# frozen_string_literal: true require "mutex_m" module ActiveRecord # = Active Record Attribute Methods module AttributeMethods extend ActiveSupport::Concern include ActiveModel::AttributeMethods included do initialize_generated_modules include Read include Write include BeforeTypeCast include Query include PrimaryKey include TimeZoneConversion include Dirty include Serialization delegate :column_for_attribute, to: :class end RESTRICTED_CLASS_METHODS = %w(private public protected allocate new name parent superclass) class GeneratedAttributeMethods < Module #:nodoc: include Mutex_m end module ClassMethods def inherited(child_class) #:nodoc: child_class.initialize_generated_modules super end def initialize_generated_modules # :nodoc: @generated_attribute_methods = const_set(:GeneratedAttributeMethods, GeneratedAttributeMethods.new) private_constant :GeneratedAttributeMethods @attribute_methods_generated = false include @generated_attribute_methods super end # Generates all the attribute related methods for columns in the database # accessors, mutators and query methods. 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. generated_attribute_methods.synchronize do return false if @attribute_methods_generated superclass.define_attribute_methods unless base_class? super(attribute_names) @attribute_methods_generated = true end end def undefine_attribute_methods # :nodoc: generated_attribute_methods.synchronize do super if defined?(@attribute_methods_generated) && @attribute_methods_generated @attribute_methods_generated = false end end # 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 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 overwrite that. defined = method_defined_within?(method_name, superclass, Base) && ! superclass.instance_method(method_name).owner.is_a?(GeneratedAttributeMethods) defined || super end end # 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.) def dangerous_attribute_method?(name) # :nodoc: method_defined_within?(name, Base) end 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 # 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.) def dangerous_class_method?(method_name) RESTRICTED_CLASS_METHODS.include?(method_name.to_s) || class_method_defined_within?(method_name, Base) end def class_method_defined_within?(name, klass, superklass = klass.superclass) # :nodoc: if klass.respond_to?(name, true) if superklass.respond_to?(name, true) klass.method(name).owner != superklass.method(name).owner else true end else false end end # 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 def attribute_method?(attribute) super || (table_exists? && column_names.include?(attribute.to_s.sub(/=$/, ""))) end # 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"] def attribute_names @attribute_names ||= if !abstract_class? && table_exists? attribute_types.keys else [] end end # Returns true if the given attribute exists, otherwise false. # # class Person < ActiveRecord::Base # end # # Person.has_attribute?('name') # => true # Person.has_attribute?(:age) # => true # Person.has_attribute?(:nothing) # => false def has_attribute?(attr_name) attribute_types.key?(attr_name.to_s) end # Returns the column object for the named attribute. # Returns a +ActiveRecord::ConnectionAdapters::NullColumn+ if the # named attribute does not exist. # # class Person < ActiveRecord::Base # end # # person = Person.new # person.column_for_attribute(:name) # the result depends on the ConnectionAdapter # # => # # # person.column_for_attribute(:nothing) # # => #, ...> def column_for_attribute(name) name = name.to_s columns_hash.fetch(name) do ConnectionAdapters::NullColumn.new(name) end end end # A Person object with a name attribute can ask person.respond_to?(:name), # person.respond_to?(:name=), and person.respond_to?(:name?) # which will all return +true+. It also defines the attribute methods if they have # not been generated. # # class Person < ActiveRecord::Base # end # # person = Person.new # person.respond_to?(:name) # => true # person.respond_to?(:name=) # => true # person.respond_to?(:name?) # => true # person.respond_to?('age') # => true # person.respond_to?('age=') # => true # person.respond_to?('age?') # => true # person.respond_to?(:nothing) # => false def respond_to?(name, include_private = false) return false unless super # If the result is true then check for the select case. # For queries selecting a subset of columns, return false for unselected columns. # We check defined?(@attributes) not to issue warnings if called on objects that # have been allocated but not yet initialized. if defined?(@attributes) if name = self.class.symbol_column_to_string(name.to_sym) return has_attribute?(name) end end true end # Returns +true+ if the given attribute is in the attributes hash, otherwise +false+. # # class Person < ActiveRecord::Base # end # # person = Person.new # person.has_attribute?(:name) # => true # person.has_attribute?('age') # => true # person.has_attribute?(:nothing) # => false def has_attribute?(attr_name) @attributes.key?