Implement null mx record, multihomed mx supporting

truemail-rb · Apr 8, 2019 · 5a819a8 · 5a819a8
1 parent 766a939
commit 5a819a8
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Showing 2 changed files with 68 additions and 23 deletions.
diff --git a/lib/truemail/validate/mx.rb b/lib/truemail/validate/mx.rb
@@ -6,12 +6,13 @@ class Mx < Truemail::Validate::Base
       require 'resolv'
 
       ERROR = 'target host(s) not found'
+      NULL_MX_RECORD = 'null_mx_record'
 
       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(mx_lookup)
-        add_error(Truemail::Validate::Mx::ERROR)
+        return true if success(mx_lookup && domain_not_include_null_mx)
+        mail_servers.clear && add_error(Truemail::Validate::Mx::ERROR)
         false
       end
 
@@ -28,17 +29,28 @@ def mx_lookup
       end
 
       def fetch_target_hosts(hosts)
-        result.mail_servers.push(*hosts)
+        mail_servers.push(*hosts)
+      end
+
+      def null_mx?(domain_mx_records)
+        mx_record = domain_mx_records.first
+        domain_mx_records.one? && mx_record.preference.zero? && mx_record.exchange.to_s.empty?
+      end
+
+      def domain_not_include_null_mx
+        !mail_servers.include?(Truemail::Validate::Mx::NULL_MX_RECORD)
       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
+        domain_mx_records = Resolv::DNS.new.getresources(domain, Resolv::DNS::Resource::IN::MX)
+        return [Truemail::Validate::Mx::NULL_MX_RECORD] if null_mx?(domain_mx_records)
+        domain_mx_records.sort_by(&:preference).map do |mx_record|
+          Resolv.getaddresses(mx_record.exchange.to_s)
+        end.flatten
       end
 
       def mail_servers_found?
-        !result.mail_servers.empty?
+        !mail_servers.empty?
       end
 
       def hosts_from_mx_records?

diff --git a/spec/truemail/validate/mx_spec.rb b/spec/truemail/validate/mx_spec.rb
@@ -8,6 +8,7 @@
 
   describe 'defined constants' do
     specify { expect(described_class).to be_const_defined(:ERROR) }
+    specify { expect(described_class).to be_const_defined(:NULL_MX_RECORD) }
   end
 
   describe '.check' do
@@ -42,26 +43,58 @@
       context 'when mx records found' do
         let(:mx_records_file) { "#{File.expand_path('../../', __dir__)}/support/objects/mx_records.yml" }
 
-        before do
-          allow(Resolv::DNS).to receive_message_chain(:new, :getresources).and_return(mx_records_object)
-          allow(Resolv).to receive(:getaddress).and_return(host_address)
-        end
+        before { allow(Resolv::DNS).to receive_message_chain(:new, :getresources).and_return(mx_records_object) }
 
-        specify do
-          expect(mx_validator_instance).to receive(:hosts_from_mx_records?).and_call_original
-          expect(mx_validator_instance).not_to receive(:hosts_from_cname_records?)
-          expect(mx_validator_instance).not_to receive(:host_from_a_record?)
+        context 'with null mx' do
+          let(:target_mx_record) { mx_records_object.first }
 
-          expect { mx_validator }
-            .to change(result_instance, :domain)
-            .from(nil).to(email[Truemail::RegexConstant::REGEX_EMAIL_PATTERN, 3])
-            .and change(result_instance, :mail_servers)
-            .from([]).to(mail_servers_by_ip)
-            .and not_change(result_instance, :success)
+          before do
+            allow(mx_validator_instance).to receive(:hosts_from_mx_records?).and_call_original
+            allow(mx_validator_instance).to receive(:mx_records).and_call_original
+            allow(mx_validator_instance).to receive(:null_mx?).and_call_original
+
+            allow(mx_records_object).to receive(:one?).and_return(true)
+            allow(target_mx_record).to receive_message_chain(:preference, :zero?).and_return(true)
+            allow(target_mx_record).to receive_message_chain(:exchange, :to_s, :empty?).and_return(true)
+          end
+
+          specify do
+            expect(mx_validator_instance).not_to receive(:hosts_from_cname_records?)
+            expect(mx_validator_instance).not_to receive(:host_from_a_record?)
+
+            expect { mx_validator }
+              .to change(result_instance, :domain)
+              .from(nil).to(email[Truemail::RegexConstant::REGEX_EMAIL_PATTERN, 3])
+              .and not_change(result_instance, :mail_servers)
+              .and change(result_instance, :success).from(true).to(false)
+          end
+
+          it 'returns false' do
+            expect(mx_validator).to be(false)
+          end
         end
 
-        it 'returns true' do
-          expect(mx_validator).to be(true)
+        context 'without null mx' do
+          before { allow(Resolv).to receive(:getaddresses).and_return([host_address]) }
+
+          specify do
+            expect(mx_validator_instance).to receive(:hosts_from_mx_records?).and_call_original
+            expect(mx_validator_instance).to receive(:mx_records).and_call_original
+            expect(mx_validator_instance).to receive(:null_mx?).and_call_original
+            expect(mx_validator_instance).not_to receive(:hosts_from_cname_records?)
+            expect(mx_validator_instance).not_to receive(:host_from_a_record?)
+
+            expect { mx_validator }
+              .to change(result_instance, :domain)
+              .from(nil).to(email[Truemail::RegexConstant::REGEX_EMAIL_PATTERN, 3])
+              .and change(result_instance, :mail_servers)
+              .from([]).to(mail_servers_by_ip)
+              .and not_change(result_instance, :success)
+          end
+
+          it 'returns true' do
+            expect(mx_validator).to be(true)
+          end
         end
       end