AuthenticationMiddleware 中的异常导致 ExceptionHandlerMiddleware 中的异常

Question

在我的 ASP.NET Core 3.1 应用程序的 AuthenticationHandler 类中，我试图从另一个 ASP.NET Core 3.1 请求一个令牌，我将其设置为令牌分发器。我想知道如果令牌分发器碰巧离线会发生什么。当然，这会导致出现HttpRequestException。

但是我也设置了一个 ExceptionHandler 使用 app.UseExceptionHandler("/error");

接收端是一个ErrorController，代码如下：

    [ApiController]
    [ApiExplorerSettings(IgnoreApi = true)]
    public class ErrorController : ControllerBase
    {
        [Route("/error")]
        public IActionResult ErrorLocalDevelopment(
            [FromServices] IWebHostEnvironment webHostEnvironment)
        {
            return Ok();
        }
    }

但没关系，因为甚至没有调用该操作。似乎 ExceptionHandlerMiddleware 内部发生了异常，从而阻止了调用该操作。 它不断地重新抛出 HttpRequestException 并增加几行。

这是堆栈跟踪：

fail: Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware[1]
      An unhandled exception has occurred while executing the request.
System.Net.Http.HttpRequestException: Connection refused
 ---> System.Net.Sockets.SocketException (61): Connection refused
   at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean allowHttp2, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.GetHttpConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
   at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.DiagnosticsHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at Microsoft.Extensions.Http.Logging.LoggingHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at Microsoft.Extensions.Http.Logging.LoggingScopeHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpClient.FinishSendAsyncUnbuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)
   at Refit.RequestBuilderImplementation.<>c__DisplayClass14_0`2.<<BuildCancellableTaskFuncForMethod>b__0>d.MoveNext() in /_/Refit/RequestBuilderImplementation.cs:line 245
--- End of stack trace from previous location where exception was thrown ---
   at [ProjectName].Assemblers.ApiKeyAssembler.GetApiKey(String key) in [ProjectPath]ApiKeyAssembler.cs:line 23
   at [ProjectName].Authentication.ApiKeyAuthenticationHandler.HandleAuthenticateAsync() in [ProjectPath]ApiKeyAuthenticationHandler.cs:line 57
   at Microsoft.AspNetCore.Authentication.AuthenticationHandler`1.AuthenticateAsync()
   at Microsoft.AspNetCore.Authentication.AuthenticationService.AuthenticateAsync(HttpContext context, String scheme)
   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.<Invoke>g__Awaited|6_0(ExceptionHandlerMiddleware middleware, HttpContext context, Task task)
fail: Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware[3]
      An exception was thrown attempting to execute the error handler.
System.Net.Http.HttpRequestException: Connection refused
 ---> System.Net.Sockets.SocketException (61): Connection refused
   at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean allowHttp2, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.GetHttpConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
   at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.DiagnosticsHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at Microsoft.Extensions.Http.Logging.LoggingHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at Microsoft.Extensions.Http.Logging.LoggingScopeHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpClient.FinishSendAsyncUnbuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)
   at Refit.RequestBuilderImplementation.<>c__DisplayClass14_0`2.<<BuildCancellableTaskFuncForMethod>b__0>d.MoveNext() in /_/Refit/RequestBuilderImplementation.cs:line 245
--- End of stack trace from previous location where exception was thrown ---
   at [ProjectName].Assemblers.ApiKeyAssembler.GetApiKey(String key) in [ProjectPath]ApiKeyAssembler.cs:line 23
   at [ProjectName].Authentication.ApiKeyAuthenticationHandler.HandleAuthenticateAsync() in [ProjectPath]ApiKeyAuthenticationHandler.cs:line 57
   at Microsoft.AspNetCore.Authentication.AuthenticationHandler`1.AuthenticateAsync()
   at Microsoft.AspNetCore.Authentication.AuthenticationService.AuthenticateAsync(HttpContext context, String scheme)
   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.HandleException(HttpContext context, ExceptionDispatchInfo edi)
fail: Microsoft.AspNetCore.Server.Kestrel[13]
      Connection id "0HM1UM7U89F38", Request id "0HM1UM7U89F38:00000001": An unhandled exception was thrown by the application.
System.Net.Http.HttpRequestException: Connection refused
 ---> System.Net.Sockets.SocketException (61): Connection refused
   at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean allowHttp2, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.GetHttpConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
   at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.DiagnosticsHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at Microsoft.Extensions.Http.Logging.LoggingHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at Microsoft.Extensions.Http.Logging.LoggingScopeHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpClient.FinishSendAsyncUnbuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)
   at Refit.RequestBuilderImplementation.<>c__DisplayClass14_0`2.<<BuildCancellableTaskFuncForMethod>b__0>d.MoveNext() in /_/Refit/RequestBuilderImplementation.cs:line 245
--- End of stack trace from previous location where exception was thrown ---
   at [ProjectName].Assemblers.ApiKeyAssembler.GetApiKey(String key) in [ProjectPath]ApiKeyAssembler.cs:line 23
   at [ProjectName].Authentication.ApiKeyAuthenticationHandler.HandleAuthenticateAsync() in [ProjectPath]ApiKeyAuthenticationHandler.cs:line 57
   at Microsoft.AspNetCore.Authentication.AuthenticationHandler`1.AuthenticateAsync()
   at Microsoft.AspNetCore.Authentication.AuthenticationService.AuthenticateAsync(HttpContext context, String scheme)
   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.<Invoke>g__Awaited|6_0(ExceptionHandlerMiddleware middleware, HttpContext context, Task task)
   at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.HandleException(HttpContext context, ExceptionDispatchInfo edi)
   at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.<Invoke>g__Awaited|6_0(ExceptionHandlerMiddleware middleware, HttpContext context, Task task)
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.ProcessRequests[TContext](IHttpApplication`1 application)
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished in 1156.4184ms 500 

调用 ApiKeyAssembler.GetApiKey(String key) 是对我们的代币分发服务的 Refit 调用，如前所述，该服务不在线。

我已经进行了几个小时，但我找不到任何解决方案。

编辑：

我更详细地弄清楚了发生了什么。当 ExceptionHandler 试图到达其目的地时发生异常时，就会发生这种情况。显然，当试图到达 ErrorController 时，AuthenticationHandler 再次运行，这正是导致异常的原因。但是，在尝试执行不需要身份验证的操作时，我似乎无法弄清楚如何阻止这种情况发生。

Answer 1

我的异常处理程序路由也有类似的问题，您上次的编辑帮助我指出了正确的方向。尝试在 ErrorController 操作上使用 [AllowAnonymous] 属性。