.Net Core:Middleware中间件管道

时间:2023-03-09 18:43:13
.Net Core:Middleware中间件管道

.NetCore中的Middleware是装配到管道处理请求和响应的组件;每个组件都可以决定是否继续进入下一个管道、并且可以在进入下一个管道前后执行逻辑;

最后一个管道或者中断管道的中间件叫终端中间件;

.Net Core:Middleware中间件管道

1、创建中间件管道IApplicationBuilder

app.Run()拦截请求后中断请求,多个Run()只执行第一个;

            app.Run(async httpcontenxt =>
{
httpcontenxt.Response.ContentType = "text/plain; charset=utf-8";
await httpcontenxt.Response.WriteAsync("截获请求!并在此后中断管道");
});
app.Run(async httpcontenxt =>
{
httpcontenxt.Response.ContentType = "text/plain; charset=utf-8";
await httpcontenxt.Response.WriteAsync("排序第二个的RUN");
});

2、连接下一个管道 Use()

使用next.invoke调用下一个管道,在向客户端发送响应后,不允许调用 next.Invoke,会引发异常

            app.Use(async (context, next) =>
{
// 执行逻辑,但不能写Response
//调用管道中的下一个委托
await next.Invoke();
// 执行逻辑,如日志等,但不能写Response
}); app.Run(async httpcontenxt =>
{
httpcontenxt.Response.ContentType = "text/plain; charset=utf-8";
await httpcontenxt.Response.WriteAsync("截获请求!并在此后中断管道");
});
app.Run(async httpcontenxt =>
{
httpcontenxt.Response.ContentType = "text/plain; charset=utf-8";
await httpcontenxt.Response.WriteAsync("排序第二个的RUN");
});

3、通过路径或条件处理管道 Map()

public class Startup
{
private static void HandleBranch(IApplicationBuilder app)
{
app.Run(async context =>
{
var branchVer = context.Request.Query["branch"];
await context.Response.WriteAsync($"Branch used = {branchVer}");
});
} private static void HandleMapTest2(IApplicationBuilder app)
{
app.Run(async context =>
{
await context.Response.WriteAsync("Map Test 2");
});
} public void Configure(IApplicationBuilder app)
{
app.MapWhen(context => context.Request.Query.ContainsKey("branch"),
HandleBranch);//localhost:1234/?branch=master app.Map("/map2", HandleMapTest2);//localhost:1234/map2 app.Run(async context =>
{
await context.Response.WriteAsync("Hello from non-Map delegate. <p>");
});
}
}

4、中间件的顺序很重要

异常/错误处理
HTTP 严格传输安全协议
HTTPS 重定向
静态文件服务器
Cookie 策略实施
身份验证
会话
MVC

app.UseExceptionHandler("/Home/Error"); // Call first to catch exceptions

app.UseStaticFiles();                   // Return static files and end pipeline.

app.UseAuthentication();               // Authenticate before you access

app.UseMvcWithDefaultRoute();  

资源

https://docs.microsoft.com/zh-cn/aspnet/core/fundamentals/middleware/index?view=aspnetcore-2.2