Clients.User().SendAsync()不与hubconnection.on通信

Question

这里我有blazor服务器应用程序，其中我有名为SessionChatHub的signalR集线器，它包含方法AssignmentCreatedNotification(HashSet<string> userIdList, string name)，该方法接收userIdList (userIdList是从数据库AspNetUsers表访问的身份id )和名称作为参数，并将名称发送到userIdList参数的所有userid。

现在的问题是，即使在获取了userIdList和name参数的值之后，也不会触发hubConnection.On<string>("ReceiveAssignmentCreatedNotification", NotifyStudentAboutAssignmentCreated);，也就是说，不会调用NotifyStudentAboutAssignmentCreated(string name)。

但当存在名称时，将调用NotifyStudentAboutAssignmentCreated(字符串名)方法，但它不会在await Clients.User(userId).SendAsync("ReceiveAssignmentCreatedNotification", name);上调用

userIdList：(userIdList是从数据库AspNetUsers表中访问的标识id )

下面是集线器

public class SessionChatHub:Hub
{            
    public async Task AssignmentCreatedNotification(HashSet<string> userIdList, string name)
    {
        foreach (var userId in userIdList)
        {
            await Clients.User(userId).SendAsync("ReceiveAssignmentCreatedNotification", name);
        }
    }
    public async override Task OnConnectedAsync()
    {
        Console.WriteLine($"{Context.ConnectionId} connected");
      
    }
    public override async Task OnDisconnectedAsync(Exception e)
    {
        Console.WriteLine($"Disconnected {e?.Message} {Context.ConnectionId}");
        await base.OnDisconnectedAsync(e);
    }
}

下面是我们接收signalr集线器的oninitialized

protected async override void OnInitialized()
    {
        var container = new CookieContainer();
        var cookie = new Cookie()
        {
            Name = ".AspNetCore.Identity.Application",
            Domain = "localhost",
            Value = CookiesProvider.Cookie
        };

        container.Add(cookie);


        hubConnection = new HubConnectionBuilder()
      .WithUrl(NavigationManager.ToAbsoluteUri("/sessionchathub"), options =>
      {
          options.Cookies = container;
      }).Build();
        hubConnection.ServerTimeout = TimeSpan.FromMinutes(60);


        hubConnection.On<string>("ReceiveAssignmentCreatedNotification", NotifyStudentAboutAssignmentCreated);

        await hubConnection.StartAsync();
    }

要调用的方法

    public void NotifyStudentAboutAssignmentCreated(string name) // This method is not called from oninitialized  hubConnection.On<string>("ReceiveAssignmentCreatedNotification", NotifyStudentAboutAssignmentCreated);
    {
        NotificationHandler.AssignmentNotificationCount = 1;
        StateHasChanged();
    } 

​

我也有OnAfterRenderAsync

 protected async override Task OnAfterRenderAsync(bool firstRender)
 {
    

    //if (firstRender)
    //{
    await jSRuntime.InvokeVoidAsync("AddSelect2ForClassIdInCreateEditTeacherAssignment");
    await jSRuntime.InvokeVoidAsync("AddSelect2ForSubjectIdInCreateEditTeacherAssignment");
    await jSRuntime.InvokeVoidAsync("AddSelect2ForChapterIdInCreateEditTeacherAssignment");
    //}
    await base.OnAfterRenderAsync(firstRender);
 }

Answer 1

在没有调试的情况下，很难准确地诊断出哪里出了问题。我建议首先检查连接状态。在HubConnection类上有这个属性。

    /// <summary>
    /// Indicates the state of the <see cref="HubConnection"/> to the server.
    /// </summary>
    public HubConnectionState State => _state.OverallState;

有时创建一个端点来返回它是很有用的，这样你就可以在你的应用程序运行的时候检查它。

我看到你在OnConnectedAsync上写了一个覆盖的控制台。你检查过控制台了吗。你见过这个吗？

集线器无法连接到像不正确的url这样简单的东西。

Answer 2

看起来SignalR身份验证有问题。可能是您从客户端发送的cookie名称或Cookie值不正确，也可能是服务器未正确配置为处理传入的身份验证cookie。