Custom RequestValidator

AccessControlRequestValidator.cs

using System;
using System.Web;
using System.Web.Util;

using Microsoft.IdentityModel.Protocols.WSFederation;

namespace Sandrino.SomeAzureApplication
{
    public class AccessControlRequestValidator : RequestValidator
    {
        protected override bool IsValidRequestString(HttpContext context, string value, RequestValidationSource requestValidationSource, string collectionKey, out int validationFailureIndex)
        {
            validationFailureIndex = 0;

            if (requestValidationSource == RequestValidationSource.Form && collectionKey.Equals(WSFederationConstants.Parameters.Result, StringComparison.Ordinal))
            {
                var message = WSFederationMessage.CreateFromFormPost(context.Request) as SignInResponseMessage;
                if (message != null)
                    return true;
            }

            return base.IsValidRequestString(context, value, requestValidationSource, collectionKey, out validationFailureIndex);
        }
    }
}