Web Api TaskCanceledException

Question

我已升级到ASP.NET Web API 5.2.2,现在在我的生产Elmah日志中看到以下异常.

System.Threading.Tasks.TaskCanceledException: A task was canceled.
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at System.Web.Http.Controllers.ApiControllerActionInvoker.<InvokeActionAsyncCore>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at System.Web.Http.Controllers.ActionFilterResult.<ExecuteAsync>d__2.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at System.Web.Http.Filters.AuthorizationFilterAttribute.<ExecuteAuthorizationFilterAsyncCore>d__2.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at System.Web.Http.Controllers.ExceptionFilterResult.<ExecuteAsync>d__0.MoveNext()

例外似乎是零星的,到目前为止我一直无法在本地重现.什么可能触发这个例外？我有什么办法可以解决或解决问题吗？

Answer 1

这看起来非常类似于这个问题:当浏览器取消请求时,ASP.NET Web API OperationCanceledException

接受的答案(/sf/answers/1583511751/)是否已在此处针对此问题提交了错误:http://aspnetwebstack.codeplex.com/workitem/1797

以下是来自上述文章的代码片段,用于解决此问题:

在此期间,您可以尝试类似下面的代码.它添加了一个顶级消息处理程序,可在取消令牌触发时删除内容.如果响应没有内容,则不应触发该错误.它可能发生的可能性很小,因为客户端可能会在消息处理程序检查取消令牌之后但在更高级别的Web API代码执行相同检查之前断开连接.但我认为在大多数情况下它会有所帮助.

config.MessageHandlers.Add(new CancelledTaskBugWorkaroundMessageHandler());

class CancelledTaskBugWorkaroundMessageHandler : DelegatingHandler
{
    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        HttpResponseMessage response = await base.SendAsync(request, cancellationToken);

        // Try to suppress response content when the cancellation token has fired; ASP.NET will log to the Application event log if there's content in this case.
        if (cancellationToken.IsCancellationRequested)
        {
            return new HttpResponseMessage(HttpStatusCode.InternalServerError);
        }

        return response;
    }
}