.net core 添加中间件

中间件类必须含有RequestDelegate 以及一个async 方法

namespace WebApplication1
{
    public class MiddleWare
    {
        private readonly RequestDelegate _requestDelegate;

        public MiddleWare(RequestDelegate requestDelegate)
        {
            _requestDelegate = requestDelegate;
        }

        public async Task InvokeAsync(HttpContext context)
        {
            string pwd = context.Request.Query["password"];
            if (pwd == "123")//假如路由中的querystring含有password且是123，则让继续访问
            {
                if (context.Request.HasJsonContentType())
                {
                    context.Items["test"] = "123";
                }
                await _requestDelegate(context);//继续往下执行
            }
            else
            {
                context.Response.StatusCode = 401;
            }
        }
    }
}

注入

app.UseMiddleware<MiddleWare>();

https://www.tutorialsteacher.com/core/how-to-add-custom-middleware-aspnet-core