Orchard提供了依赖注入机制，并且框架的实现也离不开依赖注入如模块管理、日志、事件等。在前一篇中提到在Global.asax中定义的HostInitialization创建了Autofac的IoC容器。
1 private static IOrchardHost HostInitialization(HttpApplication application) { 2 var host = OrchardStarter.CreateHost(MvcSingletons); 3 4 host.Initialize(); 5 6 // initialize shells to speed up the first dynamic query 7 host.BeginRequest(); 8 host.EndRequest(); 9 10 return host; 11 }
其中OrchardStarter是位于Orchard.Framework项目中Environment目录下的类型
1 public static IOrchardHost CreateHost(Action<ContainerBuilder> registrations) { 2 var container = CreateHostContainer(registrations); 3 return container.Resolve<IOrchardHost>(); 4 }
以下是容器创建的全量代码：
1 public static IContainer CreateHostContainer(Action<ContainerBuilder> registrations) { 2 ExtensionLocations extensionLocations = new ExtensionLocations(); 3 4 var builder = new ContainerBuilder(); 5 // Application paths and parameters 6 builder.RegisterInstance(extensionLocations); 7 8 builder.RegisterModule(new CollectionOrderModule()); 9 builder.RegisterModule(new LoggingModule()); 10 builder.RegisterModule(new EventsModule()); 11 builder.RegisterModule(new CacheModule()); 12 13 // a single default host implementation is needed for bootstrapping a web app domain 14 builder.RegisterType<DefaultOrchardEventBus>().As<IEventBus>().SingleInstance(); 15 builder.RegisterType<DefaultCacheHolder>().As<ICacheHolder>().SingleInstance(); 16 builder.RegisterType<DefaultCacheContextAccessor>().As<ICacheContextAccessor>().SingleInstance(); 17 builder.RegisterType<DefaultParallelCacheContext>().As<IParallelCacheContext>().SingleInstance(); 18 builder.RegisterType<DefaultAsyncTokenProvider>().As<IAsyncTokenProvider>().SingleInstance(); 19 builder.RegisterType<DefaultHostEnvironment>().As<IHostEnvironment>().SingleInstance(); 20 builder.RegisterType<DefaultHostLocalRestart>().As<IHostLocalRestart>().Named<IEventHandler>(typeof(IShellSettingsManagerEventHandler).Name).SingleInstance(); 21 builder.RegisterType<DefaultBuildManager>().As<IBuildManager>().SingleInstance(); 22 builder.RegisterType<DynamicModuleVirtualPathProvider>().As<ICustomVirtualPathProvider>().SingleInstance(); 23 builder.RegisterType<AppDataFolderRoot>().As<IAppDataFolderRoot>().SingleInstance(); 24 builder.RegisterType<DefaultExtensionCompiler>().As<IExtensionCompiler>().SingleInstance(); 25 builder.RegisterType<DefaultRazorCompilationEvents>().As<IRazorCompilationEvents>().SingleInstance(); 26 builder.RegisterType<DefaultProjectFileParser>().As<IProjectFileParser>().SingleInstance(); 27 builder.RegisterType<DefaultAssemblyLoader>().As<IAssemblyLoader>().SingleInstance(); 28 builder.RegisterType<AppDomainAssemblyNameResolver>().As<IAssemblyNameResolver>().SingleInstance(); 29 builder.RegisterType<GacAssemblyNameResolver>().As<IAssemblyNameResolver>().SingleInstance(); 30 builder.RegisterType<OrchardFrameworkAssemblyNameResolver>().As<IAssemblyNameResolver>().SingleInstance(); 31 builder.RegisterType<HttpContextAccessor>().As<IHttpContextAccessor>().InstancePerDependency(); 32 builder.RegisterType<ViewsBackgroundCompilation>().As<IViewsBackgroundCompilation>().SingleInstance(); 33 builder.RegisterType<DefaultExceptionPolicy>().As<IExceptionPolicy>().SingleInstance(); 34 builder.RegisterType<DefaultCriticalErrorProvider>().As<ICriticalErrorProvider>().SingleInstance(); 35 //builder.RegisterType<RazorTemplateCache>().As<IRazorTemplateProvider>().SingleInstance(); 36 37 RegisterVolatileProvider<WebSiteFolder, IWebSiteFolder>(builder); 38 