c# - Azure 网站 - 502 - Web 服务器在充当网关或代理服务器时收到无效响应

Question

我的 Web 应用程序在本地计算机上运行良好，但当发布到 Windows Azure 网站时，我在其中一种 Controller 操作方法上收到以下错误:

502 - Web 服务器在充当网关或代理服务器时收到无效响应。您要查找的页面有问题，无法显示。当 Web 服务器(充当网关或代理)联系上游内容服务器时，它从内容服务器收到无效响应。

我使用 Elmah 捕获更多信息，我得到:系统参数NullException值不能为空。参数名称:path2

所以当我在我的方法中使用 path.combine(path1, path2) 时它是引用的。我不知道发生了什么，当我检查输出目录时，输入文件读取良好并且输出文件生成良好。

关于可能发生的情况还有其他建议吗？

这是我的操作方法的代码:

        [HttpPost]
        public ActionResult ProcessProducts(UploadViewModel model)
        {
            DateTime startTime = DateTime.UtcNow;
            DateTime endTime;
            TimeSpan totalTime;            
            PulProcessor prodManager = new PulProcessor();
            string filePath = Path.Combine(Server.MapPath("~/files/incoming"), model.ProductsFileName);

            try
            {                
                using (TextReader prodFile = System.IO.File.OpenText(filePath))
                {
                    CsvReader csv = new CsvReader(prodFile);
                    // map is at end of this file
                    csv.Configuration.RegisterClassMap<PulMap>();
                    List<PulProduct> prodList = csv.GetRecords<PulProduct>().ToList();

                    foreach (var product in prodList)
                    {
                        prodManager.ProcessProduct(product);
                    }
                }
            }
            catch (Exception ex)
            {
                Elmah.ErrorSignal.FromCurrentContext().Raise(ex);
            }
            string currentDate = DateTime.UtcNow.ToString("yyyyMMdd");
            string productFileName = "PUL" + currentDate + ".txt";
            string exceptionsFileName = "PUL" + currentDate + "belowcost.txt";

            WriteFile(prodManager.Products, productFileName);
            WriteFile(prodManager.BelowCost, exceptionsFileName);

            endTime = DateTime.UtcNow;
            totalTime = endTime - startTime;

            ViewBag.StartTime = startTime.ToString();
            ViewBag.EndTime = endTime.ToString();
            ViewBag.TotalTime = totalTime.ToString();
            ViewBag.TotalOutput = prodManager.Products.Count.ToString();
            ViewBag.ProductCounter = prodManager.RecordsProcessed;
            ViewBag.FileName = productFileName;
            ViewBag.ExFileName = exceptionsFileName;
            ViewBag.Exceptions = prodManager.BelowCost.Count.ToString();

            return View();
        }

    private void WriteFile(List<PulFinalProduct> prodList, string fileName)
    {
        try
        {
            string filePath = Path.Combine(Server.MapPath("~/files/pul"), fileName);
            StreamWriter writer = new StreamWriter(filePath, false);
            StringBuilder fileHeader = new StringBuilder();

            fileHeader.Append("Inventory Number\t");
            fileHeader.Append("MPN\t");
            fileHeader.Append("Retail Price\t");
            fileHeader.Append("Seller Cost\t");
            fileHeader.Append("Buy It Now Price\t");
            fileHeader.Append("Starting Bid\t");
            fileHeader.Append("ChannelAdvisor Store Price\t");
            fileHeader.Append("Quantity\t");
            fileHeader.Append("Quantity Update Type\t");
            fileHeader.Append("UPC\t");
            fileHeader.Append("Weight\t");
            fileHeader.Append("Brand\t");
            fileHeader.Append("Manufacturer\t");

            using (writer)
            {
                writer.WriteLine(fileHeader.ToString());

                foreach (var product in prodList)
                {
                    StringBuilder productLine = new StringBuilder();
                    productLine.Append(product.InventoryNumber + "\t");
                    productLine.Append(product.MPN + "\t");
                    productLine.Append(product.RetailPrice.ToString() + "\t");
                    productLine.Append(product.SellerCost.ToString() + "\t");
                    productLine.Append(product.BINPrice.ToString() + "\t");
                    productLine.Append(product.StartingBid.ToString() + "\t");
                    productLine.Append(product.CAStorePrice + "\t");
                    productLine.Append(product.Quantity + "\t");
                    productLine.Append(product.QUType + "\t");
                    productLine.Append(product.UPC + "\t");
                    productLine.Append(product.Weight + "\t");
                    productLine.Append(product.Brand + "\t");
                    productLine.Append(product.Manufacturer + "\t");

                    writer.WriteLine(productLine.ToString());
                }
            }
        }
        catch (Exception ex)
        {
            Elmah.ErrorSignal.FromCurrentContext().Raise(ex);
        }
    }

这是 Azure 事件日志给我的内容:

Value cannot be null. Parameter name: path2 at System.IO.Path.Combine(String path1, String path2) at Jemco.Web.Controllers.PartsUnlimitedController.ProcessProducts(UploadViewModel model) at lambda_method(Closure , ControllerBase , Object[] ) at System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters) at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) at System.Web.Mvc.Async.AsyncControllerActionInvoker.<BeginInvokeSynchronousActionMethod>b__36(IAsyncResult asyncResult, ActionInvocation innerInvokeState) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`2.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End() at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3c() at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass45.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3e() at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass30.<BeginInvokeActionMethodWithFilters>b__2f(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End() at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass1e.<>c__DisplayClass28.<BeginInvokeAction>b__19() at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass1e.<BeginInvokeAction>b__1b(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End() at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) at System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End() at System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) at System.Web.Mvc.Controller.<BeginExecute>b__15(IAsyncResult asyncResult, Controller controller) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End() at System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) at System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) at System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__4(IAsyncResult asyncResult, ProcessRequestState innerState) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End() at System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) at System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) 

好的，我能够在这个 azure 的站点上进行远程调试。我的 Controller 操作中的代码运行良好。在我收到原始 502 错误后， Controller 继续处理输入数据，然后写入输出文件。一切工作正常，我遇到的唯一问题是在等待它处理和加载下一个 View 时出现 502 页面。 Controller 是否有一定的时间来返回 View ，如果没有，这就是我收到 502 错误的原因？

编辑:我很确定我遇到的是超时错误，因为我的 Controller 方法运行时间太长。我可能无法加速 Controller 方法，所以我不确定我能做什么。我不认为我可以或应该更改服务器上的超时设置，因此也许可以使用 ajax 来完成某些操作，例如每隔一段时间向浏览器发送状态更新。我对此完全陌生，所以我必须做一些研究。

Answer 1

事实证明，整个子例程运行时间太长，并且超时，因此出现 502 错误。我通过重写类以使用 SignalR 运行任务来创建文件，然后向用户更新正在进行的进度来解决这个问题。