实现WCF和Unity 的集成-CFANZ编程社区

Artech 已经写过一篇[原创]WCF后续之旅（7）：通过WCF Extension实现和Enterprise Library Unity Container的集成，在这个解决方案中Unity的侵入性有点强，本文介绍一种具有更少的侵入性的解决方案。

第一步：创建一个自定义的InstanceProvider 来处理WCF服务。

InstanceProvider就是用于创建或者提供service instance的。除了提供service instance的创建者或者提供者的身份外，InstanceProvider还用于service instance的释放和回收。所有的IntanceProvider实现了System.ServiceModel.Dispatcher.IInstanceProvider 接口：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using Microsoft.Practices.Unity;

using System.ServiceModel.Dispatcher;

using System.ServiceModel;

using System.ServiceModel.Channels;
namespace Tencent.OA.Framework.ServiceModel

{

    public class UnityInstanceProvider : IInstanceProvider

    {
        public UnityContainer Container { set; get; }

        public Type ServiceType { set; get; }
        public UnityInstanceProvider()

            : this(null)

        {
        }

        public UnityInstanceProvider(Type type)

        {
            ServiceType = type;

            Container = new UnityContainer();
        }

        #region IInstanceProvider Members

        public object GetInstance(InstanceContext instanceContext, Message message)

        {

            return Container.Resolve(ServiceType);

        }
        public object GetInstance(InstanceContext instanceContext)

        {

            return GetInstance(instanceContext, null);

        }
        public void ReleaseInstance(InstanceContext instanceContext, object instance)

        {
        }

        #endregion

    }

}

可以看到GetInstance方法用来获取服务实例，通过Unity的Resolve方法解析。

第二步：创建UnityInstanceProvider对应的Behavior

第一步已经创建了自定义的UnityInstanceProvider，现在需要在运行时插入我们这个新的Provider，这项工作可以通过IServiceProvider（定义一种检索服务对象的机制，服务对象是为其他对象提供自定义支持的对象）来完成。

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.ServiceModel.Dispatcher;

using System.ServiceModel.Description;

using System.ServiceModel;

using System.Collections.ObjectModel;

using System.ServiceModel.Channels;

using Microsoft.Practices.Unity;
namespace Tencent.OA.Framework.ServiceModel

{

    public class UnityServiceBehavior : IServiceBehavior

    {
        public UnityInstanceProvider InstanceProvider

        { get; set; }

        private ServiceHost serviceHost = null;

        public UnityServiceBehavior()

        {
            InstanceProvider = new UnityInstanceProvider();

        }

        public UnityServiceBehavior(UnityContainer unity)

        {

            InstanceProvider = new UnityInstanceProvider();

            InstanceProvider.Container = unity;
        }

        public void ApplyDispatchBehavior(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)

        {
            foreach (ChannelDispatcherBase cdb in serviceHostBase.ChannelDispatchers)

            {
                ChannelDispatcher cd = cdb as ChannelDispatcher;

                if (cd != null)

                {
                    foreach (EndpointDispatcher ed in cd.Endpoints)

                    {

                        InstanceProvider.ServiceType = serviceDescription.ServiceType;

                        ed.DispatchRuntime.InstanceProvider = InstanceProvider;

                    }
                }

            }

        }

        public void Validate(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase) 

        { }
        public void AddBindingParameters(ServiceDescription serviceDescription,ServiceHostBase serviceHostBase,Collection<ServiceEndpoint> endpoints,

            BindingParameterCollection bindingParameters)

        {
        }

    }

}

当调用ApplyDispatchBehav

iour，代码通过循环收集在我们的项目Endpoints，并传递给相应的服务类型的InstanceProvider。

第三步：创建自定义的增加新的Behavior的 Service Host

ServiceHost 提供了基本的“加载服务，配置endpoints，应用安全设置以及启动监听请求”机制。通过自定义一个ServiceHost将我们自己的Behavior添加进去。

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.ServiceModel;

using Microsoft.Practices.Unity;
namespace Tencent.OA.Framework.ServiceModel

{

    public class UnityServiceHost : ServiceHost

    {
        public UnityContainer Container { set; get; }

        public UnityServiceHost()

            : base()

        {

            Container = new UnityContainer();

        }
        public UnityServiceHost(Type serviceType, params Uri[] baseAddresses)

            : base(serviceType, baseAddresses)

        {
            Container = new UnityContainer();

        }

        protected override void OnOpening()

        {
            if (this.Description.Behaviors.Find<UnityServiceBehavior>() == null)

                this.Description.Behaviors.Add(new UnityServiceBehavior(Container));
            base.OnOpening();

        }
    }

}

当Service Host启动的时候，它就会检查我们的UnityServiceBehavior是否已经添加到Behaviors里面，如果没有就把它加入到Behaviors集合。

第四步：创建自定义的ServiceHostFactory

如果只是承载在Console Application、Windows Service或者其他非Web应用程序，我们的工作已经完成了。但在Web的.svc中，ServiceHost是动态创建的，没有显示的指定ServiceHost的Factory,那它在默认情况下是使用ServiceHostFactory的，而ServiceHostFactory产生的是ServiceHost对象，想要使用我们上一步中自定义的UnityServiceHost ，需要实现一个自定义的ServcieHostFactory,实现代码非常简单：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using Microsoft.Practices.Unity.Configuration;

using Microsoft.Practices.Unity;

using System.ServiceModel.Activation;

using System.ServiceModel;

using System.Configuration;
namespace Tencent.OA.Framework.ServiceModel

{

    public class UnityServiceHostFactory : ServiceHostFactory

    {
        protected override ServiceHost CreateServiceHost(

                                    Type serviceType, Uri[] baseAddresses)

        {
            UnityServiceHost serviceHost = new UnityServiceHost(serviceType, baseAddresses);

            UnityContainer container = new UnityContainer();

            serviceHost.Container = container;

            //configure container 

            UnityConfigurationSection section = (UnityConfigurationSection)ConfigurationManager.GetSection("unity");

            section.Containers.Default.Configure(serviceHost.Container);

            return serviceHost;
        }

    }

}