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如何：使用代码发布服务的元数据

  • 项目

这是讨论为 Windows Communication Foundation (WCF) 服务发布元数据的两个操作方法主题之一。 有两种方式可以指定服务应如何发布元数据：使用配置文件和使用代码。 本主题演示如何使用代码发布服务的元数据。

注意

本主题演示如何以不安全的方式发布元数据。 任何客户端都可以检索服务的元数据。 如果您要求服务以安全方式发布元数据， 请参阅自定义安全元数据终结点。

有关在配置文件中发布元数据的详细信息，请参阅如何使用配置文件发布服务的元数据。 通过发布元数据，客户端可以使用 WS-Transfer GET 请求或使用 ?wsdl 查询字符串的 HTTP/GET 来检索元数据。 若要确保代码能够工作，必须创建一个基本的 WCF 服务。 在以下代码中提供了一个基本的自承载服务。

using System;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Description;

namespace Metadata.Samples
{
    [ServiceContract]
    public interface ISimpleService
    {
        [OperationContract]
        string SimpleMethod(string msg);
    }

    class SimpleService : ISimpleService
    {
        public string SimpleMethod(string msg)
        {
            Console.WriteLine("The caller passed in " + msg);
            return "Hello " + msg;
        }
    }

Imports System.Runtime.Serialization
Imports System.ServiceModel
Imports System.ServiceModel.Description

<ServiceContract()> _
Public Interface ISimpleService
    <OperationContract()> _
    Function SimpleMethod(ByVal msg As String) As String
End Interface

Class SimpleService
    Implements ISimpleService

    Public Function SimpleMethod(ByVal msg As String) As String Implements ISimpleService.SimpleMethod
        Console.WriteLine("The caller passed in " + msg)
        Return "Hello " + msg
    End Function
End Class

在代码中发布元数据

  1. 在控制台应用程序的主方法中，通过传入服务类型和基址来实例化 ServiceHost 对象。

    ServiceHost svcHost = new ServiceHost(typeof(SimpleService), new Uri("http://localhost:8001/MetadataSample"));

    Dim svcHost As New ServiceHost(GetType(SimpleService), New Uri("http://localhost:8001/MetadataSample"))

  2. 紧接在步骤 1 的代码下面创建一个 try 块，这将捕获在服务运行过程中引发的任何异常。

    try
{

    Try

    }
catch (CommunicationException commProblem)
{
    Console.WriteLine("There was a communication problem. " + commProblem.Message);
    Console.Read();
}

    Catch commProblem As CommunicationException

    Console.WriteLine("There was a communication problem. " + commProblem.Message)
    Console.Read()
End Try

  3. 检查服务主机是否已经包含一个 ServiceMetadataBehavior，如果没有，则创建一个新的 ServiceMetadataBehavior 实例。

    // Check to see if the service host already has a ServiceMetadataBehavior
ServiceMetadataBehavior smb = svcHost.Description.Behaviors.Find<ServiceMetadataBehavior>();
// If not, add one
if (smb == null)
    smb = new ServiceMetadataBehavior();

    'Check to see if the service host already has a ServiceMetadataBehavior
Dim smb As ServiceMetadataBehavior = svcHost.Description.Behaviors.Find(Of ServiceMetadataBehavior)()
'If not, add one
If (smb Is Nothing) Then
    smb = New ServiceMetadataBehavior()
End If

  4. 将 HttpGetEnabled 属性设置为 true.

    smb.HttpGetEnabled = true;

    smb.HttpGetEnabled = True

  5. ServiceMetadataBehavior 包含一个 MetadataExporter 属性。 MetadataExporter 包含一个 PolicyVersion 属性。 将 PolicyVersion 属性的值设置为 Policy15。 还可以将 PolicyVersion 属性设置为 Policy12。 当设置为 Policy15 时，元数据导出程序会使用符合 WS-Policy 1.5 的元数据生成策略信息。 当设置为 Policy12 时，元数据导出程序会生成符合 WS-Policy 1.2 的策略信息。

    smb.MetadataExporter.PolicyVersion = PolicyVersion.Policy15;

    smb.MetadataExporter.PolicyVersion = PolicyVersion.Policy15

  6. 将 ServiceMetadataBehavior 实例添加到服务主机的行为集合。

    svcHost.Description.Behaviors.Add(smb);

    svcHost.Description.Behaviors.Add(smb)

  7. 将元数据交换终结点添加到服务主机。

    // Add MEX endpoint
svcHost.AddServiceEndpoint(
  ServiceMetadataBehavior.MexContractName,
  MetadataExchangeBindings.CreateMexHttpBinding(),
  "mex"
);

    'Add MEX endpoint
svcHost.AddServiceEndpoint( _
      ServiceMetadataBehavior.MexContractName, _
      MetadataExchangeBindings.CreateMexHttpBinding(), _
      "mex")

  8. 将应用程序终结点添加到服务主机。

    // Add application endpoint
svcHost.AddServiceEndpoint(typeof(ISimpleService), new WSHttpBinding(), "");

    'Add application endpoint
svcHost.AddServiceEndpoint(GetType(ISimpleService), New WSHttpBinding(), "")

