Orchard详解--第三篇依赖注入之基础设施-白红宇

Orchard详解--第三篇依赖注入之基础设施

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发布时间：2019-06-15

本文共 17841 字，大约阅读时间需要 59 分钟。

　　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
      
        registrations) {2             var container = CreateHostContainer(registrations);3             return container.Resolve
       
        ();4         }

以下是容器创建的全量代码：

1         public static IContainer CreateHostContainer(Action
       
         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
        
         ().As
         
          ().SingleInstance(); 15             builder.RegisterType
          
           ().As
           
            ().SingleInstance(); 16             builder.RegisterType
            
             ().As
             
              ().SingleInstance(); 17             builder.RegisterType
              
               ().As
               
                ().SingleInstance(); 18             builder.RegisterType
                
                 ().As
                 
                  ().SingleInstance(); 19             builder.RegisterType
                  
                   ().As
                   
                    ().SingleInstance(); 20             builder.RegisterType
                    
                     ().As
                     
                      ().Named
                      
                       (typeof(IShellSettingsManagerEventHandler).Name).SingleInstance(); 21             builder.RegisterType
                       
                        ().As
                        
                         ().SingleInstance(); 22             builder.RegisterType
                         
                          ().As
                          
                           ().SingleInstance(); 23             builder.RegisterType
                           
                            ().As
                            
                             ().SingleInstance(); 24             builder.RegisterType
                             
                              ().As
                              
                               ().SingleInstance(); 25             builder.RegisterType
                               
                                ().As
                                
                                 ().SingleInstance(); 26             builder.RegisterType
                                 
                                  ().As
                                  
                                   ().SingleInstance(); 27             builder.RegisterType
                                   
                                    ().As
                                    
                                     ().SingleInstance(); 28             builder.RegisterType
                                     
                                      ().As
                                      
                                       ().SingleInstance(); 29             builder.RegisterType
                                       
                                        ().As
                                        
                                         ().SingleInstance(); 30             builder.RegisterType
                                         
                                          ().As
                                          
                                           ().SingleInstance(); 31             builder.RegisterType
                                           
                                            ().As
                                            
                                             ().InstancePerDependency(); 32             builder.RegisterType
                                             
                                              ().As
                                              
                                               ().SingleInstance(); 33             builder.RegisterType
                                               
                                                ().As
                                                
                                                 ().SingleInstance(); 34             builder.RegisterType
                                                 
                                                  ().As
                                                  
                                                   ().SingleInstance(); 35             //builder.RegisterType
                                                   
                                                    ().As
                                                    
                                                     ().SingleInstance(); 36   37             RegisterVolatileProvider
                                                     
                                                      (builder); 38             RegisterVolatileProvider
                                                      
                                                       (builder); 39             RegisterVolatileProvider
                                                       
                                                        (builder); 40             RegisterVolatileProvider
                                                        
                                                         (builder); 41             RegisterVolatileProvider
                                                         
                                                          (builder); 42             RegisterVolatileProvider
                                                          
                                                           (builder); 43             RegisterVolatileProvider
                                                           
                                                            (builder); 44             RegisterVolatileProvider
                                                            
                                                             (builder); 45             RegisterVolatileProvider
                                                             
                                                              (builder); 46             47             builder.RegisterType
                                                              
                                                               ().As
                                                               
                                                                ().As
                                                                
                                                                 () 48                 .Named
                                                                 
                                                                  (typeof(IShellSettingsManagerEventHandler).Name) 49                 .Named
                                                                  
                                                                   (typeof(IShellDescriptorManagerEventHandler).Name) 50                 .SingleInstance(); 51             { 52                 builder.RegisterType
                                                                   
                                                                    ().As
                                                                    
                                                                     ().SingleInstance(); 53   54                 builder.RegisterType
                                                                     
                                                                      ().As
                                                                      
                                                                       ().SingleInstance(); 55                 { 56                     builder.RegisterType
                                                                       
                                                                        ().As
                                                                        
                                                                         ().SingleInstance(); 57   58                     builder.RegisterType
                                                                         
                                                                          ().As
                                                                          
                                                                           ().SingleInstance(); 59                     { 60                         builder.RegisterType
                                                                           
