How to: Retrieve Metadata and Implement a Compliant Service

Article
09/15/2021

Often, the same person does not design and implement services. In environments where interoperating applications are important, contracts can be designed or described in Web Services Description Language (WSDL) and a developer must implement a service that complies with the provided contract. You may also want to migrate an existing service to Windows Communication Foundation (WCF) but preserve the wire format. In addition, duplex contracts require callers to implement a callback contract as well.

In these cases, you must use the ServiceModel Metadata Utility Tool (Svcutil.exe) (or an equivalent tool) to generate a service contract interface in a managed language that you can implement to fulfill the requirements of the contract. Typically the ServiceModel Metadata Utility Tool (Svcutil.exe) is used to acquire a service contract that is used with a channel factory or a WCF client type as well as with a client configuration file that sets up the correct binding and address. To use the generated configuration file, you must change it into a service configuration file. You may also need to modify the service contract.

To retrieve data and implement a compliant service

Use the ServiceModel Metadata Utility Tool (Svcutil.exe) against metadata files or a metadata endpoint to generate a code file.

Search for the portion of the output code file that contains the interface of interest (in case there is more than one) that is marked with the System.ServiceModel.ServiceContractAttribute attribute. The following code example shows the two interfaces generated by ServiceModel Metadata Utility Tool (Svcutil.exe). The first (ISampleService) is the service contract interface that you implement to create a compliant service. The second (ISampleServiceChannel) is a helper interface for client use that extends both the service contract interface and System.ServiceModel.IClientChannel and is for use in a client application.

[System.CodeDom.Compiler.GeneratedCodeAttribute("System.ServiceModel", "3.0.0.0")]
[System.ServiceModel.ServiceContractAttribute(
  Namespace="http://microsoft.wcf.documentation"
)]
public interface ISampleService
{

    [System.ServiceModel.OperationContractAttribute(
      Action="http://microsoft.wcf.documentation/ISampleService/SampleMethod",
      ReplyAction="http://microsoft.wcf.documentation/ISampleService/SampleMethodResponse"
    )]
    [System.ServiceModel.FaultContractAttribute(
      typeof(microsoft.wcf.documentation.SampleFault),
      Action="http://microsoft.wcf.documentation/ISampleService/SampleMethodSampleFaultFault"
    )]
    string SampleMethod(string msg);
}

[System.CodeDom.Compiler.GeneratedCodeAttribute("System.ServiceModel", "3.0.0.0")]
public interface ISampleServiceChannel : ISampleService, System.ServiceModel.IClientChannel
{
}

If the WSDL does not specify a reply action for all of the operations, the generated operation contracts may have the ReplyAction property set to the wildcard character (*). Remove this property setting. Otherwise, when you implement the service contract metadata, the metadata cannot be exported for those operations.
Implement the interface on a class and host the service. For an example, see How to: Implement a Service Contract, or see a simple implementation below in the Example section.
In the client configuration file that the ServiceModel Metadata Utility Tool (Svcutil.exe) generates, change the <client> configuration section to a <services> configuration section. (For an example of a generated client application configuration file, see the following "Example" section.)
Within the <services> configuration section, create a name attribute in the <services> configuration section for your service implementation.
Set the service name attribute to the configuration name for your service implementation.
Add the endpoint configuration elements that use the implemented service contract to the service configuration section.

Example

The following code example shows the majority of a code file generated by running the ServiceModel Metadata Utility Tool (Svcutil.exe) against metadata files.

The following code shows:

The service contract interface that, when implemented, complies with the contract requirements (ISampleService).
The helper interface for client use that extends both the service contract interface and System.ServiceModel.IClientChannel and is for use in a client application (ISampleServiceChannel).
The helper class that extends System.ServiceModel.ClientBase<TChannel> and is for use in a client application (SampleServiceClient).
The configuration file generated from the service.
A simple ISampleService service implementation.
A conversion of the client-side configuration file to a service-side version.

//------------------------------------------------------------------------------
// <auto-generated>
//     This code was generated by a tool.
//     Runtime Version:2.0.50727.42
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------

[assembly: System.Runtime.Serialization.ContractNamespaceAttribute("http://microsoft.wcf.documentation", ClrNamespace="microsoft.wcf.documentation")]

namespace microsoft.wcf.documentation
{
    using System.Runtime.Serialization;

    [System.CodeDom.Compiler.GeneratedCodeAttribute("System.Runtime.Serialization", "3.0.0.0")]
    [System.Runtime.Serialization.DataContractAttribute()]
    public partial class SampleFault : object, System.Runtime.Serialization.IExtensibleDataObject
    {

        private System.Runtime.Serialization.ExtensionDataObject extensionDataField;

        private string FaultMessageField;

        public System.Runtime.Serialization.ExtensionDataObject ExtensionData
        {
            get
            {
                return this.extensionDataField;
            }
            set
            {
                this.extensionDataField = value;
            }
        }

