I managed to find out how to do it. The custom content loader service should look like this:

public class CustomContentLoaderService : ContentLoaderService
    {
        private readonly IHttpContextAccessor _httpContextAccessor;

        protected CustomContentLoaderService() : base()
        {
        }

        public CustomContentLoaderService(IHttpContextAccessor httpContextAccessor, IContentLoader contentLoader, IPermanentLinkMapper permanentLinkMapper, IContentProviderManager providerManager) : base(contentLoader, permanentLinkMapper, providerManager)
        {
            _httpContextAccessor = httpContextAccessor;
        }

        protected override bool ShouldContentBeExposed(IContent content)
        {
            if (_httpContextAccessor.HttpContext.Request.Query.TryGetValue("draft_content", out var _))
            {
                return true;
            }
            return base.ShouldContentBeExposed(content);
        }
 }

Hi Eric

ContentLoadedService has been moved to an Internal namespace now. So is there a workaround for these classes that alow us to skip calling internal namespaces directly and avoid future code breakages? Or should we request for these to be moved to public API instead?

Regards

Ritu