Don't define unnecessary accessors with ActiveRecord Adapter.

Without DB connection, ActiveRecord doesn't define methods for columns
and AttrEncrypted define attr_reader and attr_writer for the encrypted
columns.
As a result, AR model with attr_encrypted column return nil for the
target column if the DB connection was lost at the load time.

To suppress this behavior, don't define accessors if DB connection was
active.
Introduce attribute_instance_methods_as_symbols_available? to detect
connection failure with AcriveRecord Adapter.

lib/attr_encrypted.rb

@@ -143,16 +143,19 @@ def attr_encrypted(*attributes)
       encrypted_attribute_name = (options[:attribute] ? options[:attribute] : [options[:prefix], attribute, options[:suffix]].join).to_sym
 
       instance_methods_as_symbols = attribute_instance_methods_as_symbols
-      attr_reader encrypted_attribute_name unless instance_methods_as_symbols.include?(encrypted_attribute_name)
-      attr_writer encrypted_attribute_name unless instance_methods_as_symbols.include?(:"#{encrypted_attribute_name}=")
 
-      iv_name = "#{encrypted_attribute_name}_iv".to_sym
-      attr_reader iv_name unless instance_methods_as_symbols.include?(iv_name)
-      attr_writer iv_name unless instance_methods_as_symbols.include?(:"#{iv_name}=")
+      if attribute_instance_methods_as_symbols_available?
+        attr_reader encrypted_attribute_name unless instance_methods_as_symbols.include?(encrypted_attribute_name)
+        attr_writer encrypted_attribute_name unless instance_methods_as_symbols.include?(:"#{encrypted_attribute_name}=")
 
-      salt_name = "#{encrypted_attribute_name}_salt".to_sym
-      attr_reader salt_name unless instance_methods_as_symbols.include?(salt_name)
-      attr_writer salt_name unless instance_methods_as_symbols.include?(:"#{salt_name}=")
+        iv_name = "#{encrypted_attribute_name}_iv".to_sym
+        attr_reader iv_name unless instance_methods_as_symbols.include?(iv_name)
+        attr_writer iv_name unless instance_methods_as_symbols.include?(:"#{iv_name}=")
+
+        salt_name = "#{encrypted_attribute_name}_salt".to_sym
+        attr_reader salt_name unless instance_methods_as_symbols.include?(salt_name)
+        attr_writer salt_name unless instance_methods_as_symbols.include?(:"#{salt_name}=")
+      end
 
       define_method(attribute) do
         instance_variable_get("@#{attribute}") || instance_variable_set("@#{attribute}", decrypt(attribute, send(encrypted_attribute_name)))
@@ -448,6 +451,10 @@ def attribute_instance_methods_as_symbols
     instance_methods.collect { |method| method.to_sym }
   end
 
+  def attribute_instance_methods_as_symbols_available?
+    true
+  end
+
 end
 
 

lib/attr_encrypted/adapters/active_record.rb

@@ -88,16 +88,17 @@ def attribute_instance_methods_as_symbols
             # methods returned to let ActiveRecord define the accessor methods
             # for the db columns
 
-            # Use with_connection so the connection doesn't stay pinned to the thread.
-            connected = ::ActiveRecord::Base.connection_pool.with_connection(&:active?) rescue false
-
-            if connected && table_exists?
+            if connected? && table_exists?
               columns_hash.keys.inject(super) {|instance_methods, column_name| instance_methods.concat [column_name.to_sym, :"#{column_name}="]}
             else
               super
             end
           end
 
+          def attribute_instance_methods_as_symbols_available?
+            connected? && table_exists?
+          end
+
           # Allows you to use dynamic methods like <tt>find_by_email</tt> or <tt>scoped_by_email</tt> for
           # encrypted attributes
           #