How to: Expose a Contract to SOAP and Web Clients

Article
08/07/2009

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

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.

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

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"));

Add a ServiceEndpoint with BasicHttpBinding for the SOAP endpoint.

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

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

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());

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

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

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.

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

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"))

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

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.

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How to: Expose a Contract to SOAP and Web Clients

To define the service contract

To host the service

To call service operations mapped to GET in Internet Explorer

To call service operations on the Web endpoint in code

To call service operations on the SOAP endpoint

To close the service host

Example

Compiling the Code

See Also

Reference

Other Resources

Additional resources