路由集成 - WCF 功能

引言

想象一下，您正在使用 WCF 编写 RESTful 服务，并决定将其托管在 IIS 中。

那么，就会出现一些问题，让我们来解答它们。

问：您将如何在 IIS 中托管 WCF 服务？

答：通过将 .svc 文件放置在虚拟目录中。

问：您将如何向该服务发出请求？

答：通过使用类似于以下内容的 URI：http://some.com/SomeService.svc。

问：上述 URI 是否是 REST 服务的最佳选择？

答：不是。

问：为什么？

答：RESTful 服务的 URI 用于标识特定的资源，而带有 .svc 等扩展名是不好的。

问：为什么？

答：即使 URI 中包含 .svc 在技术上并非不符合 REST 规范，但我们是否通过显示 .svc 泄露了实现细节？

背景 

.Net 4.0 为 WCF 添加了许多功能，其中之一就是 System.Web.Routing 集成。此功能允许 WCF RESTful 服务在没有 .svc 的情况下在 IIS 中托管。

答：路由 只是一个 URL 模式，它映射到一个处理程序，在这种情况下，处理程序将是一个服务请求的类。

示例代码（服务器）

让我们构建一个执行算术级数和几何级数求和的 RESTful 服务。

步骤 1：创建一个新的 WCF 项目并删除 .svc 文件。

步骤 2：添加一个文件 IService.cs。

步骤 3：添加两个文件 GPService.cs 和 APService.cs。

步骤 4：如果不存在，则添加 Global.asax 文件。

 路由集成步骤

1：在 Global.asax.cs 中的 Application_Start 事件中，将 ServiceRoute 添加到 RouteTable。添加的这些路由表示服务在被调用时将响应的虚拟 URI。

2：在 Web.config 文件中，添加 System.Web.Routing.UrlRoutingModule 模块，并将 runAllManagedModulesForAllRequests 属性设置为 true。 此外，将 UrlRoutingHandler 处理程序添加到 <system.webServer> 元素，如下所示。

3：启用 ASP.NET 兼容性要求，以用于实现服务的类（在本例中为 GPService 和 APService）。

// IService.cs file is as below. Nothing special here. Contains one operation contract and one data contract.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.Text;

namespace RoutingIntegration
{
    [ServiceContract]
    public interface ISeriesService
    {
        /// <summary>
        /// Calculates the sequence summation.
        /// </summary>
        /// <param name="input">Input is of type SeqInput</param>
        /// <returns>SeqInput updated with the answer</returns>
        [OperationContract]
        SeqInput CalculateSeriesSummation(SeqInput input);
    }

    /// <summary>
    /// Data contract used as a entity which contains variables required for sequence summation
    /// Once calculated answer is assigned back and this class is sent back as response.
    /// </summary>
    [DataContract]
    public class SeqInput
    {
        [DataMember]
        public int numberOfItems;

        [DataMember]
        public int firstTerm;

        [DataMember]
        public int commonDiff;

        [DataMember]
        public double Answer;
        
        public SeqInput(int numberOfItems1, int firstTerm1, int commonDiff1)
        {
            this.numberOfItems = numberOfItems1;
            this.firstTerm = firstTerm1;
            this.commonDiff = commonDiff1;
        }

        public override string ToString()
        {
            return String.Format("{0} {1} {2}", numberOfItems, firstTerm, commonDiff);
        }
    }

} 

//GPService.cs as below. Simply impliments the ISeriesService.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.Text;
using System.ServiceModel.Activation;
using System.ComponentModel;

namespace RoutingIntegration
{
    //Applied to a service to indicate whether that service can be run in ASP.NET compatibility code.
    [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Required)]
    public class GPService : ISeriesService
    {
        //Indicates a service operation is logically an invoke
        // operation and that it can be called by the REST programming model.
        [WebInvoke(Method = "POST", UriTemplate = ""), Description("Geometric Sequences.")]
        public SeqInput CalculateSeriesSummation(SeqInput input)
        {
            double answer = 0;
            answer = (double.Parse((Math.Pow(input.commonDiff, 
              input.numberOfItems) - 1).ToString() )/ (input.commonDiff - 1));
            answer = answer * input.firstTerm;
            input.Answer = answer;
            return input;
        }
    }
} 

 //APService.cs as below. Simply impliments the ISeriesService.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.Text;
using System.ServiceModel.Activation;
using System.ComponentModel;

namespace RoutingIntegration
{
    //Applied to a service to indicate whether that service can be run in ASP.NET compatibility code.
    [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Required)]
    public class APService : ISeriesService
    {
        //Indicates a service operation is logically an invoke
        // operation and that it can be called by the REST programming model.
        [WebInvoke(Method = "POST", UriTemplate = ""), Description("Arithmetic Sequences.")]
        public SeqInput CalculateSeriesSummation(SeqInput input)
        {
            double answer = 0;
            answer = ((2 * input.firstTerm) + (input.numberOfItems - 1) * input.commonDiff);
            answer = answer * (double.Parse(input.numberOfItems.ToString()) / 2);
            input.Answer = answer;
            return input;
        }
    }
} 

