WCF应用 简单的Rest服务

1. 什么是REST?

  Rest的全称是Representational State Transfer, 普通的WCF使用SOAP,而使用REST构建的WCF服务

使用其他数据传输方式,例如JSON

Rest的四种操作:

1. GET - Requests a specific representation of a resource
2. PUT - Creates or updates a resource with the supplied representation
3. DELETE - Deletes the specified resource
4. POST - Submits data to be processed by the identified resource

2. 什么情况下使用REST?

1. Less overhead (no SOAP envelope to wrap every call in)
2. Less duplication (HTTP already represents operations like DELETE, PUT, GET, etc. that have to otherwise be represented in a SOAP envelope).
3. More standardized - HTTP operations are well understood and operate consistently. Some SOAP implementations can get finicky.
4. More human readable and testable (harder to test SOAP with just a browser).
5. Don't need to use XML (well, you kind of don't have to for SOAP either but it hardly makes sense since you're already doing parsing of the envelope).
6. Libraries have made SOAP (kind of) easy. But you are abstracting away a lot of redundancy underneath as I have noted. Yes, in theory, SOAP can go over other transports so as to avoid riding atop a layer doing similar things, but in reality just about all SOAP work you'll ever do is over HTTP.

3. 简单的例子

  1) 首先,制作服务契约的接口

  IHelloService

using System.ServiceModel;
using System.ServiceModel.Web;

namespace Perseus.WCF.REST.Contract.Service
{
    [ServiceContract]
    public interface IHelloService
    {
        [OperationContract]
        [WebInvoke(Method = "GET",
            ResponseFormat = WebMessageFormat.Xml,
            BodyStyle = WebMessageBodyStyle.Wrapped,
            UriTemplate = "xml/{name}/{age}")]
        string HelloXml(string name, string age);

        [OperationContract]
        [WebInvoke(Method = "GET",
            ResponseFormat = WebMessageFormat.Json,
            BodyStyle = WebMessageBodyStyle.Wrapped,
            UriTemplate = "json/{name}/{age}")]
        string HelloJson(string name, string age);
    }
}

  2) 然后, 新建一个WCF服务项目,在项目中添加WCF服务文件svc

HelloService.svc

using Perseus.WCF.REST.Contract.Service;

namespace Perseus.WCF.REST.Service
{
    public class HelloService : IHelloService
    {
        public string HelloXml(string name, string age)
        {
            return "Hello " + name + " "
                   + "Your Age: " + age;
        }

        public string HelloJson(string name, string age)
        {
            return "Hello " + name + " "
                   + "Your Age: " + age;
        }
    }
}

  3) 配置文件

<?xml version="1.0"?>
<configuration>
  <connectionStrings>
    <add name="NorthwindConnectionString" connectionString="Data Source=localhost;Initial Catalog=Northwind;Integrated Security=True" providerName="System.Data.SqlClient"/>
  </connectionStrings>
  <system.web>
    <compilation debug="true" targetFramework="4.0" />
  </system.web>
  <system.serviceModel>
    <services>
      <service name="Perseus.WCF.REST.Service.HelloService" behaviorConfiguration="ServiceBehaviour">
        <!-- Service Endpoints -->
        <!-- Unless fully qualified, address is relative to base address supplied above -->
        <endpoint address=""  binding="webHttpBinding" contract="Perseus.WCF.REST.Contract.Service.IHelloService" behaviorConfiguration="web">
          <!-- 
              Upon deployment, the following identity element should be removed or replaced to reflect the 
              identity under which the deployed service runs.  If removed, WCF will infer an appropriate identity 
              automatically.
          -->
        </endpoint>
      </service>
      </services>

    <behaviors>
      <endpointBehaviors>
        <behavior name="web">
          <webHttp />
        </behavior>
      </endpointBehaviors>
      <serviceBehaviors>
        <behavior name="ServiceBehaviour">
          <serviceMetadata httpGetEnabled="true" />
          <serviceDebug includeExceptionDetailInFaults="false" />
        </behavior>
        <behavior name="">
          <serviceMetadata httpGetEnabled="true" />
          <serviceDebug includeExceptionDetailInFaults="false" />
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <serviceHostingEnvironment multipleSiteBindingsEnabled="true" />
  </system.serviceModel>
  <system.webServer>
    <modules runAllManagedModulesForAllRequests="true"/>
  </system.webServer>

</configuration>

   4) 地址栏调试

http://localhost:7695/HelloService.svc/xml/david/30

返回结果:

 <HelloXmlResponse xmlns="http://tempuri.org/">
  <HelloXmlResult>Hello david Your Age: 30</HelloXmlResult> 
  </HelloXmlResponse>

http://localhost:7695/HelloService.svc/json/david/30

返回结果:

{"HelloJsonResult":"Hello david Your Age: 30"}

   5) 编写客户端调用代码

HelloRestTest

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ServiceModel;
using System.ServiceModel.Web;
using Perseus.WCF.REST.Contract.Service;

namespace Perseus.WCF.Client
{
    class HelloRestTest : ITestCase
    {
        public void Run()
        {
            Console.Write("Please Input Your Name: ");
            string name = Console.ReadLine();
            Console.Write("Please Input Your Age: ");
            string age = Console.ReadLine();

            string url = "http://localhost:7695/HelloService.svc";

            using (WebChannelFactory<IHelloService> wcf 
                = new WebChannelFactory<IHelloService>(new Uri(url)))
            {
                var channel = wcf.CreateChannel();
                IClientChannel clientchanel = channel as IClientChannel;
                string result = channel.HelloJson(name, age);
                Console.WriteLine(result);
            }


        }
    }
}

  运行结果:

Hello david Your Age: 30