Feature/verifier domain audit, #18 (#31)

* Implement auditor feature, #18

.reek.yml

@@ -21,18 +21,21 @@ detectors:
   Attribute:
     exclude:
       - Truemail::Configuration#smtp_safe_check
-      - Truemail::Validate::ResolverExecutionWrapper#attempts
+      - Truemail::Wrapper#attempts
 
   UtilityFunction:
     exclude:
       - Truemail::Validate::Smtp::Request#compose_from
       - Truemail::Validator#select_validation_type
       - Truemail::Validate::Mx#null_mx?
+      - Truemail::Validate::Mx#a_record
+      - Truemail::Audit::Ptr#current_host_address
 
   ControlParameter:
     exclude:
       - Truemail::GenerateEmailHelper#calculate_email_size
-      - Truemail::Validate::Base#success
+      - Truemail::Worker#success
+      - Truemail#raise_unless
 
   FeatureEnvy:
     exclude:

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    truemail (0.1.6)
+    truemail (0.1.7)
 
 GEM
   remote: https://rubygems.org/

README.md

@@ -2,7 +2,7 @@
 
 [![Maintainability](https://api.codeclimate.com/v1/badges/657aa241399927dcd2e2/maintainability)](https://codeclimate.com/github/rubygarage/truemail/maintainability) [![Test Coverage](https://api.codeclimate.com/v1/badges/657aa241399927dcd2e2/test_coverage)](https://codeclimate.com/github/rubygarage/truemail/test_coverage) [![Gem Version](https://badge.fury.io/rb/truemail.svg)](https://badge.fury.io/rb/truemail) [![CircleCI](https://circleci.com/gh/rubygarage/truemail/tree/master.svg?style=svg)](https://circleci.com/gh/rubygarage/truemail/tree/master) [![Contributor Covenant](https://img.shields.io/badge/Contributor%20Covenant-v1.4%20adopted-ff69b4.svg)](CODE_OF_CONDUCT.md)
 
-The Truemail gem helps you validate emails by regex pattern, presence of domain mx-records, and real existence of email account on a current email server.
+The Truemail gem helps you validate emails by regex pattern, presence of domain mx-records, and real existence of email account on a current email server. Also Truemail gem allows performing an audit of the host in which runs.
 
 ## Features
 
@@ -137,7 +137,7 @@ Truemail.configuration
 
 #### Regex validation
 
-Validation with regex pattern is the first validation level. By default this validation not performs strictly following RFC 5322 standart, so you can override Truemail default regex pattern if you want.
+Validation with regex pattern is the first validation level. By default this validation not performs strictly following RFC 5322 standard, so you can override Truemail default regex pattern if you want.
 
 Example of usage:
 
