How to: Expose a Contract to SOAP and Web Clients

By default, Windows Communication Foundation (WCF) makes endpoints available only to SOAP clients. In How to: Create a Basic WCF REST Service, an endpoint is made available to non-SOAP clients. There may be times when you want to make the same contract available both ways, as a Web endpoint and as a SOAP endpoint. This topic shows an example of how to do this.

To define the service contract

1. Define a service contract using an interface marked with the ServiceContractAttribute, WebInvokeAttribute and the WebGetAttribute attributes.

   <ServiceContract()> _
   Public Interface IService
   
       <OperationContract()> _
       <WebGet()> _
       Function EchoWithGet(ByVal s As String) As String
   
       <OperationContract()> _
       <WebInvoke()> _
       Function EchoWithPost(ByVal s As String) As String
   End Interface
   

   [ServiceContract]
   public interface IService
   {
       [OperationContract]
       [WebGet]
       string EchoWithGet(string s);
   
       [OperationContract]
       [WebInvoke]
       string EchoWithPost(string s);
   }
   

   Note:
   By default WebInvokeAttribute maps POST calls to the operation. You can, however, specify the method to map to the operation by specifying a "method=" parameter. WebGetAttribute does not have a "method=" parameter and only maps GET calls to the service operation.

2. Implement the service contract.

   Public Class Service
       Implements IService
       Public Function EchoWithGet(ByVal s As String) As String Implements IService.EchoWithGet
           Return "You said " + s
       End Function
   
       Public Function EchoWithPost(ByVal s As String) As String Implements IService.EchoWithPost
           Return "You said " + s
       End Function
   End Class
   

   public class Service : IService
   {
       public string EchoWithGet(string s)
       {
           return "You said " + s;
       }
   
       public string EchoWithPost(string s)
       {
           return "You said " + s;
       }
   }
   

To host the service

1. Create a ServiceHost object.

   Dim host As New ServiceHost(GetType(Service), New Uri("https://localhost:8000"))
   

   ServiceHost host = new ServiceHost(typeof(Service), new Uri("https://localhost:8000"));
   

2. Add a ServiceEndpoint with BasicHttpBinding for the SOAP endpoint.

   host.AddServiceEndpoint(GetType(IService), New BasicHttpBinding(), "Soap")
   

   host.AddServiceEndpoint(typeof(IService), new BasicHttpBinding(), "Soap");
   

3. Add a ServiceEndpoint with WebHttpBinding for the non-SOAP endpoint and add the WebHttpBehavior to the endpoint.

   Dim endpoint As ServiceEndpoint
   endpoint = host.AddServiceEndpoint(GetType(IService), New WebHttpBinding(), "Web")
   endpoint.Behaviors.Add(New WebHttpBehavior())
   

   ServiceEndpoint endpoint = host.AddServiceEndpoint(typeof(IService), new WebHttpBinding(), "Web");
   endpoint.Behaviors.Add(new WebHttpBehavior());
   

4. Call Open() on a ServiceHost instance to open the service host.

   host.Open()
   

   host.Open();
   

To call service operations mapped to GET in Internet Explorer

1. Open Internet Explorer and type "https://localhost:8000/Web/EchoWithGet?s=Hello, world!" and press ENTER. The URL contains the base address of the service ("https://localhost:8000/"), the relative address of the endpoint (""), the service operation to call ("EchoWithGet"), and a question mark followed by a list of named parameters separated by an ampersand (&).

To call service operations on the Web endpoint in code

1. Create an instance of WebChannelFactory within a using block.

   Using wcf As New WebChannelFactory(Of IService)(New Uri("https://localhost:8000/Web"))
   

   using (WebChannelFactory<IService> wcf = new WebChannelFactory<IService>(new Uri("https://localhost:8000/Web")))
   

Note:
Close() is automatically called on the channel at the end of the using block.

1. Create the channel and call the service.

   Dim channel As IService = wcf.CreateChannel()
   
   Dim s As String
   
   Console.WriteLine("Calling EchoWithGet by HTTP GET: ")
   s = channel.EchoWithGet("Hello, world")
   Console.WriteLine("   Output:  {0}", s)
   
   Console.WriteLine("")
   Console.WriteLine("This can also be accomplished by navigating to")
   Console.WriteLine("https://localhost:8000/Web/EchoWithGet?s=Hello, world!")
   Console.WriteLine("in a web browser while this sample is running.")
   
