Module: ActiveModel::AttributeMethods::ClassMethods
Relationships & Source Files | |
Namespace Children | |
Classes:
| |
Defined in: | activemodel/lib/active_model/attribute_methods.rb |
Instance Method Summary
-
#alias_attribute(new_name, old_name)
Allows you to make aliases for attributes.
-
#attribute_alias(name)
Returns the original name for the alias
name
-
#attribute_alias?(new_name) ⇒ Boolean
Is
new_name
an alias? -
#attribute_method_affix(*affixes)
Declares a method available for all attributes with the given prefix and suffix.
-
#attribute_method_prefix(*prefixes, parameters: nil)
Declares a method available for all attributes with the given prefix.
-
#attribute_method_suffix(*suffixes, parameters: nil)
Declares a method available for all attributes with the given suffix.
-
#define_attribute_method(attr_name, _owner: generated_attribute_methods, as: attr_name)
Declares an attribute that should be prefixed and suffixed by
::ActiveModel::AttributeMethods
. -
#define_attribute_methods(*attr_names)
Declares the attributes that should be prefixed and suffixed by
::ActiveModel::AttributeMethods
. -
#undefine_attribute_methods
Removes all the previously dynamically defined methods from the class, including alias attribute methods.
-
#attribute_method_patterns_cache
private
The methods #method_missing and #respond_to? of this module are invoked often in a typical rails, both of which invoke the method #matched_attribute_method.
- #attribute_method_patterns_matching(method_name) private
- #build_mangled_name(name) private
- #define_call(code_generator, name, target_name, mangled_name, parameters, call_args, namespace:, as:) private
-
#define_proxy_call(code_generator, name, proxy_target, parameters, *call_args, namespace:, as: name)
private
Define a method
name
inmod
that dispatches tosend
using the givenextra
args. - #generated_attribute_methods private
- #instance_method_already_implemented?(method_name) ⇒ Boolean private
- #resolve_attribute_name(name) private
- #alias_attribute_method_definition(code_generator, pattern, new_name, old_name) Internal use only
- #aliases_by_attribute_name Internal use only
- #define_attribute_method_pattern(pattern, attr_name, owner:, as:, override: false) Internal use only
- #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
- #inherited(base) private Internal use only
Instance Method Details
#alias_attribute(new_name, old_name)
Allows you to make aliases for attributes.
class Person
include ActiveModel::AttributeMethods
attr_accessor :name
attribute_method_suffix '_short?'
define_attribute_methods :name
alias_attribute :nickname, :name
private
def attribute_short?(attr)
send(attr).length < 5
end
end
person = Person.new
person.name = 'Bob'
person.name # => "Bob"
person.nickname # => "Bob"
person.name_short? # => true
person.nickname_short? # => true
# File 'activemodel/lib/active_model/attribute_methods.rb', line 203
def alias_attribute(new_name, old_name) old_name = old_name.to_s new_name = new_name.to_s self.attribute_aliases = attribute_aliases.merge(new_name => old_name) aliases_by_attribute_name[old_name] << new_name eagerly_generate_alias_attribute_methods(new_name, old_name) end
#alias_attribute_method_definition(code_generator, pattern, new_name, old_name)
# File 'activemodel/lib/active_model/attribute_methods.rb', line 226
def alias_attribute_method_definition(code_generator, pattern, new_name, old_name) # :nodoc: method_name = pattern.method_name(new_name).to_s target_name = pattern.method_name(old_name).to_s parameters = pattern.parameters mangled_name = build_mangled_name(target_name) call_args = [] call_args << parameters if parameters define_call(code_generator, method_name, target_name, mangled_name, parameters, call_args, namespace: :alias_attribute, as: method_name) end
#aliases_by_attribute_name
# File 'activemodel/lib/active_model/attribute_methods.rb', line 382
def aliases_by_attribute_name # :nodoc: @aliases_by_attribute_name ||= Hash.new { |h, k| h[k] = [] } end
#attribute_alias(name)
Returns the original name for the alias name
# File 'activemodel/lib/active_model/attribute_methods.rb', line 245
def attribute_alias(name) attribute_aliases[name.to_s] end
#attribute_alias?(new_name) ⇒ Boolean
Is new_name
an alias?
