如何在错误的 .NET Core API 路由上抛出 404？

Question

我有一个具有 API 的 .NET Core Web 应用程序。我已经定义了一个基于this 答案的中间件类，如下所示：

public class ErrorHandlingMiddleware
{
    private readonly RequestDelegate next;
    private readonly ILogger logger;

    public ErrorHandlingMiddleware(RequestDelegate next,
        ILoggerFactory loggerFactory)
    {
        this.next = next;
        logger = loggerFactory.CreateLogger<ErrorHandlingMiddleware>();
    }

    public async Task Invoke(HttpContext context)
    {
        try
        {
            await next(context);
        }
        catch (Exception ex)
        {
            logger.LogError(0, ex, "An unhandled exception has occurred: " + ex.StackTrace);
            await HandleExceptionAsync(context, ex);
        }
    }

    private static Task HandleExceptionAsync(HttpContext context, Exception exception)
    {
        var code = HttpStatusCode.InternalServerError;
        var message = exception.Message;
        if (exception is BadRequestException)
        {
            code = HttpStatusCode.BadRequest;
        }
        else if (exception is NotFoundException)
        {
            code = HttpStatusCode.NotFound;
        }
        else if (exception is NotAuthorizedException)
        {
            code = HttpStatusCode.Forbidden;
        }
        else if (exception is NotAuthenticatedException)
        {
            code = HttpStatusCode.Unauthorized;
        }
        else
        {
            message = "An unexpected error occurred.";
        }

        var result = JsonConvert.SerializeObject(new { error = message });
        context.Response.ContentType = "application/json";
        context.Response.StatusCode = (int)code;
        return context.Response.WriteAsync(result);
    }
}

错误处理仅在代码中引发异常时处理。错误的路线不会引发异常。问题是，如果我尝试访问不存在的 API 路由（即遵循 API 路由约定并以“/api/adfasdf”开头的路由），API 会返回 HTML（或错误页面或主页，我忘了）。

我收到了一些建议在await next(context); 执行后检查context.Response.StatusCode，但它是200。

如何配置我的网络应用程序，使其识别错误的 API 路由并返回 404？

更新 这是我在 Startup 类中加载中间件的位置/时间：

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory, IApplicationLifetime appLifetime, IOptions<OidcConfig> oidcConfigOptions)
{
    loggerFactory.AddConsole(Configuration.GetSection("Logging"));
    loggerFactory.AddDebug();

    // Add Serilog to the logging pipeline
    loggerFactory.AddSerilog();

    app.UseMiddleware<ErrorHandlingMiddleware>();

    if (env.IsLocal())
    {
        app.UseWebpackDevMiddleware(new WebpackDevMiddlewareOptions
        {
            HotModuleReplacement = true
        });
    }

    var oidcConfig = oidcConfigOptions.Value;

    // Configure the app to use Jwt Bearer Authentication
    app.UseJwtBearerAuthentication(new JwtBearerOptions
    {
        AutomaticAuthenticate = true,
        AutomaticChallenge = true,
        Authority = oidcConfig.GetAuthority(),
        Audience = oidcConfig.ResourceAppId,
        TokenValidationParameters = new TokenValidationParameters
        {
            RequireExpirationTime = true,
            RequireSignedTokens = true,
            ValidateAudience = true,
            ValidIssuer = oidcConfig.GetIssuer(),
            ValidateIssuer = true,
            ValidateActor = false,
            ValidateLifetime = true,
            ValidateIssuerSigningKey = true
        },
    });

    app.UseSiteIdClaimInjection();

    app.UseStaticFiles();

    app.UseMvc(routes =>
    {
        routes.MapRoute(
            name: "default",
            template: "{controller=Home}/{action=Index}/{id?}");

        routes.MapSpaFallbackRoute(
            name: "spa-fallback",
            defaults: new { controller = "Home", action = "Index" });
    });

    appLifetime.ApplicationStopped.Register(() => this.ApplicationContainer.Dispose());
}

Answer 1

对于后人来说，@Nkosi 帮助发现我获得 200 分的原因与 Startup 类中的 MVC 路由定义有关。这是自动从https://github.com/aspnet/JavaScriptServices 进来的。

解决方案是将我的路由配置更改为以下内容：

app.UseMvc(routes =>
{
    routes.MapRoute(
        name: "default",
        template: "{controller=Home}/{action=Index}/{id?}");
});

app.MapWhen(x => !x.Request.Path.Value.StartsWith("/api"), builder =>
{
    builder.UseMvc(routes =>
    {
        routes.MapSpaFallbackRoute(
            name: "spa-fallback",
            defaults: new { controller = "Home", action = "Index" });
    });
});

Answer 2

引用ASP.NET Core Middleware Fundamentals - Ordering

Configure方法中添加中间件组件的顺序 定义在请求中调用它们的顺序，以及 响应顺序相反。这种排序对于 安全性、性能和功能。

Configure 方法（如下所示）添加了以下中间件 组件：

• 异常/错误处理
• 静态文件服务器
• 身份验证
• MVC

C#

public void Configure(IApplicationBuilder app)
{
    app.UseExceptionHandler("/Home/Error"); // Call first to catch exceptions
                                            // thrown in the following middleware.

    app.UseStaticFiles();                   // Return static files and end pipeline.

    app.UseIdentity();                     // Authenticate before you access
                                           // secure resources.

    app.UseMvcWithDefaultRoute();          // Add MVC to the request pipeline.
}

在上面的代码中，UseExceptionHandler 是第一个中间件 添加到管道的组件——因此，它会捕获任何异常 在以后的调用中发生。

根据 OP 中提供的代码和引用的文档，我建议您提前或首先将您的异常添加到管道中。

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory, IApplicationLifetime appLifetime) {
    loggerFactory.AddConsole(Configuration.GetSection("Logging"));
    loggerFactory.AddDebug();
    loggerFactory.AddSerilog();

    app.UseMiddleware<ErrorHandlingMiddleware>(); // Call first to catch exceptions
                                                  // thrown in the following middleware.    
    if (env.IsLocal()) {
        app.UseWebpackDevMiddleware(new WebpackDevMiddlewareOptions { HotModuleReplacement = true });
    }

    //Bunch of other stuff
}

更新基于 cmets。

我怀疑管道下游的中间件之一导致了这个问题。尝试一一删除它们并检查是否有相同的行为，以缩小罪魁祸首。

Answer 3

与上述答案类似，我们在 Angular 和 ASP.NET MVC Core 项目中使用它：

        public virtual void Configure(IHostingEnvironment environment, IApplicationBuilder app)
{

            // configurations...

            app.UseMvc(routes =>
            {
                routes.MapRoute("default", "{controller=Home}/{action=Index}/{id?}");
            });

            app.MapWhen(o => !o.Request.Path.Value.StartsWith("/api"), builder =>
            {
                builder.UseMvc(routes =>
                {
                    routes.MapRoute("spa-fallback", "{*anything}", new { controller = "Home", action = "Index" });
                });
            });

}