开发机器上的网络核心 Web api 应用程序上的 Kestrel 错误，但在另一台机器上却没有

Posted 2023-04-12

【中文标题】开发机器上的网络核心 Web api 应用程序上的 Kestrel 错误，但在另一台机器上却没有

【英文标题】：Kestrel error on a netcore web api app on a dev machine but not on another

【发布时间】：2016-11-22 23:16:23

【问题描述】：

执行 netcore WebApi 应用程序时出现错误，奇怪的是它在另一台机器上运行正常。

这是我调用导致错误的方法时的控制台信息：

info: Microsoft.AspNetCore.Hosting.Internal.WebHost[2]
      Request finished in 1640.1033ms 200
info: Microsoft.AspNetCore.Hosting.Internal.WebHost[1]
      Request starting HTTP/1.1 GET http://localhost:5000/api/weather/provider/1/latitude/37.8267/longitude/-122.423
info: Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker[1]
      Executing action method WeatherServices.Controllers.WeatherController.Get (WeatherServices) with arguments (1, 37.8267, -122.423) - ModelState is Valid 
fail: Microsoft.AspNetCore.Server.Kestrel[13]
      Connection id "0HKTG39DAMIHF": An unhandled exception was thrown by the application.
System.AggregateException: One or more errors occurred. (Object reference not set to an instance of an object.) ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at WeatherServices.WeatherApiWrappers.Wunderground.Wunderground.<GetLocalWeather>d__6.MoveNext() in C:\Workspace\ChathamWeatherAPI\WeatherServices\WeatherApiWrappers\Wunderground\Wunderground.cs:line 37
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)
   at WeatherServices.Controllers.WeatherController.Get(Int32 source, String latitude, String longitude) in C:\Workspace\ChathamWeatherAPI\WeatherServices\Controllers\WeatherController.cs:line 50
   at lambda_method(Closure , Object , Object[] )
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeActionFilterAsync>d__28.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeAsync>d__18.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 Microsoft.AspNetCore.Builder.RouterMiddleware.<Invoke>d__4.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 Microsoft.AspNetCore.Hosting.Internal.RequestServicesContainerMiddleware.<Invoke>d__3.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 Microsoft.AspNetCore.Server.Kestrel.Internal.Http.Frame`1.<RequestProcessingAsync>d__2.MoveNext()
---> (Inner Exception #0) System.NullReferenceException: Object reference not set to an instance of an object.
   at WeatherServices.WeatherApiWrappers.Wunderground.Wunderground.<GetLocalWeather>d__6.MoveNext() in C:\Workspace\ChathamWeatherAPI\WeatherServices\WeatherApiWrappers\Wunderground\Wunderground.cs:line 37<---

info: Microsoft.AspNetCore.Hosting.Internal.WebHost[2]
      Request finished in 526.1252ms 200

由此看来，错误似乎与程序的一种异步方法有关，但我不明白为什么，以及为什么它会在另一台机器上工作。

project.json:

  "dependencies": 
    "Microsoft.NETCore.App": 
      "version": "1.0.0",
      "type": "platform"
    ,
    "Microsoft.AspNetCore.Mvc": "1.0.0",
    "Microsoft.AspNetCore.Server.IISIntegration": "1.0.0",
    "Microsoft.AspNetCore.Server.Kestrel": "1.0.0",
    "Microsoft.Extensions.Configuration.EnvironmentVariables": "1.0.0",
    "Microsoft.Extensions.Configuration.FileExtensions": "1.0.0",
    "Microsoft.Extensions.Configuration.Json": "1.0.0",
    "Microsoft.Extensions.Configuration.CommandLine": "1.0.0",
    "Microsoft.Extensions.Logging": "1.0.0",
    "Microsoft.Extensions.Logging.Console": "1.0.0",
    "Microsoft.Extensions.Logging.Debug": "1.0.0",
    "Microsoft.Extensions.Options.ConfigurationExtensions": "1.0.0",
    "Microsoft.Extensions.Caching.Memory": "1.0.0-*",
    "RestClientHelper": "1.0.0-*"
  ,

  "tools": 
    "Microsoft.AspNetCore.Server.IISIntegration.Tools": "1.0.0-preview2-final"
  ,

  "frameworks": 
    "netcoreapp1.0": 
      "imports": [
        "dotnet5.6",
        "portable-net45+win8"
      ]
    
  ,

  "buildOptions": 
    "emitEntryPoint": true,
    "preserveCompilationContext": true
  ,

  "runtimeOptions": 
    "configProperties": 
      "System.GC.Server": true
    
  ,

  "publishOptions": 
    "include": [
      "wwwroot",
      "Views",
      "Areas/**/Views",
      "appsettings.json",
      "web.config"
    ]
  ,

  "scripts": 
    "postpublish": [ "dotnet publish-iis --publish-folder %publish:OutputPath% --framework %publish:FullTargetFramework%" ]
  ,

  "tooling": 
    "defaultNamespace": "WeatherServices"
  

触发错误的方法，错误发生在return语句上：

    public async Task<IList<Forecast>> GetLocalWeather(double latitude, double longitude)
    
        var url = $"http://Domain/api/ApiKey/forecast10day/q/latitude,longitude.json";
        var result = await _restApiCaller.CallListEndPoint(url);

        //Limit the query to 8 days
        return result.Forecast.Txt_Forecast.ForecastDay.Where(day => day.Period < 16)
            .Select(day => day.MapToForecast()).ToList();
    

【问题讨论】：

刚刚看到 Omnisharp 也有此消息：发生了未处理的异常：必须能够聚合响应以将它们分散到 /updatebuffer 的所有插件中

你调试了吗？它告诉你有些东西是空的——在第 37 行设置一个断点，看看什么是空的。

由于某种原因，vs2015 安装程序在出现问题的机器上崩溃，并且 Rider 没有达到断点，所以我无法做到。但是......昨天我设法在机器上重现了错误，如果它工作正常，并修复它（这个确实有 vs2015）。我将在发生错误的机器上尝试修复，如果有效，我会在此处发布。

好的，我设法避免了抛出的错误，但它仍然无法正常工作。该程序构建一个查询并使用它执行获取请求，在有问题的机器上所有请求都返回空对象，而在没有问题的机器上，相同的查询返回数据。我将关闭这个问题，因为这是一个不同的问题。

【参考方案1】：

更新

好的，终于找到了问题，它与文化有关，查询中有一些双打（由于我的文化确实有正确的格式，我仍然不清楚），其中使用“，”而不是'。'用于小数点分隔符。

使用文化不变的字符串转换解决了这个问题

原始答案

发生错误是因为在调用 get 请求后，结果是一个空对象，我在处理该对象之前检查了空值，这解决了这个问题。

问题是，这指向了一个不同的问题，完全相同的请求确实在另一台机器上返回了数据，但仍然没有找到原因。