处理ASP.NET核心筛选器引发的异常

Question

public async void OnAuthorization(AuthorizationFilterContext context){
     Convert.ToInt32("NotConvertable");
}

try
{
    await _next(context);
}
catch (Exception ex)
{
    _logger.LogError("FATAL ERROR", ex);
}

但这无济于事，仍然令人崩溃。

我在考虑make try{}catch返回500，并在每个过滤器中进行某种日志记录，但这将导致大量的重复。

有什么办法可以在全球范围内处理吗？

  public class PermissionAttribute:TypeFilterAttribute
  {
       public PermissionAttribute():base(typeof(PermissionFilter))
       {
       }
  }

 public class PermissionFilter : IAuthorizationFilter
 {
      public async void OnAuthorization(AuthorizationFilterContext context)
      {
           Convert.ToInt32("NotConvertable");
      }
 }

[Route("api/nav/")]
public class AController : Controller{

    ...

    [HttpGet]
    [Route("{id}")]
    [PermissionAttribute]
    [ProducesResponseType(typeof(SomeClass), 200)]
    public async Task<SomeClass> GetAll()
    {
         ...
    }
}

... some app.Use UseLogger, HealthCheck
app.UseMiddleware<PleaseDontCrushMiddleware>(); // Middleware mentioned above
app.UseExceptionHandler(errorHandler.Handle);

a lot of middlewares

app.UseMvc(RouteTable);

MVC服务的添加方式如下：

services.AddMvc(config =>
        {
            var policy = new AuthorizationPolicyBuilder()
                .RequireAuthenticatedUser()
                .Build();
            config.Filters.Add(new AuthorizeFilter(policy));
            config.Filters.Add(new ResponseCacheFilter(new CacheProfile()
            {
                NoStore = true,
                Location = ResponseCacheLocation.None
            }, 
            services.BuildServiceProvider().GetService<ILoggerFactory()));
         }

Answer 1

假设您将在某些方法中抛出一些特定的异常，而另一些方法只想作为System.Exception捕获，也许您可以使用以下方法：

您可以创建异常处理扩展方法（如果您也想使用Logger，只需在方法中添加ILogger参数并从startup.configure传递它）：

public static class ExceptionHandler
    {
        /// <summary>
        /// 
        /// </summary>
        /// <param name="app"></param>
        public static void UseCustomExceptionHandler(this IApplicationBuilder app)
        {
            app.UseExceptionHandler(eApp =>
            {
                eApp.Run(async context =>
                {
                    context.Response.StatusCode = 500;
                    context.Response.ContentType = "application/json";

                    var errorCtx = context.Features.Get<IExceptionHandlerFeature>();
                    if (errorCtx != null)
                    {
                        var ex = errorCtx.Error;
                        var message = "Unspecified error ocurred.";
                        var traceId = traceIdentifierService.TraceId;

                        if (ex is ValidationException)
                        {
                            var validationException = ex as ValidationException;
                            context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
                            message = string.Join(" | ", validationException.Errors.Select(v => string.Join(",", v.Value)));
                        }
                        else if (ex is SomeCustomException)
                        {
                            var someCustomException = ex as SomeCustomException;
                            ...
                        }

                        var jsonResponse = JsonConvert.SerializeObject(new ErrorResponse
                        {
                            TraceId = traceId,
                            Message = message
                        });
                        await context.Response.WriteAsync(jsonResponse, Encoding.UTF8);
                    }
                });
            });
        }
    }

然后您只需在Startup Configure中注册它：

public void Configure(IApplicationBuilder app)
        {
            ...

            app.UseCustomExceptionHandler();

            ...
        }

不要在授权筛选器中引发异常：

The exception will not be handled.
Exception filters will not handle the exception.

考虑在授权筛选器中发生异常时发出质询

您可以在这里阅读更多关于它的信息:https://docs.microsoft.com/en-us/aspnet/core/mvc/controllers/filters？view=aspnetcore-3.1#action-filters