   Console.WriteLine("")
   
   Console.WriteLine("Calling EchoWithPost by HTTP POST: ")
   s = channel.EchoWithPost("Hello, world")
   Console.WriteLine("   Output:  {0}", s)
   

   IService channel = wcf.CreateChannel();
   
   string s;
   
   Console.WriteLine("Calling EchoWithGet by HTTP GET: ");
   s = channel.EchoWithGet("Hello, world");
   Console.WriteLine("   Output: {0}", s);
   
   Console.WriteLine("");
   Console.WriteLine("This can also be accomplished by navigating to");
   Console.WriteLine("https://localhost:8000/Web/EchoWithGet?s=Hello, world!");
   Console.WriteLine("in a web browser while this sample is running.");
   
   Console.WriteLine("");
   
   Console.WriteLine("Calling EchoWithPost by HTTP POST: ");
   s = channel.EchoWithPost("Hello, world");
   Console.WriteLine("   Output: {0}", s);
   

To call service operations on the SOAP endpoint

1. Create an instance of ChannelFactory within a using block.

   Using scf As New ChannelFactory(Of IService)(New BasicHttpBinding(), "https://localhost:8000/Soap")
   

   using (ChannelFactory<IService> scf = new ChannelFactory<IService>(new BasicHttpBinding(), "https://localhost:8000/Soap"))
   

2. Create the channel and call the service.

   Dim channel As IService = scf.CreateChannel()
   
   Dim s As String
   
   Console.WriteLine("Calling EchoWithGet on SOAP endpoint: ")
   s = channel.EchoWithGet("Hello, world")
   Console.WriteLine("   Output:  {0}", s)
   
   Console.WriteLine("")
   
   Console.WriteLine("Calling EchoWithPost on SOAP endpoint: ")
   s = channel.EchoWithPost("Hello, world")
   Console.WriteLine("   Output:  {0}", s)
   

   IService channel = scf.CreateChannel();
   
   string s;
   
   Console.WriteLine("Calling EchoWithGet on SOAP endpoint: ");
   s = channel.EchoWithGet("Hello, world");
   Console.WriteLine("   Output: {0}", s);
   
   Console.WriteLine("");
   
   Console.WriteLine("Calling EchoWithPost on SOAP endpoint: ");
   s = channel.EchoWithPost("Hello, world");
   Console.WriteLine("   Output: {0}", s);
   

To close the service host

1. Close the service host.

   host.Close()
   

   host.Close();
   

Example

The following is the full code listing for this topic.

Imports System
Imports System.Collections.Generic
Imports System.ServiceModel
Imports System.ServiceModel.Description
Imports System.ServiceModel.Web
Imports System.Text

<ServiceContract()> _
Public Interface IService

    <OperationContract()> _
    <WebGet()> _
    Function EchoWithGet(ByVal s As String) As String

    <OperationContract()> _
    <WebInvoke()> _
    Function EchoWithPost(ByVal s As String) As String
End Interface

Public Class Service
    Implements IService
    Public Function EchoWithGet(ByVal s As String) As String Implements IService.EchoWithGet
        Return "You said " + s
    End Function

    Public Function EchoWithPost(ByVal s As String) As String Implements IService.EchoWithPost
        Return "You said " + s
    End Function
End Class
Module Program

    Sub Main()
        Dim host As New ServiceHost(GetType(Service), New Uri("https://localhost:8000"))
        host.AddServiceEndpoint(GetType(IService), New BasicHttpBinding(), "Soap")
        Dim endpoint As ServiceEndpoint
        endpoint = host.AddServiceEndpoint(GetType(IService), New WebHttpBinding(), "Web")
        endpoint.Behaviors.Add(New WebHttpBehavior())

        Try
            host.Open()

            Using wcf As New WebChannelFactory(Of IService)(New Uri("https://localhost:8000/Web"))

                Dim channel As IService = wcf.CreateChannel()

                Dim s As String

                Console.WriteLine("Calling EchoWithGet by HTTP GET: ")
                s = channel.EchoWithGet("Hello, world")
                Console.WriteLine("   Output:  {0}", s)

                Console.WriteLine("")
                Console.WriteLine("This can also be accomplished by navigating to")
                Console.WriteLine("https://localhost:8000/Web/EchoWithGet?s=Hello, world!")
                Console.WriteLine("in a web browser while this sample is running.")

