.net core 中间件实战

1、新建一个ASP.NET Core Web Application项目，选择空模板。

2、新建一个类RequestIPMiddleware.cs

using Microsoft.AspNetCore.Http;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace MiddlewareDemo
{
    public class RequestIPMiddleware
    {
        private readonly RequestDelegate _next;

        public RequestIPMiddleware(RequestDelegate next)
        {
            _next = next;
        }

        public async Task Invoke(HttpContext context)
        {
            await context.Response.WriteAsync("to do something 

");
            await context.Response.WriteAsync("IP:" + context.Connection.RemoteIpAddress.ToString() + "

");
            await _next.Invoke(context);
        }
    }
}

　　

3、再新建一个扩展类 RequestIPExtensions.cs

using Microsoft.AspNetCore.Builder;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace MiddlewareDemo
{
    public static class RequestIPExtensions
    {
        public static IApplicationBuilder UseRequestIP(this IApplicationBuilder builder)
        {
            return builder.UseMiddleware<RequestIPMiddleware>();
        }
    }
}

4、使用中间件。在Startup.cs中添加app.UseRequestIP():

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;

namespace MiddlewareDemo
{
    public class Startup
    {
        // This method gets called by the runtime. Use this method to add services to the container.
        // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
        public void ConfigureServices(IServiceCollection services)
        {
           
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            app.UseRequestIP();
            app.Run(async (context) =>
            {
                await context.Response.WriteAsync("Hello World!");
            });
        }
    }
}

5、运行效果