新建一个MVC项目启动后,首先访问的地址是http://localhost:xxx/Home/Index,这时候我们也明白因为在程序中有个叫做Home的控制器,并且在这个控制器下面有个叫做Index的方法,基于这种对应的关系,才有了这种结果,那么这种对应关系是如何产生,如何工作的了?
在我们网站在第一次启动的时候,会去访问一个全局的配置文件Global.asax下面的Application_Start()方法,代码如下
1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Web; 5 using System.Web.Mvc; 6 using System.Web.Optimization; 7 using System.Web.Routing; 8 ?9 namespace Test10 {11 ????public class MvcApplication : System.Web.HttpApplication12 ????{13 ????????protected void Application_Start()14 ????????{15 ????????????AreaRegistration.RegisterAllAreas();16 ????????????FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);17 ????????????RouteConfig.RegisterRoutes(RouteTable.Routes);18 ????????????BundleConfig.RegisterBundles(BundleTable.Bundles);19 ????????}20 ????}21 }在这个方法中就注册了我们的路由配置,相关的注册文件都是在在App_Data目录下
路由配置文件RouteConfig.cs,内容如下
1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Web; 5 using System.Web.Mvc; 6 using System.Web.Routing; 7 ?8 namespace Test 9 {10 ????public class RouteConfig11 ????{12 ????????public static void RegisterRoutes(RouteCollection routes)13 ????????{14 ????????????routes.IgnoreRoute("{resource}.axd/{*pathInfo}");15 16 ????????????routes.MapRoute(17 ????????????????name: "Default",18 ????????????????url: "{controller}/{action}/{id}",19 ????????????????defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }20 ????????????);21 ????????}22 ????}23 }首先是忽略路由,满足匹配会被忽略,如果没有特殊需求,这个地方就不需要更改,
name表示路由的名称,同一个路由集合中,路由名称必须唯一,不能够有重名,
url就是正则表达式,用于http://localhost:xxx/后路径地址的匹配,
defaults表示缺省路由,也就是默认的路由.这是一个路由规则增删的方法,并且默认的路由为home/index,
还有一个比较常用的参数是constraints,用于条件约束,简单实例如下:
1 ????public class RouteConfig 2 ????{ 3 ????????public static void RegisterRoutes(RouteCollection routes) 4 ????????{ 5 ????????????routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); 6 ?7 ????????????//假若Home下有Test(int year,int month,int day)方法 8 ????????????//home/Test_2017_06_05可以访问至该方法 9 ????????????//home/Test_2017_6_05是无法访问10 ????????????routes.MapRoute(11 ??????????????name: "Constraints",12 ??????????????url: "{controller}/{action}_{year}_{month}_{day}",13 ??????????????defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional },14 ??????????????//条件参数,约束后面参数(此处简单正则:4位数字,2位数字,2位数字)15 ??????????????constraints: new { year = @"^\d{4}", month = @"^\d{2}", day = @"^\d{2}" });16 17 ????????????routes.MapRoute(18 ????????????????name: "Default",19 ????????????????url: "{controller}/{action}/{id}",20 ????????????????defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional });21 ????????}22 ????}路由浅析
那么路由究竟是如何工作的,下面是2个与路由工作十分紧密的2个方法的源码,任何http请求进入后,都会先被它们处理
1 public virtual void PostResolveRequestCache(HttpContextBase context) 2 ????{ 3 ????????RouteData routeData = RouteCollection.GetRouteData(context); 4 ????????if (routeData != null) 5 ????????{ 6 ????????????IRouteHandler routeHandler = routeData.RouteHandler; 7 ????????????if (routeHandler == null) 8 ????????????{ 9 ????????????????throw new InvalidOperationException(string.Format(CultureInfo.CurrentCulture, SR.GetString("UrlRoutingModule_NoRouteHandler")));10 ????????????}11 ????????????if (!(routeHandler is StopRoutingHandler))12 ????????????{13 ????????????????RequestContext requestContext = new RequestContext(context, routeData);14 ????????????????context.Request.RequestContext = requestContext;15 ????????????????IHttpHandler httpHandler = routeHandler.GetHttpHandler(requestContext);16 ????????????????if (httpHandler == null)17 ????????????????{18 ????????????????????throw new InvalidOperationException(string.Format(CultureInfo.CurrentUICulture, SR.GetString("UrlRoutingModule_NoHttpHandler"), new object[1]19 ????????????????????{20 ????????????????????????routeHandler.GetType()21 ????????????????????}));22 ????????????????}23 ????????????????if (httpHandler is UrlAuthFailureHandler)24 ????????????????{25 ????????????????????if (FormsAuthenticationModule.FormsAuthRequired)26 ????????????????????{27 ????????????????????????UrlAuthorizationModule.ReportUrlAuthorizationFailure(HttpContext.Current, this);28 ????????????????????????return;29 ????????????????????}30 ????????????????????throw new HttpException(401, SR.GetString("Assess_Denied_Description3"));31 ????????????????