Module: ActiveRecord::AttributeMethods::ClassMethods
Relationships & Source Files | |
Defined in: | activerecord/lib/active_record/attribute_methods.rb |
Instance Method Summary
- #alias_attribute(new_name, old_name)
- #alias_attribute_method_definition(code_generator, pattern, new_name, old_name)
-
#attribute_method?(attribute) ⇒ Boolean
Returns
true
ifattribute
is an attribute method and table exists,false
otherwise. -
#attribute_names
Returns an array of column names as strings if it’s not an abstract class and table exists.
-
#dangerous_class_method?(method_name) ⇒ Boolean
A class method is ‘dangerous’ if it is already (re)defined by Active Record, but not by any ancestors.
-
#has_attribute?(attr_name) ⇒ Boolean
Returns true if the given attribute exists, otherwise false.
-
#instance_method_already_implemented?(method_name) ⇒ Boolean
Raises an
::ActiveRecord::DangerousAttributeError
exception when an Active Record method is defined in the model, otherwisefalse
.
Instance Method Details
#alias_attribute(new_name, old_name)
[ GitHub ]# File 'activerecord/lib/active_record/attribute_methods.rb', line 53
def alias_attribute(new_name, old_name) super if @alias_attributes_mass_generated ActiveSupport::CodeGenerator.batch(generated_attribute_methods, __FILE__, __LINE__) do |code_generator| generate_alias_attribute_methods(code_generator, new_name, old_name) end end end
#alias_attribute_method_definition(code_generator, pattern, new_name, old_name)
[ GitHub ]# File 'activerecord/lib/active_record/attribute_methods.rb', line 85
def alias_attribute_method_definition(code_generator, pattern, new_name, old_name) method_name = pattern.method_name(new_name).to_s target_name = pattern.method_name(old_name).to_s parameters = pattern.parameters old_name = old_name.to_s method_defined = method_defined?(target_name) || private_method_defined?(target_name) manually_defined = method_defined && !self.instance_method(target_name).owner.is_a?(GeneratedAttributeMethods) reserved_method_name = ::ActiveRecord::AttributeMethods.dangerous_attribute_methods.include?(target_name) if !abstract_class? && !has_attribute?(old_name) # We only need to issue this deprecation warning once, so we issue it when defining the original reader method. should_warn = target_name == old_name if should_warn ActiveRecord.deprecator.warn( "#{self} model aliases `#{old_name}`, but `#{old_name}` is not an attribute. " \ "Starting in Rails 7.2, alias_attribute with non-attribute targets will raise. " \ "Use `alias_method :#{new_name}, :#{old_name}` or define the method manually." ) end super elsif manually_defined && !reserved_method_name aliased_method_redefined_as_well = method_defined_within?(method_name, self) return if aliased_method_redefined_as_well ActiveRecord.deprecator.warn( "#{self} model aliases `#{old_name}` and has a method called `#{target_name}` defined. " \ "Starting in Rails 7.2 `#{method_name}` will not be calling `#{target_name}` anymore. " \ "You may want to additionally define `#{method_name}` to preserve the current behavior." ) super else define_proxy_call(code_generator, method_name, pattern.proxy_target, parameters, old_name, namespace: :proxy_alias_attribute ) end end
#attribute_method?(attribute) ⇒ Boolean
Returns true
if attribute
is an attribute method and table exists, false
otherwise.
class Person < ActiveRecord::Base
end
Person.attribute_method?('name') # => true
Person.attribute_method?(:age=) # => true
Person.attribute_method?(:nothing) # => false
# File 'activerecord/lib/active_record/attribute_methods.rb', line 219
def attribute_method?(attribute) super || (table_exists? && column_names.include?(attribute.to_s.delete_suffix("="))) end
#attribute_names
Returns an array of column names as strings if it’s not an abstract class and table exists. Otherwise it returns an empty array.
class Person < ActiveRecord::Base
end
Person.attribute_names
# => ["id", "created_at", "updated_at", "name", "age"]
# File 'activerecord/lib/active_record/attribute_methods.rb', line 231
def attribute_names @attribute_names ||= if !abstract_class? && table_exists? attribute_types.keys else [] end.freeze end
#dangerous_class_method?(method_name) ⇒ Boolean
A class method is ‘dangerous’ if it is already (re)defined by Active Record, but not by any ancestors. (So ‘puts’ is not dangerous but ‘new’ is.)
# File 'activerecord/lib/active_record/attribute_methods.rb', line 196
def dangerous_class_method?(method_name) return true if RESTRICTED_CLASS_METHODS.include?(method_name.to_s) if Base.respond_to?(method_name, true) if Object.respond_to?(method_name, true) Base.method(method_name).owner != Object.method(method_name).owner else true end else false end end
#has_attribute?(attr_name) ⇒ Boolean
Returns true if the given attribute exists, otherwise false.
class Person < ActiveRecord::Base
alias_attribute :new_name, :name
end
Person.has_attribute?('name') # => true
Person.has_attribute?('new_name') # => true
Person.has_attribute?(:age) # => true
Person.has_attribute?(:nothing) # => false
# File 'activerecord/lib/active_record/attribute_methods.rb', line 249
def has_attribute?(attr_name) attr_name = attr_name.to_s attr_name = attribute_aliases[attr_name] || attr_name attribute_types.key?(attr_name) end
#instance_method_already_implemented?(method_name) ⇒ Boolean
Raises an ::ActiveRecord::DangerousAttributeError
exception when an Active Record method is defined in the model, otherwise false
.
class Person < ActiveRecord::Base
def save
'already defined by Active Record'
end
end
Person.instance_method_already_implemented?(:save)
# => ActiveRecord::DangerousAttributeError: save is defined by Active Record. Check to make sure that you don't have an attribute or method with the same name.
Person.instance_method_already_implemented?(:name)
# => false
# File 'activerecord/lib/active_record/attribute_methods.rb', line 160
def instance_method_already_implemented?(method_name) if dangerous_attribute_method?(method_name) raise DangerousAttributeError, "#{method_name} is defined by Active Record. Check to make sure that you don't have an attribute or method with the same name." end if superclass == Base super else # If ThisClass < ... < SomeSuperClass < ... < Base and SomeSuperClass # defines its own attribute method, then we don't want to override that. defined = method_defined_within?(method_name, superclass, Base) && ! superclass.instance_method(method_name).owner.is_a?(GeneratedAttributeMethods) defined || super end end