RegisterVolatileProvider<AppDataFolder, IAppDataFolder>(builder); 39 RegisterVolatileProvider<DefaultLockFileManager, ILockFileManager>(builder); 40 RegisterVolatileProvider<Clock, IClock>(builder); 41 RegisterVolatileProvider<DefaultDependenciesFolder, IDependenciesFolder>(builder); 42 RegisterVolatileProvider<DefaultExtensionDependenciesManager, IExtensionDependenciesManager>(builder); 43 RegisterVolatileProvider<DefaultAssemblyProbingFolder, IAssemblyProbingFolder>(builder); 44 RegisterVolatileProvider<DefaultVirtualPathMonitor, IVirtualPathMonitor>(builder); 45 RegisterVolatileProvider<DefaultVirtualPathProvider, IVirtualPathProvider>(builder); 46 47 builder.RegisterType<DefaultOrchardHost>().As<IOrchardHost>().As<IEventHandler>() 48 .Named<IEventHandler>(typeof(IShellSettingsManagerEventHandler).Name) 49 .Named<IEventHandler>(typeof(IShellDescriptorManagerEventHandler).Name) 50 .SingleInstance(); 51 { 52 builder.RegisterType<ShellSettingsManager>().As<IShellSettingsManager>().SingleInstance(); 53 54 builder.RegisterType<ShellContextFactory>().As<IShellContextFactory>().SingleInstance(); 55 { 56 builder.RegisterType<ShellDescriptorCache>().As<IShellDescriptorCache>().SingleInstance(); 57 58 builder.RegisterType<CompositionStrategy>().As<ICompositionStrategy>().SingleInstance(); 59 { 60 builder.RegisterType<ShellContainerRegistrations>().As<IShellContainerRegistrations>().SingleInstance(); 61 builder.RegisterType<ExtensionLoaderCoordinator>().As<IExtensionLoaderCoordinator>().SingleInstance(); 62 builder.RegisterType<ExtensionMonitoringCoordinator>().As<IExtensionMonitoringCoordinator>().SingleInstance(); 63 builder.RegisterType<ExtensionManager>().As<IExtensionManager>().SingleInstance(); 64 { 65 builder.RegisterType<ExtensionHarvester>().As<IExtensionHarvester>().SingleInstance(); 66 builder.RegisterType<ModuleFolders>().As<IExtensionFolders>().SingleInstance() 67 .WithParameter(new NamedParameter("paths", extensionLocations.ModuleLocations)); 68 builder.RegisterType<CoreModuleFolders>().As<IExtensionFolders>().SingleInstance() 69 .WithParameter(new NamedParameter("paths", extensionLocations.CoreLocations)); 70 builder.RegisterType<ThemeFolders>().As<IExtensionFolders>().SingleInstance() 71 .WithParameter(new NamedParameter("paths", extensionLocations.ThemeLocations)); 72 73 builder.RegisterType<CoreExtensionLoader>().As<IExtensionLoader>().SingleInstance(); 74 builder.RegisterType<ReferencedExtensionLoader>().As<IExtensionLoader>().SingleInstance(); 75 builder.RegisterType<PrecompiledExtensionLoader>().As<IExtensionLoader>().SingleInstance(); 76 builder.RegisterType<DynamicExtensionLoader>().As<IExtensionLoader>().SingleInstance(); 77 builder.RegisterType<RawThemeExtensionLoader>().As<IExtensionLoader>().SingleInstance(); 78 } 79 } 80 81 builder.RegisterType<ShellContainerFactory>().As<IShellContainerFactory>().SingleInstance(); 82 } 83 84 builder.RegisterType<DefaultProcessingEngine>().As<IProcessingEngine>().SingleInstance(); 85 } 86 87 builder.RegisterType<RunningShellTable>().As<IRunningShellTable>().SingleInstance(); 88 builder.RegisterType<DefaultOrchardShell>().As<IOrchardShell>().InstancePerMatchingLifetimeScope("shell"); 89 builder.RegisterType<SessionConfigurationCache>().As<ISessionConfigurationCache>().InstancePerMatchingLifetimeScope("shell"); 90 91 registrations(builder); 92 93 var autofacSection = ConfigurationManager.GetSection(ConfigurationSettingsReaderConstants.DefaultSectionName); 94 if (autofacSection != null) 95 builder.RegisterModule(new