Question

我已经设置了一个非常简单的中间件作为要学习的测试项目，目前它只是转储请求标头。

我想知道，如果有可能的话，下面的设置：

在Startup类中填充一个字段（然后可以通过DI访问）
或直接访问中间件中的字段（例如在OnActionExecuting中）

启动：

using HeaderAuthentication;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;

namespace ServiceLayer
{
    // ReSharper disable once ClassNeverInstantiated.Global
    public class Startup
    {
        private IConfiguration Configuration { get; }

        public Startup(IConfiguration Configuration)
        {
            this.Configuration = Configuration;
        }

        // ReSharper disable once UnusedMember.Global
        public void ConfigureServices(IServiceCollection Services)
        {
            Services.AddMvc().AddJsonOptions(Options =>
               Options.SerializerSettings.ReferenceLoopHandling =
                   Newtonsoft.Json.ReferenceLoopHandling.Ignore
            );
        }

        // ReSharper disable once UnusedMember.Global
        public void Configure(
            IApplicationBuilder App,
            IHostingEnvironment Env,
            ILoggerFactory LoggerFactory
        )
        {
            App.UseHeaderChecking();

            if (Env.IsDevelopment())
            {
                App.UseDeveloperExceptionPage();
            }

            App.UseMvc();
        }
    }
}

扩展方法：

using Microsoft.AspNetCore.Builder;

namespace HeaderAuthentication
{
    public static class RequestHeaderCheckingMiddleware
    {
        public static IApplicationBuilder UseHeaderChecking(
            this IApplicationBuilder Builder
        )
        {
            return Builder.UseMiddleware<CheckHeaders>();
        }
    }
}

CheckHeader代码：

using InterfaceLayer.Entities;
using Microsoft.AspNetCore.Http;
using System;
using System.Threading.Tasks;

namespace HeaderAuthentication
{
    public class CheckHeaders
    {
        private readonly RequestDelegate Next;

        public CheckHeaders(RequestDelegate NextDelegate)
        {
            Next = NextDelegate;
        }

        public Task Invoke(HttpContext Context, SupportContext Support)
        {
            if (Context.Request == null)
            {
                //return null;
            }

            var testA = GetRequestHeader(Context, "X-HeaderTest-A"); // sandwich
            var testB = GetRequestHeader(Context, "X-HeaderTest-B"); // biscuit

            return Next(Context);
        }

        private static string GetRequestHeader(HttpContext Context, string Key)
        {
            if (!Context.Request.Headers.TryGetValue(Key, out var buffer))
            {
                return string.Empty;
            }

            return buffer;
        }
    }
}

我希望在我的BaseController中的testA方法中访问testB和OnActionExecuting内的值，以触发＆＃34;三明治＆＃34;和＆＃34;饼干＆＃34;案例如下：

using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Filters;
using System.Threading.Tasks;

namespace ServiceLayer.Controllers
{
    public partial class BaseController : Controller
    {
        public BaseController()
        {
        }

        public override void OnActionExecuting(ActionExecutingContext Context)
        {
            switch (testValue)
            {
                case "sandwich":
                    break;
                case "biscuit":
                    break;
            }

            base.OnActionExecuting(Context);
        }
    }
}

这可行吗？

Answer 1

一种肮脏的方式可能是您在CheckHeaders.Invoke方法中的单独的已知密钥下的Context.Items集合中的值，并在BaseController.OnActionExecuting方法中查询上下文项是否存在值并依赖于它采取适当的行动。

是否可以访问中间件中生成的数据？

1 个答案: