byte[] decoded = new byte[msglen];
                    byte[] masks = new byte[4] { bytes[offset], bytes[offset + 1], bytes[offset + 2], bytes[offset + 3] };
                    offset += 4;

                    for (int i = 0; i < msglen; ++i)
                        decoded[i] = (byte)(bytes[offset + i] ^ masks[i % 4]);

                    string text = Encoding.UTF8.GetString(decoded);
                    Debug.Log(text);
                }
                else
                    Debug.Log("mask bit not set");

                //Debug.Log();
                //StopSwitch = false;
            }
        }
        
        Console.WriteLine("server thread interrupted by main thread.");
        stream.Close();
        Debug.Log("stream closed...");
        client.Close();
        Debug.Log("TcpClient closed...");
        
        
                
    }
}

我考虑过使用调用例程中的外部静态变量“stop”并将其设置为“true” 并将 WHILE 子句替换为“while(!stop)”之类的内容，但文档对此提出警告，那么解决方案是什么？

查看 Microsoft 文档中关于 Thread.Interrupt.Method 的示例，我看到了他们如何使用 public 变量与线程通信并更改代码以使用该变量..."server.stopSwitch ”。查看似乎停止线程的 cpu 用法，但 Unity 编辑器也卡住了...所以我必须从任务管理器中终止任务:-/

Answer 1

您可以使用 Interlocked class 从 long 变量读取和写入线程保存。

所以在某处定义变量long isRunning。

然后在开始或安排服务器之前，您只需 isRunning 到 0

...
isRunning = 0;
...
jobHandle = server.Schedule();
...

服务器可以读取这个变量来检查它是否应该运行

while (Interlocked.Read(ref isRunning) == 0) { .. }

传达服务器应该停止使用Interlocked.Increment

Interlocked.Increment(ref isRunning);

服务器将在当前循环迭代完成后停止工作。

Answer 2

如果可以使用CancellationTokenSource class并且可以给服务器一些参数。然后做

var cts = new CancellationTokenSource();

var token = cts.Token;

// somehow give the token to the server

jobHandle = server.Schedule();

然后服务器可以检查他是否应该停止，比如

while (!token.IsCancellationRequested) { ... }

停止服务器

cts.Cancel();

如何通过转义键停止无尽的服务器线程

How to stop an endless server thread by escape key

c#

jobs

terminate

unity3d