(attr_name.to_s) end # Returns an array of names for the attributes available on this object. # # class Person < ActiveRecord::Base # end # # person = Person.new # person.attribute_names # # => ["id", "created_at", "updated_at", "name", "age"] def attribute_names @attributes.keys end # Returns a hash of all the attributes with their names as keys and the values of the attributes as values. # # class Person < ActiveRecord::Base # end # # person = Person.create(name: 'Francesco', age: 22) # person.attributes # # => {"id"=>3, "created_at"=>Sun, 21 Oct 2012 04:53:04, "updated_at"=>Sun, 21 Oct 2012 04:53:04, "name"=>"Francesco", "age"=>22} def attributes @attributes.to_hash end # Returns an #inspect-like string for the value of the # attribute +attr_name+. String attributes are truncated up to 50 # characters, Date and Time attributes are returned in the # :db format. Other attributes return the value of # #inspect without modification. # # person = Person.create!(name: 'David Heinemeier Hansson ' * 3) # # person.attribute_for_inspect(:name) # # => "\"David Heinemeier Hansson David Heinemeier Hansson ...\"" # # person.attribute_for_inspect(:created_at) # # => "\"2012-10-22 00:15:07\"" # # person.attribute_for_inspect(:tag_ids) # # => "[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]" def attribute_for_inspect(attr_name) value = _read_attribute(attr_name) format_for_inspect(value) end # Returns +true+ if the specified +attribute+ has been set by the user or by a # database load and is neither +nil+ nor empty? (the latter only applies # to objects that respond to empty?, most notably Strings). Otherwise, +false+. # Note that it always returns +true+ with boolean attributes. # # class Task < ActiveRecord::Base # end # # task = Task.new(title: '', is_done: false) # task.attribute_present?(:title) # => false # task.attribute_present?(:is_done) # => true # task.title = 'Buy milk' # task.is_done = true # task.attribute_present?(:title) # => true # task.attribute_present?(:is_done) # => true def attribute_present?(attribute) value = _read_attribute(attribute) !value.nil? && !(value.respond_to?(:empty?) && value.empty?) end # Returns the value of the attribute identified by attr_name after it has been typecast (for example, # "2004-12-12" in a date column is cast to a date object, like Date.new(2004, 12, 12)). It raises # ActiveModel::MissingAttributeError if the identified attribute is missing. # # Note: +:id+ is always present. # # class Person < ActiveRecord::Base # belongs_to :organization # end # # person = Person.new(name: 'Francesco', age: '22') # person[:name] # => "Francesco" # person[:age] # => 22 # # person = Person.select('id').first # person[:name] # => ActiveModel::MissingAttributeError: missing attribute: name # person[:organization_id] # => ActiveModel::MissingAttributeError: missing attribute: organization_id def [](attr_name) read_attribute(attr_name) { |n| missing_attribute(n, caller) } end # Updates the attribute identified by attr_name with the specified +value+. # (Alias for the protected #write_attribute method). # # class Person < ActiveRecord::Base # end # # person = Person.new # person[:age] = '22' # person[:age] # => 22 # person[:age].class # => Integer def []=(attr_name, value) write_attribute(attr_name, value) end # Returns the name of all database fields which have been read from this # model. This can be useful in development mode to determine which fields # need to be selected. For performance critical pages, selecting only the # required fields can be an easy performance win (assuming you aren't using # all of the fields on the model). # # For example: # # class PostsController < ActionController::Base # after_action :print_accessed_fields, only: :index # # def index # @posts = Post.all # end # # private # # def print_accessed_fields # p @posts.first.accessed_fields # end # end # # Which allows you to quickly change your code to: # # class PostsController < ActionController::Base # def index # @posts = Post.select(:id, :title, :author_id, :updated_at) # end # end def accessed_fields @attributes.accessed end private def attribute_method?(attr_name) # We check defined? because Syck calls respond_to? before actually calling initialize. defined?(@attributes) && @attributes.key?(attr_name) end def attributes_with_values(attribute_names) attribute_names.each_with_object({}) do |name, attrs| attrs[name] = _read_attribute(name) end end # Filters the primary keys and readonly attributes from the attribute names. def attributes_for_update(attribute_names) attribute_names &= self.class.column_names attribute_names.delete_if do |name| self.class.readonly_attribute?(name) end end # Filters out the primary keys, from the attribute names, when the primary # key is to be generated (e.g. the id attribute has no value). def attributes_for_create(attribute_names) attribute_names &= self.class.column_names attribute_names.delete_if do |name| pk_attribute?(name) && id.nil? end end def format_for_inspect(value) if value.is_a?(String) && value.length > 50 "#{value[0, 50]}...".inspect elsif value.is_a?(Date) || value.is_a?(Time) %("#{value.to_s(:db)}") else value.inspect end end def pk_attribute?(name) name == @primary_key end end end