Question

我正在尝试使用我的机器人的Web套接字与服务器进行通信。但是在运行时它会抛出System.NullReferenceException。我在后台运行套接字在不同的线程上，以便它不与机器人相互干扰。

我正在使用WebsocketSharp库。

第一条消息很好，但是在第二条消息中，它会在HumanCollaboratorDialog类的后续行引发异常。

await  context.PostAsync(e.Data);

我的套接字流类如下：

public static class SocketStream
{
    public static WebSocket ws;
    private static List<string> serverMsg = new List<string>();

    public static void initializeSocket()
    {

        ws = new WebSocket("ws://Some IP:8080/human-collaborator/data");
        Debug.WriteLine("****** INITIALIZED SOCKET (should happen only once) *****");
        Task.Run(() => startSocketStream());

    }

    private static void startSocketStream()
    {
        int attempts = 0;
        while (!ws.IsAlive)
        {
            try
            {
                attempts++;
                ws.Connect();
            }
            catch (WebSocketException)
            {

                Debug.WriteLine("Connection attempts: " + attempts.ToString());
            }

        }

        ws.OnOpen += (sender, args) =>
        {
            Debug.WriteLine("# SOCKET OPENED");

        };

        ws.OnError += (sender, args) =>
        {
            Debug.WriteLine("# SOME ERROR OCCURED");
        };

        ws.OnClose += (sender, args) =>
       {
           Debug.WriteLine("# SOCKET CLOSED");

        };
    }
}

我在Global.asx中调用initializeSocket（）方法在应用程序级别运行它

public class WebApiApplication : System.Web.HttpApplication
{
    protected void Application_Start()
    {
        GlobalConfiguration.Configure(WebApiConfig.Register);
        SocketStream.initializeSocket();

    }
}

My HumanCollaboratorDialog类如下：

[Serializable]
public class HumanCollaboratorDialog : IDialog<object>
{

    public async Task StartAsync(IDialogContext context)
    {

        context.Wait(this.MessageReceivedAsync);

    }

    private async Task MessageReceivedAsync(IDialogContext context, IAwaitable<IMessageActivity> result)
    {

        var message = await result;

        SocketStream.ws.OnMessage += async (sender, e) =>
        {
            try
            {
                await  context.PostAsync(e.Data);
            }
            catch (HttpRequestException ex)
            {
                throw ex;
            }
        };

            Thread.Sleep(500);
            string output = message.Text;
            SocketStream.ws.Send(output);
            Thread.Sleep(500);

        context.Wait(MessageReceivedAsync);

    }
}

我的MessagesController有以下POST方法：

public virtual async Task<HttpResponseMessage> Post([FromBody]Activity activity)
    {
        if (activity.Type == ActivityTypes.Message)
        {
            await Conversation.SendAsync(activity, () => new HumanCollaboratorDialog());
        }
        else
        {
            HandleSystemMessage(activity);
        }
        var response = Request.CreateResponse(HttpStatusCode.OK);
        return response;
    }

Neithet e.Data和上下文都是空的。我认为问题在于套接字连接，或者我在SocketStream类中做错了。以下是图片

Exception-Image

Answer 1

您的机器人是一项网络服务。消息由客户端（网页，应用程序，其他服务等）发送到服务，并在MessagesController的Post方法中接收。没有必要在服务器上安装套接字代码以满足您的要求。 Web套接字对于通过直接线路连接从机器人接收客户端上的消息非常有用。

以下是使用Bot Framework的Direct Line Client并创建Web套接字连接的示例。请注意如何通过对话的StreamUrl创建Web套接字：

DirectLineClientCredentials creds = new DirectLineClientCredentials(directLineSecret);
DirectLineClient directLineClient = new DirectLineClient(creds);
Conversation conversation = await directLineClient.Conversations.StartConversationAsync();

using (var webSocketClient = new WebSocket(conversation.StreamUrl))
{
    webSocketClient.OnMessage += WebSocketClient_OnMessage;
    webSocketClient.Connect();
    while (true)

    {
        string input = Console.ReadLine().Trim();

        if (input.ToLower() == "exit")
        {
            break;
        }
        else
        {
            if (input.Length > 0)
            {
                Activity userMessage = new Activity
                {
                    From = new ChannelAccount(fromUser),
                    Text = input,
                    Type = ActivityTypes.Message
                };

                await directLineClient.Conversations.PostActivityAsync(conversation.ConversationId, userMessage);
            }
        }
    }
}
private static void WebSocketClient_OnMessage(object sender, MessageEventArgs e)
{
    // avoid null reference exception when no data received
    if (string.IsNullOrWhiteSpace(e.Data))
    {
        return;
    }

    var activitySet = JsonConvert.DeserializeObject<ActivitySet>(e.Data);
    var activities = from x in activitySet.Activities
                        where x.From.Id == botId
                        select x;

    foreach (Activity activity in activities)
    {
        Console.WriteLine(activity.Text);
    }
}

这是来自使用Direct Line与Bot通信的控制台应用程序，并在此处使用Web套接字侦听消息： https://github.com/Microsoft/BotBuilder-Samples/tree/master/CSharp/core-DirectLineWebSockets

套接字，无效引用异常

1 个答案: