Feature/smtp retry if one mx found (#24)

* Implement SMTP retry
* Update gem documentation
* Refactor
* Update gem version

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    truemail (0.1.4)
+    truemail (0.1.5)
 
 GEM
   remote: https://rubygems.org/

README.md

@@ -64,8 +64,10 @@ Truemail.configure do |config|
   # Optional parameter. A SMTP server response timeout is equal to 2 ms by default.
   config.response_timeout = 1
 
-  # Optional parameter. Total of timeout retry. It is equal to 1 by default.
-  config.retry_count = 2
+  # Optional parameter. Total of connection attempts. It is equal to 2 by default.
+  # This parameter uses in mx lookup timeout error and smtp request (for cases when
+  # there is one mx server).
+  config.connection_attempts = 3
 
   # Optional parameter. You can predefine which type of validation will be used for domains.
   # Available validation types: :regex, :mx, :smtp
@@ -91,7 +93,7 @@ Truemail.configuration
  @connection_timeout=1,
  @email_pattern=/regex_pattern/,
  @response_timeout=1,
- @retry_count=2,
+ @connection_attempts=3,
  @validation_type_by_domain={},
  @verifier_domain="somedomain.com",
  @verifier_email="verifier@example.com"
@@ -105,15 +107,15 @@ Truemail.configuration.connection_timeout = 3
 => 3
 Truemail.configuration.response_timeout = 4
 => 4
-Truemail.configuration.retry_count = 1
+Truemail.configuration.connection_attempts = 1
 => 1
 
 Truemail.configuration
 => #<Truemail::Configuration:0x000055590cb17b40
  @connection_timeout=3,
  @email_pattern=/regex_pattern/,
  @response_timeout=4,
- @retry_count=1,
+ @connection_attempts=1,
  @validation_type_by_domain={},
  @verifier_domain="somedomain.com",
  @verifier_email="verifier@example.com",
@@ -187,7 +189,13 @@ Truemail.validate('email@example.com', with: :regex)
 
 #### MX validation
 
-Validation by MX records is the second validation level. It uses Regex validation before running itself. When regex validation has completed successfully then runs itself. Truemail MX validation performs strictly following the [RFC 5321](https://tools.ietf.org/html/rfc5321#section-5) standard.
+Validation by MX records is the second validation level. It uses Regex validation before running itself. When regex validation has completed successfully then runs itself.
+
+```code
+[Regex validation] -> [MX validation]
+```
+
+Truemail MX validation performs strictly following the [RFC 5321](https://tools.ietf.org/html/rfc5321#section-5) standard.
 
 Example of usage:
 
