WCF(三) Message pattern

上次咱们稍稍讨论了WCF中的contract,这次咱们讨论Message Pattern.

WCF中为何会有message pattern呢?

我们知道WCF的Server端与client端是通过xml 来进行交互的.message pattern其实就是指server端与client端交互xml的方式.

wcf提供以下三种pattern:

1.Request-reply:client端调用server端的公开的method后,client端需等server端method返回结果(即:reply响应)以后,才能做继续client端的下一步操作.(如:client调用server端的method往数据库中插入一条数据.server端插入数据成功以后,返回相应的数据库插入成功信息.很多情况下使用的是这种.

2.one-way:client端调用server端的公开的method后,client端不需等server端的method返回结果,便可继续client端下一步操作.(如:server端记录client端的日志(log)信息).标识为One-way的operation(函数)的返回值只能是void. 当client向server 发起了request后,不需要server做出回应的情况使用one-way message pattern.

3.duplicate:Request-Reply 和One-way都是先由client端发起的request(请求);duplicate则允许有server端发起request.

两种方式实现duplicate:一种是tcp(这里先不讲tcp的方式,先讲http的方式).一种是http. Http方式的话:是先由client端发起一次one-way 的request,然后client不等待server端返回结果,而是端继续往下执行.当server端有结果返回时,再有server端发起一次one-way的request.所以duplicate也叫callback. 我们知道当一个操作很费时的话,为了减少UI的无响应,有更好的用户体验,会使用callback.wcf也是:当server的执行很耗时的话,我们可以使用duplicate的message pattern.

4.实现:

4.1:Requst-Reply:是最简单的

 1     [ServiceContract(CallbackContract = typeof(IDuplicateDemoCallback))]
 2     public interface IService1
 3     {
 4         // 在函数中,我们让线程暂停,模拟耗时的操作.
 5         // 参数:interval为暂停的毫秒数,由调用该method的client端设定.
 6         [OperationContract]
 7         void RequestReply(int interval);
 8 
 9         [OperationContract]
10         void DuplicateCommunicate(int interval);
11 
12     }

4.2:One-Way:(只需要在requst-reply的基础上,使operationContract 的IsOneWay=true即可)

 1     [ServiceContract(CallbackContract = typeof(IDuplicateDemoCallback))]
 2     public interface IService1
 3     {
 4         // 在函数中,我们让线程暂停,模拟耗时的操作.
 5         // 参数:interval为暂停的毫秒数,由调用该method的client端设定.
 6         [OperationContract(IsOneWay = true)]
 7         void RequestReply(int interval);
 8 
 9         [OperationContract(IsOneWay = true)]
10         void DuplicateCommunicate(int interval);
11 
12     }

4.3Duplicate:(有些复杂)有以下步骤:
4.3.1:在server端IService.cs文件中添加代码:

 1     // NOTE: You can use the "Rename" command on the "Refactor" menu to change the interface name "IService1" in both code and config file together.
 2     [ServiceContract(CallbackContract = typeof(IDuplicateDemoCallback))]
 3     public interface IService1
 4     {
 5         // 在函数中,我们让线程暂停,模拟耗时的操作.
 6         // 参数:interval为暂停的毫秒数,由调用该method的client端设定.
 7         [OperationContract(IsOneWay=true)]
 8         void RequestReply(int interval);
 9        
10         [OperationContract(IsOneWay=true)]
11         void DuplicateCommunicate(int interval);
12 
13 
14     }
15 
16     public interface IDuplicateDemoCallback
17     {
18         [OperationContract(IsOneWay=true)]
19         void DuplicateCommunicateCallback(string callbackMessage);
20     }

4.3.2:在web site项目下的web.config文件:使其支持wsDua

 1 <?xml version="1.0"?>
 2 <configuration>
 3 
 4   <system.web>
 5     <compilation debug="false" targetFramework="4.0" />
 6   </system.web>
 7   <system.serviceModel>
 8     <behaviors>
 9       <serviceBehaviors>
10         <behavior>
11           <!-- To avoid disclosing metadata information, set the value below to false and remove the metadata endpoint above before deployment -->
12           <serviceMetadata httpGetEnabled="true"/>
13           <!-- To receive exception details in faults for debugging purposes, set the value below to true.  Set to false before deployment to avoid disclosing exception information -->
14           <serviceDebug includeExceptionDetailInFaults="false"/>
15         </behavior>
16       </serviceBehaviors>
17     </behaviors>
18     <serviceHostingEnvironment multipleSiteBindingsEnabled="true" />
19 
20     <services>
21       <service name="WcfMessagePatternLib.Service1" behaviorConfiguration="">
22         <!-- Service Endpoints -->
23         <endpoint address="" binding="wsDualHttpBinding" contract="WcfMessagePatternLib.IService1">     
24           <identity>
25             <dns value="localhost"/>
26           </identity>
27         </endpoint>
28         <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"/>
29       </service>
30     </services>
31     
32     
33     </system.serviceModel>
34   <system.webServer>
35     <modules runAllManagedModulesForAllRequests="true"/>
36   </system.webServer>
37   
38 </configuration>

4.3.3在client端添加一个类文件命名为Callback.cs:
使其实现IDuplicateDemoCallback接口.

1     class Callback:ServiceReference1.IService1Callback
2     {
3         public void DuplicateCommunicateCallback(string callbackMessage)
4         {
5             MessageBox.Show(callbackMessage);
6         }
7     }

1         private void Form1_Load(object sender, EventArgs e)
2         {
3             var context = new InstanceContext(new Callback());
4             proxy = new Service1Client(context);
5         }

4.3.4修改client项目下的app.config文件:使其支持wsdualhttp

 1 <?xml version="1.0" encoding="utf-8" ?>
 2 <configuration>
 3     <system.serviceModel>
 4         <bindings>
 5             <wsDualHttpBinding>
 6                 <binding name="WSDualHttpBinding_IService1" closeTimeout="00:01:00"
 7                     openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00"
 8                     bypassProxyOnLocal="false" transactionFlow="false" hostNameComparisonMode="StrongWildcard"
 9                     maxBufferPoolSize="524288" maxReceivedMessageSize="65536"
10                     messageEncoding="Text" textEncoding="utf-8" useDefaultWebProxy="true">
11                     <readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="16384"
12                         maxBytesPerRead="4096" maxNameTableCharCount="16384" />
13                     <reliableSession ordered="true" inactivityTimeout="00:10:00" />
14                     <security mode="Message">
15                         <message clientCredentialType="Windows" negotiateServiceCredential="true"
16                             algorithmSuite="Default" />
17                     </security>
18                 </binding>
19             </wsDualHttpBinding>
20         </bindings>
21         <client>
22             <endpoint address="http://localhost:8167/WebHost/Service.svc"
23                 binding="wsDualHttpBinding" bindingConfiguration="WSDualHttpBinding_IService1"
24                 contract="ServiceReference1.IService1" name="WSDualHttpBinding_IService1">
25                 <identity>
26                     <dns value="localhost" />
27                 </identity>
28             </endpoint>
29         </client>
30     </system.serviceModel>
31 </configuration>