                                                                            ().As
                                                                            
                                                                             ().SingleInstance(); 61                         builder.RegisterType
                                                                             
                                                                              ().As
                                                                              
                                                                               ().SingleInstance(); 62                         builder.RegisterType
                                                                               
                                                                                ().As
                                                                                
                                                                                 ().SingleInstance(); 63                         builder.RegisterType
                                                                                 
                                                                                  ().As
                                                                                  
                                                                                   ().SingleInstance(); 64                         { 65                             builder.RegisterType
                                                                                   
                                                                                    ().As
                                                                                    
                                                                                     ().SingleInstance(); 66                             builder.RegisterType
                                                                                     
                                                                                      ().As
                                                                                      
                                                                                       ().SingleInstance() 67                                 .WithParameter(new NamedParameter("paths", extensionLocations.ModuleLocations)); 68                             builder.RegisterType
                                                                                       
                                                                                        ().As
                                                                                        
                                                                                         ().SingleInstance() 69                                 .WithParameter(new NamedParameter("paths", extensionLocations.CoreLocations)); 70                             builder.RegisterType
                                                                                         
                                                                                          ().As
                                                                                          
                                                                                           ().SingleInstance() 71                                 .WithParameter(new NamedParameter("paths", extensionLocations.ThemeLocations)); 72   73                             builder.RegisterType
                                                                                           
                                                                                            ().As
                                                                                            
                                                                                             ().SingleInstance(); 74                             builder.RegisterType
                                                                                             
                                                                                              ().As
                                                                                              
                                                                                               ().SingleInstance(); 75                             builder.RegisterType
                                                                                               
                                                                                                ().As
                                                                                                
                                                                                                 ().SingleInstance(); 76                             builder.RegisterType
                                                                                                 
                                                                                                  ().As
                                                                                                  
                                                                                                   ().SingleInstance(); 77                             builder.RegisterType
                                                                                                   
                                                                                                    ().As
                                                                                                    
                                                                                                     ().SingleInstance(); 78                         } 79                     } 80   81                     builder.RegisterType
                                                                                                     
                                                                                                      ().As
                                                                                                      
                                                                                                       ().SingleInstance(); 82                 } 83   84                 builder.RegisterType
                                                                                                       
                                                                                                        ().As
                                                                                                        
                                                                                                         ().SingleInstance(); 85             } 86   87             builder.RegisterType
                                                                                                         
                                                                                                          ().As
                                                                                                          
                                                                                                           ().SingleInstance(); 88             builder.RegisterType
                                                                                                           
                                                                                                            ().As
                                                                                                            
                                                                                                             ().InstancePerMatchingLifetimeScope("shell"); 89             builder.RegisterType
                                                                                                             
                                                                                                              ().As
                                                                                                              
                                                                                                               ().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 Providers109             //110             if (HostingEnvironment.IsHosted) {111                 foreach (var vpp in container.Resolve
                                                                                                               
                                                                                                                
                                                                                                                 >()) {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 annotations135             ModelValidatorProviders.Providers.Clear();136             ModelValidatorProviders.Providers.Add(new LocalizedModelValidatorProvider());137  138             return container;139         }

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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

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 instance12             registration.Activated += (s, e) => {13                 foreach (var injector in injectors)14                     injector(e.Context, e.Instance);15             };16         }17  18         private IEnumerable
       
        
         > BuildLoggerInjectors(Type componentType) {19             // Look for settable properties of type "ILogger"20             var loggerProperties = componentType21                 .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 logger29                 .Where(x => x.IndexParameters.Count() == 0) // must not be an indexer30                 .Where(x => x.Accessors.Length != 1 || x.Accessors[0].ReturnType == typeof(void)); //must have get/set, or only set31  32             // Return an array of actions that resolve a logger and assign the property33             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
         
          (new TypedParameter(typeof(Type), componentType)));42                     propertyInfo.SetValue(instance, logger, null);43                 };44             }45         }

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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：

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 : IBoilHandler37         {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 : IBoilHandler46         {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
       
         RegistrationsFor(Service service, Func
        
         > 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 = RegistrationBuilder28                 .ForDelegate((ctx, parameters) => {29                     var interceptors = new IInterceptor[] { new EventsInterceptor(ctx.Resolve
         
          ()) };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
          
            _enumerableOfTypeTDictionary = new ConcurrentDictionary
           
            ();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
            
              IEnumerable.OfType
             
              (this IEnumerable source)69             // where T is from returnType's IEnumerable
              
               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     }

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　　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
      
       (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
      
       (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：

转载于:https://www.cnblogs.com/selimsong/p/5999181.html

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