    注意

    如果您不希望向服务添加任何终结点，则运行时为您添加默认终结点。 在此示例中，由于服务的 ServiceMetadataBehavior 设置为 true，所以服务还启用了发布元数据。 有关默认终结点的详细信息，请参阅简化配置和 WCF 服务的简化配置。

  9. 打开服务主机并等待传入调用。 当用户按 Enter 时，关闭服务主机。

    // Open the service host to accept incoming calls
svcHost.Open();

// The service can now be accessed.
Console.WriteLine("The service is ready.");
Console.WriteLine("Press <ENTER> to terminate service.");
Console.WriteLine();
Console.ReadLine();

// Close the ServiceHostBase to shutdown the service.
svcHost.Close();

    'Open the service host to accept incoming calls
svcHost.Open()

'The service can now be accessed.
Console.WriteLine("The service is ready.")
Console.WriteLine("Press <ENTER> to terminate service.")
Console.WriteLine()
Console.ReadLine()

'Close the ServiceHostBase to shutdown the service.
svcHost.Close()

  10. 生成并运行控制台应用程序。

  11. 浏览到服务的基址（本示例中的 http://localhost:8001/MetadataSample）并验证已打开元数据发布。 你应会看到一个网页，该网页的顶部紧接在“你已创建服务”下面的位置显示“简单服务”。如果没有，则生成的页面顶部会显示一条消息：“此服务的元数据发布当前处于禁用状态”。

示例

下面的代码示例演示如何在代码中实现发布服务的元数据的基本 WCF 服务。

using System;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Description;

namespace Metadata.Samples
{
    [ServiceContract]
    public interface ISimpleService
    {
        [OperationContract]
        string SimpleMethod(string msg);
    }

    class SimpleService : ISimpleService
    {
        public string SimpleMethod(string msg)
        {
            Console.WriteLine("The caller passed in " + msg);
            return "Hello " + msg;
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            ServiceHost svcHost = new ServiceHost(typeof(SimpleService), new Uri("http://localhost:8001/MetadataSample"));
            try
            {
                // Check to see if the service host already has a ServiceMetadataBehavior
                ServiceMetadataBehavior smb = svcHost.Description.Behaviors.Find<ServiceMetadataBehavior>();
                // If not, add one
                if (smb == null)
                    smb = new ServiceMetadataBehavior();
                smb.HttpGetEnabled = true;
                smb.MetadataExporter.PolicyVersion = PolicyVersion.Policy15;
                svcHost.Description.Behaviors.Add(smb);
                // Add MEX endpoint
                svcHost.AddServiceEndpoint(
                  ServiceMetadataBehavior.MexContractName,
                  MetadataExchangeBindings.CreateMexHttpBinding(),
                  "mex"
                );
                // Add application endpoint
                svcHost.AddServiceEndpoint(typeof(ISimpleService), new WSHttpBinding(), "");
                // Open the service host to accept incoming calls
                svcHost.Open();

                // The service can now be accessed.
                Console.WriteLine("The service is ready.");
                Console.WriteLine("Press <ENTER> to terminate service.");
                Console.WriteLine();
                Console.ReadLine();

                // Close the ServiceHostBase to shutdown the service.
                svcHost.Close();
            }
            catch (CommunicationException commProblem)
            {
                Console.WriteLine("There was a communication problem. " + commProblem.Message);
                Console.Read();
            }
        }
    }
}

Imports System.Runtime.Serialization
Imports System.ServiceModel
Imports System.ServiceModel.Description

<ServiceContract()> _
Public Interface ISimpleService
    <OperationContract()> _
    Function SimpleMethod(ByVal msg As String) As String
End Interface

Class SimpleService
    Implements ISimpleService

    Public Function SimpleMethod(ByVal msg As String) As String Implements ISimpleService.SimpleMethod
        Console.WriteLine("The caller passed in " + msg)
        Return "Hello " + msg
    End Function
End Class

Module Module1

    Sub Main()
        Dim svcHost As New ServiceHost(GetType(SimpleService), New Uri("http://localhost:8001/MetadataSample"))
        Try
            'Check to see if the service host already has a ServiceMetadataBehavior
            Dim smb As ServiceMetadataBehavior = svcHost.Description.Behaviors.Find(Of ServiceMetadataBehavior)()
            'If not, add one
            If (smb Is Nothing) Then
                smb = New ServiceMetadataBehavior()
            End If
            smb.HttpGetEnabled = True
            smb.MetadataExporter.PolicyVersion = PolicyVersion.Policy15
            svcHost.Description.Behaviors.Add(smb)
            'Add MEX endpoint
            svcHost.AddServiceEndpoint( _
                  ServiceMetadataBehavior.MexContractName, _
                  MetadataExchangeBindings.CreateMexHttpBinding(), _
                  "mex")
            'Add application endpoint
            svcHost.AddServiceEndpoint(GetType(ISimpleService), New WSHttpBinding(), "")
            'Open the service host to accept incoming calls
            svcHost.Open()

            'The service can now be accessed.
            Console.WriteLine("The service is ready.")
            Console.WriteLine("Press <ENTER> to terminate service.")
            Console.WriteLine()
            Console.ReadLine()

            'Close the ServiceHostBase to shutdown the service.
            svcHost.Close()
        Catch commProblem As CommunicationException

            Console.WriteLine("There was a communication problem. " + commProblem.Message)
            Console.Read()
        End Try
    End Sub
End Module

另请参阅