HttpListner在执行线程时停止.Join()

本文关键字：Join 执行 线程 HttpListner | 更新日期: 2023-09-27 18:21:06

通过使用此代码，我创建了一个HttpListner，用于向某些网站的浏览器发送自定义消息。代码工作正常，并且正在显示消息。但是，当我试图停止Httpserver时，应用程序在这一行被阻止：_listenerThread.Join();我是线程的新手，所以任何帮助我如何使我的代码工作。下面是我的代码

private readonly HttpListener _listener;
private readonly Thread _listenerThread;
private readonly Thread[] _workers;
private readonly ManualResetEvent _stop, _ready;
private Queue<HttpListenerContext> _queue;

public HttpServer(int MaxThreads)
{
    _workers = new Thread[MaxThreads];
    _queue = new Queue<HttpListenerContext>();
    _stop = new ManualResetEvent(false);
    _ready = new ManualResetEvent(false);
    _listener = new HttpListener();
    _listenerThread = new Thread(HandleRequests);
}
private void HandleRequests()
{
    while (_listener.IsListening)
    {
        var context = _listener.BeginGetContext(GetContextCallBack, null);
        if (0 == WaitHandle.WaitAny(new WaitHandle[] { _stop, context.AsyncWaitHandle }))
        {
            return;
        }
    }
}
private void GetContextCallBack(IAsyncResult result)
{
    try
    {
        lock(_queue)
        {
            _queue.Enqueue(_listener.EndGetContext(result));                   
            _ready.Set();
         }
    }
    catch
    { return; }
}
public void Start(int port)
{
    _listener.Prefixes.Add(String.Format(@"http://+:{0}/", port));
    _listener.Start();
    _listenerThread.Start();
    for (int i = 0; i < _workers.Length; i++)
    {
        _workers[i] = new Thread(Worker);
        _workers[i].Start();
    }
}
private void Worker(object obj)
{
    WaitHandle[] wait = new[] { _ready, _stop };
    while (0 == WaitHandle.WaitAny(wait))
    {
        HttpListenerContext context;
        lock (_queue)
        {
            if (_queue.Count > 0)
                context = _queue.Dequeue();
            else
            {
                _ready.Reset();
                continue;
            }
        }
        try
        {
            ProcessRequest(context);
        }
        catch(Exception ex)
        {
            MessageBox.Show(ex.Message + ex.StackTrace);
        }
    }
}
public void Dispose()
{
    Stop();
}
private void Stop()
{
    try
    {
        _stop.Reset();
        _listenerThread.Join();
        foreach (Thread worker in _workers)
        {
            worker.Join();
        }
        _listener.Stop();
        App.Current.MainWindow.Close();
    }
    catch(Exception ex)
    {
        MessageBox.Show(ex.Message + ex.StackTrace);
    }
}

public void  ProcessRequest(HttpListenerContext context)
{
    HttpListenerRequest request = context.Request;
    HttpListenerResponse response = context.Response;
    System.Text.StringBuilder sb = new StringBuilder();
    sb.Append("");
    sb.Append(string.Format("HttpMethod: {0}", request.HttpMethod));
    sb.Append(string.Format("Uri:        {0}", request.Url.AbsoluteUri));
    sb.Append(string.Format("LocalPath:  {0}", request.Url.LocalPath));
    foreach (string key in request.QueryString.Keys)
    {
        sb.Append(string.Format("Query:      {0} = {1}", key, request.QueryString[key]));
    }
    sb.Append("");
    string responseString = sb.ToString();
    byte[] buffer = System.Text.Encoding.UTF8.GetBytes(responseString);
    response.ContentLength64 = buffer.Length;
    using (System.IO.Stream outputStream = response.OutputStream)
    {
        outputStream.Write(buffer, 0, buffer.Length);
    }
}

此代码可能也有助于其他希望向web浏览器发送自定义消息的人。

HttpListner在执行线程时停止.Join()

这是"停止"线程中的第一个问题：

_listenerThread.Join();
...
_listener.Stop();

在告诉侦听器停止侦听之前，您正在等待侦听器线程停止。。。但是侦听线程具有：

private void HandleRequests()
{
    while (_listener.IsListening)
    {
        ...
    }
}

因此它只会在侦听器停止后终止。你基本上陷入了僵局。您应该更改停止代码的顺序：

_listener.Stop();
_listenerThread.Join();
...

另外这一行：

_stop.Reset();

应该是：

_stop.Set();

当您想发出信号表示您正在停止时，请不要清除该信号。

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