WCF技术剖析之二十九:换种不同的方式调用WCF服务[提供源代码下载]

原文:WCF技术剖析之二十九:换种不同的方式调用WCF服务[提供源代码下载]

我们有两种典型的WCF调用方式:通过SvcUtil.exe(或者添加Web引用)导入发布的服务元数据生成服务代理相关的代码和配置;通过ChannelFactory<TChannel>创建服务代理对象。在这篇文章中,我们采用一种独特的方式进行服务的调用。从本质上讲,我们只要能够创建于服务端相匹配的终结点,就能够实现正常的服务调用。在WCF客户端元数据架构体系中,利用MetadataExchangeClient可以获取服务的元数据,而利用MetadataImporter将获取的元数据导入成ServiceEndpoint对象。在本例中,我们将利用这两个组件定义了一个独特的服务调用的简单的例子,相信可以帮助读者进一步加深对WCF元数据框架体系的理解。 (Source从这里下载)

我们依然采用我们熟悉的计算服务的例子,下面是该服务相应的服务契约、服务类型的定义和寄宿该服务采用的配置。

   1: using System.ServiceModel;

   2: namespace Artech.ServiceInvocationViaMetadata.Contracts

   3: {

   4:     [ServiceContract(Namespace = "http://www.artech.com/")]

   5:     public interface ICalculator

   6:     {

   7:         [OperationContract]

   8:         double Add(double x, double y);

   9:     }

  10: }

服务类型:

   1: using System.ServiceModel;

   2: using Artech.ServiceInvocationViaMetadata.Contracts;

   3:  

   4: namespace Artech.ServiceInvocationViaMetadata.Services

   5: {

   6:     public class CalculatorService : ICalculator

   7:     {

   8:         public double Add(double x, double y)

   9:         {

  10:             return x + y;

  11:         }

  12:     }

  13: }

配置:

   1: <?xml version="1.0" encoding="utf-8" ?>

   2: <configuration>

   3:     <system.serviceModel>

   4:         <behaviors>

   5:             <serviceBehaviors>

   6:                 <behavior name="mexBehavior">

   7:                     <serviceMetadata />

   8:                 </behavior>

   9:             </serviceBehaviors>

  10:         </behaviors>

  11:         <services>

  12:             <service behaviorConfiguration="mexBehavior" name="Artech.ServiceInvocationViaMetadata.Services.CalculatorService">

  13:                 <endpoint address="http://127.0.0.1:3721/calculatorservice" binding="ws2007HttpBinding" contract="Artech.ServiceInvocationViaMetadata.Contracts.ICalculator" />

  14:                 <endpoint address="http://127.0.0.1:3721/calculatorservice/mex" binding="mexHttpBinding" contract="IMetadataExchange" />

  15:             </service>

  16:         </services>

  17:     </system.serviceModel>

  18: </configuration>

从上面的配置我们可以看到,服务的元数据通过WS-MEX模式发布出来,发布的地址和采用的MEX绑定分别为:http://127.0.0.1:3721/calculatorservice/mex和mexHttpBinding。

接下来,我们就可以通过下面的方式对该服务进行调用了。我们先创建MetadataExchangeClient对象并利用它获取包含元数据的MetadataSet对象,并利用该对象创建WsdlImporter对象。接下来,我们将基于ICalculator接口的服务契约添加到该WsdlImporter的已知契约列表中,调用ImportAllEndpoints方法得到导入的ServiceEndpoint列表。最后根据导出的ServiceEndpoint对象创建ChannelFactory<ICalculator>对象,并创建服务代理进行服务调用。

   1: sing System;

   2: using System.ServiceModel;

   3: using System.ServiceModel.Description;

   4: using System.Xml;

   5: using Artech.ServiceInvocationViaMetadata.Contracts;

   6: namespace Artech.ServiceInvocationViaMetadata.Client

   7: {

   8:     class Program

   9:     {

  10:         static void Main(string[] args)

  11:         {

  12:             MetadataExchangeClient metadataExchangeClient = new MetadataExchangeClient(MetadataExchangeBindings.CreateMexHttpBinding());

  13:             MetadataSet metadata = metadataExchangeClient.GetMetadata(new EndpointAddress("http://127.0.0.1:3721/calculatorservice/mex"));

  14:             WsdlImporter wsdlImporter = new WsdlImporter(metadata);

  15:             //添加已知契约类型

  16:             ContractDescription contract = ContractDescription.GetContract(typeof(ICalculator));

  17:             wsdlImporter.KnownContracts.Add(new XmlQualifiedName(contract.Name, contract.Namespace), contract);

  18:             ServiceEndpointCollection endpoints = wsdlImporter.ImportAllEndpoints();

  19:             using (ChannelFactory<ICalculator> channelFactory = new ChannelFactory<ICalculator>(endpoints[0]))

  20:             {

  21:                 ICalculator calculator = channelFactory.CreateChannel();

  22:                 using (calculator as IDisposable)

  23:                 {

  24:                     try

  25:                     {

  26:                         Console.WriteLine("x + y = {2} when x = {0} and y = {1}", 1, 2, calculator.Add(1, 2));

  27:                     }

  28:                     catch(TimeoutException)

  29:                     {

  30:                         (calculator as ICommunicationObject).Abort();

  31:                         throw;

  32:                     }

  33:                     catch(CommunicationException)

  34:                     {

  35:                         (calculator as ICommunicationObject).Abort();

  36:                         throw;

  37:                     }

  38:                 }

  39:             }

  40:             Console.Read();

  41:         }

  42:     }

  43: }

作者:Artech
出处:http://artech.cnblogs.com
本文版权归作者和博客园共有,欢迎转载,但未经作者同意必须保留此段声明,且在文章页面明显位置给出原文连接,否则保留追究法律责任的权利。
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