《ASP.NET Core技术内幕与项目实战》精简集-WebApi3.2：中间件Middleware

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

//指定处理“/test”路径请求的管道
app.Map("/test", async appBuilder =>
{
    //第一个中间件
    appBuilder.Use(async (context, next) =>
    {
        context.Response.ContentType = "text/html";
        await context.Response.WriteAsync("1 Start<br/>");
        await next.Invoke();
        await context.Response.WriteAsync("1 End<br/>");
    });
    //第二个中间件
    appBuilder.Use(async (context, next) =>
    {
        context.Response.ContentType = "text/html";
        await context.Response.WriteAsync("2 Start<br/>");
        await next.Invoke();
        await context.Response.WriteAsync("2 End<br/>");
    });
    //Run终点
    appBuilder.Run(async ctx =>
    {
        await ctx.Response.WriteAsync("hello,it is run<br/>");
    });
});

app.Run();

var app = builder.Build();

if (app.Environment.IsDevelopment())
{
    //开发环境中，捕捉异常
    app.UseDeveloperExceptionPage();
    //OpenApi+Swagger中间件
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseExceptionHandler("/Error"); //生产环境中，捕捉异常

app.UseCors(); //跨域中间件，设置响应报文头允许跨域

app.UseHttpsRedirection(); //HTTP请求重定向到HTTPS

app.UseCookiePolicy(); //Cookie策略中间件

app.UseSession(); //会话中间件，建立和维护会话状态

app.UseAuthentication(); //认证，哪些用户可以登陆访问

app.UseAuthorization(); //授权，登陆用户可以访问哪些资源

app.UseFileServer(); //默认文件、静态文件、目录浏览

app.MapControllers(); //控制器，包括路由

app.Run();

 1 //定义一个中间类
 2 //CheckMiddleware.cs
 3 public class CheckMiddleware
 4 {
 5     private readonly RequestDelegate next;
 6     public CheckMiddleware(RequestDelegate next)
 7     {
 8         this.next = next;
 9     }
10 
11     public async Task InvokeAsync(HttpContext context)
12     {
13         string pwd = context.Request.Query["password"];
14         if (pwd == "123")
15         {
16             await next(context);
17         }
18         else
19         {
20             context.Response.StatusCode = 401;
21         }
22     }
23 }
24 
25 
26 //使用中间件
27 //Program.cs
28 var builder = WebApplication.CreateBuilder(args);
29 ......
30 var app = builder.Build();
31 ......
32 app.Map("/test", async appBuilder =>
33 {
34     appBuilder.UseMiddleware<CheckMiddleware>();
35     appBuilder.Run(async context =>
36     {
37         context.Response.ContentType = "text/html";
38         context.Response.StatusCode = 200;
39         await context.Response.WriteAsync("<h1>success!</h1>");
40     });
41 });
42 app.Run();