WCF - Session 剖析

WCF中的Session

WCF是MS基于SOA建立的一套在分布式环境中各个相对独立系统进行通信的构架，实现了最新的基于WS-*规范。按照SOA的原则，相对独自的业务逻辑以service的形式封装，调用者通过Messaging的方式调用Service。对于承载着某个业务功能的实现的Service应该具有上下文无关性，也就是说个构成Service的operation不应该绑定到具体的调用上下文。因为SOA的一个最大的目标就是尽可能地实现重用，只有具有上下文无关性，Service才能实现最大限度的重用。WCF中Session属于Service Contract的范畴，是一个相对抽象的概念，并在Service Contract定义中通过SessionModel参数来实现。Session的创建和结束都有来自Client端的调用来实现。

如何实现和维护Session？

Client不能和Service进行直接交互，只能通过客户端创建的Proxy来间接地实现和service的交互，WCF在创建具体的Service Instance时会构建相关的Instance Context。我们可以制定Service的Instance context model。不同的Instance Context Mode体现为Proxy、Service 调用和Service Instance之间的对应关系，Instance Context Mode决定着不同的Session表现。在WCF中，支持以下3中不同类型的Instance Context Mode：

PerCall：WCF为每个Serivce调用创建一个Service Instance，调用完成后回收该Instance。

PerSession：在Session期间的所有Service调用绑定到某一个Service Instance，Session被终止后，Service Instance被回收。

Singleton：为具体的Service type进行Host的时候，与之对应的Service Instance就被创建出来，此后所有的Service调用都被关联到该Instance。

PerCall

  1 //IService
  2 [ServiceContract]
  3  public interface ICalculatorService
  4  {
  5      [OperationContract(IsOneWay = true)]
  6      void PerCall(double x, double y);
  7      [OperationContract]
  8      double PerSession(double x, double y);
  9      [OperationContract]
 10      double Singleton(double x, double y);
 11 
 16  }
 17 //Service
 18 public class CalculatorService : ICalculatorService
 19 {
 20     #region Constructor
 21     public CalculatorService()
 22     {
 23         Console.WriteLine("Create Service Instance:Current session ID is: {0}", OperationContext.Current.SessionId);
 24     }
 25     #endregion
 26 
 27     #region Destructor 
 28     ~CalculatorService()
 29     {
 30         Console.WriteLine("Destory Service Instance:Current session ID is: {0}", OperationContext.Current.SessionId);
 31     }
 32     #endregion
 33 
 34     #region Result
 35     private double _result;
 36     public double Result
 37         {
 38             get
 39             {
 40                 return _result;
 41             }
 42         }
 43     #endregion
 44 
 45     #region ICalculator Members
 46 
 47     public void PerCall(double x, double y)
 48     {            
 49         _result += x + y;
 50         Console.WriteLine("PerCall:Current session ID is: {0}", OperationContext.Current.SessionId);
 51         Console.WriteLine("Current result is {0}", _result.ToString());
 52     }
 53 
 54     public double PerSession(double x, double y)
 55     {            
 56         _result += x + y;
 57         Console.WriteLine("PerSession:Current session ID is: {0}", OperationContext.Current.SessionId);
 58         Console.WriteLine("Current result is {0}", _result.ToString());
 59         return _result;
 60     }
 61 
 62     public double Singleton(double x, double y)
 63     {            
 64         _result += x + y;
 65         Console.WriteLine("Singleton:Current session ID is: {0}", OperationContext.Current.SessionId);
 66         Console.WriteLine("Current result is {0}", _result.ToString());
 67         return _result;
 68     }
 69 
 78 
 79     #endregion
 80 }
 81 
 82 //Host  httpBasicBinding
 83 using (ServiceHost host = new ServiceHost(typeof(CalculatorService)))
 84 {
 85     Console.Title = "WCF Service Host: Session";           
 86     host.Opened += delegate
 87     {
 88         Console.WriteLine("Calculator service has been host");
 89     }; 
 90     host.Open(); 
 91     Console.Read();
 92 }
 93 
 94 //Client  httpBasicBinding

 95 Console.Title = "WCF Session: Client";
 96 
 97 ChannelFactory<ICalculatorService> channelFactory = new ChannelFactory<ICalculatorService>("CalculatorServiceEndpoint");
 98 ICalculatorService channel = channelFactory.CreateChannel();
 99 try
100 {
101     channel.PerCall(1, 1);
102     Console.WriteLine("Channel PerCall 1");
103     channel.PerCall(1, 1);
104     Console.WriteLine("Channel PerCall 2");
105 }
106 catch (Exception ex)
107 {
108     Console.WriteLine("Channel Exception:" + ex.Message);
109 }
110 (channel as ICommunicationObject).Close();
111  
112 ICalculatorService channel2 = channelFactory.CreateChannel();
113 try
114 {
115     channel2.PerCall(1, 1);
116     Console.WriteLine("Channel2 PerCall 1");
117     channel2.PerCall(1, 1);
118     Console.WriteLine("Channel2 PerCall 2");
119 } 
120 catch (Exception ex)
121 {
122     Console.WriteLine("Channel2 Exception:" + ex.Message);
123 }
124 (channel2 as ICommunicationObject).Close();
125 Console.Read();

