WCF利用企业库Unity框架的IOC层次解耦

     由于工作几个月来框架开发已经好久没写博客了，今天想抽点时间出来冒泡。在领域驱动开发中SOA已经成为我们开发的主流技术，在面对当前众多的UI框架选择（asp.net mvc,silverlight,wpf,winform,wp7等一些列甚至跨语言），我们能够重用和抽象的业务逻辑是不会变化的，为了屏蔽这些UI的复杂性和差异性，我们可能会采用诸如wcf soap的服务发布。再说在领域驱动开发中我们肯定会把各个逻辑分层次隔离解除耦合，这就出现了N层架构，在于我们的每一层次之间的耦合度当前流程的解决方案IOC框架，以及业务解耦AOP。这里要解决的是SOA框架WCF和IOC框架的结合。

    WCF框架是一个极易扩展的框架，提供了非常多的扩展点（InstanceProvider，MessageInspector，CallContextInitializer，MessageFilter，MessageFormatter，ParameterInspector等等）。在这里IOC是作为一个容器组装创建的框架，我们需要的是对服务对象的创建，所以我们选择的当然是InstanceProvider扩展点。

     多说一句废话，正如前篇利用Attribute简化Unity框架IOC注入和 AOP之PostSharp7-解决IOC 不能直接new问题，简化IOC开发和IOC对象LazyLoad中所说，我是一个固执的人，个人希望注入支持自定义配置文件，不喜欢把配置信息全部写在一个web.config/app.config中，也不喜欢el的写在同一个外部配置文件中，倾向于每个模块在一个不同的配置文件，并在模块中在区分container容器，所以特别写了每个单独配置文件的延时加载，缓存。

      下面就是对InstanceProvider的扩展：

public class ELUnityInstanceProvider : IInstanceProvider 
   { 
       private Type contractType; 
       private string container; 
       private string configFile; 
       private string name; 
       private static object lockObj = new object(); 
       private static Dictionary<string, UnityConfigurationSection> sectionDict = new Dictionary<string, UnityConfigurationSection>(); 

       public ELUnityInstanceProvider(Type contractType, string container, string configFile, string name) 
       { 
           this.name = name; 
           this.configFile = configFile; 
           this.contractType = contractType; 
           this.container = container; 
       } 

       #region IInstanceProvider 成员 

       public object GetInstance(System.ServiceModel.InstanceContext instanceContext, System.ServiceModel.Channels.Message message) 
       { 
           Microsoft.Practices.Unity.Configuration.UnityConfigurationSection unitySection = GetUnityConfigurationSection(); 

           if (unitySection != null) 
           { 
               var container = new Microsoft.Practices.Unity.UnityContainer().LoadConfiguration(unitySection, string.IsNullOrEmpty(this.container) ? unitySection.Containers.Default.Name : this.container); 
               var obj = string.IsNullOrEmpty(this.name) ? container.Resolve(this.contractType) : container.Resolve(this.contractType, this.name); 

               var piabAtttr = obj.GetType().GetCustomAttributes(typeof(ELPolicyinjectionAttribute), false) as ELPolicyinjectionAttribute[]; 
               if (piabAtttr.Length > 0) 
               { 
                   obj = Microsoft.Practices.EnterpriseLibrary.PolicyInjection.PolicyInjection.Wrap(this.contractType, obj); 
               } 
               return obj; 
           } 
           return null; 
       } 
       private Microsoft.Practices.Unity.Configuration.UnityConfigurationSection GetUnityConfigurationSection() 
       { 
           if (!string.IsNullOrEmpty(this.configFile)) 
           { 
               if (!sectionDict.ContainsKey(this.configFile)) 
               { 
                   lock (lockObj) 
                   { 
                       if (!sectionDict.ContainsKey(this.configFile)) 
                       { 
                           Microsoft.Practices.Unity.Configuration.UnityConfigurationSection unitySection = null; 
                           var fileMap = new System.Configuration.ExeConfigurationFileMap { ExeConfigFilename = System.IO.Path.Combine(System.AppDomain.CurrentDomain.BaseDirectory, this.configFile) }; 
                           System.Configuration.Configuration configuration = System.Configuration.ConfigurationManager.OpenMappedExeConfiguration(fileMap, System.Configuration.ConfigurationUserLevel.None); 
                           unitySection = configuration == null ? null : configuration.GetSection(Microsoft.Practices.Unity.Configuration.UnityConfigurationSection.SectionName) as Microsoft.Practices.Unity.Configuration.UnityConfigurationSection; 
                           if (unitySection == null) 
                               return null; 
                           sectionDict.Add(this.configFile, unitySection); 
                       } 
                   } 
               } 
               return sectionDict[this.configFile]; 
           } 

           return System.Configuration.ConfigurationManager.GetSection(Microsoft.Practices.Unity.Configuration.UnityConfigurationSection.SectionName) as Microsoft.Practices.Unity.Configuration.UnityConfigurationSection; 

       } 

       public object GetInstance(System.ServiceModel.InstanceContext instanceContext) 
       { 
           return this.GetInstance(instanceContext, null); 
       } 

       public void ReleaseInstance(System.ServiceModel.InstanceContext instanceContext, object instance) 
       { 
           IDisposable disposable = instance as IDisposable; 
           if (disposable != null) 
           { 
               disposable.Dispose(); 
           } 
           instance = null; 
       } 

