Middleware In ASP.NET Core

中间件简介

ASP.NET Core 由很多中间件构成，实现了一个HTTP请求管道（pipeline）。

Request的Response的管道可以看成一个Push Stack 和 Pop Stack。

在Startup.cs的Configure方法中配置中间件。

实现一个中间件

构造函数RequestDelegate参数；

Invoke(HttpContext context)方法；

using Microsoft.AspNetCore.Http;
using System.Threading.Tasks;
using System.Diagnostics;
using System.IO;

namespace WebAppWithIndividualUserAccounts
{
public class ResponseTime
{
RequestDelegate _next;
public ResponseTime(RequestDelegate next)
{
_next = next;
}

public async Task Invoke(HttpContext context)
{
var sw = new Stopwatch();
sw.Start();

await _next(context);

var isHtml = context.Response.ContentType?.ToLower().Contains("text/html");
if (context.Response.StatusCode == 200 && isHtml.GetValueOrDefault())
{
var body = context.Response.Body;

using (var streamWriter = new StreamWriter(body))
{
var txtHtml = $"<footer><div id='process'>Response Time {sw.ElapsedMilliseconds} milliseconds.</div></footer>";

streamWriter.Write(txtHtml);
}
}
}
}
}

注册一个中间件

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
app.UseMiddleware<ResponseTime>();
//......

运行

即可看到效果