使用自定义响应类处理 .NET5 中的错误

Question

我来自 Java/Spring 背景，我正在尝试学习 .NET 5。我正在开发 Web API，一切都很好，但不知何故我无法理解或使其工作，我已经尝试过在网上找到了一些解决方案，但随着多年来情况的变化，我不知道它们是否不再有效，或者是否有更好的方法来做到这一点。

基本上，我想处理 .NET API 中的错误。

我的服务有这个代码：

public Users execute(int id)
{
    var foundUser = this.userRepository.findById(id);
    if (foundUser == null)
    {
        throw new HttpException(HttpStatusCode.NotFound, "User not found");
    }
    return foundUser;
}

HttpException 是我制作的自定义异常，因此我可以控制状态代码

using System;
using System.Net;

namespace dotnetex.shared.Errors
{
    public class HttpException : Exception
    {

        public HttpStatusCode Status { get; set; }

        public HttpException(HttpStatusCode status, string msg) : base(msg)
        {
            Status = status;
        }
    }
}

我的启动类有指向我的路线的异常处理程序：

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        app.UseExceptionHandler("/error"); // Add this
[...]

我的路线看起来像这样

using System.Net;
using Microsoft.AspNetCore.Diagnostics;
using Microsoft.AspNetCore.Mvc;

namespace dotnetex.shared.Errors.Controller
{
    [ApiController]
    public class ErrorController : ControllerBase
    {
        [Route("/error")]
        public IActionResult Error()
        {
            var exception = HttpContext.Features.Get<IExceptionHandlerFeature>();
            HttpException error = (HttpException)exception.Error;
            var statusCode = (int)error.Status;
            return Problem(detail: error.Message, statusCode: statusCode);
        }
    }
}

由于某种原因，当我从“错误”变量中获取 statusCode 时，我的响应被破坏了，我的失眠症告诉我Error: Transferred a partial file。调试显示 statusCode 变量已设置。当我通过代码设置一个数字时，事情会按预期进行。

我尝试在 Insomnia、Postman、Chrome 浏览器、CURL 中调用端点。全部都显示错误

最后，如果可能的话。我想从此路由返回一个名为 API Error 而不是“问题”的自定义错误对象，如下所示：

namespace dotnetex.shared.Errors
{
    public class APIError
    {
        private int status_code = 500;
        private string message = "";
        public APIError(int status_code, string message)
        {
            this.status_code = status_code;
            this.message = message;
        }
    }
}

控制台中的例外是：

fail: Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware[1]
      An unhandled exception has occurred while executing the request.
      dotnetex.shared.Errors.HttpException: User not found
         at dotnetex.modules.users.Services.Implementations.GetUserByIdService.GetUserByIdService.execute(Int32 id) in /home/matt/Source/net/dotnetexSl/dotnetex/modules/users/Services/Implementations/GetUserByIdService/GetUserByIdService.cs:line 23
         at modules.users.Services.UserServices.GetUserById(Int32 id) in /home/matt/Source/net/dotnetexSl/dotnetex/modules/users/Services/UserServices.cs:line 45
         at modules.users.Controllers.UsersControllers.getSingleUser(Int32 id) in /home/matt/Source/net/dotnetexSl/dotnetex/modules/users/Controllers/UsersControllers.cs:line 53
         at lambda_method1(Closure , Object , Object[] )
         at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.SyncObjectResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)
         at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeActionMethodAsync()
         at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
         at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeNextActionFilterAsync()
      --- End of stack trace from previous location ---
         at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)
         at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
         at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync()
      --- End of stack trace from previous location ---
         at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeFilterPipelineAsync>g__Awaited|19_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
         at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
         at Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
         at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
         at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.<Invoke>g__Awaited|6_0(ExceptionHandlerMiddleware middleware, HttpContext context, Task task)
warn: Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware[4]
      No exception handler was found, rethrowing original exception.
fail: Microsoft.AspNetCore.Server.Kestrel[13]
      Connection id "0HM6S5CSRT4C8", Request id "0HM6S5CSRT4C8:00000002": An unhandled exception was thrown by the application.
      dotnetex.shared.Errors.HttpException: User not found
         at dotnetex.modules.users.Services.Implementations.GetUserByIdService.GetUserByIdService.execute(Int32 id) in /home/matt/Source/net/dotnetexSl/dotnetex/modules/users/Services/Implementations/GetUserByIdService/GetUserByIdService.cs:line 23
         at modules.users.Services.UserServices.GetUserById(Int32 id) in /home/matt/Source/net/dotnetexSl/dotnetex/modules/users/Services/UserServices.cs:line 45
         at modules.users.Controllers.UsersControllers.getSingleUser(Int32 id) in /home/matt/Source/net/dotnetexSl/dotnetex/modules/users/Controllers/UsersControllers.cs:line 53
         at lambda_method1(Closure , Object , Object[] )
         at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.SyncObjectResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)
         at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeActionMethodAsync()
         at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
         at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeNextActionFilterAsync()
      --- End of stack trace from previous location ---
         at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)
         at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
         at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync()
      --- End of stack trace from previous location ---
         at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeFilterPipelineAsync>g__Awaited|19_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
         at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
         at Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
         at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.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)

因此，如果您能帮助我找到解决方案，我将不胜感激。

先感谢您！

Answer 1

ASP.NET Core 5在处理响应状态代码方面引入了重大更改NotFound 404。使用ExceptionHandlerOptions.AllowStatusCode404Response属性。

修复 UseExceptionHandler方法如下：

启动.cs

 public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
 {
    app.UseExceptionHandler(
          new ExceptionHandlerOptions()
          {
              AllowStatusCode404Response = true, // important!
              ExceptionHandlingPath = "/error"                  
          }
      );      
  }