@@ -206,7 +214,7 @@ Truemail.validate('email@example.com', with: :mx)
       success=true,
       email="email@example.com",
       domain="example.com",
-      mail_servers=["mx1.example.com", "mx2.example.com"],
+      mail_servers=["127.0.1.1", "127.0.1.2"],
       errors={},
       smtp_debug=nil>,
   @validation_type=:mx>
@@ -220,6 +228,8 @@ SMTP validation is a final, third validation level. This type of validation trie
 [Regex validation] -> [MX validation] -> [SMTP validation]
 ```
 
+If total count of MX servers is equal to one, ```Truemail::Smtp``` validator will use value from ```Truemail.configuration.connection_attempts``` as connection attempts. By default it's equal 2.
+
 By default, you don't need pass with-parameter to use it. Example of usage is specified below:
 
 With ```smtp_safe_check = false```
@@ -240,7 +250,7 @@ Truemail.validate('email@example.com')
       success=true,
       email="email@example.com",
       domain="example.com",
-      mail_servers=["mx1.example.com", "mx2.example.com"],
+      mail_servers=["127.0.1.1", "127.0.1.2"],
       errors={},
       smtp_debug=nil>,
   @validation_type=:smtp>
@@ -252,7 +262,7 @@ Truemail.validate('email@example.com')
         success=false,
         email="email@example.com",
         domain="example.com",
-        mail_servers=["mx1.example.com", "mx2.example.com", "mx3.example.com"],
+        mail_servers=["127.0.1.1", "127.0.1.2"],
         errors={:smtp=>"smtp error"},
         smtp_debug=
           [#<Truemail::Validate::Smtp::Request:0x0000000002d49b10
@@ -261,20 +271,22 @@ Truemail.validate('email@example.com')
               @connection_timeout=2,
               @email_pattern=/regex_pattern/,
               @response_timeout=2,
+              @connection_attempts=2,
               @smtp_safe_check=false,
               @validation_type_by_domain={},
               @verifier_domain="example.com",
               @verifier_email="verifier@example.com">,
             @email="email@example.com",
-            @host="mx1.example.com",
+            @host="127.0.1.1",
+            @attempts=nil,
             @response=
               #<struct Truemail::Validate::Smtp::Response
                 port_opened=true,
                 connection=true,
                 helo=
                   #<Net::SMTP::Response:0x0000000002d5aca8
                     @status="250",
-                    @string="250 mx1.example.com Hello example.com\n">,
+                    @string="250 127.0.1.1 Hello example.com\n">,
                 mailfrom=
                   #<Net::SMTP::Response:0x0000000002d5a618
                     @status="250",
@@ -303,7 +315,7 @@ Truemail.validate('email@example.com')
         success=true,
         email="email@example.com",
         domain="example.com",
-        mail_servers=["mx1.example.com"],
+        mail_servers=["127.0.1.1", "127.0.1.2"],
         errors={},
         smtp_debug=
           [#<Truemail::Validate::Smtp::Request:0x0000000002c95d40
@@ -312,20 +324,22 @@ Truemail.validate('email@example.com')
                 @connection_timeout=2,
                 @email_pattern=/regex_pattern/,
                 @response_timeout=2,
+                @connection_attempts=2,
                 @smtp_safe_check=true,
                 @validation_type_by_domain={},
                 @verifier_domain="example.com",
                 @verifier_email="verifier@example.com">,
               @email="email@example.com",
-              @host="mx1.example.com",
+              @host="127.0.1.1",
+              @attempts=nil,
               @response=
                 #<struct Truemail::Validate::Smtp::Response
                   port_opened=true,
                   connection=false,
                   helo=
                     #<Net::SMTP::Response:0x0000000002c934c8
                     @status="250",
-                    @string="250 mx1.example.com\n">,
+                    @string="250 127.0.1.1\n">,
                   mailfrom=false,
                   rcptto=nil,
                   errors={:mailfrom=>"554 5.7.1 Client host blocked\n", :connection=>"server dropped connection after response"}>>,]>,
@@ -338,7 +352,7 @@ Truemail.validate('email@example.com')
       success=false,
       email="email@example.com",
       domain="example.com",
-      mail_servers=["mx1.example.com", "mx2.example.com", "mx3.example.com"],
+      mail_servers=["127.0.1.1", "127.0.1.2"],
       errors={:smtp=>"smtp error"},
       smtp_debug=