        [System.Runtime.Serialization.DataMemberAttribute()]
        public string FaultMessage
        {
            get
            {
                return this.FaultMessageField;
            }
            set
            {
                this.FaultMessageField = value;
            }
        }
    }
}

[System.CodeDom.Compiler.GeneratedCodeAttribute("System.ServiceModel", "3.0.0.0")]
[System.ServiceModel.ServiceContractAttribute(
  Namespace="http://microsoft.wcf.documentation"
)]
public interface ISampleService
{

    [System.ServiceModel.OperationContractAttribute(
      Action="http://microsoft.wcf.documentation/ISampleService/SampleMethod",
      ReplyAction="http://microsoft.wcf.documentation/ISampleService/SampleMethodResponse"
    )]
    [System.ServiceModel.FaultContractAttribute(
      typeof(microsoft.wcf.documentation.SampleFault),
      Action="http://microsoft.wcf.documentation/ISampleService/SampleMethodSampleFaultFault"
    )]
    string SampleMethod(string msg);
}

[System.CodeDom.Compiler.GeneratedCodeAttribute("System.ServiceModel", "3.0.0.0")]
public interface ISampleServiceChannel : ISampleService, System.ServiceModel.IClientChannel
{
}

[System.CodeDom.Compiler.GeneratedCodeAttribute("System.ServiceModel", "3.0.0.0")]
public partial class SampleServiceClient : System.ServiceModel.ClientBase<ISampleService>, ISampleService
{

    public SampleServiceClient()
    {
    }

    public SampleServiceClient(string endpointConfigurationName) :
            base(endpointConfigurationName)
    {
    }

    public SampleServiceClient(string endpointConfigurationName, string remoteAddress) :
            base(endpointConfigurationName, remoteAddress)
    {
    }

    public SampleServiceClient(string endpointConfigurationName, System.ServiceModel.EndpointAddress remoteAddress) :
            base(endpointConfigurationName, remoteAddress)
    {
    }

    public SampleServiceClient(System.ServiceModel.Channels.Binding binding, System.ServiceModel.EndpointAddress remoteAddress) :
            base(binding, remoteAddress)
    {
    }

    public string SampleMethod(string msg)
    {
        return base.Channel.SampleMethod(msg);
    }
}

<configuration>
    <system.serviceModel>
        <bindings>
            <basicHttpBinding>
                <binding name="BasicHttpBinding_ISampleService" closeTimeout="00:01:00"
                    openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00"
                    allowCookies="false" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard"
                    maxBufferSize="65536" maxBufferPoolSize="524288" maxReceivedMessageSize="65536"
                    messageEncoding="Text" textEncoding="utf-8" transferMode="Buffered"
                    useDefaultWebProxy="true">
                    <readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="16384"
                        maxBytesPerRead="4096" maxNameTableCharCount="16384" />
                    <security mode="None">
                        <transport clientCredentialType="None" proxyCredentialType="None"
                            realm="" />
                        <message clientCredentialType="UserName" algorithmSuite="Default" />
                    </security>
                </binding>
            </basicHttpBinding>
        </bindings>
        <client>
            <endpoint address="http://localhost:8080/SampleService" binding="basicHttpBinding"
                bindingConfiguration="BasicHttpBinding_ISampleService" contract="ISampleService"
                name="BasicHttpBinding_ISampleService" />
        </client>
    </system.serviceModel>
</configuration>

// Implement the service. This is a very simple service.
class SampleService : ISampleService
{
  public string SampleMethod(string msg)
  {
    Console.WriteLine("The caller said: \"{0}\"", msg);
    return "The service greets you: " + msg;
  }
}

<configuration>
  <system.serviceModel>
    <bindings>
      <basicHttpBinding>
        <binding name="BasicHttpBinding_ISampleService" closeTimeout="00:01:00"
            openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00"
            allowCookies="false" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard"
            maxBufferSize="65536" maxBufferPoolSize="524288" maxReceivedMessageSize="65536"
            messageEncoding="Text" textEncoding="utf-8" transferMode="Buffered"
            useDefaultWebProxy="true">
          <readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="16384"
              maxBytesPerRead="4096" maxNameTableCharCount="16384" />
          <security mode="None">
            <transport clientCredentialType="None" proxyCredentialType="None"
                realm="" />
            <message clientCredentialType="UserName" algorithmSuite="Default" />
          </security>
        </binding>
      </basicHttpBinding>
    </bindings>
    <services>
      <service
          name="Microsoft.WCF.Documentation.SampleService">
        <endpoint address="http://localhost:8080/SampleService" binding="basicHttpBinding"
            bindingConfiguration="BasicHttpBinding_ISampleService" contract="Microsoft.WCF.Documentation.ISampleService"
            />
      </service>
    </services>
  </system.serviceModel>
</configuration>

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How to: Retrieve Metadata and Implement a Compliant Service

To retrieve data and implement a compliant service

Example

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