如何解决带有通用记录程序参数的.NET Core 3 ExceptionHandler-AmbiguousMatchException
我正在尝试为一个API项目实现.NET Core 3 app.UseExceptionHandler,但是每个API控制器都有一个通用的记录器,我希望将其传递给error方法。例如,如果错误发生在我的WorkingController中,我想让ILogger<WorkingController>
作为日志记录实体。我发现使用内置的ExceptionHandler会丢失请求的某些上下文,并且我希望在可能的情况下捕获此上下文。
这是我以前所有API方法的外观:
[Route("api/working")]
[ApiController]
public class WorkingController
{
private readonly ILogger<WorkingController> _logger;
public WorkingController(ILogger<WorkingController> logger)
{
_logger = logger;
}
[Route("workingRoute")]
public IActionResult SomeMethod()
{
_logger.LogInformation("Starting SomeMethod");
try
{
// doing some stuff here
}
catch(Exception ex)
{
_logger.LogError(ex,"Something happened");
return Problem();
}
return Ok();
}
}
我尝试设置BaseErrorController,其他Controller可以从中继承:
[ApiController]
public abstract class BaseErrorController<T> : ControllerBase
{
protected readonly ILogger<T> Logger;
public BaseErrorController(ILogger<T> logger)
{
Logger = logger;
}
[AllowAnonymous]
[Route("/error")]
public IActionResult Error()
{
var context = HttpContext.Features.Get<IExceptionHandlerPathFeature>();
if (context != null)
{
var ex = context.Error;
Logger.LogError(ex,$"{context.Path} failed - {ex.Message}");
return Problem(
detail: context.Error.StackTrace,title: context.Error.Message);
}
return Problem();
}
}
现在我以前的WorkingController看起来像这样,可以说它更简洁(代码更少):
[Route("api/working")]
[ApiController]
public class WorkingController : BaseErrorController<WorkingController>
{
public WorkingController(ILogger<WorkingController> logger) : base(logger) { }
[Route("workingRoute")]
public IActionResult SomeMethod()
{
Logger.LogInformation("Starting SomeMethod");
// doing some stuff here
return Ok();
}
}
在Startup.cs中,我正在app.UseExceptionHandler("/error")
中注册所有这些,并且看来工作正常。 。 。现在,在我的日志中,除了 之外,我看到以下错误(因为我有多个控制器在实现此基本控制器):
An exception was thrown attempting to execute the error handler.
Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware
Microsoft.AspNetCore.Routing.Matching.AmbiguousMatchException: The request matched multiple endpoints.
Matches: Namespace.Controllers.WorkingController.Error (Namespace)
Namespace.Controllers.AnotherController.Error (Namespace)
at Microsoft.AspNetCore.Routing.Matching.DefaultEndpointSelector.ReportAmbiguity(CandidateState[] candidateState)
at Microsoft.AspNetCore.Routing.Matching.DefaultEndpointSelector.ProcessFinalCandidates(HttpContext httpContext,CandidateState[] candidateState)
at Microsoft.AspNetCore.Routing.Matching.DefaultEndpointSelector.Select(HttpContext httpContext,CandidateState[] candidateState)
at Microsoft.AspNetCore.Routing.Matching.DfaMatcher.MatchAsync(HttpContext httpContext)
at Microsoft.AspNetCore.Routing.Matching.DataSourceDependentMatcher.MatchAsync(HttpContext httpContext)
at Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware.Invoke(HttpContext httpContext)
at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.HandleException(HttpContext context,ExceptionDispatchInfo edi)
有人知道这里可能有什么解决方案吗?我可能正在寻找ExceptionHandler的重载吗?这个解决方案是否太精致了,我应该回到以前的工作吗?帮我,堆栈溢出。谢谢!
解决方法
不幸的是,根本没有内置的方法可以做到这一点。您可以在这里找到一个可以提供帮助的软件包(我没有看过),或者您想重新编写ASP.NET Core的某些部分,但是我真的不想这么做。
还有另一种方法,建议/推荐根据您更喜欢哪个版本的方法,但我是前者的专家。我没有在Controller级别上引发/捕获异常,而是将Controller视为最愚蠢的事情,因此它们只调用某些服务即可。
如果您想知道在哪里引发了异常,或者您特别想让异常未被捕获,我的团队遵循的策略是创建自定义异常。然后,您可以保留这些未捕获的内容(HTTP500将返回给调用者),或者您可以使用自定义的中间件并定义应该发生的情况。
下面是一个示例,完全在此处编写,因此可能需要进行一些更改,这仅仅是为了演示一种可行的方法,而不是有效的演示。
给出一些对您的域有效的例外:
public class UserNotFoundException : Exception { public Guid UserId { get; set; } }
public class InvalidModelException : Exception { }
还有一个异常处理程序:
public class MyCustomExceptionHandlerMiddleware
{
private readonly ILogger<MyCustomExceptionHandlerMiddleware> _logger;
public MyCustomExceptionHandlerMiddleware(ILogger<MyCustomExceptionHandlerMiddleware> logger)
{
_logger = logger;
}
public async Task Invoke(RequestDelegate next)
{
try
{
await next(); // without this,the request doesn't execute any further
}
catch (UserNotFoundException userNotFound)
{
_logger.LogError(userNotFound,"The user was not found");
// manipulate the response here,possibly return HTTP404
}
catch (Exception ex)
{
_logger.LogError(ex,"Something really bad happened");
// manipulate the response here
}
}
}
您可能会遇到这样的事情:
public class UsersService : IUsersService
{
private readonly ILogger<UsersService> _logger;
private readonly UsersContext _context;
// assume UsersContext is an EntityFramework context or some database service
public UsersService(ILogger<UsersService> logger,UsersContext context)
{
_logger = logger;
_context = context;
}
public async Task<User> GetUserAsync(Guid userId)
{
try
{
if (userId == Guid.Empty)
{
throw new InvalidModelException();
}
var user = await _context.FindUserAsync(userId);
if (user == null)
{
throw new UserNotFoundException(userId);
}
return user;
}
catch (InvalidModelException invalidModel)
{
_logger.LogWarning("The received user id is empty");
return null;
}
}
}
及其对应的控制器:
public class UsersController : ControllerBase
{
private readonly IUsersService _usersService;
public UsersController(IUsersService usersService)
{
_usersService = usersService;
}
[HttpGet("userId:guid")]
public async Task<IActionResult> GetUser(Guid userId)
{
var user = await _usersService.GetUserAsync(userId);
if (user == null)
{
return BadRequest();
}
return Ok(user);
}
}
同样,这只是一个示例,展示了如何实现此目的,通常您将以更一致的方式进行输入验证。
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