HTTP GET request handling with empty absolute url

Question

I have created a self hosted service to handle HTTP GET requests.

My WCF Get service getting called for a HTTP GET request with an absolute URL.

but cannot calling with out an absolute URL.

Eg :- 

http://172.18.2.101:8910/Sample       =>   will invoke into "GetResponse()" method

http://172.18.2.101:8910/      =>   will not invoke into "GetResponse()" method

[ServiceContract]

public interface ITestService

{

    [OperationContract]

    [WebGet(UriTemplate = "{*pathname}", BodyStyle = WebMessageBodyStyle.Bare)]

    Stream GetResponse(string pathname);

}

[ServiceBehavior(AddressFilterMode = AddressFilterMode.Exact)]

public class TestServiceListner : ITestService

{

    private ServiceHost Host { get; set; }

    private string BaseAddress { get; set; }

    private string Port { get; set; }

    private Uri ListenUri { get; set; }

    public TestServiceListner(string baseAddress, string port)

    {

        this.BaseAddress = baseAddress;

        this.Port = port;

        Host = SetupHost(); //  set properties for service host

        Host.Open();    // Open service host

    }

    private ServiceHost SetupHost()

    {

        this.ListenUri = new Uri(string.Format("http://{0}:{1}/", this.BaseAddress, Convert.ToString(this.Port)));

        var host = new ServiceHost(this, this.ListenUri);

        //  Add binding

        WebHttpBinding binding = new WebHttpBinding(WebHttpSecurityMode.None);

        binding.Security.Transport.ClientCredentialType = HttpClientCredentialType.None;

        binding.HostNameComparisonMode = HostNameComparisonMode.Exact;

        //  Add Endpoints

        host.AddServiceEndpoint(typeof(ITestService), binding, this.ListenUri).Behaviors.Add(new WebHttpBehavior());

        return host;

    }

    public Stream GetResponse(string pathname)

    {

        Stream response = null;

        // GET pathName

        switch (pathname.Trim())

        { 

            case "/":

            case "":

                    // GET default response

                break;

            default:

                response = ReadReasponse(pathname);

                break;

        }

        return response;

    }

    private Stream ReadReasponse(string pathname)

    {

        // Read file and Generate response

        return null;

    }

}

Any guidance would be great.