require 'active_support/core_ext/enumerable'
require 'active_support/deprecation'
module ActiveRecord
# = Active Record Attribute Methods
module AttributeMethods #:nodoc:
extend ActiveSupport::Concern
include ActiveModel::AttributeMethods
included do
include Read
include Write
include BeforeTypeCast
include Query
include PrimaryKey
include TimeZoneConversion
include Dirty
include Serialization
# Returns the value of the attribute identified by attr_name after it has been typecast (for example,
# "2004-12-12" in a data column is cast to a date object, like Date.new(2004, 12, 12)).
# (Alias for the protected read_attribute method).
def [](attr_name)
read_attribute(attr_name)
end
# Updates the attribute identified by attr_name with the specified +value+.
# (Alias for the protected write_attribute method).
def []=(attr_name, value)
write_attribute(attr_name, value)
end
end
module ClassMethods
# Generates all the attribute related methods for columns in the database
# accessors, mutators and query methods.
def define_attribute_methods
# Use a mutex; we don't want two thread simaltaneously trying to define
# attribute methods.
@attribute_methods_mutex.synchronize do
return if attribute_methods_generated?
superclass.define_attribute_methods unless self == base_class
super(column_names)
@attribute_methods_generated = true
end
end
def attribute_methods_generated?
@attribute_methods_generated ||= false
end
# We will define the methods as instance methods, but will call them as singleton
# methods. This allows us to use method_defined? to check if the method exists,
# which is fast and won't give any false positives from the ancestors (because
# there are no ancestors).
def generated_external_attribute_methods
@generated_external_attribute_methods ||= Module.new { extend self }
end
def undefine_attribute_methods
super if attribute_methods_generated?
@attribute_methods_generated = false
end
def instance_method_already_implemented?(method_name)
if dangerous_attribute_method?(method_name)
raise DangerousAttributeError, "#{method_name} is defined by ActiveRecord"
end
if [Base, Model].include?(active_record_super)
super
else
# If B < A and A defines its own attribute method, then we don't want to overwrite that.
defined = method_defined_within?(method_name, superclass, superclass.generated_attribute_methods)
defined && !ActiveRecord::Base.method_defined?(method_name) || super
end
end
# A method name is 'dangerous' if it is already defined by Active Record, but
# not by any ancestors. (So 'puts' is not dangerous but 'save' is.)
def dangerous_attribute_method?(name)
method_defined_within?(name, Base)
end
def method_defined_within?(name, klass, sup = klass.superclass)
if klass.method_defined?(name) || klass.private_method_defined?(name)
if sup.method_defined?(name) || sup.private_method_defined?(name)
klass.instance_method(name).owner != sup.instance_method(name).owner
else
true
end
else
false
end
end
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.
def attribute_names
@attribute_names ||= if !abstract_class? && table_exists?
column_names
else
[]
end
end
end
# If we haven't generated any methods yet, generate them, then
# see if we've created the method we're looking for.
def method_missing(method, *args, &block)
unless self.class.attribute_methods_generated?
self.class.define_attribute_methods
if respond_to_without_attributes?(method)
send(method, *args, &block)
else
super
end
else
super
end
end
def attribute_missing(match, *args, &block)
if self.class.columns_hash[match.attr_name]
ActiveSupport::Deprecation.warn(
"The method `#{match.method_name}', matching the attribute `#{match.attr_name}' has " \
"dispatched through method_missing. This shouldn't happen, because `#{match.attr_name}' " \
"is a column of the table. If this error has happened through normal usage of Active " \
"Record (rather than through your own code or external libraries), please report it as " \
"a bug."
)
end
super
end
def respond_to?(name, include_private = false)
self.class.define_attribute_methods unless self.class.attribute_methods_generated?
super
end
# Returns true if the given attribute is in the attributes hash
def has_attribute?(attr_name)
@attributes.has_key?(attr_name.to_s)
end
# Returns an array of names for the attributes available on this object.
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.
def attributes
Hash[@attributes.map { |name, _| [name, read_attribute(name)] }]
end
# Returns an #inspect-like string for the value of the
# attribute +attr_name+. String attributes are truncated upto 50
# characters, and 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 D..."'
#
# person.attribute_for_inspect(:created_at)
# # => '"2009-01-12 04:48:57"'
def attribute_for_inspect(attr_name)
value = read_attribute(attr_name)
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
# 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).
def attribute_present?(attribute)
value = read_attribute(attribute)
!value.nil? && !(value.respond_to?(:empty?) && value.empty?)
end
# Returns the column object for the named attribute.
def column_for_attribute(name)
# FIXME: should this return a null object for columns that don't exist?
self.class.columns_hash[name.to_s]
end
protected
def clone_attributes(reader_method = :read_attribute, attributes = {})
attribute_names.each do |name|
attributes[name] = clone_attribute_value(reader_method, name)
end
attributes
end
def clone_attribute_value(reader_method, attribute_name)
value = send(reader_method, attribute_name)
value.duplicable? ? value.clone : value
rescue TypeError, NoMethodError
value
end
def arel_attributes_with_values_for_create(pk_attribute_allowed)
arel_attributes_with_values(attributes_for_create(pk_attribute_allowed))
end
def arel_attributes_with_values_for_update(attribute_names)
arel_attributes_with_values(attributes_for_update(attribute_names))
end
def attribute_method?(attr_name)
defined?(@attributes) && @attributes.include?(attr_name)
end
private
# Returns a Hash of the Arel::Attributes and attribute values that have been
# type casted for use in an Arel insert/update method.
def arel_attributes_with_values(attribute_names)
attrs = {}
arel_table = self.class.arel_table
attribute_names.each do |name|
attrs[arel_table[name]] = typecasted_attribute_value(name)
end
attrs
end
# Filters the primary keys and readonly attributes from the attribute names.
def attributes_for_update(attribute_names)
attribute_names.select do |name|
column_for_attribute(name) && !pk_attribute?(name) && !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(pk_attribute_allowed)
@attributes.keys.select do |name|
column_for_attribute(name) && (pk_attribute_allowed || !pk_attribute?(name))
end
end
def readonly_attribute?(name)
self.class.readonly_attributes.include?(name)
end
def pk_attribute?(name)
column_for_attribute(name).primary
end
def typecasted_attribute_value(name)
if self.class.serialized_attributes.include?(name)
@attributes[name].serialized_value
else
# FIXME: we need @attributes to be used consistently.
# If the values stored in @attributes were already typecasted, this code
# could be simplified
read_attribute(name)
end
end
end
end