// 重写抽象类的DiscoveryProxy的abstract方法。 
[ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Multiple)] 
         public  class DiscoveryProxyService : DiscoveryProxy 
        { 
                 // 存储服务地址和元数据信息 
                Dictionary<EndpointAddress, EndpointDiscoveryMetadata> onlineServices; 
                 public DiscoveryProxyService() 
                { 
                         this.onlineServices =  new Dictionary<EndpointAddress, EndpointDiscoveryMetadata>(); 
                } 
                 // 接收到服务通告消息调用OnBeginOnlineAnnouncement 
                 protected  override IAsyncResult OnBeginOnlineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback,  object state) 
                {                 
                         this.AddOnlineService(endpointDiscoveryMetadata); 
                         return  new OnOnlineAnnouncementAsyncResult(callback, state); 
                } 
                 // 接收到离线消息时候调用OnBeginOfflineAnnouncement    
                 protected  override IAsyncResult OnBeginOfflineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback,  object state) 
                { 
                         this.RemoveOnlineService(endpointDiscoveryMetadata); 
                         return  new OnOfflineAnnouncementAsyncResult(callback, state); 
                } 
                 // 接受到查找消息调用OnBeginFind    
                 protected  override IAsyncResult OnBeginFind(FindRequestContext findRequestContext, AsyncCallback callback,  object state) 
                { 
                         this.MatchFromOnlineService(findRequestContext); 
                         return  new OnFindAsyncResult(callback, state); 
                } 
                 //新增服务 
                 void AddOnlineService(EndpointDiscoveryMetadata endpointDiscoveryMetadata) 
                { 
                         lock ( this.onlineServices) 
                        { 
                                 this.onlineServices[endpointDiscoveryMetadata.Address] = endpointDiscoveryMetadata;                                 
                        } 
 
                        PrintDiscoveryMetadata(endpointDiscoveryMetadata,  "Adding"); 
                } 
　　　　 //移除服务 
                 void RemoveOnlineService(EndpointDiscoveryMetadata endpointDiscoveryMetadata) 
                { 
                         if (endpointDiscoveryMetadata !=  null) 
                        { 
                                 lock ( this.onlineServices) 
                                { 
                                         this.onlineServices.Remove(endpointDiscoveryMetadata.Address);                                         
                                } 
                                PrintDiscoveryMetadata(endpointDiscoveryMetadata,  "Removing"); 
                        }         
                } 
              //打印服务 
                 void PrintDiscoveryMetadata(EndpointDiscoveryMetadata endpointDiscoveryMetadata,  string verb) 
                { 
                        Console.WriteLine( "********<" + verb +  " service of the following type"); 
                         foreach (XmlQualifiedName contractName  in endpointDiscoveryMetadata.ContractTypeNames) 
                        { 
                                Console.WriteLine( "********" + contractName.ToString()); 
                                 break; 
                        } 
                        Console.WriteLine( "********Done"); 
                } 
}

public  static  void Main() 
                { 
                         //添加客户端探测消息地址 
                        Uri probeEndpointAddress =  new Uri( "http://localhost:9001/Probe"); 

                        //添加服务端通告地址 

                        Uri announcementEndpointAddress = new Uri("http://localhost:9002/Announcement"); 

                        // 托管DiscoveryProxy 服务 

                        ServiceHost proxyServiceHost = new ServiceHost(new DiscoveryProxyService()); 

                        try 

                        { 

                                // 添加接收Probe和Resolve 消息的DiscoveryEndpoint终结点    

                                DiscoveryEndpoint discoveryEndpoint = new DiscoveryEndpoint(new WSHttpBinding(), new EndpointAddress(probeEndpointAddress)); 

                                discoveryEndpoint.IsSystemEndpoint = false; 

                                // 添加接收Hello合Bye消息的AnnouncementEndpoint终结点    

                                AnnouncementEndpoint announcementEndpoint = new AnnouncementEndpoint(new WSHttpBinding(), new EndpointAddress(announcementEndpointAddress));                                 

 

                                proxyServiceHost.AddServiceEndpoint(discoveryEndpoint); 

                                proxyServiceHost.AddServiceEndpoint(announcementEndpoint); 

                                //打开服务代理 

                                proxyServiceHost.Open(); 

                                Console.ForegroundColor = ConsoleColor.Magenta; 

                                Console.WriteLine("DiscoveryProxy Service started."); 

                                Console.WriteLine("Press any key to exit"); 

                                Console.WriteLine(); 

                                Console.ReadLine(); 

                                proxyServiceHost.Close(); 

                        } 

                }

 【2.3】WCF服务代码：

     现在我们启动服务发现代理的宿主程序。其它服务可以直接通道服务代理。当然客户端也可以通过单播直接与服务代理通信。WCF服务可以在启动的时候直接向代理服务DiscoveryProxy通告自己的地址信息。在服务行为里添加通告地址，我们可以通过配置文件实现：

     启动WCF服务宿主，WCF服务会向DiscoveryProxy通告自己的地址信息。我们观察一下DiscoveryProxy和WCF服务宿主窗口的信息，可以看到注册了三个终结点信息：

【2.4】客户端：

　　现在我们可以来配置自己的客户端直接与代理服务DiscoveryProxy通信。这时我们可以给客户端指定特定的探测消息地址。客户端会像特定的服务代理发送探测Probe消息。

　　启动客户端，向服务发现代理DiscoveryProxy，服务探测地址：Uri probeEndpointAddress = new Uri(" "); 发送服务探测消息，第一次没加任何限制，返回所有的服务信息，第二次我们使用了URI作为Scope，Uri scope = new Uri(" ")，限制查找范围，只返回一个匹配的服务地址，然后调用WCF服务。运行结果如下图：

【3】总结：

　　托管服务Managed Service发现模式的好处就是它可以跨越网络边界，因为其是基于传统的服务调用来注册和查找服务。这可以大大降低Ad-Hoc模式多播带来的网络资源消耗问题。此外，客户端可以通过服务发现代理DiscoveryProxy来查找特定的服务，而不需要每次服务都来监听特定的客户端多播消息。

 

参考文章：

1.

2.

3.

4.

5.

6.OASIS WS-Discovery 1.1：

 本文转自 frankxulei 51CTO博客，原文链接：http://blog.51cto.com/frankxulei/320259 ，如需转载请自行联系原作者