# File 'activemodel/lib/active_model/attribute_methods.rb', line 240
def attribute_alias?(new_name) attribute_aliases.key? new_name.to_s end
#attribute_method_affix(*affixes)
Declares a method available for all attributes with the given prefix and suffix. Uses ActiveModel::AttributeMethods#method_missing and ActiveModel::AttributeMethods#respond_to? to rewrite the method.
#{prefix}#{attr}#{suffix}(*args, &block)
to
#{prefix}attribute#{suffix}(#{attr}, *args, &block)
An #{prefix}attribute#{suffix}
instance method must exist and accept at least the attr
argument.
class Person
include ActiveModel::AttributeMethods
attr_accessor :name
attribute_method_affix prefix: 'reset_', suffix: '_to_default!'
define_attribute_methods :name
private
def reset_attribute_to_default!(attr)
send("#{attr}=", 'Default Name')
end
end
person = Person.new
person.name # => 'Gem'
person.reset_name_to_default!
person.name # => 'Default Name'
# File 'activemodel/lib/active_model/attribute_methods.rb', line 175
def attribute_method_affix(*affixes) self.attribute_method_patterns += affixes.map! { |affix| AttributeMethodPattern.new(**affix) } undefine_attribute_methods end
#attribute_method_patterns_cache (private)
The methods ActiveModel::AttributeMethods#method_missing and ActiveModel::AttributeMethods#respond_to? of this module are invoked often in a typical rails, both of which invoke the method ActiveModel::AttributeMethods#matched_attribute_method. The latter method iterates through an array doing regular expression matches, which results in a lot of object creations. Most of the time it returns a nil
match. As the match result is always the same given a method_name
, this cache is used to alleviate the GC, which ultimately also speeds up the app significantly (in our case our test suite finishes 10% faster with this cache).
# File 'activemodel/lib/active_model/attribute_methods.rb', line 417
def attribute_method_patterns_cache @attribute_method_patterns_cache ||= Concurrent::Map.new(initial_capacity: 4) end
#attribute_method_patterns_matching(method_name) (private)
[ GitHub ]# File 'activemodel/lib/active_model/attribute_methods.rb', line 421
def attribute_method_patterns_matching(method_name) attribute_method_patterns_cache.compute_if_absent(method_name) do attribute_method_patterns.filter_map { |pattern| pattern.match(method_name) } end end
#attribute_method_prefix(*prefixes, parameters: nil)
Declares a method available for all attributes with the given prefix. Uses ActiveModel::AttributeMethods#method_missing and ActiveModel::AttributeMethods#respond_to? to rewrite the method.
#{prefix}#{attr}(*args, &block)
to
#{prefix}attribute(#{attr}, *args, &block)
An instance method #{prefix}attribute
must exist and accept at least the attr
argument.
class Person
include ActiveModel::AttributeMethods
attr_accessor :name
attribute_method_prefix 'clear_'
define_attribute_methods :name
private
def clear_attribute(attr)
send("#{attr}=", nil)
end
end
person = Person.new
person.name = 'Bob'
person.name # => "Bob"
person.clear_name
person.name # => nil
# File 'activemodel/lib/active_model/attribute_methods.rb', line 106
def attribute_method_prefix(*prefixes, parameters: nil) self.attribute_method_patterns += prefixes.map! { |prefix| AttributeMethodPattern.new(prefix: prefix, parameters: parameters) } undefine_attribute_methods end
#attribute_method_suffix(*suffixes, parameters: nil)
Declares a method available for all attributes with the given suffix. Uses ActiveModel::AttributeMethods#method_missing and ActiveModel::AttributeMethods#respond_to? to rewrite the method.
