MVC路由之浅见

以你之姓@ 2021-11-02 12:42 322阅读 0赞

1、定义路由、路由规则

public static void RegisterRoutes(RouteCollection routes)
            {
                routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
    
                routes.MapRoute(
                    name: "Default",
                    url: "{controller}/{action}/{id}",
                    defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
                );
            }

路由是什么？  
Route派生于RouteBase基类，如下：  
[![1][]][1 1]

路由能提供什么？  
● 通过路由的GetRouteData()方法，获取到封装路由信息的RouteData类型；  
● 通过路由的Constraints属性获取路由约束；  
......

MapRoute()是RouteCollection的扩展方法：  
[![2][]][2 1]

RouteCollection是什么？  
RouteCollection是RouteBase的集合类。  
[![3][]][3 1]

2、注册路由规则

在全局文件中注册路由规则：

public class MvcApplication : System.Web.HttpApplication
        {
            protected void Application_Start()
            {
                ......
                RouteConfig.RegisterRoutes(RouteTable.Routes);
                ......
            }
        }

原来，所有的路由规则都存放在RouteTable中类型为RouteCollection的Routes属性中了。

3、UrlRoutingModule处理url请求，输出MvcHandler以处理HTTP请求

[![4][]][4 1]

UrlRoutingModule实现IHttpModule接口，对HttpApplication的PostResolveRequest事件进行侦听：

public class UrlRoutingModule : IHttpModule
    {
        public void Init(HttpApplication context)
        {
            context.PostResolveRequestCache += OnPostResolveRequestCache;
        }
    
        portected virtual void OnPostResolveRequestCache(object sender, EventArgs e)
        {
            //把当前上下文封装
            HttpContextWrapper httpContext = new HttpContextWrapper(HttpContext.Current);
    
            //获取当前请求中的RouteData类型
            RouteData routeData = RouteTable.Routes.GetRouteData(httpContext);
            if(routeData == null)
            {
                return;
            }
    
            //把routeData再封装起来
            RequestContext requestContext = new RequestContext{
                RouteData = routeData,
                HttpContext = httpContext
            };
    
            //从RouteData的RouteHandler属性获取IRouteHandler类型
            //IRouteHandler的GetHttpHandler()方法获取IHttpHandler
            IHttpHandler handler = routeData.RouteHandler.GetHttpHandler(requestContext);
    
            //为当前上下文设置HttpHandler,用于对当前HTTP请求的处理
            httpContext.RemapHandler(handler);
        }
    }

IRouteHandler是什么？  
他的唯一职责是生产IHttpHandler实例。

public interface IRouteHandler
    {
        IHttpHandler GetHttpHandler(RequestContext requestContext);
    }

在MVC中默认使用的是MvcRouteHandler，是IRouteHandler的实现,返回类型为IHttpHandler的MvcHandler：

public class MvcRouteHandler : IRouteHander
    {
        public IHttpHandler GetHttpHandler(RequestContext requestContext)
        {
            return new MvcHandler(requestContext);
        }
    }

MvcHandler是MVC中IHttpHandler的默认实现：

public class MvcHandler : IHttpHandler
    {
        publci bool IsReusable{
        get {
        return false;}}
    
        public RequestContext RequestContext{
        get; private set;}
    
        public MvcHandler(RequestContext requestContext)
        {
            this.RequestContext = requestContext;
        }
    
        public void ProcessRequest(HttpContext context)
        {
            string controllerName = this.RequestContext.RouteData.Controller;
            IControllerFactory controllerFactory = COntrollerBuilder.Current.GetControllerFactory();
            IController controller = controllerFactory.CreateController(this.RequestContext, controllerName);
            controller.execute(this.RequestContext);
        }
    }

转载于:https://www.cnblogs.com/darrenji/p/3816945.html

[1]: /images/20211101/19eefa59c09e441baad3f1ee726b8ca6.png
[1 1]: https://images0.cnblogs.com/blog/417212/201406/301717329493578.png
[2]: /images/20211101/df5d34e1a32c47f98aa64bf3cba02b4a.png
[2 1]: https://images0.cnblogs.com/blog/417212/201406/301717336374423.png
[3]: /images/20211101/8ff6d59a78084b249fa959f31d46e973.png
[3 1]: https://images0.cnblogs.com/blog/417212/201406/301717341685050.png
[4]: /images/20211101/8498df65089c42069901979c58f144d5.png
[4 1]: https://images0.cnblogs.com/blog/417212/201406/301717349494923.png