无法在 WebSocket 客户端中接收消息

Question

我正在使用websocket4net在C#中创建WebSocket客户端并与服务器通信。

我能够发送数据，但无法收到服务器发回的回复。根本不会触发Client_MessageReceived。不过，我能够在WireShark中看到回复。

我使用的代码如下：

class CommandRPC
{
    public String jsonrpc;
    public String method;
    public Parameter @params;
    public String id;
}    
class Parameter
{
    public String cmd;
}
class Program
{
    static WebSocket Client;
    static CommandRPC command;
    static void Main(string[] args)
    {
        Client = new WebSocket("ws://10.131.35.32/DIAG");
        Client.Opened += new EventHandler(Client_Opened);
        Client.Error += new EventHandler<SuperSocket.ClientEngine.ErrorEventArgs>(Client_Error);
        Client.Closed += new EventHandler(Client_Closed);
        Client.MessageReceived += new EventHandler<MessageReceivedEventArgs>(Client_MessageReceived);
        Client.DataReceived += new EventHandler<DataReceivedEventArgs>(Client_DataReceived);

        command = new CommandRPC();
        command.jsonrpc = "2.0";
        command.method = "SystemExec";
        command.@params = new Parameter();
        [e-mail] = "ls";
        command.id = "8302144";
        Client.Open();
        System.Threading.Thread.Sleep(2000);
        Console.WriteLine(Client.State);
        Console.ReadLine();
    }

    static void Client_DataReceived(object sender, DataReceivedEventArgs e)
    {
        Console.WriteLine("DATA received : " + e.Data);
    }
    static void Client_MessageReceived(object sender, MessageReceivedEventArgs e)
    {
        Console.WriteLine("Message received : " + e.Message);            
    }
    static void Client_Closed(object sender, EventArgs e)
    {
        Console.WriteLine("Websocket closed");
    }
    static void Client_Error(object sender, SuperSocket.ClientEngine.ErrorEventArgs e)
    {
        Console.WriteLine("Error thrown trying to open websocket : " + e.Exception.Message);
    }
    static void Client_Opened(object sender, EventArgs e)
    {
        var json = new JavaScriptSerializer().Serialize(command);            
        Console.WriteLine("Websocket connection open.");
        for (int i = 1; i <= 2; i++)
        {
            Console.WriteLine("Sending Json: " + i.ToString());
            Client.Send(json);
            System.Threading.Thread.Sleep(500);
        }   
    }
}

Answer 1

使用

   Task.Delay(300) //instead of Thread.Sleep(2000)

它应该可以解决问题

Answer 2

我不熟悉websocket4net，但它可能是在同一线程上运行并且Thread.Sleep阻止客户端接收回复。

也有可能是在Console.ReadLine();阻止执行时回复，因此它没有到达Client_MessageReceived。

第三种选择是答复的内容为空。在这种情况下，WebSocket 将不会触发该事件。我说的是，基于查看此处WebSocket的代码：http://websocket4net.codeplex.com/SourceControl/latest#WebSocket4Net/WebSocket.cs

Answer 3

我参加聚会很晚了，但刚刚在 WebSocket4Net 上遇到了同样的问题。

github上提出了一个问题，可以解释为什么_send消息永远不会被发送：https://github.com/kerryjiang/WebSocket4Net/issues/170

这在发送多个连接请求时为我显现出来。每个请求都会在发送其他请求之前等待确认，当然，最终确认永远不会到达并阻止应用程序。 到目前为止，唯一有效的方法是在发送之前进行Thread.Sleep调用。