@@ -383,6 +383,30 @@ Truemail.validate('[email protected]')
     @validation_type=:smtp>
 ```
 
+### Host audit features
+
+Truemail gem allows performing an audit of the host in which runs. Only PTR record audit performs for today.
+
+#### PTR audit
+
+So what is a PTR record? A PTR record, or pointer record, enables someone to perform a reverse DNS lookup. This allows them to determine your domain name based on your IP address. Because generic domain names without a PTR are often associated with spammers, incoming mail servers identify email from hosts without PTR records as spam and you can't verify yours emails qualitatively.
+
+```ruby
+Truemail.host_audit
+# Everything is good
+=> #<Truemail::Auditor:0x00005580df358828
+   @result=
+     #<struct Truemail::Auditor::Result
+       warnings={}>>
+
+# Has PTR warning
+=> #<Truemail::Auditor:0x00005580df358828
+   @result=
+     #<struct Truemail::Auditor::Result
+       warnings=
+         {:ptr=>"ptr record does not reference to current verifier domain"}>>
+```
+
 ### Truemail helpers
 
 #### .valid?

lib/truemail.rb

@@ -1,9 +1,6 @@
 # frozen_string_literal: true
 
-require 'truemail/version'
 require 'truemail/core'
-require 'truemail/configuration'
-require 'truemail/validator'
 
 module Truemail
   INCOMPLETE_CONFIG = 'verifier_email is required parameter'
@@ -15,7 +12,7 @@ def configuration
         return unless block_given?
         configuration = Truemail::Configuration.new
         yield(configuration)
-        raise ConfigurationError, INCOMPLETE_CONFIG unless configuration.complete?
+        raise_unless(configuration.complete?, INCOMPLETE_CONFIG)
         configuration
       end
     end
@@ -29,12 +26,23 @@ def reset_configuration!
     end
 
     def validate(email, **options)
-      raise ConfigurationError, NOT_CONFIGURED unless configuration
+      raise_unless(configuration, NOT_CONFIGURED)
       Truemail::Validator.new(email, **options).run
     end
 
     def valid?(email, **options)
       validate(email, **options).result.valid?
     end
+
+    def host_audit
+      raise_unless(configuration, NOT_CONFIGURED)
+      Truemail::Auditor.run
+    end
+
+    private
+
+    def raise_unless(condition, message)
+      raise ConfigurationError, message unless condition
+    end
   end
 end

lib/truemail/audit/base.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module Truemail
+  module Audit
+    class Base < Truemail::Worker
+      private
+
+      def add_warning(message)
+        result.warnings[self.class.name.split('::').last.downcase.to_sym] = message
+      end
+    end
+  end
+end

lib/truemail/audit/ptr.rb

@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+module Truemail
+  module Audit
+    class Ptr < Truemail::Audit::Base
+      require 'ipaddr'
+      require 'resolv'
+
+      NOT_FOUND = 'ptr record for current host address was not found'
+      NOT_REFERENCES = 'ptr record does not reference to current verifier domain'
+
+      def run
+        return if ptr_records.empty? && add_warning(Truemail::Audit::Ptr::NOT_FOUND)
+        return if ptr_references_to_verifier_domain?
+        add_warning(Truemail::Audit::Ptr::NOT_REFERENCES)
+      end
+
+      private
+
+      def current_host_address
+        Resolv.getaddress(Socket.gethostname)
+      end
+
+      def current_host_reverse_lookup
+        IPAddr.new(current_host_address).reverse
+      end
+
+      def ptr_records
+        @ptr_records ||= Truemail::Wrapper.call do
+          Resolv::DNS.new.getresources(
+            current_host_reverse_lookup, Resolv::DNS::Resource::IN::PTR
+          ).map { |ptr_record| ptr_record.name.to_s }
+        end || []
+      end
+
+      def ptr_references_to_verifier_domain?
+        ptr_records.include?(Truemail.configuration.verifier_domain)
+      end
+    end
+  end
+end

lib/truemail/auditor.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module Truemail
+  class Auditor
+    Result = Struct.new(:warnings, keyword_init: true) do
+      def initialize(warnings: {}, **args)
+        super
+      end
+    end
+
+    def self.run
+      new.run
+    end
+
+    def result
+      @result ||= Truemail::Auditor::Result.new
+    end
+
+    def run
+      Truemail::Audit::Ptr.check(result)
+      self
+    end
+  end
+end

lib/truemail/core.rb

@@ -1,6 +1,13 @@
 # frozen_string_literal: true
 
 module Truemail
+  require 'truemail/version'
+  require 'truemail/configuration'
+  require 'truemail/worker'
+  require 'truemail/wrapper'
+  require 'truemail/auditor'
+  require 'truemail/validator'
+
   class ConfigurationError < StandardError; end
 
   class ArgumentError < StandardError
@@ -16,10 +23,14 @@ module RegexConstant
     REGEX_DOMAIN_FROM_EMAIL = /\A.+@(.+)\z/
   end
 
+  module Audit
+    require 'truemail/audit/base'
+    require 'truemail/audit/ptr'
+  end
+
   module Validate
     require 'truemail/validate/base'
     require 'truemail/validate/regex'
-    require 'truemail/validate/resolver_execution_wrapper'
     require 'truemail/validate/mx'
     require 'truemail/validate/smtp'
     require 'truemail/validate/smtp/response'

lib/truemail/validate/base.rb

@@ -2,23 +2,9 @@
 
 module Truemail
   module Validate
-    class Base
-      attr_reader :result
-
-      def self.check(result)
-        new(result).run
-      end
-
-      def initialize(result)
-        @result = result
-      end
-
+    class Base < Truemail::Worker
       private
 
-      def success(condition)
-        result.success = condition || false
-      end
-
       def add_error(message)
         result.errors[self.class.name.split('::').last.downcase.to_sym] = message
       end

lib/truemail/validate/mx.rb

@@ -24,7 +24,7 @@ def host_extractor_methods
 
       def mx_lookup
         host_extractor_methods.any? do |method|
-          Truemail::Validate::ResolverExecutionWrapper.call { send(method) }
+          Truemail::Wrapper.call { send(method) }
         end
       end
 
@@ -41,8 +41,8 @@ def domain_not_include_null_mx
         !mail_servers.include?(Truemail::Validate::Mx::NULL_MX_RECORD)
       end
 
-      def mx_records(domain)
-        domain_mx_records = Resolv::DNS.new.getresources(domain, Resolv::DNS::Resource::IN::MX)
+      def mx_records(hostname)
+        domain_mx_records = Resolv::DNS.new.getresources(hostname, 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)
@@ -53,16 +53,24 @@ def mail_servers_found?
         !mail_servers.empty?
       end
 
+      def domain
+        result.domain
+      end
+
       def hosts_from_mx_records?
-        fetch_target_hosts(mx_records(result.domain))
+        fetch_target_hosts(mx_records(domain))
         mail_servers_found?
       end
 
+      def a_record(hostname)
+        Resolv.getaddress(hostname)
+      end
+
       def hosts_from_cname_records?
-        cname_records = Resolv::DNS.new.getresources(result.domain, Resolv::DNS::Resource::IN::CNAME)
+        cname_records = Resolv::DNS.new.getresources(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)
+          host = a_record(cname_record.name.to_s)
           hostname = Resolv.getname(host)
           found_hosts = mx_records(hostname)
           fetch_target_hosts(found_hosts.empty? ? [host] : found_hosts)
@@ -71,7 +79,7 @@ def hosts_from_cname_records?
       end
 
       def host_from_a_record?
-        fetch_target_hosts([Resolv.getaddress(result.domain)])
+        fetch_target_hosts([a_record(domain)])
         mail_servers_found?
       end
     end

lib/truemail/validate/smtp.rb

@@ -4,7 +4,7 @@ module Truemail
   module Validate
     class Smtp < Truemail::Validate::Base
       ERROR = 'smtp error'
-      ERROR_BODY = /(?=.*550)(?=.*(user|account)).*/i
+      ERROR_BODY = /(?=.*550)(?=.*(user|account|customer|mailbox)).*/i
 
       attr_reader :smtp_results
 

lib/truemail/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Truemail
-  VERSION = '0.1.6'
+  VERSION = '0.1.7'
 end

lib/truemail/worker.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module Truemail
+  class Worker
+    attr_reader :result
+
+    def self.check(result)
+      new(result).run
+    end
+
+    def initialize(result)
+      @result = result
+    end
+
+    private
+
+    def success(condition)
+      result.success = condition || false
+    end
+  end
+end