Refactor to put all cache into Dns class

Author: IvanTakarlikov-st

lib/valid_email2/address.rb

@@ -132,24 +132,7 @@ def domain_is_in?(domain_list)
     end
 
     def mx_server_is_in?(domain_list)
-      mx_servers = @dns.mx_servers(address.domain)
-
-      cache_key = generate_mx_cache_key(domain_list, mx_servers)
-
-      return self.class.cache_mx_server_is_in[cache_key] if !cache_key.nil? && self.class.cache_mx_server_is_in.key?(cache_key)
-
-      result = mx_servers.any? do |mx_server|
-        return false unless mx_server.respond_to?(:exchange)
-
-        mx_server = mx_server.exchange.to_s
-
-        domain_list.any? do |domain|
-          mx_server.end_with?(domain) && mx_server =~ /\A(?:.+\.)*?#{domain}\z/
-        end
-      end
-
-      self.class.cache_mx_server_is_in[cache_key] = result unless cache_key.nil?
-      result
+      @dns.mx_servers_disposable?(address.domain, domain_list)
     end
 
     def address_contain_multibyte_characters?
@@ -164,18 +147,5 @@ def null_mx?
       mx_servers = @dns.mx_servers(address.domain)
       mx_servers.length == 1 && mx_servers.first.preference == 0 && mx_servers.first.exchange.length == 0
     end
-
-    def generate_mx_cache_key(domain_list, mx_servers)
-      return nil if mx_servers.length == 0 || domain_list.length == 0
-
-      mx_servers_str = mx_servers.map(&:exchange).map(&:to_s).sort.join
-      return address.domain if mx_servers_str == ""
-
-      "#{domain_list.object_id}_#{domain_list.length}_#{mx_servers_str.downcase}"
-    end
-
-    def self.cache_mx_server_is_in
-      @cache_mx_server_is_in
-    end
   end
 end

lib/valid_email2/dns.rb

@@ -4,7 +4,7 @@ module ValidEmail2
   class Dns
     MAX_CACHE_SIZE = 1_000
     CACHE = {}
-
+    MX_SERVERS_CACHE = {}
     CacheEntry = Struct.new(:records, :cached_at, :ttl)
 
     def self.prune_cache
@@ -26,6 +26,26 @@ def mx_servers(domain)
       fetch(domain, Resolv::DNS::Resource::IN::MX)
     end
 
+    def mx_servers_disposable?(domain, domain_list)
+      servers = mx_servers(domain)
+      cache_key = generate_mx_cache_key(domain, domain_list, servers)
+      return MX_SERVERS_CACHE[cache_key] if !cache_key.nil? && MX_SERVERS_CACHE.key?(cache_key)
+
+      result = servers.any? do |mx_server|
+        return false unless mx_server.respond_to?(:exchange)
+
+        mx_server = mx_server.exchange.to_s
+
+        domain_list.any? do |disposable_domain|
+          mx_server.end_with?(disposable_domain) && mx_server =~ /\A(?:.+\.)*?#{disposable_domain}\z/
+        end
+      end
+
+      MX_SERVERS_CACHE[cache_key] = result unless cache_key.nil?
+
+      result
+    end
+
     def a_servers(domain)
       fetch(domain, Resolv::DNS::Resource::IN::A)
     end
@@ -67,5 +87,14 @@ def resolv_config
       config[:nameserver] = @dns_nameserver if @dns_nameserver
       config
     end
+
+    def generate_mx_cache_key(domain, domain_list, mx_servers)
+      return nil if mx_servers.empty? || domain_list.empty?
+
+      mx_servers_str = mx_servers.map(&:exchange).map(&:to_s).sort.join
+      return domain if mx_servers_str == ""
+
+      "#{domain_list.object_id}_#{domain_list.length}_#{mx_servers_str.downcase}"
+    end
   end
 end