WCF Proxy Using Post Even Though WebGet Attribute is Specified (Only when called from another WCF service) - Causes 405 Error

Question

I have a Restful WCF service sitting on another server configured with the WebGet attribute to respond to the HTTP Get method. I know the service works correctly because I can call the service directly through the browser and manually do a Get with Fiddler and receive a correct response.

I have an Asp.NET project on my local machine that is calling this service with the following code:

Proxy Interface 'IProductService':

using System.ServiceModel;
using System.ServiceModel.Web;

namespace Hugo.Infrastructure.Services.Products
{
    [ServiceContract]
    [XmlSerializerFormat]
    public interface IProductService
    {
        [OperationContract(Name = "GetProductById")]
        [WebGet(UriTemplate = "Products/Titles/{id}",
            ResponseFormat = WebMessageFormat.Xml,
            RequestFormat = WebMessageFormat.Xml,
            BodyStyle = WebMessageBodyStyle.Bare)]
        TitleDto GetTitleById(string id);
    }
}

Implementation 'ProductService':

using System.ServiceModel;

namespace Hugo.Infrastructure.Services.Products
{
    public class ProductService : ClientBase<IProductService>, IProductService
    {
        public TitleDto GetTitleById(string id)
        {
            return Channel.GetTitleById(id);
        }
    }
}

Related Web.config section:

<system.serviceModel>
    <serviceHostingEnvironment aspNetCompatibilityEnabled="true">
        <baseAddressPrefixFilters>
        </baseAddressPrefixFilters>      
    </serviceHostingEnvironment>
    ...
    <client>
        <endpoint address="http://server/directory/product.svc" bindingConfiguration="ProductServiceBinding" binding="webHttpBinding" behaviorConfiguration="productService" contract="Project.Infrastructure.Services.Products.IProductService" name="ProductServiceRest" />
    </client>
    <behaviors>
        ...
        <endpointBehaviors>
            <behavior name="productService">
                <webHttp />
            </behavior>
            ...
        </endpointBehaviors>
    </behaviors>
</system.serviceModel>

This works fine when we call the method from a page within the project, however it errors out on this line return Channel.GetTitleById(id); when we call it from within a WCF service from the same project. The error we receive is an HTTP 405 'Method not allowed' error. When we look at the IIS logs on the remote server we see that the ProductService proxy is making an HTTP GET request when the method call is initiated from the page but it is making an HTTP POST request when the method is called from the WCF service. The POST method is not configured on the service, thus the 405 error.

Even when the page and the service are in the same folder and namespace we still receive the same error from the service. If we use a classic asmx soap service instead then a GET call is made and the service executes and responds correctly. If we manually do a get from the WCF service using the System.Net.WebRequest object, the service call succeeds.

Bottom line, the WCF client proxy tries to do a POST instead of a GET when used from within another WCF Rest service but works correctly when used from a page or pretty much anywhere else.

Help please!

Answer 1

This might work: http://www.rgoarchitects.com/nblog/2008/09/28/AnotherWCFGotchaCallingAnotherServiceresourceWithinACall.aspx