PerSession Demo

  1 //IService
  2 [ServiceContract(SessionMode = SessionMode.Required)]
  3  public interface ICalculatorService
  4  {
  5      [OperationContract]
  6      void PerCall(double x, double y);
  7      [OperationContract]
  8      double PerSession(double x, double y);
  9      [OperationContract]
 10      double Singleton(double x, double y);
 11 
 12  }
 13 
 14 
 15 //Service
 16 public class CalculatorService : ICalculatorService
 17 {
 18     #region Constructor
 19     public CalculatorService()
 20     {
 21         Console.WriteLine("Create Service Instance:Current session ID is: {0}", OperationContext.Current.SessionId);
 22     }
 23     #endregion
 24 
 25     #region Destructor 
 26     ~CalculatorService()
 27     {
 28         Console.WriteLine("Destory Service Instance:Current session ID is: {0}", OperationContext.Current.SessionId);
 29     }
 30     #endregion
 31 
 32     #region Result
 33     private double _result;
 34     public double Result
 35         {
 36             get
 37             {
 38                 return _result;
 39             }
 40         }
 41     #endregion
 42 
 43     #region ICalculator Members
 44 
 45     public void PerCall(double x, double y)
 46     {            
 47         _result += x + y;
 48         Console.WriteLine("PerCall:Current session ID is: {0}", OperationContext.Current.SessionId);
 49         Console.WriteLine("Current result is {0}", _result.ToString());
 50     }
 51 
 52     public double PerSession(double x, double y)
 53     {            
 54         _result += x + y;
 55         Console.WriteLine("PerSession:Current session ID is: {0}", OperationContext.Current.SessionId);
 56         Console.WriteLine("Current result is {0}", _result.ToString());
 57         return _result;
 58     }
 59 
 60     public double Singleton(double x, double y)
 61     {            
 62         _result += x + y;
 63         Console.WriteLine("Singleton:Current session ID is: {0}", OperationContext.Current.SessionId);
 64         Console.WriteLine("Current result is {0}", _result.ToString());
 65         return _result;
 66     }
 67 
 68     #endregion
 69 }
 70 
 71 
 72 //Host
 73 using (ServiceHost host = new ServiceHost(typeof(CalculatorService)))
 74 {
 75     Console.Title = "WCF Service Host: Session";           
 76     host.Opened += delegate
 77     {
 78         Console.WriteLine("Calculator service has been host");
 79     }; 
 80     host.Open(); 
 81     Console.Read();
 82 }
 83 
 84 //Client
 85 Console.Title = "WCF Session: Client";
 86 
 87 ChannelFactory<ICalculatorService> channelFactory = new ChannelFactory<ICalculatorService>("CalculatorServiceEndpoint")
 88 ICalculatorService channel = channelFactory.CreateChannel();
 89 try
 90 {
 91     double retValue = 0;
 92     retValue = channel.PerSession(1, 1);
 93     Console.WriteLine(string.Format("Channel PerCall 1,reback value is {0}",retValue.ToString()));
 94     retValue = channel.PerSession(1, 1);
 95     Console.WriteLine(string.Format("Channel PerCall 1,reback value is {0}", retValue.ToString()));
 96 }
 97 catch (Exception ex)
 98 {
 99     Console.WriteLine("Channel Exception:" + ex.Message);
100 }
101 (channel as ICommunicationObject).Close();
102  
103 ICalculatorService channel2 = channelFactory.CreateChannel();
104 try
105 {
106     double retValue = 0;
107     retValue = channel2.PerSession(1, 1);
108     Console.WriteLine(string.Format("Channel PerCall 2,reback value is {0}", retValue.ToString()));
109     retValue = channel2.PerSession(1, 1);
110     Console.WriteLine(string.Format("Channel PerCall 2,reback value is {0}", retValue.ToString()));
111 } 
112 catch (Exception ex)
113 {
114     Console.WriteLine("Channel2 Exception:" + ex.Message);
115 }
116 (channel2 as ICommunicationObject).Close();
117 Console.Read();

posted @ 2011-09-21 20:35 Robert-Fang 阅读(2709) 评论(0) 编辑收藏举报

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WCF - Session 剖析

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