         [#<Truemail::Validate::Smtp::Request:0x0000000002d49b10
@@ -347,20 +361,22 @@ Truemail.validate('email@example.com')
               @connection_timeout=2,
               @email_pattern=/regex_pattern/,
               @response_timeout=2,
+              @connection_attempts=2,
               @smtp_safe_check=true,
               @validation_type_by_domain={},
               @verifier_domain="example.com",
               @verifier_email="verifier@example.com">,
           @email="email@example.com",
-          @host="mx1.example.com",
+          @host="127.0.1.1",
+          @attempts=nil,
           @response=
             #<struct Truemail::Validate::Smtp::Response
               port_opened=true,
               connection=true,
               helo=
               #<Net::SMTP::Response:0x0000000002d5aca8
                 @status="250",
-                @string="250 mx1.example.com Hello example.com\n">,
+                @string="250 127.0.1.1 Hello example.com\n">,
               mailfrom=#<Net::SMTP::Response:0x0000000002d5a618 @status="250", @string="250 OK\n">,
               rcptto=false,
               errors={:rcptto=>"550 User not found\n"}>>]>,

lib/truemail/configuration.rb

@@ -4,23 +4,25 @@ module Truemail
   class Configuration
     DEFAULT_CONNECTION_TIMEOUT = 2
     DEFAULT_RESPONSE_TIMEOUT = 2
-    DEFAULT_RETRY_COUNT = 1
+    DEFAULT_CONNECTION_ATTEMPTS = 2
 
     attr_reader :email_pattern,
                 :verifier_email,
                 :verifier_domain,
                 :connection_timeout,
                 :response_timeout,
-                :retry_count,
+                :connection_attempts,
                 :validation_type_by_domain
 
     attr_accessor :smtp_safe_check
 
+    alias retry_count connection_attempts
+
     def initialize
       @email_pattern = Truemail::RegexConstant::REGEX_EMAIL_PATTERN
       @connection_timeout = Truemail::Configuration::DEFAULT_CONNECTION_TIMEOUT
       @response_timeout = Truemail::Configuration::DEFAULT_RESPONSE_TIMEOUT
-      @retry_count = Truemail::Configuration::DEFAULT_RETRY_COUNT
+      @connection_attempts = Truemail::Configuration::DEFAULT_CONNECTION_ATTEMPTS
       @validation_type_by_domain = {}
       @smtp_safe_check = false
     end
@@ -41,7 +43,7 @@ def verifier_domain=(domain)
       @verifier_domain = domain.downcase
     end
 
-    %i[connection_timeout response_timeout retry_count].each do |method|
+    %i[connection_timeout response_timeout connection_attempts].each do |method|
       define_method("#{method}=") do |argument|
         raise ArgumentError.new(argument, __method__) unless argument.is_a?(Integer) && argument.positive?
         instance_variable_set(:"@#{method}", argument)

lib/truemail/validate/resolver_execution_wrapper.rb

@@ -10,7 +10,7 @@ def self.call(&block)
       end
 
       def initialize
-        @attempts = Truemail.configuration.retry_count
+        @attempts = Truemail.configuration.connection_attempts
       end
 
       def call(&block)

lib/truemail/validate/smtp.rb

@@ -29,13 +29,24 @@ def request
         smtp_results.last
       end
 
+      def mail_servers
+        result.mail_servers
+      end
+
+      def attempts
+        @attempts ||=
+          mail_servers.one? ? { attempts: Truemail.configuration.connection_attempts } : {}
+      end
+
       def rcptto_error
         request.response.errors[:rcptto]
       end
 
       def establish_smtp_connection
-        result.mail_servers.each do |mail_server|
-          smtp_results << Truemail::Validate::Smtp::Request.new(host: mail_server, email: result.email)
+        mail_servers.each do |mail_server|
+          smtp_results << Truemail::Validate::Smtp::Request.new(
+            host: mail_server, email: result.email, **attempts
+          )
           next unless request.check_port
           request.run || rcptto_error ? break : next
         end

lib/truemail/validate/smtp/request.rb

@@ -13,17 +13,19 @@ class Request
 
         attr_reader :host, :email, :response
 
-        def initialize(host:, email:)
+        def initialize(host:, email:, attempts: nil)
           @host = host
           @email = email
           @response = Truemail::Validate::Smtp::Response.new
+          @attempts = attempts
         end
 
         def check_port
           Timeout.timeout(configuration.connection_timeout) do
             return response.port_opened = !TCPSocket.new(host, Truemail::Validate::Smtp::Request::SMTP_PORT).close
