How to: Expose a Contract to SOAP and Web Clients

Article
03/30/2023

By default, Windows Communication Foundation (WCF) makes endpoints available only to SOAP clients. In How to: Create a Basic WCF Web HTTP 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, as shown in the following code:

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

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

<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

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, as shown in the following code:

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

    public string EchoWithPost(string s)
    {
        return "You said " + s;
    }
}

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

To host the service

Create a ServiceHost object, as shown in the following code:

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

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

Add a ServiceEndpoint with BasicHttpBinding for the SOAP endpoint, as shown in the following code:

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

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

Add a ServiceEndpoint with WebHttpBinding for the non-SOAP endpoint and add the WebHttpBehavior to the endpoint, as shown in the following code:

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

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

Call Open() on a ServiceHost instance to open the service host, as shown in the following code:
```
host.Open();
```
```
host.Open()
```

To call service operations mapped to GET in a browser

In a web browser, browse to "http://localhost:8000/Web/EchoWithGet?s=Hello, world!". The URL contains the base address of the service (http://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<TChannel> within a using block, as shown in the following code.

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

Using wcf As New WebChannelFactory(Of IService)(New Uri("http://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, as shown in the following code.

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("http://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);

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("http://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, as shown in the following code.

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

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

Create the channel and call the service, as shown in the following code.

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);

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)

To close the service host

Close the service host, as shown in the following code.
```
host.Close();
```
```
host.Close()
```

Example

The following is the full code listing for this topic:

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("http://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("http://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("http://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(), "http://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();
            }
        }
    }
}

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("http://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("http://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("http://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(), "http://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

Compiling the code

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

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