ConfigurationSettingsReader()); 96 97 var optionalHostConfig = HostingEnvironment.MapPath("~/Config/Host.config"); 98 if (File.Exists(optionalHostConfig)) 99 builder.RegisterModule(new ConfigurationSettingsReader(ConfigurationSettingsReaderConstants.DefaultSectionName, optionalHostConfig)); 100 101 var optionalComponentsConfig = HostingEnvironment.MapPath("~/Config/HostComponents.config"); 102 if (File.Exists(optionalComponentsConfig)) 103 builder.RegisterModule(new HostComponentsConfigModule(optionalComponentsConfig)); 104 105 var container = builder.Build(); 106 107 // 108 // Register Virtual Path Providers 109 // 110 if (HostingEnvironment.IsHosted) { 111 foreach (var vpp in container.Resolve<IEnumerable<ICustomVirtualPathProvider>>()) { 112 HostingEnvironment.RegisterVirtualPathProvider(vpp.Instance); 113 } 114 } 115 116 ControllerBuilder.Current.SetControllerFactory(new OrchardControllerFactory()); 117 FilterProviders.Providers.Add(new OrchardFilterProvider()); 118 119 GlobalConfiguration.Configuration.Services.Replace(typeof(IHttpControllerSelector), new DefaultOrchardWebApiHttpControllerSelector(GlobalConfiguration.Configuration)); 120 GlobalConfiguration.Configuration.Services.Replace(typeof(IHttpControllerActivator), new DefaultOrchardWebApiHttpControllerActivator(GlobalConfiguration.Configuration)); 121 GlobalConfiguration.Configuration.DependencyResolver = new AutofacWebApiDependencyResolver(container); 122 123 GlobalConfiguration.Configuration.Filters.Add(new OrchardApiActionFilterDispatcher()); 124 GlobalConfiguration.Configuration.Filters.Add(new OrchardApiExceptionFilterDispatcher()); 125 GlobalConfiguration.Configuration.Filters.Add(new OrchardApiAuthorizationFilterDispatcher()); 126 127 ViewEngines.Engines.Clear(); 128 ViewEngines.Engines.Add(new ThemeAwareViewEngineShim()); 129 130 var hostContainer = new DefaultOrchardHostContainer(container); 131 //MvcServiceLocator.SetCurrent(hostContainer); 132 OrchardHostContainerRegistry.RegisterHostContainer(hostContainer); 133 134 // Register localized data annotations 135 ModelValidatorProviders.Providers.Clear(); 136 ModelValidatorProviders.Providers.Add(new LocalizedModelValidatorProvider()); 137 138 return container; 139 }
代码很长，但是可以分为以下几个部分：
- 基础组件：日志、事件、缓存
- 环境相关：路径、程序集、编译器，Http上下文
- 异常处理：异常策略
- 拓展相关：拓展目录、拓展依赖、拓展管理。
- 多租户相关：Shell表、Shell启动。
- 拓展的依赖注入：拓展模块中的自定义注入、Host及HostComponents配置文件的注入。
- MVC相关：ControllerFactory替换，过滤器加载
- WebAPI相关：Selector、Activator替换，DependencyResolver替换、过滤器加载
- ViewEngine：使用ThemeAwareViewEngineShim。
- Model相关：使用LocalizedModelValidatorProvider作为Model验证器。
相对特殊的地方有：
- 日志的自动属性注入：
Orchard使用Autofac实现了日志的属性自动注入，具体代码如下：
1 protected override void AttachToComponentRegistration(IComponentRegistry componentRegistry, IComponentRegistration registration) { 2 var implementationType = registration.Activator.LimitType; 3 4 // build an array of actions on this type to assign loggers to member properties 5 var injectors = BuildLoggerInjectors(implementationType).ToArray(); 6 7 // if there are no logger properties, there's no reason to hook the activated event 8 if (!injectors.Any()) 9 return; 10 11 // otherwise, whan an instance of this component is activated, inject the loggers on the instance 12 registration.Activated += (s, e) => { 13 foreach (var injector in injectors) 14 injector(e.Context, e.Instance); 15 }; 16 } 17 18 private IEnumerable<Action<IComponentContext, object>> BuildLoggerInjectors(Type componentType) { 19 // Look for settable properties of type "ILogger" 20 var