//Global.asax.cs,  Most important part. 
using System;
using System.Collections.Generic;
using System.ServiceModel.Activation;
using System.ServiceModel.Syndication;
using System.Web.Routing;

namespace RoutingIntegration
{
    public class Global : System.Web.HttpApplication
    {
        /// <summary>
        /// Adds the ServiceRoute to the RouteTable
        /// </summary>
        protected void Application_Start(object sender, EventArgs e)
        {
            RouteTable.Routes.Add(new ServiceRoute("GPService", new WebServiceHostFactory(), typeof(GPService)));
            RouteTable.Routes.Add(new ServiceRoute("APService", new WebServiceHostFactory(), typeof(APService)));
        }

        protected void Session_Start(object sender, EventArgs e)
        {

        }

        protected void Application_BeginRequest(object sender, EventArgs e)
        {

        }

        protected void Application_AuthenticateRequest(object sender, EventArgs e)
        {

        }

        protected void Application_Error(object sender, EventArgs e)
        {

        }

        protected void Session_End(object sender, EventArgs e)
        {

        }

        protected void Application_End(object sender, EventArgs e)
        {

        }
    }
}

<!--This is how Web.config looks-->
<?xml version="1.0"?>
<configuration>

  <system.web>
    <compilation debug="true" targetFramework="4.0" />
  </system.web>
  
  <!-- Below part that needs to be added for routing integration -->
  <system.webServer>
    <modules runAllManagedModulesForAllRequests="true">
      <add name="UrlRoutingModule" 
        type="System.Web.Routing.UrlRoutingModule, System.Web, Version=4.0.0.0, 
              Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
    </modules>
    <handlers>
      <add name="UrlRoutingHandler" preCondition="integratedMode" verb="*" path="UrlRouting.axd"/>
    </handlers>
  </system.webServer>
  
  <system.serviceModel>
    <behaviors>
      <serviceBehaviors>
        <behavior>
          <!-- To avoid disclosing metadata information, set the value below 
                to false and remove the metadata endpoint above before deployment -->
          <serviceMetadata httpGetEnabled="true"/>
          <!-- 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 -->
          <serviceDebug includeExceptionDetailInFaults="false"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <!--Set the aspNetCompatibilityEnabled attribute to true"-->
    <serviceHostingEnvironment multipleSiteBindingsEnabled="true" 
              aspNetCompatibilityEnabled ="true" />
  </system.serviceModel>
   
</configuration>

示例代码（客户端）

让我们构建一个小型客户端来使用我们上面创建的 RESTful 服务。

为了演示，我只使用 APService。

读者可以发挥创造力，创建一个控制台应用程序、WinForms 应用程序或 Web 应用程序并设计一个消耗方式。我将只解释服务消耗的主要部分。

步骤 1：我们需要在客户端中也包含我们的 SeqInput 类，因为服务的 CalculateSeriesSummation 方法接受类型为 SeqInput 的参数，并在更新答案后返回该参数。

namespace RoutingIntegration
{
    [DataContract]
    public class SeqInput
    {
        [DataMember]
        public int numberOfItems;

        [DataMember]
        public int firstTerm;

        [DataMember]
        public int commonDiff;

        [DataMember]
        public double Answer;


        public SeqInput(int numberOfItems1, int firstTerm1, int commonDiff1)
        {
            this.numberOfItems = numberOfItems1;
            this.firstTerm = firstTerm1;
            this.commonDiff = commonDiff1;
        }

        public override string ToString()
        {
            return String.Format("{0} {1} {2}", numberOfItems, firstTerm, commonDiff);
        }
    }
}

第二步

static readonly DataContractSerializer customerSerializer = 
       new DataContractSerializer(typeof(RoutingIntegration.SeqInput));
try
{
    Uri address = null;
    HttpWebRequest request = null;
    RoutingIntegration.SeqInput finalAnswer = null;
    
    address = new Uri("https://:1254/APService");
    request = (HttpWebRequest)WebRequest.Create(address);
    request.Method = "POST";
    request.ContentType = "application/xml";                                        
    RoutingIntegration.SeqInput si = new  RoutingIntegration.SeqInput(1,1,1);

    using (Stream requestStream = request.GetRequestStream())
    {
        customerSerializer.WriteObject(requestStream, si);
    }
    HttpWebResponse response = (HttpWebResponse)request.GetResponse();
    using (Stream responseStream = response.GetResponseStream())
    {
        finalAnswer = (RoutingIntegration.SeqInput)customerSerializer.ReadObject(responseStream);
    }
    response.Close();

    lblAnswer.Text = "Answer is: " + finalAnswer.Answer.ToString();
}
catch (Exception ex)
{
    //Handle the exception
}

兴趣点 

.NET 4.0 为 WCF 提供的的新功能非常有趣，并且让每个人都感到好奇。