How to implement WebServiceHost Authentication?

I'm aware that the authentication on the webservicehost class does not adhere fully to authentication standards (returns 403 forbidden rather than prompting for another set of credentials when the user enters incorrect credentials).

I'd still like to implement this basic authentication (username and password at the start of the session, HTTPS unnecessary - see picture below) as it suits my needs for a small home project.

The code I have for myService is as follows:

Imports System.IO
Imports System.Text
Imports System.ServiceModel
Imports System.ServiceModel.Web
Imports System.ServiceModel.Channels

<ServiceContract()>
Public Class myService
    <OperationContract(), WebGet(UriTemplate:="/xml/{argument1}/{argument2}")>
    Public Function XML(argument1 As String, argument2 As String) As Stream
        requestCounter += 1
        Console.WriteLine("xml data request at " & DateTime.Now.ToString() & ", request count= " & requestCounter)
        Console.WriteLine(WebOperationContext.Current.IncomingRequest.UserAgent.ToString())
        Return _ReturnXML("<xmlresponse><data><argument1>" & argument1 & "</argument1><argument2>" & argument2 & "</argument2></data><server><serverlivesince>" & serverStart.ToString() & "</serverlivesince><pageservetime>" & DateTime.Now.ToString() & "</pageservetime><requestcount>" & requestCounter & "</requestcount></server></xmlresponse>")
        'returns the first two parameters, and the time and date
    End Function

    Private Shared Function _ReturnXML(_result As String) As Stream
        Dim data = Encoding.UTF8.GetBytes(_result)

        WebOperationContext.Current.OutgoingResponse.ContentType = "text/xml; charset=utf-8"
        WebOperationContext.Current.OutgoingResponse.ContentLength = data.Length

        Return New MemoryStream(data)
    End Function
End Class

I then have similar code to return HTML as well as accept other parameter combinations.

In my Main class I've instantiated and opened this service as:

Dim varWebService = New WebServiceHost(GetType(MyWebService), New Uri("http://0.0.0.0/"))
varWebService.Open()

Could anyone provide me with code to implement this simple authentication? Or point me to a thorough tutorial? Thanks for any help

You can write a custom WebServiceHost by inheriting from it and change some default parameters like below.

The only change in your code would be

Dim varWebService = New AuthenticatedWebServiceHost(GetType(MyWebService), New Uri("http://0.0.0.0/"))

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IdentityModel;
using System.IdentityModel.Selectors;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.ServiceModel.Security;
using System.ServiceModel.Description;

namespace StackOverflow
{
    public class AuthenticatedWebServiceHost : WebServiceHost
    {
        public AuthenticatedWebServiceHost(Type type, Uri url)
        {
            IDictionary<string, ContractDescription> desc = null;
            base.InitializeDescription(type, new UriSchemeKeyedCollection());
            base.CreateDescription(out desc);
            var val = desc.Values.First();

            WebHttpBinding binding = new WebHttpBinding();
            binding.Security.Mode = WebHttpSecurityMode.TransportCredentialOnly;
            binding.Security.Transport.ClientCredentialType = HttpClientCredentialType.Basic;

            base.Credentials.UserNameAuthentication.UserNamePasswordValidationMode = UserNamePasswordValidationMode.Custom;
            base.Credentials.UserNameAuthentication.CustomUserNamePasswordValidator = new CustomUserNamePasswordValidator();

            base.AddServiceEndpoint(val.ContractType, binding, url);
        }

        //Possible next question:
        //"How can I get the name of the authenticated user?"
        public static string UserName
        {
            get
            {
                if (OperationContext.Current == null) return null;
                if (OperationContext.Current.ServiceSecurityContext == null) return null;
                if (OperationContext.Current.ServiceSecurityContext.PrimaryIdentity == null) return null;
                return OperationContext.Current.ServiceSecurityContext.PrimaryIdentity.Name;
            }
        }



        public class CustomUserNamePasswordValidator : UserNamePasswordValidator
        {
            public override void Validate(string userName, string password)
            {
                //Your logic to validate username/password
                if (userName != password)
                    throw new SecurityAccessDeniedException();
            }
        }
    }
}