loggerProperties = componentType 21 .GetProperties(BindingFlags.SetProperty | BindingFlags.Public | BindingFlags.Instance) 22 .Select(p => new { 23 PropertyInfo = p, 24 p.PropertyType, 25 IndexParameters = p.GetIndexParameters(), 26 Accessors = p.GetAccessors(false) 27 }) 28 .Where(x => x.PropertyType == typeof(ILogger)) // must be a logger 29 .Where(x => x.IndexParameters.Count() == 0) // must not be an indexer 30 .Where(x => x.Accessors.Length != 1 || x.Accessors[0].ReturnType == typeof(void)); //must have get/set, or only set 31 32 // Return an array of actions that resolve a logger and assign the property 33 foreach (var entry in loggerProperties) { 34 var propertyInfo = entry.PropertyInfo; 35 36 yield return (ctx, instance) => { 37 string component = componentType.ToString(); 38 if (component != instance.GetType().ToString()) { 39 return; 40 } 41 var logger = _loggerCache.GetOrAdd(component, key => ctx.Resolve<ILogger>(new TypedParameter(typeof(Type), componentType))); 42 propertyInfo.SetValue(instance, logger, null); 43 }; 44 } 45 }
其实它的核心就是注册时通过对象类型查找是否有一个类型为Ilogger的可读写属性，拿出来赋值。
2. 通过动态代理实现的事件机制：
在.Net中提到事件就会想到委托，但是Orchard的事件比较特殊，它将事件定义为一个接口(实现IEventHandler的接口)，对于生产者(事件发布者)它仅需要通过Orchard的容器注入一个相应接口类型即可，而观察者(事件的真实处理器)则仅需要实现相应接口即可(其余框架会自动处理)。
对.Net的委托不了解的可参考张子阳老师的博客：http://www.cnblogs.com/JimmyZhang/archive/2007/09/23/903360.html
Orchard事件的使用如下(使用张子阳老师例子改了一下)：
1 public interface IBoilHandler : IEventHandler 2 { 3 void OnTemperatureChanged(int temperature); 4 } 5 6 // 热水器 7 public class Heater 8 { 9 private int temperature; 10 private IBoilHandler _boilhandler; 11 12 public Heater(IBoilHandler boilhandler) 13 { 14 _boilhandler = boilhandler; 15 } 16 17 // 烧水 18 public void BoilWater() 19 { 20 for (int i = 0; i <= 100; i++) 21 { 22 temperature = i; 23 24 if (temperature > 95) 25 { 26 if (_boilhandler != null) 27 { //如果有对象注册 28 _boilhandler.OnTemperatureChanged(temperature); //调用所有注册对象的方法 29 } 30 } 31 } 32 } 33 } 34 35 // 警报器 36 public class Alarm : IBoilHandler 37 { 38 public void OnTemperatureChanged(int temperature) 39 { 40 Console.WriteLine("Alarm：嘀嘀嘀，水已经 {0} 度了：", temperature); 41 } 42 } 43 44 // 显示器 45 public class Display : IBoilHandler 46 { 47 public void OnTemperatureChanged(int temperature) 48 { 49 Console.WriteLine("Display：水快烧开了，当前温度：{0}度。", temperature); 50 } 51 }
那么这是如何实现的呢？
两个要点：
1. 在注册服务时将所有通过继承IEventhandler的子接口(如上面代码的IBoilHandler)通过动态代理，将相应接口的方法执行全部拦截并转到EventBus上，调用Notify方法，其参数为当前接口名称+方法名称和相应的参数。--生产者
1 public class EventsRegistrationSource : IRegistrationSource { 2 private readonly DefaultProxyBuilder _proxyBuilder; 3 4 public EventsRegistrationSource() { 5 _proxyBuilder = new DefaultProxyBuilder(); 6 } 7 8 public bool IsAdapterForIndividualComponents { 9 get { return false; } 10 } 11 12 public IEnumerable<IComponentRegistration> RegistrationsFor(Service service, Func<Service, IEnumerable<IComponentRegistration>> registrationAccessor) { 13 var serviceWithType = service as IServiceWithType; 14 if (serviceWithType == null) 15 yield break; 16 17 var serviceType = serviceWithType.ServiceType; 18 if (!serviceType.IsInterface || !typeof(IEventHandler).IsAssignableFrom(serviceType) || serviceType == typeof(IEventHandler)) 19 yield break; 20 21 var interfaceProxyType = _proxyBuilder.CreateInterfaceProxyTypeWithoutTarget( 22 serviceType, 23 new Type[0], 24 ProxyGenerationOptions.Default); 25 26 27 var rb = RegistrationBuilder 28 .ForDelegate((ctx, parameters) => { 29 var interceptors = new IInterceptor[] { new EventsInterceptor(ctx.Resolve<IEventBus>()) }; 