       #endregion 
   }

     下面我们需要已Attribute方式贴在Contract上：

public class ELUnityBehaviorAttribute : Attribute, IContractBehavior 
   { 
       public string Container 
       { 
           get; 
           set; 
       } 

       public string ConfigFile 
       { 
           get; 
           set; 
       } 

       public string Name 
       { 
           get; 
           set; 
       } 

       #region IContractBehavior 成员 

       public void AddBindingParameters(ContractDescription contractDescription, ServiceEndpoint endpoint, System.ServiceModel.Channels.BindingParameterCollection bindingParameters) 
       { 

       } 

       public void ApplyClientBehavior(ContractDescription contractDescription, ServiceEndpoint endpoint, System.ServiceModel.Dispatcher.ClientRuntime clientRuntime) 
       { 

       } 

       public void ApplyDispatchBehavior(ContractDescription contractDescription, ServiceEndpoint endpoint, System.ServiceModel.Dispatcher.DispatchRuntime dispatchRuntime) 
       { 
           dispatchRuntime.InstanceProvider = new ELUnityInstanceProvider(contractDescription.ContractType, this.Container, this.ConfigFile, this.Name); 
       } 

       public void Validate(ContractDescription contractDescription, ServiceEndpoint endpoint) 
       { 
       } 

       #endregion 
   }

 

     对于wcf同时我们也该支持配置文件扩展：

public class ELUnityBehaviorElement : BehaviorExtensionElement 
   { 
       [ConfigurationProperty("Container", IsRequired = false, DefaultValue = "")] 
       public string Container 
       { 
           get; 
           set; 
       } 

       [ConfigurationProperty("ConfigFile", IsRequired = false, DefaultValue = "")] 
       public string ConfigFile 
       { 
           get; 
           set; 
       } 

       [ConfigurationProperty("Name", IsRequired = false, DefaultValue = "")] 
       public string Name 
       { 
           get; 
           set; 
       } 

       protected override object CreateBehavior() 
       { 
           return new ELUnityBehavior(this.Container, this.ConfigFile, this.Name); 
       } 

       public override Type BehaviorType 
       { 
           get { return typeof(ELUnityBehavior); } 
       } 
   }

public class ELUnityBehavior : IEndpointBehavior 
   { 
       public string Container 
       { 
           get; 
           set; 
       } 

       public string ConfigFile 
       { 
           get; 
           set; 
       } 

       public string Name 
       { 
           get; 
           set; 
       } 

       public ELUnityBehavior(string container, string configFile, string name) 
       { 
           this.Name = name; 
           this.ConfigFile = configFile; 
           this.Container = container; 
       } 
       #region IEndpointBehavior 成员 

       public void AddBindingParameters(ServiceEndpoint endpoint, System.ServiceModel.Channels.BindingParameterCollection bindingParameters) 
       { 

       } 

       public void ApplyClientBehavior(ServiceEndpoint endpoint, System.ServiceModel.Dispatcher.ClientRuntime clientRuntime) 
       { 

       } 

       public void ApplyDispatchBehavior(ServiceEndpoint endpoint, System.ServiceModel.Dispatcher.EndpointDispatcher endpointDispatcher) 
       { 
           endpointDispatcher.DispatchRuntime.InstanceProvider = new ELUnityInstanceProvider(endpoint.Contract.ContractType, this.Container, this.ConfigFile, this.Name); 
       } 

       public void Validate(ServiceEndpoint endpoint) 
       { 

       } 

       #endregion 
   }

目前我们已经简单实现了：看看测试：

Contract：

   [ServiceContract()] 
   [Green.WCFExtensions.ELUnityBehavior(Container = "test", ConfigFile = "App1.config")]   
  public interface IHelloService 
  { 
      [OperationContract] 
      string Say(string name); 
  }

Service：

public class HelloService1 : IHelloService 
   { 
       [Microsoft.Practices.Unity.Dependency("proxy")] 
       public IHelloService Service 
       { 
           get; 
           set; 
       } 

       #region IHelloService 成员 
          public string Say(string name) 
       { 
                     return Service.Say(name); 

       } 

       #endregion 
   } 

   public class HelloServiceProxy : IHelloService 
   { 
       #region IHelloService 成员 
       public string Say(string name) 
       { 
           return string.Format("Hello:{0}", name); 
       } 

       #endregion 
   }

配置app1.config:

<register type="WcfService.IHelloService,WcfService" mapTo="WcfService.HelloServiceProxy,WcfService"  name="proxy"> </register> 
<register type="WcfService.IHelloService,WcfService" mapTo="WcfService.HelloService1,WcfService" > </register>

IOC,AOP博客参考：

AOP之PostSharp初见-OnExceptionAspect

AOP之PostSharp2-OnMethodBoundaryAspect

AOP之PostSharp3-MethodInterceptionAspect

AOP之PostSharp4-实现类INotifyPropertyChanged植入

AOP之PostSharp5-LocationInterceptionAspect

AOP之PostSharp6-EventInterceptionAspect

AOP之PostSharp7-解决IOC 不能直接new问题，简化IOC开发和IOC对象LazyLoad

http://www.cnblogs.com/whitewolf/category/312638.html

利用Attribute简化Unity框架IOC注入