#{attr}#{suffix}(*args, &block)
to
attribute#{suffix}(#{attr}, *args, &block)
An attribute#{suffix}
instance method must exist and accept at least the attr
argument.
class Person
include ActiveModel::AttributeMethods
attr_accessor :name
attribute_method_suffix '_short?'
define_attribute_methods :name
private
def attribute_short?(attr)
send(attr).length < 5
end
end
person = Person.new
person.name = 'Bob'
person.name # => "Bob"
person.name_short? # => true
# File 'activemodel/lib/active_model/attribute_methods.rb', line 140
def attribute_method_suffix(*suffixes, parameters: nil) self.attribute_method_patterns += suffixes.map! { |suffix| AttributeMethodPattern.new(suffix: suffix, parameters: parameters) } undefine_attribute_methods end
#build_mangled_name(name) (private)
[ GitHub ]# File 'activemodel/lib/active_model/attribute_methods.rb', line 445
def build_mangled_name(name) mangled_name = name unless NAME_COMPILABLE_REGEXP.match?(name) mangled_name = :"__temp__#{name.unpack1("h*")}" end mangled_name end
#define_attribute_method(attr_name, _owner: generated_attribute_methods, as: attr_name)
Declares an attribute that should be prefixed and suffixed by ::ActiveModel::AttributeMethods
.
To use, pass an attribute name (as string or symbol). Be sure to declare define_attribute_method
after you define any prefix, suffix or affix method, or they will not hook in.
class Person
include ActiveModel::AttributeMethods
attr_accessor :name
attribute_method_suffix '_short?'
# Call to define_attribute_method must appear after the
# attribute_method_prefix, attribute_method_suffix or
# attribute_method_affix declarations.
define_attribute_method :name
private
def attribute_short?(attr)
send(attr).length < 5
end
end
person = Person.new
person.name = 'Bob'
person.name # => "Bob"
person.name_short? # => true
# File 'activemodel/lib/active_model/attribute_methods.rb', line 311
def define_attribute_method(attr_name, _owner: generated_attribute_methods, as: attr_name) ActiveSupport::CodeGenerator.batch(_owner, __FILE__, __LINE__) do |owner| attribute_method_patterns.each do |pattern| define_attribute_method_pattern(pattern, attr_name, owner: owner, as: as) end attribute_method_patterns_cache.clear end end
#define_attribute_method_pattern(pattern, attr_name, owner:, as:, override: false)
# File 'activemodel/lib/active_model/attribute_methods.rb', line 320
def define_attribute_method_pattern(pattern, attr_name, owner:, as:, override: false) # :nodoc: canonical_method_name = pattern.method_name(attr_name) public_method_name = pattern.method_name(as) # If defining a regular attribute method, we don't override methods that are explicitly # defined in parent classes. if instance_method_already_implemented?(public_method_name) # However, for `alias_attribute`, we always define the method. # We check for override second because `instance_method_already_implemented?` # also check for dangerous methods. return unless override end generate_method = "define_method_#{pattern.proxy_target}" if respond_to?(generate_method, true) send(generate_method, attr_name.to_s, owner: owner, as: as) else define_proxy_call( owner, canonical_method_name, pattern.proxy_target, pattern.parameters, attr_name.to_s, namespace: :active_model_proxy, as: public_method_name ) end end
#define_attribute_methods(*attr_names)
Declares the attributes that should be prefixed and suffixed by ::ActiveModel::AttributeMethods
.
To use, pass attribute names (as strings or symbols). Be sure to declare define_attribute_methods
after you define any prefix, suffix, or affix methods, or they will not hook in.
class Person
include ActiveModel::AttributeMethods
attr_accessor :name, :age, :address
attribute_method_prefix 'clear_'
