信号序列化疑难解答

Question

我有以下代码：

 try {
            _hubConnection = new HubConnection(_baseUrl);
            _hubConnection.CookieContainer = new CookieContainer();
            _hubConnection.CookieContainer.Add(_cookie);
            _hubProxy = _hubConnection.CreateHubProxy("appHub");
            _hubConnection.Start().Wait();
        }
 catch (Exception e) {
            Elmah.ErrorSignal.FromCurrentContext().Raise(new Exception("Serialization error [hubConnection] - " + e.Message + ", " + e.InnerException.Message + ", " + e.ToString()));
        }

通常，这是有效的。 每隔一段时间，我就会收到一个随机序列化错误：

Serialization error [hubConnection] - One or more errors occurred., Unexpected character encountered while parsing value: <. Path '', line 0, position 0., System.AggregateException: One or more errors occurred. ---> Newtonsoft.Json.JsonReaderException: Unexpected character encountered while parsing value: <. Path '', line 0, position 0.
 at Newtonsoft.Json.JsonTextReader.ParseValue()
 at Newtonsoft.Json.JsonTextReader.Read()
 at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.ReadForType(JsonReader reader, JsonContract contract, Boolean hasConverter)
 at 

这个Unexpected character encountered while parsing value: <似乎很难复制，我不知道如何获得有关此的详细信息。 我确实配置了这个：

        var hubConfiguration = new HubConfiguration { EnableDetailedErrors = true };
        app.MapSignalR(hubConfiguration);

有谁知道可能导致这种情况的原因，或者我如何进行故障排除？

完整跟踪：

System.Exception: Messaging Error [hubConnection]    at App.Services.NotificationService.SignalObjectToUser(Object data, String username, Boolean isTypingNotification)    at App.Services.NotificationService.MessageSentNotification(User toUser, Message message, Int32 conversationId, Boolean isOnline)    at App.Services.MessageService.SendMessage(MessageDto message, FStopContext altContext)    at App.ApiControllers.MessageController.SendMessage(MessageDto message) at lambda_method(Closure , Object , Object[] )    at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.<>c__DisplayClass10.b__9(Object instance, Object[] methodParameters)    at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.Execute(Object instance, Object[] arguments)    at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ExecuteAsync(HttpControllerContext controllerContext, IDictionary`2 arguments, CancellationToken cancellationToken)
--- End of stack trace from previous location where exception was thrown ---    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)    at System.Web.Http.Controllers.ApiControllerActionInvoker.d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)    at System.Web.Http.Filters.ActionFilterAttribute.d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---    at System.Web.Http.Filters.ActionFilterAttribute.d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)    at System.Web.Http.Filters.ActionFilterAttribute.d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)    at System.Web.Http.Filters.ActionFilterAttribute.d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---    at System.Web.Http.Filters.ActionFilterAttribute.d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)    at System.Web.Http.Filters.ActionFilterAttribute.d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)    at System.Web.Http.Filters.ActionFilterAttribute.d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---    at System.Web.Http.Filters.ActionFilterAttribute.d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)    at System.Web.Http.Filters.ActionFilterAttribute.d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)    at System.Web.Http.Filters.ActionFilterAttribute.d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---    at System.Web.Http.Filters.ActionFilterAttribute.d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)    at System.Web.Http.Filters.ActionFilterAttribute.d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)    at System.Web.Http.Controllers.ActionFilterResult.d__2.MoveNext()
--- End of stack trace from previous location where exception was thrown ---    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)    at System.Web.Http.Filters.AuthorizationFilterAttribute.d__2.MoveNext()
--- End of stack trace from previous location where exception was thrown ---    at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)    at System.Web.Http.Controllers.ExceptionFilterResult.d__0.MoveNext()

Answer 1

在深入研究正在传输的内容之前，我会尝试几件事：

1. 在没有 Cookie 容器的情况下设置集线器连接。这将缩小这是否导致问题的范围。
2. 而不是使用 .Wait（） 在您的集线器连接上，尝试使用 async/await 函数。我似乎记得过去使用 Wait（） 时也有类似的异常。

发回您的结果。