Azure网站上的"任务已取消"错误

Question

随着我们Azure网站的流量增加,我们看到越来越多的"任务被取消"错误.典型的跟踪可能如下所示:

Fatal web api error: Controller: CustomerUserEventsController; 
Url: http://app.payboard.com/api/organizations/9ddf55d1-e0c1-4a8f-9327-eef38682e090/addcustomeruserevent?callback=jQuery210035782216349616647_1398442710964&cookieId=05be2755-dc0d-414d-b0d2-ea1986a929c3&customerId=&customerName=&customerUserId=&customerUserFirstName=&customerUserLastName=&eventName=hr-index-GET&_=1398442710965; 
Error: A task was canceled. ( at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
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.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.Web.Http.Controllers.ExceptionFilterResult.<ExecuteAsync>d__0.MoveNext())

我们过去常常每天得一个; 它一直在逐渐增加,所以现在我们得到了几十个.

您会注意到堆栈跟踪中只有框架代码 - 我们的代码根本就没有.所以我对如何解决它有点不知所措.关于如何跟踪这些问题的任何建议？

Answer 1

请参阅此处的答案：

浏览器取消请求时出现 ASP.NET Web API OperationCanceledException

这里的 WebAPI 错误：

http://aspnetwebstack.codeplex.com/workitem/1797

基本上，当 HTTP 请求被取消时，例如，如果用户关闭发起请求的页面，这是预期的。为了防止它出现在日志中，基本上，您只需要创建一个自定义消息处理程序来抑制错误：

/// <summary>
/// See /sf/ask/1551031751/
/// </summary>
public class CancelledTaskBugWorkaroundMessageHandler : DelegatingHandler
{
    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        var 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;
    }
}