# Call to define_attribute_methods must appear after the
# attribute_method_prefix, attribute_method_suffix or
# attribute_method_affix declarations.
define_attribute_methods :name, :age, :address
private
def clear_attribute(attr)
send("#{attr}=", nil)
end
end
# File 'activemodel/lib/active_model/attribute_methods.rb', line 272
def define_attribute_methods(*attr_names) ActiveSupport::CodeGenerator.batch(generated_attribute_methods, __FILE__, __LINE__) do |owner| attr_names.flatten.each do |attr_name| define_attribute_method(attr_name, _owner: owner) aliases_by_attribute_name[attr_name.to_s].each do |aliased_name| generate_alias_attribute_methods owner, aliased_name, attr_name end end end end
#define_call(code_generator, name, target_name, mangled_name, parameters, call_args, namespace:, as:) (private)
[ GitHub ]# File 'activemodel/lib/active_model/attribute_methods.rb', line 455
def define_call(code_generator, name, target_name, mangled_name, parameters, call_args, namespace:, as:) code_generator.define_cached_method(mangled_name, as: as, namespace: namespace) do |batch| body = if CALL_COMPILABLE_REGEXP.match?(target_name) "self.#{target_name}(#{call_args.join(", ")})" else call_args.unshift(":'#{target_name}'") "send(#{call_args.join(", ")})" end batch << "def #{mangled_name}(#{parameters || ''})" << body << "end" end end
#define_proxy_call(code_generator, name, proxy_target, parameters, *call_args, namespace:, as: name) (private)
Define a method name
in mod
that dispatches to send
using the given extra
args. This falls back on send
if the called name cannot be compiled.
# File 'activemodel/lib/active_model/attribute_methods.rb', line 430
def define_proxy_call(code_generator, name, proxy_target, parameters, *call_args, namespace:, as: name) mangled_name = build_mangled_name(name) call_args.map!(&:inspect) call_args << parameters if parameters # We have to use a different namespace for every target method, because # if someone defines an attribute that look like an attribute method we could clash, e.g. # attribute :title_was # attribute :title namespace = :"#{namespace}_#{proxy_target}" define_call(code_generator, name, proxy_target, mangled_name, parameters, call_args, namespace: namespace, as: as) end
#eagerly_generate_alias_attribute_methods(new_name, old_name)
# File 'activemodel/lib/active_model/attribute_methods.rb', line 211
def eagerly_generate_alias_attribute_methods(new_name, old_name) # :nodoc: ActiveSupport::CodeGenerator.batch(generated_attribute_methods, __FILE__, __LINE__) do |code_generator| generate_alias_attribute_methods(code_generator, new_name, old_name) end end
#generate_alias_attribute_methods(code_generator, new_name, old_name)
# File 'activemodel/lib/active_model/attribute_methods.rb', line 217
def generate_alias_attribute_methods(code_generator, new_name, old_name) # :nodoc: ActiveSupport::CodeGenerator.batch(code_generator, __FILE__, __LINE__) do |owner| attribute_method_patterns.each do |pattern| alias_attribute_method_definition(code_generator, pattern, new_name, old_name) end attribute_method_patterns_cache.clear end end
#generated_attribute_methods (private)
[ GitHub ]# File 'activemodel/lib/active_model/attribute_methods.rb', line 400
def generated_attribute_methods @generated_attribute_methods ||= Module.new.tap { |mod| include mod } end
#inherited(base) (private)
# File 'activemodel/lib/active_model/attribute_methods.rb', line 387
def inherited(base) # :nodoc: super base.class_eval do @attribute_method_patterns_cache = nil @aliases_by_attribute_name = nil @generated_attribute_methods = nil end end
#instance_method_already_implemented?(method_name) ⇒ Boolean
(private)
# File 'activemodel/lib/active_model/attribute_methods.rb', line 404
def instance_method_already_implemented?(method_name) generated_attribute_methods.method_defined?(method_name) end
#resolve_attribute_name(name) (private)
[ GitHub ]# File 'activemodel/lib/active_model/attribute_methods.rb', line 396
def resolve_attribute_name(name) attribute_aliases.fetch(super, &:itself) end
#undefine_attribute_methods
Removes all the previously dynamically defined methods from the class, including alias attribute methods.
class Person
include ActiveModel::AttributeMethods
attr_accessor :name
attribute_method_suffix '_short?'
define_attribute_method :name
alias_attribute :first_name, :name
private
def attribute_short?(attr)
send(attr).length < 5
end
end
person = Person.new
person.name = 'Bob'
person.first_name # => "Bob"
person.name_short? # => true
Person.undefine_attribute_methods
person.name_short? # => NoMethodError
person.first_name # => NoMethodError
# File 'activemodel/lib/active_model/attribute_methods.rb', line 375
def undefine_attribute_methods generated_attribute_methods.module_eval do undef_method(*instance_methods) end attribute_method_patterns_cache.clear end