lib/truemail/validate/mx.rb in truemail-0.1.3 vs lib/truemail/validate/mx.rb in truemail-0.1.4

@@ -3,24 +3,65 @@
 module Truemail
   module Validate
     class Mx < Truemail::Validate::Base
       require 'resolv'
 
-      ERROR = 'mx records not found'
+      ERROR = 'target host(s) not found'
 
       def run
         return false unless Truemail::Validate::Regex.check(result)
         result.domain = result.email[Truemail::RegexConstant::REGEX_DOMAIN_FROM_EMAIL, 1]
-        return true if success(!result.mail_servers.push(*mx_records).empty?)
+        return true if success(mx_lookup)
         add_error(Truemail::Validate::Mx::ERROR)
         false
       end
 
       private
 
-      def mx_records
-        mx_records = Resolv::DNS.open { |dns| dns.getresources(result.domain, Resolv::DNS::Resource::IN::MX) }
-        mx_records.sort_by(&:preference).map { |mx_record| mx_record.exchange.to_s }
+      def host_extractor_methods
+        %i[hosts_from_mx_records? hosts_from_cname_records? host_from_a_record?]
+      end
+
+      def mx_lookup
+        host_extractor_methods.any? do |method|
+          Truemail::Validate::ResolverExecutionWrapper.call { send(method) }
+        end
+      end
+
+      def fetch_target_hosts(hosts)
+        result.mail_servers.push(*hosts)
+      end
+
+      def mx_records(domain)
+        Resolv::DNS.new.getresources(domain, Resolv::DNS::Resource::IN::MX).sort_by(&:preference).map do |mx_record|
+          Resolv.getaddress(mx_record.exchange.to_s)
+        end
+      end
+
+      def mail_servers_found?
+        !result.mail_servers.empty?
+      end
+
+      def hosts_from_mx_records?
+        fetch_target_hosts(mx_records(result.domain))
+        mail_servers_found?
+      end
+
+      def hosts_from_cname_records?
+        cname_records = Resolv::DNS.new.getresources(result.domain, Resolv::DNS::Resource::IN::CNAME)
+        return if cname_records.empty?
+        cname_records.each do |cname_record|
+          host = Resolv.getaddress(cname_record.name.to_s)
+          hostname = Resolv.getname(host)
+          found_hosts = mx_records(hostname)
+          fetch_target_hosts(found_hosts.empty? ? [host] : found_hosts)
+        end
+        mail_servers_found?
+      end
+
+      def host_from_a_record?
+        fetch_target_hosts([Resolv.getaddress(result.domain)])
+        mail_servers_found?
       end
     end
   end
 end