Orchard源码分析（7.2）：Controller相关

概述

默认情况下，ASP.NET MVC内置的DefaultControllerFactory负责Controller实例的创建。Orchard定义了一个继承自DefaultControllerFactory类的Orchard.Mvc.OrchardControllerFactory类并在OrchardStarter类中进行注册：

         // 以下代码来在Orchard.Environment.OrchardStarter类

          ControllerBuilder .Current.SetControllerFactory( new   OrchardControllerFactory ());

OrchardControllerFactory作用是能从Shell生命周期的Autofac"子容器"中解析(Resolver)Controller类型，再根据类型解析Controller实例。这里就引出这些问题：Controller类型在什么时候被注册到Autofac容器中，Controller的类型如何被解析出来，Controller的实例如何被解析出来。

 

一、Controller注册

在激活Shell之前，会创建Shell的上下文对象ShellContext，在这个过程中会将Shell需要用到的Controller注册到Shell作用域的Autofac容器中：

                     // 以下代码来在Orchard.Environment.ShellBuilders.ShellContainerFactory类的CreateContainer方法

                      foreach   ( var   item   in   blueprint.Controllers) {

                          var   serviceKeyName = (item.AreaName +   "/"   + item.ControllerName).ToLowerInvariant();

                          var   serviceKeyType = item.Type;

                        RegisterType(builder, item)

                            .EnableDynamicProxy(dynamicProxyContext)

                            .Keyed<   IController >(serviceKeyName)

                            .Keyed<   IController >(serviceKeyType)

                            .WithMetadata(   "ControllerType" , item.Type)

                            .InstancePerDependency()

                            .OnActivating(e =>s {

                                  // necessary to inject custom filters dynamically

                                  // see FilterResolvingActionInvoker

                                  var   controller = e.Instance   as   Controller ;

                                  if   (controller !=   null   )

                                    controller.ActionInvoker = (   IActionInvoker )e.Context.ResolveService( new   TypedService ( typeof   ( IActionInvoker )));

                            });

                    }

 

                      foreach   ( var   item   in   blueprint.HttpControllers) {

                          var   serviceKeyName = (item.AreaName +   "/"   + item.ControllerName).ToLowerInvariant();

                          var   serviceKeyType = item.Type;

                        RegisterType(builder, item)

                            .EnableDynamicProxy(dynamicProxyContext)

                            .Keyed<   IHttpController >(serviceKeyName)

                            .Keyed<   IHttpController >(serviceKeyType)

                            .WithMetadata(   "ControllerType" , item.Type)

                            .InstancePerDependency();

                    }

 

          // 以下代码来在Orchard.Environment.ShellBuilders.ShellContainerFactory类

        private   IRegistrationBuilder < object   ,   ConcreteReflectionActivatorData ,   SingleRegistrationStyle > RegisterType( ContainerBuilder   builder,   ShellBlueprintItem   item) {

              return   builder.RegisterType(item.Type)

                .WithProperty(   "Feature" , item.Feature)

                .WithMetadata(   "Feature" , item.Feature);

        }

二、ControllerFactory

既然Controller已经被注册到了Autofac容器中，则很容易提取出来：

      // 以下代码来在Orchard.Mvc.ControllerFactory类

     ///   <summary>

      ///   Overrides the default controller factory to resolve controllers using LoC, based their areas and names.

      ///   </summary>

      public   class   OrchardControllerFactory   :   DefaultControllerFactory   {

          ///   <summary>

          ///   Tries to resolve an instance for the controller associated with a given service key for the work context scope.

          ///   </summary>

          ///   <typeparam name="T">   The type of the controller. </typeparam>

          ///   <param name="workContext">   The work context. </param>

          ///   <param name="serviceKey">   The service key for the controller.   </param>

          ///   <param name="instance">   The controller instance. </param>

          ///   <returns>   True if the controller was resolved; false otherwise.   </returns>

          protected   bool   TryResolve<T>( WorkContext   workContext,   object   serviceKey,   out   T instance) {

              if   (workContext !=   null   && serviceKey !=   null ) {

                  var   key =   new   KeyedService (serviceKey,   typeof   (T));

                  object   value;

                  if   (workContext.Resolve< ILifetimeScope   >().TryResolveService(key,   out   value)) {

                    instance = (T) value;

                      return   true   ;

                }

            }

 

            instance =   default (T);

              return   false   ;

        }

 

          ///   <summary>

          ///   Returns the controller type based on the name of both the controller and area.

