使用ThreadPool.打开TcpClient连接并读取ASP中的数据.. NET和SignalR

本文关键字：数据 NET SignalR ASP 读取 打开 ThreadPool TcpClient 连接 使用 | 更新日期: 2023-09-27 18:16:40

我读了几篇关于SignalR的文章，想到了一个有趣的测试项目，我可以创建一个web应用程序来轮询我的onkyo接收器的状态，并在浏览器中显示结果。对于初始测试，我成功地将服务器上的当前时间发送回客户端，方法是使用Application_Start中的以下代码:

ThreadPool.QueueUserWorkItem(_ =>
{               
    dynamic clients = Hub.GetClients<KudzuHub>();
    while (true)
    {                
        clients.addMessage(DateTime.Now.ToString());
        Thread.Sleep(1000);
    }
});
在客户端javascript中，我有以下代码: 
// Proxy created on the fly
var kHub = $.connection.kudzuHub;
// Declare a function on the hub so that the server can invoke it
kHub.addMessage = function (message) {
    console.log('message added');
    $('#messages').append('<li>' + message + '</li>');
};
// start the connection
$.connection.hub.start();

这些都很好。每秒钟，我都会得到一个包含当前服务器日期和时间的新列表项。

现在，当我添加这段代码从Onkyo接收器读取数据时，它会中断:(仍然在Application_Start中)

ThreadPool.QueueUserWorkItem(_ =>
{  
    dynamic clients = Hub.GetClients<KudzuHub>();
    try
    {
        while (true)
        {
            string host = ConfigurationManager.AppSettings["receiverIP"].ToString();
            int port = Convert.ToInt32(ConfigurationManager.AppSettings["receiverPort"]);
            TcpClient tcpClient = new TcpClient(host, port);
            NetworkStream clientSockStream = tcpClient.GetStream();
            byte[] bytes = new byte[tcpClient.ReceiveBufferSize];
            clientSockStream.Read(bytes, 0, (int)tcpClient.ReceiveBufferSize);
            tcpClient.Close();
            clients.addMessage(System.Text.Encoding.ASCII.GetString(bytes));
            Thread.Sleep(50);
        }
    }
    catch (SocketException ex)
    {
        // do something to handle the error
    }
});

我设置了一个断点并逐步执行代码。它到达这一行，然后返回。

clientSockStream.Read(bytes, 0, (int)tcpClient.ReceiveBufferSize);

它永远不会完成向客户端发送消息的其余代码。我做错了什么?

谢谢。

使用ThreadPool.打开TcpClient连接并读取ASP中的数据.. NET和SignalR

我会对您的循环进行一些结构更改，以允许接收方有时间响应，消除每50毫秒检索配置的开销，并清理打开的网络流:

ThreadPool.QueueUserWorkItem(_ =>
{  
    dynamic clients = Hub.GetClients<KudzuHub>();
    TcpClient tcpClient = null;
    NetworkStream clientSockStream = null;
    try
    {
        string host = ConfigurationManager.AppSettings["receiverIP"].ToString();
        int port = Convert.ToInt32(ConfigurationManager.AppSettings["receiverPort"]);
        while (true)
        {
            if (tcpClient == null) {
              tcpClient = new TcpClient(host, port);
              clientSockStream = tcpClient.GetStream();
            }
            if (clientSockStream.CanRead) {
                byte[] bytes = new byte[tcpClient.ReceiveBufferSize];
                try {
                   clientSockStream.Read(bytes, 0, (int)tcpClient.ReceiveBufferSize);
                } catch (Exception ex) {
                  // Add some debug code here to examine the exception that is thrown
                }
                tcpClient.Close();
                // Closing the client does not automatically close the stream
                clientSockStream.Close();
                tcpClient = null;
                clientSockStream = null;
                clients.addMessage(System.Text.Encoding.ASCII.GetString(bytes));
            }
            Thread.Sleep(50);
        }
    }
    catch (SocketException ex)
    {
        // do something to handle the error
    } finally {
       if (tcpClient != null) {
         tcpClient.Close();
         clientSockStream.Close();
       }
    } 
});
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