SignalR 核心控制台客户端未收到通知

Question

我看了一些类似的问题，但没有弄清楚这个问题。我的 .NET 核心 Web API 项目中有一个简单的 Hub。这是中心：

 public class NotificationHub : Hub<INotificationClient>
{
  public async Task SendMessage(string user, string msg)
    {
        await Clients.All.ReceiveMessage(user, msg);
    }
    public Task SendMessageToCaller(string msg)
    {
        return Clients.Caller.ReceiveMessage(msg);
    }

    public Task SendMessageToPartner(string user, string msg)
    {
        return Clients.Client(user).ReceiveMessageToPartner(msg);
    }
}

这是界面：

 public interface INotificationClient
{
    Task ReceiveMessage(string user, string msg);
    Task ReceiveMessage(string msg);
    Task ReceiveMessageToPartner( string msg);

}

这是来自控制器的代码：

[Route("[controller]")]
[ApiController]
public class NotificationsController : ControllerBase
{
    private IHubContext<NotificationHub> _hub;

    public NotificationsController(IHubContext<NotificationHub> hub)
    {
        _hub = hub;

    }
    [HttpGet]
    public async Task<IActionResult> Get()
    {
        var msg = new NotificationData { ClientId = "12345", Notification = "Somone just connected" };
        await _hub.Clients.All.SendAsync("Notification", msg);
        return Ok(new { Message = "Request complete" });
    }
}

最后是控制台客户端代码：

 Console.WriteLine("Press a key to start listening");
        Console.ReadKey();

        Console.WriteLine("Client Listening!");
        var connection = new HubConnectionBuilder()
           .WithUrl("http://localhost:61514/notifications")

           .Build();


        connection.On<NotificationData>("Notification", (notificationData) =>
            Console.WriteLine($"Somebody connected: {notificationData.ClientId}"));

        connection.StartAsync().GetAwaiter().GetResult();

        Console.WriteLine("Listening. Press a key to quit");
        Console.ReadKey();

这是使用映射启动的网络应用程序：

 public void ConfigureServices(IServiceCollection services)
    {
        services.AddSignalR();
        services.AddControllers();
    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }

        app.UseRouting();

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllers();
            endpoints.MapHub<NotificationHub>("/Notifications");
        });
    }

我不断收到此错误：System.IO.IOException：'The server disconnected before the handshake could be started.'我一定是错过了一些东西。

更新：
打开日志并收到此错误：

dbug: Microsoft.AspNetCore.Http.Connections.Client.HttpConnection[8] Establishing connection with server at 'http://localhost:61514/notifications'. dbug: Microsoft.AspNetCore.Http.Connections.Client.HttpConnection[9] Established connection 'BdROAEEQnGUeDYAW5EspRA' with the server. dbug: Microsoft.AspNetCore.Http.Connections.Client.HttpConnection[7] Starting transport 'ServerSentEvents' with Url: http://localhost:61514/notifications. info: Microsoft.AspNetCore.Http.Connections.Client.Internal.ServerSentEventsTransport[1] Starting transport. Transfer mode: Text. dbug: Microsoft.AspNetCore.Http.Connections.Client.Internal.ServerSentEventsTransport[3] Starting receive loop. dbug: Microsoft.AspNetCore.Http.Connections.Client.Internal.ServerSentEventsTransport[9] Received 30 bytes. Parsing SSE frame. dbug: Microsoft.AspNetCore.Http.Connections.Client.Internal.ServerSentEventsTransport[4] Receive loop stopped. dbug: Microsoft.AspNetCore.Http.Connections.Client.Internal.ServerSentEventsTransport[100] Starting the send loop. dbug: Microsoft.AspNetCore.Http.Connections.Client.HttpConnection[18] Transport 'ServerSentEvents' started. dbug: Microsoft.AspNetCore.Http.Connections.Client.Internal.ServerSentEventsTransport[102] Send loop canceled. dbug: Microsoft.AspNetCore.Http.Connections.Client.Internal.ServerSentEventsTransport[101] Send loop stopped. Unhandled exception. info: Microsoft.AspNetCore.Http.Connections.Client.HttpConnection[3] HttpConnection Started. info: Microsoft.AspNetCore.SignalR.Client.HubConnection[24] Using HubProtocol 'json v1'. System.IO.IOException: The server disconnected before the handshake could be started. at Microsoft.AspNetCore.SignalR.Client.HubConnection.HandshakeAsync(ConnectionState startingConnectionState, CancellationToken cancellationToken) at Microsoft.AspNetCore.SignalR.Client.HubConnection.StartAsyncCore(CancellationToken cancellationToken) at Microsoft.AspNetCore.SignalR.Client.HubConnection.StartAsyncCore(CancellationToken cancellationToken) at Microsoft.AspNetCore.SignalR.Client.HubConnection.StartAsyncInner(CancellationToken cancellationToken) at System.Threading.Tasks.ForceAsyncAwaiter.GetResult() at Microsoft.AspNetCore.SignalR.Client.HubConnection.StartAsync(CancellationToken cancellationToken) at NotificationClient.Program.Main(String[] args)

Answer 1

所以在为这个问题烦恼了一整天之后，我发现了问题所在，所以我想我会 post 在这里找到解决方案，以防其他人遇到这个问题。

集线器端点指向控制器。因此，当客户端链接时，它会两次点击控制器，导致服务器关闭连接。所以我改变了这一行：

app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllers();
            endpoints.MapHub<NotificationHub>("/Notify");
        });

从击中控制器的“/Notifications”到上面代码中的 "Notify"，将客户端从 Notifications 重新指向 Notify

 var connection = new HubConnectionBuilder()
           .WithUrl("http://localhost:61514/Notify")
          .ConfigureLogging(logging =>
          {
              logging.AddConsole();
              logging.SetMinimumLevel(LogLevel.Debug);
          })
           .Build();

消息开始涌入。

SignalR 核心控制台客户端未收到通知

SignalR core console client not receiving notifications

signalr

asp.net-core-signalr

signalr-client