}32 ????????????????context.RemapHandler(httpHandler);33 ????????????}34 ????????}35 ????} 1 public RouteData GetRouteData(HttpContextBase httpContext) 2 { 3 ????if (httpContext == null) 4 ????{ 5 ????????throw new ArgumentNullException("httpContext"); 6 ????} 7 ????if (httpContext.Request == null) 8 ????{ 9 ????????throw new ArgumentException(SR.GetString("RouteTable_ContextMissingRequest"), "httpContext");10 ????}11 ????if (base.Count == 0)12 ????{13 ????????return null;14 ????}15 ????bool flag = false;16 ????bool flag2 = false;17 ????if (!RouteExistingFiles)18 ????{19 ????????flag = IsRouteToExistingFile(httpContext);20 ????????flag2 = true;21 ????????if (flag)22 ????????{23 ????????????return null;24 ????????}25 ????}26 ????using (GetReadLock())27 ????{28 ????????foreach (RouteBase item in this)29 ????????{30 ????????????RouteData routeData = item.GetRouteData(httpContext);31 ????????????if (routeData != null)32 ????????????{33 ????????????????if (!item.RouteExistingFiles)34 ????????????????{35 ????????????????????if (!flag2)36 ????????????????????{37 ????????????????????????flag = IsRouteToExistingFile(httpContext);38 ????????????????????????flag2 = true;39 ????????????????????}40 ????????????????????if (flag)41 ????????????????????{42 ????????????????????????return null;43 ????????????????????}44 ????????????????}45 ????????????????return routeData;46 ????????????}47 ????????}48 ????}49 ????return null;50 }大致分析下这段源码,我们可以得出下列比较重要的结论
1在路由匹配之前,先一步检查了物理文件的存在,所以mvc和webform可以共存,如果存在满足路径条件的aspx文件,它会优先被访问
2路由是从上到下逐个匹配的,所以排列的顺序对于路由匹配是非常重要的
路由扩展
在上述基础下,我们对路由有了大概的了解,对此我们可以简单扩展一下
路由并不是只能够在路径规则上做文章,我们也可以继承路由的基类RouteBase自定义一些路由,然后把自定义的路由放入注册路由集合中,调准好顺序,实现我们想要的结果.因为能够得到HttpContext这个用户请求的上下文,我们可以完成很多扩展,例如检查ip,浏览器类型,参数等等,下面我们就简单的实现不同浏览器访问到不同路径的功能,如下:
1 ????public class RouteConfig 2 ????{ 3 ????????public static void RegisterRoutes(RouteCollection routes) 4 ????????{ 5 ????????????routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); 6 ?7 ????????????//注意顺序 8 ????????????routes.Add("Agent",new Agent()); 9 10 ????????????routes.MapRoute(11 ????????????????name: "Default",12 ????????????????url: "{controller}/{action}/{id}",13 ????????????????defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional });14 ????????}15 16 ??????17 ????}18 ????public class Agent : RouteBase19 ????{20 ????????public override RouteData GetRouteData(HttpContextBase httpContext)21 ????????{22 ????????????if (httpContext.Request.UserAgent.Contains("Chrome/63.0.3239.132"))23 ????????????{24 ????????????????var data = new RouteData(this, new MvcRouteHandler());25 ????????????????data.Values.Add("controller", "Home");26 ????????????????data.Values.Add("action", "About");27 ????????????????return data;28 ????????????}29 ????????????else30 ????????????{31 ????????????????return null;32 ????????????}33 ????????}34 35 ????????public override VirtualPathData GetVirtualPath(RequestContext requestContext, RouteValueDictionary values)36 ????????{37 ????????????return null;38 ????????}39 ????}一定得注意路由排列的顺序,如果将上面的Agent路由放在Default路由后面,那么就直接会访问到Home/Index,而不会去判断.
我们也可以通过自定义继承了RouteBase的Route类,来完成特殊路径的扩展,如下
1 ??public class RouteConfig 2 ????{ 3 ????????public static void RegisterRoutes(RouteCollection routes) 4 ????????{ 5 ????????????routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); 6 ?7 ????????????routes.Add(new Route("Test",new TestRouteHandler())); 8 ?9 ????????????routes.MapRoute(10 ????????????????name: "Default",11 ????????????????url: "{controller}/{action}/{id}",12 ????????????????defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional });13 ????????}14 ????}15 16 ????public class TestRouteHandler : IRouteHandler17 ????{18 ????????public IHttpHandler GetHttpHandler(RequestContext requestContext)19 ????????{20 ????????????return new TestHandler();21 ????????}22 ????}23 ????public class TestHandler : IHttpHandler24 ????{25 ????????public bool IsReusable => true;26 27 ????????public void ProcessRequest(HttpContext context)28 ????????{29 ????????????context.Response.Write("Test");30 ????????}31 ????}效果如下:
出自:博客园-半路独行
原文地址:https://www.cnblogs.com/banluduxing/p/9185159.html
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.Net MVC5路由机制与扩展
原文地址：https://www.cnblogs.com/banluduxing/p/9185159.html