                Console.WriteLine("")

                Console.WriteLine("Calling EchoWithPost by HTTP POST: ")
                s = channel.EchoWithPost("Hello, world")
                Console.WriteLine("   Output:  {0}", s)
                Console.WriteLine("")
            End Using
            Using scf As New ChannelFactory(Of IService)(New BasicHttpBinding(), "https://localhost:8000/Soap")

                Dim channel As IService = scf.CreateChannel()

                Dim s As String

                Console.WriteLine("Calling EchoWithGet on SOAP endpoint: ")
                s = channel.EchoWithGet("Hello, world")
                Console.WriteLine("   Output:  {0}", s)

                Console.WriteLine("")

                Console.WriteLine("Calling EchoWithPost on SOAP endpoint: ")
                s = channel.EchoWithPost("Hello, world")
                Console.WriteLine("   Output:  {0}", s)
                Console.WriteLine("")
            End Using


            Console.WriteLine("Press <Enter> to terminate")
            Console.ReadLine()
            host.Close()
        Catch cex As CommunicationException
            Console.WriteLine("An exception occurred:  {0}", cex.Message)
            host.Abort()
        End Try

    End Sub
End Module

using System;
using System.Collections.Generic;
using System.ServiceModel;
using System.ServiceModel.Description;
using System.ServiceModel.Web;
using System.Text;

namespace Microsoft.ServiceModel.Samples.BasicWebProgramming
{
    [ServiceContract]
    public interface IService
    {
        [OperationContract]
        [WebGet]
        string EchoWithGet(string s);

        [OperationContract]
        [WebInvoke]
        string EchoWithPost(string s);
    }

    public class Service : IService
    {
        public string EchoWithGet(string s)
        {
            return "You said " + s;
        }

        public string EchoWithPost(string s)
        {
            return "You said " + s;
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            ServiceHost host = new ServiceHost(typeof(Service), new Uri("https://localhost:8000"));
            host.AddServiceEndpoint(typeof(IService), new BasicHttpBinding(), "Soap");
            ServiceEndpoint endpoint = host.AddServiceEndpoint(typeof(IService), new WebHttpBinding(), "Web");
            endpoint.Behaviors.Add(new WebHttpBehavior());
            
            try
            {
                host.Open();

                using (WebChannelFactory<IService> wcf = new WebChannelFactory<IService>(new Uri("https://localhost:8000/Web")))
                {
                    IService channel = wcf.CreateChannel();

                    string s;

                    Console.WriteLine("Calling EchoWithGet by HTTP GET: ");
                    s = channel.EchoWithGet("Hello, world");
                    Console.WriteLine("   Output: {0}", s);

                    Console.WriteLine("");
                    Console.WriteLine("This can also be accomplished by navigating to");
                    Console.WriteLine("https://localhost:8000/Web/EchoWithGet?s=Hello, world!");
                    Console.WriteLine("in a web browser while this sample is running.");

                    Console.WriteLine("");

                    Console.WriteLine("Calling EchoWithPost by HTTP POST: ");
                    s = channel.EchoWithPost("Hello, world");
                    Console.WriteLine("   Output: {0}", s);
                    Console.WriteLine("");
                }
                using (ChannelFactory<IService> scf = new ChannelFactory<IService>(new BasicHttpBinding(), "https://localhost:8000/Soap"))
                {
                    IService channel = scf.CreateChannel();

                    string s;

                    Console.WriteLine("Calling EchoWithGet on SOAP endpoint: ");
                    s = channel.EchoWithGet("Hello, world");
                    Console.WriteLine("   Output: {0}", s);

                    Console.WriteLine("");

                    Console.WriteLine("Calling EchoWithPost on SOAP endpoint: ");
                    s = channel.EchoWithPost("Hello, world");
                    Console.WriteLine("   Output: {0}", s);
                    Console.WriteLine("");
                }


                Console.WriteLine("Press [Enter] to terminate");
                Console.ReadLine();
                host.Close();
            }
            catch (CommunicationException cex)
            {
                Console.WriteLine("An exception occurred: {0}", cex.Message);
                host.Abort();
            }
        }
    }
}

Compiling the Code

When compiling Service.cs, reference System.ServiceModel.dll and System.ServiceModel.Web.dll.

See Also

Reference

WebHttpBinding
WebGetAttribute
WebInvokeAttribute
WebServiceHost
ChannelFactory
WebHttpBehavior

Other Resources

WCF REST Programming Model

© 2007 Microsoft Corporation. All rights reserved.
Build Date: 2009-08-07