DRIVERS 2922 Allow valid SRV hostnames with less than 3 parts (#2972)

* Original solution

* Updating tests and implementation to allow 3 parts to SRV string

* Fixing tests

* updating tests

* typo

* Making changes according to copilot autoreview

* reverting changes to invalid-uris

* responding to comments - rewriting tests and moving logic

Author: kyleburgess2025

lib/mongo/srv/result.rb

@@ -110,17 +110,27 @@ def normalize_hostname(host)
       # A hostname's domain name consists of each of the '.' delineated
       # parts after the first. For example, the hostname 'foo.bar.baz'
       # has the domain name 'bar.baz'.
+      # 
+      # If the hostname has less than three parts, its domain name is the hostname itself.
       #
       # @param [ String ] record_host The host of the SRV record.
       #
       # @raise [ Mongo::Error::MismatchedDomain ] If the record's domain name doesn't match that of
       #   the hostname.
       def validate_same_origin!(record_host)
-        domain_name ||= query_hostname.split('.')[1..-1]
-        host_parts = record_host.split('.')
+        srv_host_domain = query_hostname.split('.')
+        srv_is_less_than_three_parts = srv_host_domain.length < 3
+        unless srv_is_less_than_three_parts
+          srv_host_domain = srv_host_domain[1..-1]
+        end
+        record_host_parts = record_host.split('.')
+
+        if (srv_is_less_than_three_parts && record_host_parts.length <= srv_host_domain.length) 
+          raise Error::MismatchedDomain.new(MISMATCHED_DOMAINNAME % [record_host, srv_host_domain])
+        end
 
-        unless (host_parts.size > domain_name.size) && (domain_name == host_parts[-domain_name.length..-1])
-          raise Error::MismatchedDomain.new(MISMATCHED_DOMAINNAME % [record_host, domain_name])
+        unless (record_host_parts.size > srv_host_domain.size) && (srv_host_domain == record_host_parts[-srv_host_domain.size..-1])
+          raise Error::MismatchedDomain.new(MISMATCHED_DOMAINNAME % [record_host, srv_host_domain])
         end
       end
     end

lib/mongo/uri/srv_protocol.rb

@@ -168,8 +168,7 @@ def parse!(remaining)
       # The hostname cannot include a port.
       #
       # The hostname must not begin with a dot, end with a dot, or have
-      # consecutive dots. The hostname must have a minimum of 3 total
-      # components (foo.bar.tld).
+      # consecutive dots. The hostname must have a minimum of 1 component
       #
       # Raises Error::InvalidURI if validation fails.
       def validate_srv_hostname(hostname)
@@ -185,8 +184,8 @@ def validate_srv_hostname(hostname)
         if parts.any?(&:empty?)
           raise_invalid_error!("Hostname cannot have consecutive dots: #{hostname}")
         end
-        if parts.length < 3
-          raise_invalid_error!("Hostname must have a minimum of 3 components (foo.bar.tld): #{hostname}")
+        if parts.length < 1
+          raise_invalid_error!("Hostname cannot be empty: #{hostname}")
         end
       end
 

spec/mongo/srv/result_spec.rb

@@ -23,6 +23,75 @@
         expect(result.address_strs).to eq(['foo.bar.com:42'])
       end
     end
+
+    example_srv_names = ['i-love-rb', 'i-love-rb.mongodb', 'i-love-ruby.mongodb.io'];
+    example_host_names = [
+      'rb-00.i-love-rb',
+      'rb-00.i-love-rb.mongodb',
+      'i-love-ruby-00.mongodb.io'
+    ];
+    example_host_names_that_do_not_match_parent = [
+      'rb-00.i-love-rb-a-little',
+      'rb-00.i-love-rb-a-little.mongodb',
+      'i-love-ruby-00.evil-mongodb.io'
+    ];
+
+    (0..2).each do |i|
+      context "when srvName has #{i+1} part#{i != 0 ? 's' : ''}" do
+        let(:srv_name) { example_srv_names[i] }
+        let(:host_name) { example_host_names[i] }
+        let(:mismatched_host_name) { example_host_names_that_do_not_match_parent[i] }
+        context 'when address does not match parent domain' do
+          let(:record) do
+            double('record').tap do |record|
+              allow(record).to receive(:target).and_return(mismatched_host_name)
+              allow(record).to receive(:port).and_return(42)
+              allow(record).to receive(:ttl).and_return(1)
+            end
+          end
+          it 'raises MismatchedDomain error' do
+            expect {
+              result = described_class.new(srv_name)
+              result.add_record(record)
+            }.to raise_error(Mongo::Error::MismatchedDomain)
+          end
+        end
+
+        context 'when address matches parent domain' do
+          let(:record) do
+            double('record').tap do |record|
+              allow(record).to receive(:target).and_return(host_name)
+              allow(record).to receive(:port).and_return(42)
+              allow(record).to receive(:ttl).and_return(1)
+            end
+          end
+          it 'adds the record' do
+            result = described_class.new(srv_name)
+            result.add_record(record)
+
+            expect(result.address_strs).to eq([host_name + ':42'])
+          end
+        end
+
+        if i < 2
+          context 'when the address is less than 3 parts' do
+            let(:record) do
+              double('record').tap do |record|
+                allow(record).to receive(:target).and_return(srv_name)
+                allow(record).to receive(:port).and_return(42)
+                allow(record).to receive(:ttl).and_return(1)
+              end
+            end
+            it 'does not accept address if it does not contain an extra domain level' do
+              expect {
+                result = described_class.new(srv_name)
+                result.add_record(record)
+              }.to raise_error(Mongo::Error::MismatchedDomain)
+            end
+          end
+        end
+      end
+    end
   end
 
   describe '#normalize_hostname' do

spec/mongo/uri/srv_protocol_spec.rb

@@ -56,16 +56,6 @@
       end
     end
 
-    context 'when the host in URI does not have {hostname}, {domainname} and {tld}' do
-
-      let(:string) { "#{scheme}#{hosts}" }
-      let(:hosts) { '10gen.cc/' }
-
-      it 'raises an error' do
-        expect { uri }.to raise_error(Mongo::Error::InvalidURI)
-      end
-    end
-
     context 'when the {tld} is empty' do
 
       let(:string) { "#{scheme}#{hosts}" }
@@ -220,24 +210,6 @@
         expect { uri }.to raise_error(Mongo::Error::InvalidURI)
       end
     end
-
-    context 'mongodb+srv://example.com?w=1' do
-
-      let(:string) { "#{scheme}example.com?w=1" }
-
-      it 'raises an error' do
-        expect { uri }.to raise_error(Mongo::Error::InvalidURI)
-      end
-    end
-
-    context 'mongodb+srv://example.com/?w' do
-
-      let(:string) { "#{scheme}example.com/?w" }
-
-      it 'raises an error' do
-        expect { uri }.to raise_error(Mongo::Error::InvalidURI)
-      end
-    end
   end
 
   describe 'valid uris' do
@@ -1302,8 +1274,8 @@
         'a'
       end
 
-      it 'raises an error' do
-        expect { validate }.to raise_error(Mongo::Error::InvalidURI)
+      it 'does not raise an error' do
+        expect { validate }.to_not raise_error
       end
     end
 
@@ -1313,8 +1285,8 @@
         'a.b'
       end
 
-      it 'raises an error' do
-        expect { validate }.to raise_error(Mongo::Error::InvalidURI)
+      it 'validates the hostname' do
+        expect { validate }.not_to raise_error
       end
     end