public static IApplicationBuilder UseInvalidRefererIdentifier(this IApplicationBuilder builder, Action <RefererRule> ruleModifier = null)
        {
            var rule = new RefererRule()
            {
                EmptyRefererIsInvalid = true, ValidHost = "localhost"
            };

            if (ruleModifier != null)
            {
                ruleModifier(rule);                                         //modify the default rule
            }
            return(builder.UseMiddleware <InvalidRefererIdentifier>(rule)); //to inject to the constructor of middleware
        }
 public InvalidRefererIdentifier(RequestDelegate next, RefererRule rule)
 {
     _next     = next;
     this.rule = rule;
 }