Creating Custom Authorization Attribute with MVC

public class CustomAuthFilter : IAuthorizationFilter
    {
        public void OnAuthorization(AuthorizationContext filterContext)
        {
            filterContext.ActionDescriptor.ActionName;
        }
    }

public class CustomAuthAttribute : AuthorizeAttribute
{
    public override void OnAuthorization(AuthorizationContext filterContext)
    {
        base.OnAuthorization(filterContext);
    }
}

if (HttpContext.Current.User.Identity.IsAuthenticated && HttpContext.Current.User.IsInRole(Roles))
    {
        return true;
    }

public class WhitelistRequirement: IAuthorizationRequirement
{
}

public class WhitelistHandler : AuthorizationHandler<WhitelistRequirement>
{

    // Implement a constructor to inject dependencies, such as your whitelist

    protected override Task HandleRequirementAsync(AuthorizationHandlerContext context,
                                                   WhitelistRequirement requirement)
    {
        if (isInWhitelist) // Your implementation here
        {
            context.Succeed(requirement);
        }

        return Task.CompletedTask;
    }
}

services.AddAuthorization(options =>
            options.AddPolicy("WhitelistPolicy",
            b => b.AddRequirements(new WhitelistRequirement())));

services.AddSingleton<IAuthorizationHandler, WhitelistHandler>();

[Authorize(Policy = "WhitelistPolicy")]

services.AddMvc(config =>
{
    var policy = new AuthorizationPolicyBuilder()
                     .AddRequirements(new WhitelistRequirement())
                     .Build();
    config.Filters.Add(new AuthorizeFilter(policy));
})