           end
-        rescue Timeout::Error
+        rescue => error
+          retry if attempts_exist? && error.is_a?(Timeout::Error)
           response.port_opened = false
         end
 
@@ -33,11 +35,19 @@ def run
             smtp_handshakes(smtp_request, response)
           end
         rescue => error
+          retry if attempts_exist?
           assign_error(attribute: :connection, message: compose_from(error))
         end
 
         private
 
+        attr_reader :attempts
+
+        def attempts_exist?
+          return false unless attempts
+          (@attempts -= 1).positive?
+        end
+
         def configuration
           @configuration ||= Truemail.configuration.dup.freeze
         end

lib/truemail/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Truemail
-  VERSION = '0.1.4'
+  VERSION = '0.1.5'
 end

spec/support/shared_examples/has_attr_accessor.rb

@@ -8,7 +8,7 @@ module Truemail
       verifier_domain
       connection_timeout
       response_timeout
-      retry_count
+      connection_attempts
       smtp_safe_check
     ].each do |attribute|
       it "has attr_accessor :#{attribute}" do

spec/support/shared_examples/request_retry_behavior.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module Truemail
+  RSpec.shared_examples 'request retry behavior' do
+    before { error_stubs }
+
+    context 'when attempts not exists' do
+      specify do
+        expect { response_instance_target_method }.to not_change(request_instance, :attempts)
+      end
+    end
+
+    context 'when attempts exists' do
+      let(:attempts) { { attempts: 5 } }
+
+      specify do
+        expect { response_instance_target_method }.to change(request_instance, :attempts).from(5).to(0)
+      end
+    end
+  end
+end

spec/support/shared_examples/sets_default_configuration.rb

@@ -8,7 +8,7 @@ module Truemail
       expect(configuration_instance.verifier_domain).to be_nil
       expect(configuration_instance.connection_timeout).to eq(Truemail::Configuration::DEFAULT_CONNECTION_TIMEOUT)
       expect(configuration_instance.response_timeout).to eq(Truemail::Configuration::DEFAULT_RESPONSE_TIMEOUT)
-      expect(configuration_instance.retry_count).to eq(Truemail::Configuration::DEFAULT_RETRY_COUNT)
+      expect(configuration_instance.connection_attempts).to eq(Truemail::Configuration::DEFAULT_CONNECTION_ATTEMPTS)
       expect(configuration_instance.validation_type_by_domain).to eq({})
       expect(configuration_instance.smtp_safe_check).to be(false)
     end

spec/truemail/configuration_spec.rb

@@ -6,7 +6,7 @@
   describe 'defined constants' do
     specify { expect(described_class).to be_const_defined(:DEFAULT_CONNECTION_TIMEOUT) }
     specify { expect(described_class).to be_const_defined(:DEFAULT_RESPONSE_TIMEOUT) }
-    specify { expect(described_class).to be_const_defined(:DEFAULT_RETRY_COUNT) }
+    specify { expect(described_class).to be_const_defined(:DEFAULT_CONNECTION_ATTEMPTS) }
   end
 
   describe '.new' do
@@ -32,7 +32,7 @@
         expect(configuration_instance.email_pattern).to eq(Truemail::RegexConstant::REGEX_EMAIL_PATTERN)
         expect(configuration_instance.connection_timeout).to eq(2)
         expect(configuration_instance.response_timeout).to eq(2)
-        expect(configuration_instance.retry_count).to eq(1)
+        expect(configuration_instance.connection_attempts).to eq(2)
         expect(configuration_instance.validation_type_by_domain).to eq({})
         expect(configuration_instance.smtp_safe_check).to be(false)
       end
@@ -190,17 +190,17 @@
         end
       end
 
-      describe '#retry_count=' do
-        context 'with valid retry count' do
-          it 'sets custom retry count' do
-            expect { configuration_instance.retry_count = 2 }
-              .to change(configuration_instance, :retry_count)
-              .from(1).to(2)
+      describe '#connection_attempts=' do
+        context 'with valid connection attempts' do
+          it 'sets custom connection attempts' do
+            expect { configuration_instance.connection_attempts = 3 }
+              .to change(configuration_instance, :connection_attempts)
+              .from(2).to(3)
           end
         end
 
-        context 'with invalid response timeout' do
-          let(:setter) { :response_timeout= }
+        context 'with invalid connection attempts' do
+          let(:setter) { :connection_attempts= }
 
           include_examples 'raises argument error'
         end