Module: ActiveRecord::AttributeMethods::ClassMethods
Relationships & Source Files | |
Defined in: | activerecord/lib/active_record/attribute_methods.rb |
Instance Attribute Summary
- #attribute_methods_generated? ⇒ Boolean readonly Internal use only
Instance Method Summary
-
#alias_attribute(new_name, old_name)
Allows you to make aliases for attributes.
-
#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
. - #inherited(child_class) private
- #_has_attribute?(attr_name) ⇒ Boolean Internal use only
- #alias_attribute_method_definition(code_generator, pattern, new_name, old_name) Internal use only
-
#dangerous_attribute_method?(name) ⇒ Boolean
Internal use only
A method name is ‘dangerous’ if it is already (re)defined by Active Record, but not by any ancestors.
-
#define_attribute_methods
Internal use only
Generates all the attribute related methods for columns in the database accessors, mutators and query methods.
- #eagerly_generate_alias_attribute_methods(_new_name, _old_name) Internal use only
- #generate_alias_attribute_methods(code_generator, new_name, old_name) Internal use only
- #generate_alias_attributes Internal use only
- #initialize_generated_modules Internal use only
- #method_defined_within?(name, klass, superklass = klass.superclass) ⇒ Boolean Internal use only
- #undefine_attribute_methods Internal use only
Instance Attribute Details
#attribute_methods_generated? ⇒ Boolean
(readonly)
# File 'activerecord/lib/active_record/attribute_methods.rb', line 98
def attribute_methods_generated? # :nodoc: @attribute_methods_generated end
Instance Method Details
#_has_attribute?(attr_name) ⇒ Boolean
# File 'activerecord/lib/active_record/attribute_methods.rb', line 259
def _has_attribute?(attr_name) # :nodoc: attribute_types.key?(attr_name) end
#alias_attribute(new_name, old_name)
Allows you to make aliases for attributes.
class Person < ActiveRecord::Base
alias_attribute :nickname, :name
end
person = Person.create(name: 'Bob')
person.name # => "Bob"
person.nickname # => "Bob"
The alias can also be used for querying:
Person.where(nickname: "Bob")
# SELECT "people".* FROM "people" WHERE "people"."name" = "Bob"
# File 'activerecord/lib/active_record/attribute_methods.rb', line 66
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)
# File 'activerecord/lib/active_record/attribute_methods.rb', line 87
def alias_attribute_method_definition(code_generator, pattern, new_name, old_name) # :nodoc: old_name = old_name.to_s if !abstract_class? && !has_attribute?(old_name) raise ArgumentError, "#{self.name} model aliases `#{old_name}`, but `#{old_name}` is not an attribute. " \ "Use `alias_method :#{new_name}, :#{old_name}` or define the method manually." else define_attribute_method_pattern(pattern, old_name, owner: code_generator, as: new_name, override: true) 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 223
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 235
def attribute_names @attribute_names ||= if !abstract_class? && table_exists? attribute_types.keys else [] end.freeze end
#dangerous_attribute_method?(name) ⇒ Boolean
A method name is ‘dangerous’ if it is already (re)defined by Active Record, but not by any ancestors. (So ‘puts’ is not dangerous but ‘save’ is.)
# File 'activerecord/lib/active_record/attribute_methods.rb', line 182
def dangerous_attribute_method?(name) # :nodoc: ::ActiveRecord::AttributeMethods.dangerous_attribute_methods.include?(name.to_s) 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 200
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
#define_attribute_methods
Generates all the attribute related methods for columns in the database accessors, mutators and query methods.
# File 'activerecord/lib/active_record/attribute_methods.rb', line 104
def define_attribute_methods # :nodoc: return false if @attribute_methods_generated # Use a mutex; we don't want two threads simultaneously trying to define # attribute methods. GeneratedAttributeMethods::LOCK.synchronize do return false if @attribute_methods_generated superclass.define_attribute_methods unless base_class? unless abstract_class? load_schema super(attribute_names) alias_attribute :id_value, :id if _has_attribute?("id") end @attribute_methods_generated = true generate_alias_attributes end true end
#eagerly_generate_alias_attribute_methods(_new_name, _old_name)
# File 'activerecord/lib/active_record/attribute_methods.rb', line 76
def eagerly_generate_alias_attribute_methods(_new_name, _old_name) # :nodoc: # alias attributes in Active Record are lazily generated end
#generate_alias_attribute_methods(code_generator, new_name, old_name)
# File 'activerecord/lib/active_record/attribute_methods.rb', line 80
def generate_alias_attribute_methods(code_generator, new_name, old_name) # :nodoc: attribute_method_patterns.each do |pattern| alias_attribute_method_definition(code_generator, pattern, new_name, old_name) end attribute_method_patterns_cache.clear end
#generate_alias_attributes
# File 'activerecord/lib/active_record/attribute_methods.rb', line 126
def generate_alias_attributes # :nodoc: superclass.generate_alias_attributes unless superclass == Base return if @alias_attributes_mass_generated ActiveSupport::CodeGenerator.batch(generated_attribute_methods, __FILE__, __LINE__) do |code_generator| aliases_by_attribute_name.each do |old_name, new_names| new_names.each do |new_name| generate_alias_attribute_methods(code_generator, new_name, old_name) end end end @alias_attributes_mass_generated = true 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 253
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
#inherited(child_class) (private)
[ GitHub ]# File 'activerecord/lib/active_record/attribute_methods.rb', line 264
def inherited(child_class) super child_class.initialize_generated_modules child_class.class_eval do @alias_attributes_mass_generated = false @attribute_names = nil end end
#initialize_generated_modules
# File 'activerecord/lib/active_record/attribute_methods.rb', line 42
def initialize_generated_modules # :nodoc: @generated_attribute_methods = const_set(:GeneratedAttributeMethods, GeneratedAttributeMethods.new) private_constant :GeneratedAttributeMethods @attribute_methods_generated = false @alias_attributes_mass_generated = false include @generated_attribute_methods super 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 164
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
#method_defined_within?(name, klass, superklass = klass.superclass) ⇒ Boolean
# File 'activerecord/lib/active_record/attribute_methods.rb', line 186
def method_defined_within?(name, klass, superklass = klass.superclass) # :nodoc: if klass.method_defined?(name) || klass.private_method_defined?(name) if superklass.method_defined?(name) || superklass.private_method_defined?(name) klass.instance_method(name).owner != superklass.instance_method(name).owner else true end else false end end
#undefine_attribute_methods
# File 'activerecord/lib/active_record/attribute_methods.rb', line 142
def undefine_attribute_methods # :nodoc: GeneratedAttributeMethods::LOCK.synchronize do super if @attribute_methods_generated @attribute_methods_generated = false @alias_attributes_mass_generated = false end end