.Net Core 创建和使用中间件

1. 定义中间内容

1.1 必须有一个RequestDelegate 委托用了进入一个中间件

1.2 通过构造函数设置这个RequestDelegate委托

1.3 必须有一个方法Task Invoke，在这个方法里编写中间件内容最后执行RequestDelegate委托

using Microsoft.AspNetCore.Http;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
namespace Haos.Develop.CoreTest
{
public class TestMiddleware
{
protected RequestDelegate Next;
/// <summary>
/// 参数
/// </summary>
public string Str { get; set; }
public TestMiddleware(RequestDelegate next,string s)
{
Next = next;
Str = s;
}
public virtual Task Invoke(HttpContext context)
{
context.Response.WriteAsync("this is test string");
return Next(context);
}
}
}

2. 编写一个扩展方法用来添加到程序中

using Haos.Develop.CoreTest.Service;
using Microsoft.AspNetCore.Builder;
using Microsoft.Extensions.DependencyInjection;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
namespace Haos.Develop.CoreTest
{
public static class Extension
{
public static IApplicationBuilder UserTestMiddleWare(this IApplicationBuilder app, string str)
{
return app.UseMiddleware<TestMiddleware>(str);
}
}
}

3.  在Startup添加中间件

// 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();
}
//扩展方式添加
app.UserTestMiddleWare("this is test param");
//直接添加中间件方式
app.Use((context, next) =>
{
context.Response.WriteAsync("this is test");
return next();
});
}