get the domain that points to pages

lib/github-pages-health-check/domain.rb

@@ -91,7 +91,7 @@ class Domain < Checkable
         host uri nameservers dns_resolves? proxied? cloudflare_ip?
         fastly_ip? old_ip_address? a_record? aaaa_record? a_record_present? aaaa_record_present?
         cname_record? mx_records_present? valid_domain? apex_domain?
-        should_be_a_record? cname_to_github_user_domain?
+        should_be_a_record? cname_to_github_user_domain? cname_to_domain_to_pages?
         cname_to_pages_dot_github_dot_com? cname_to_fastly?
         pointed_to_github_pages_ip? non_github_pages_ip_present? pages_domain?
         served_by_pages? valid? reason valid_domain? https?
@@ -240,12 +240,15 @@ def non_github_pages_ip_present?
 
       # Is the domain's first response a CNAME to a pages domain?
       def cname_to_github_user_domain?
-        # If the domain does not match check if the host value points to a pages
-        # domain.
-        #
-        # e.g 'www.domain.com' -> 'domain.com' -> 'Pages' is valid
-        binding.pry
-        cname? && !cname_to_pages_dot_github_dot_com? && (cname.pages_domain?)
+        cname? && !cname_to_pages_dot_github_dot_com? && cname.pages_domain?
+      end
+
+      # Check if the CNAME points to a Domain that points to pages 
+      # e.g. CNAME -> Domain -> Pages 
+      def cname_to_domain_to_pages?
+        a_record_to_pages = dns.select { |d| d.type == Dnsruby::Types::A && d.name.to_s == host }.first
+        return false unless a_record_to_pages && cname? && !cname_to_pages_dot_github_dot_com?
+        CURRENT_IP_ADDRESSES.include?(a_record_to_pages.address.to_s.downcase)
       end
 
       # Is the given domain a CNAME to pages.github.(io|com)
@@ -309,6 +312,7 @@ def proxied?
         return true if cloudflare_ip?
         return false if pointed_to_github_pages_ip?
         return false if cname_to_github_user_domain?
+        return false if cname_to_domain_to_pages?
         return false if cname_to_pages_dot_github_dot_com?
         return false if cname_to_fastly? || fastly_ip?
 
@@ -459,8 +463,7 @@ def https_eligible?
         return false if host.include?("_")
 
         # Must be a CNAME or point to our IPs.
-        # Only check the one domain if a CNAME. Don't check the parent domain.
-        return true if cname_to_github_user_domain?
+        return true if cname_to_github_user_domain? || cname_to_domain_to_pages?
 
         # Check CAA records for the full domain and its parent domain.
         pointed_to_github_pages_ip? && caa.lets_encrypt_allowed?

spec/github_pages_health_check/domain_spec.rb

@@ -258,7 +258,7 @@
       end
 
       it "knows it's a Pages IP at the end" do
-        binding.require 'pry'; binding.pry
+        expect(subject).to be_a_cname_to_domain_to_pages
       end
     end