30 var args = new object[] { interceptors, null }; 31 return Activator.CreateInstance(interfaceProxyType, args); 32 }) 33 .As(service); 34 35 yield return rb.CreateRegistration(); 36 } 37 } 38 39 public class EventsInterceptor : IInterceptor { 40 private readonly IEventBus _eventBus; 41 private static readonly ConcurrentDictionary<Type,MethodInfo> _enumerableOfTypeTDictionary = new ConcurrentDictionary<Type, MethodInfo>(); 42 43 public EventsInterceptor(IEventBus eventBus) { 44 _eventBus = eventBus; 45 } 46 47 public void Intercept(IInvocation invocation) { 48 var interfaceName = invocation.Method.DeclaringType.Name; 49 var methodName = invocation.Method.Name; 50 51 var data = invocation.Method.GetParameters() 52 .Select((parameter, index) => new { parameter.Name, Value = invocation.Arguments[index] }) 53 .ToDictionary(kv => kv.Name, kv => kv.Value); 54 55 var results = _eventBus.Notify(interfaceName + "." + methodName, data); 56 57 invocation.ReturnValue = Adjust(results, invocation.Method.ReturnType); 58 } 59 60 public static object Adjust(IEnumerable results, Type returnType) { 61 if (returnType == typeof(void) || 62 results == null || 63 results.GetType() == returnType) { 64 return results; 65 } 66 67 // acquire method: 68 // static IEnumerable<T> IEnumerable.OfType<T>(this IEnumerable source) 69 // where T is from returnType's IEnumerable<T> 70 var enumerableOfTypeT = _enumerableOfTypeTDictionary.GetOrAdd( returnType, type => typeof(Enumerable).GetGenericMethod("OfType", type.GetGenericArguments(), new[] { typeof(IEnumerable) }, typeof(IEnumerable<>))); 71 return enumerableOfTypeT.Invoke(null, new[] { results }); 72 } 73 }
上面代码有个重点就是：
1 if (!serviceType.IsInterface || !typeof(IEventHandler).IsAssignableFrom(serviceType) || serviceType == typeof(IEventHandler)) 2 yield break;
如果不是接口、如果类型不是IEventHandler的子类型(子接口)且当前类型就是IEventHandler，满足这三个接口就跳出。正过来说就是：
- 类型一定是接口
- 一定是继承IEventHandler的接口
- 一定不是IEventHandler本身
2. 把所有实现了IEventHandler的实现全部解析到EventBus的_eventHandlers字段中。 --消费者
换句话说就是，当应用程序初始化的时候EventBus里面的处理器都已经被加载了，但真正触发事件时，仅仅是通过拦截器将相应接口的方法转到了Notify方法上，进而去通知相应的Handlers执行。
下面代码位于ShellContainerFactory.cs文件中
1 if (typeof(IEventHandler).IsAssignableFrom(item.Type)) { 2 var interfaces = item.Type.GetInterfaces(); 3 foreach (var interfaceType in interfaces) { 4 5 // register named instance for each interface, for efficient filtering inside event bus 6 // IEventHandler derived classes only 7 if (interfaceType.GetInterface(typeof (IEventHandler).Name) != null) { 8 registration = registration.Named<IEventHandler>(interfaceType.Name); 9 } 10 } 11 }
3. ICacheManager的注入：
ICacheManager的特殊之处就在于依赖它的对象在通过构造注入ICacheManager会将当前对象作为参数来实例化ICacheManager。
1 protected override void AttachToComponentRegistration(Autofac.Core.IComponentRegistry componentRegistry, Autofac.Core.IComponentRegistration registration) { 2 var needsCacheManager = registration.Activator.LimitType 3 .GetConstructors() 4 .Any(x => x.GetParameters() 5 .Any(xx => xx.ParameterType == typeof(ICacheManager))); 6 7 if (needsCacheManager) { 8 registration.Preparing += (sender, e) => { 9 var parameter = new TypedParameter( 10 typeof(ICacheManager), 11 e.Context.Resolve<ICacheManager>(new TypedParameter(typeof(Type), registration.Activator.LimitType))); 12 e.Parameters = e.Parameters.Concat(new[] { parameter }); 13 }; 14 } 15 }
小结：
本章主要是分析了Orchard中IoC容器的创建以及基础设施的注册，其中对Log、Event和CacheManager进行了特殊处理，并且处理方式均是使用Autofac提供的一系列特性，动态的对注册的组件进行额外操作，另外在Orchard中它还针对Shell级别创建了一个子容器，所以后续将对Orchard的依赖注入进一步分析。
参考：