          ///   </summary>

          ///   <param name="requestContext">   The request context from where to fetch the route data containing the area. </param>

          ///   <param name="controllerName">   The controller name. </param>

          ///   <returns>   The controller type. </returns>

          ///   <example>   ControllerName: Item, Area: Containers would return the type for the ItemController class. </example>

          protected   override   Type   GetControllerType(   RequestContext   requestContext,   string   controllerName) {

              var   routeData = requestContext.RouteData;

 

              // Determine the area name for the request, and fall back to stock orchard controllers

              var   areaName = routeData.GetAreaName();

 

              // Service name pattern matches the identification strategy

              var   serviceKey = (areaName +   "/"   + controllerName).ToLowerInvariant();

 

              // Now that the request container is known - try to resolve the controller information

              Meta < Lazy   < IController >> info;

              var   workContext = requestContext.GetWorkContext();

              if   (TryResolve(workContext, serviceKey,   out   info)) {

                  return   ( Type   ) info.Metadata[ "ControllerType" ];

            }

 

              return   null   ;

        }

 

          ///   <summary>

          ///   Returns an instance of the controller.

          ///   </summary>

          ///   <param name="requestContext">   The request context from where to fetch the route data containing the area. </param>

          ///   <param name="controllerType">   The controller type. </param>

          ///   <returns>   An instance of the controller if it's type is registered; null if otherwise.   </returns>

          protected   override   IController   GetControllerInstance(   RequestContext   requestContext,   Type   controllerType) {

              IController   controller;

              var   workContext = requestContext.GetWorkContext();

              if   (TryResolve(workContext, controllerType,   out   controller)) {

                  return   controller;

            }

 

              // fail as appropriate for MVC's expectations

              return   base   .GetControllerInstance(requestContext, controllerType);

        }

    }

 

 

三、ActionInvoker

在成功创建Controller实例后，会将其ActionInvoker设置成Orchard.Mvc.FilterResolvingActionInvoker。

我们知道，ASP.NET MVC中，我们可以将Filter以Attribute的形式定义在Controller或Action上。Orchard提供了一个Filter Provider机制，即可以将一些Filter定义在其他地方，在使用Filter之前再提取出来。这方面比较简单，直接看FilterResolvingActionInvoker的定义：

      // 以下代码来在Orchard.Mvc.Filters.FilterResolvingActionInvoker类

     public   class   FilterResolvingActionInvoker   :   ControllerActionInvoker   {

          private   readonly   IEnumerable <   IFilterProvider > _filterProviders;

 

          public   FilterResolvingActionInvoker( IEnumerable   < IFilterProvider > filterProviders) {

            _filterProviders = filterProviders;

        }

 

          protected   override   FilterInfo   GetFilters( ControllerContext   controllerContext,   ActionDescriptor   actionDescriptor) {

              var   filters=   base   .GetFilters(controllerContext, actionDescriptor);

              foreach ( var   provider   in   _filterProviders) {

                provider.AddFilters(filters);

            }

              return   filters;

        }

    }

 

只要一个Filter实现了Orchard.Mvc.Filters.FilterProvider:FilterProvider抽象类，就能非常方便的将Filter应用到所有Action之上。另外，高级的应用可以直接实现IFilterProvider接口，不过一般实现FilterProvider抽象类就行了。

 

相关类型：

Orchard.Mvc.OrchardControllerFactory:System.Web.Mvc.DefaultActionInvoker

Orchard.Mvc.Filters.FilterResolvingActionInvoker:System.Web.Mvc.ControllerActionInvoker

Orchard.Mvc.Filters.IFilterProvider

Orchard.Environment.ShellBuilders.ShellContainerFactory

Orchard.Environment.AutofacUtil.DynamicProxy2.DynamicProxyContext