例外：在 WebAPI 2 中实现自定义过滤器时，给定过滤器必须实现以下一个或多个过滤器接口

Question

我正在尝试构建用于身份验证的自定义过滤器，但是当我尝试运行我的 WebAPI 解决方案时遇到了这个问题：

给定的过滤器实例必须实现以下一项或多项 过滤器接口：System.Web.Mvc.IAuthorizationFilter， System.Web.Mvc.IActionFilter, System.Web.Mvc.IResultFilter, System.Web.Mvc.IExceptionFilter, System.Web.Mvc.Filters.IAuthenticationFilter.

FilterConfig类出现错误：

public class FilterConfig
{
   public static void RegisterGlobalFilters(GlobalFilterCollection filters)
   {
        filters.Add(new HandleErrorAttribute());
        filters.Add(new AuthAttribute());
   }
}

在我尝试将 AuthAttribute 添加到过滤器的行中。

这是整个 AuthAttribute 类：

using Examino.Business;
using System;
using System.Collections.Generic;
using System.Diagnostics.Contracts;
using System.IdentityModel;
using System.IdentityModel.Tokens;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Threading;
using System.Web;
using System.Web.Http;
using System.Web.Http.Controllers;

namespace Examino.API.Filters
{
    public class AuthAttribute : AuthorizeAttribute
    {
        public ITokenProviderService TokenProviderService { get; set; }

        public override void OnAuthorization(HttpActionContext actionContext)
        {
            SetDependencies(actionContext);

            if (!IsAuthorized(actionContext) && !SkipAuthorization(actionContext))
            {
                if (Authenticate(actionContext) == AuthenticationErrors.UNAUTHORIZED)
                {
                    actionContext.Response = actionContext.Request.CreateResponse(HttpStatusCode.Unauthorized,
                        new HttpResponseMessage(HttpStatusCode.Unauthorized));
                }
                else if (Authenticate(actionContext) == AuthenticationErrors.TOKEN_EXPIRED)
                {
                    actionContext.Response = actionContext.Request.CreateResponse(HttpStatusCode.Unauthorized,
                        //token expired status code?
                        new HttpResponseMessage(HttpStatusCode.Unauthorized));
                }
            }
        }

        private void SetDependencies(HttpActionContext actionContext)
        {
            var requestScope = actionContext.Request.GetDependencyScope();

            if (TokenProviderService == null)
            {
                TokenProviderService = requestScope.GetService(typeof(ITokenProviderService)) as ITokenProviderService;
            }
        }

        private AuthenticationErrors Authenticate(HttpActionContext actionContext)
        {
            IEnumerable<string> authHeaderValues;
            actionContext.Request.Headers.TryGetValues("Authorization", out authHeaderValues);

            try
            {
                if (authHeaderValues != null)
                {
                    string bearerToken = authHeaderValues.ElementAt(0);
                    string token = bearerToken.StartsWith("Bearer ") ? bearerToken.Substring(7) : bearerToken;

                    Thread.CurrentPrincipal = TokenProviderService.ValidateJwtToken(token);
                    if (Thread.CurrentPrincipal != null)
                    {
                        return AuthenticationErrors.AUTHORIZED;
                    }
                }
            }
            catch (SecurityTokenExpiredException)
            {
                return AuthenticationErrors.TOKEN_EXPIRED;
            }
            catch (Exception)
            {
                return AuthenticationErrors.UNAUTHORIZED;
            }

            return AuthenticationErrors.UNAUTHORIZED;
        }

        private bool SkipAuthorization(HttpActionContext actionContext)
        {
            Contract.Assert(actionContext != null);

            return actionContext.ActionDescriptor.GetCustomAttributes<AllowAnonymousAttribute>().Any()
                || actionContext.ControllerContext.ControllerDescriptor.GetCustomAttributes<AllowAnonymousAttribute>().Any();
        }

        private enum AuthenticationErrors
        {
            UNAUTHORIZED,
            TOKEN_EXPIRED,
            AUTHORIZED
        }
    }
}

如您所见，它继承自 AuthorizeAttribute 类。

这是一个堆栈跟踪：

[InvalidOperationException：给定的过滤器实例必须实现 以下一个或多个过滤器接口： System.Web.Mvc.IAuthorizationFilter, System.Web.Mvc.IActionFilter, System.Web.Mvc.IResultFilter, System.Web.Mvc.IExceptionFilter, System.Web.Mvc.Filters.IAuthenticationFilter.]
System.Web.Mvc.GlobalFilterCollection.ValidateFilterInstance（对象 实例）+403
System.Web.Mvc.GlobalFilterCollection.AddInternal（对象过滤器， 可空`1个订单）+26
System.Web.Mvc.GlobalFilterCollection.Add(对象过滤器) +31
Examino.API.FilterConfig.RegisterGlobalFilters(GlobalFilterCollection 过滤器）在 C:\examino\src\Examino.API\App_Start\FilterConfig.cs:12
Examino.API.WebApiApplication.Application_Start() 在 C:\examino\src\Examino.API\Global.asax.cs:22

[HttpException (0x80004005): 给定的过滤器实例必须实现 以下一个或多个过滤器接口： System.Web.Mvc.IAuthorizationFilter, System.Web.Mvc.IActionFilter, System.Web.Mvc.IResultFilter, System.Web.Mvc.IExceptionFilter, System.Web.Mvc.Filters.IAuthenticationFilter.]
System.Web.HttpApplicationFactory.EnsureAppStartCalledForIntegratedMode（HttpContext 上下文，HttpApplication 应用程序）+540
System.Web.HttpApplication.RegisterEventSubscriptionsWithIIS（IntPtr appContext、HttpContext 上下文、MethodInfo[] 处理程序）+186
System.Web.HttpApplication.InitSpecial（HttpApplicationState 状态， MethodInfo[] 处理程序、IntPtr appContext、HttpContext 上下文）+172
System.Web.HttpApplicationFactory.GetSpecialApplicationInstance（IntPtr appContext、HttpContext 上下文）+402
System.Web.Hosting.PipelineRuntime.InitializeApplication（IntPtr appContext) +343

[HttpException (0x80004005): 给定的过滤器实例必须实现 以下一个或多个过滤器接口： System.Web.Mvc.IAuthorizationFilter, System.Web.Mvc.IActionFilter, System.Web.Mvc.IResultFilter, System.Web.Mvc.IExceptionFilter, System.Web.Mvc.Filters.IAuthenticationFilter.]
System.Web.HttpRuntime.FirstRequestInit(HttpContext 上下文) +539
System.Web.HttpRuntime.EnsureFirstRequestInit（HttpContext 上下文） +125 System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest WR，HttpContext 上下文）+731

即使我实现了例如IAuthenticationFilter 接口，无论如何都会抛出相同的异常。

有人有类似的例外吗？我无法在 WebAPI 中找到更多相关信息。

Answer 1

已解决：问题是过滤器的注册位置。在 MVC 中，您将在 FilterConfing 类中注册过滤器，但在 WebAPI 中，您在 WebApiConfig 类的 Register 方法中执行此操作，如下所示：

config.Filters.Add(new AuthAttribute());

现在一切正常。