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rails/activerecord/lib/active_record/base.rb
Hiroshige Umino 55a1765942 Do not override attributes on dup by default scopes
2013-02-26 11:08:50 -08:00

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begin
require 'psych'
rescue LoadError
end
require 'yaml'
require 'set'
require 'thread'
require 'active_support/benchmarkable'
require 'active_support/dependencies'
require 'active_support/descendants_tracker'
require 'active_support/time'
require 'active_support/core_ext/class/attribute'
require 'active_support/core_ext/class/attribute_accessors'
require 'active_support/core_ext/class/delegating_attributes'
require 'active_support/core_ext/class/attribute'
require 'active_support/core_ext/array/extract_options'
require 'active_support/core_ext/hash/deep_merge'
require 'active_support/core_ext/hash/indifferent_access'
require 'active_support/core_ext/hash/slice'
require 'active_support/core_ext/string/behavior'
require 'active_support/core_ext/kernel/singleton_class'
require 'active_support/core_ext/module/delegation'
require 'active_support/core_ext/module/introspection'
require 'active_support/core_ext/object/duplicable'
require 'active_support/core_ext/object/blank'
require 'active_support/deprecation'
require 'arel'
require 'active_record/errors'
require 'active_record/log_subscriber'
require 'active_record/explain_subscriber'
module ActiveRecord #:nodoc:
# = Active Record
#
# Active Record objects don't specify their attributes directly, but rather infer them from
# the table definition with which they're linked. Adding, removing, and changing attributes
# and their type is done directly in the database. Any change is instantly reflected in the
# Active Record objects. The mapping that binds a given Active Record class to a certain
# database table will happen automatically in most common cases, but can be overwritten for the uncommon ones.
#
# See the mapping rules in table_name and the full example in link:files/activerecord/README_rdoc.html for more insight.
#
# == Creation
#
# Active Records accept constructor parameters either in a hash or as a block. The hash
# method is especially useful when you're receiving the data from somewhere else, like an
# HTTP request. It works like this:
#
# user = User.new(:name => "David", :occupation => "Code Artist")
# user.name # => "David"
#
# You can also use block initialization:
#
# user = User.new do |u|
# u.name = "David"
# u.occupation = "Code Artist"
# end
#
# And of course you can just create a bare object and specify the attributes after the fact:
#
# user = User.new
# user.name = "David"
# user.occupation = "Code Artist"
#
# == Conditions
#
# Conditions can either be specified as a string, array, or hash representing the WHERE-part of an SQL statement.
# The array form is to be used when the condition input is tainted and requires sanitization. The string form can
# be used for statements that don't involve tainted data. The hash form works much like the array form, except
# only equality and range is possible. Examples:
#
# class User < ActiveRecord::Base
# def self.authenticate_unsafely(user_name, password)
# where("user_name = '#{user_name}' AND password = '#{password}'").first
# end
#
# def self.authenticate_safely(user_name, password)
# where("user_name = ? AND password = ?", user_name, password).first
# end
#
# def self.authenticate_safely_simply(user_name, password)
# where(:user_name => user_name, :password => password).first
# end
# end
#
# The <tt>authenticate_unsafely</tt> method inserts the parameters directly into the query
# and is thus susceptible to SQL-injection attacks if the <tt>user_name</tt> and +password+
# parameters come directly from an HTTP request. The <tt>authenticate_safely</tt> and
# <tt>authenticate_safely_simply</tt> both will sanitize the <tt>user_name</tt> and +password+
# before inserting them in the query, which will ensure that an attacker can't escape the
# query and fake the login (or worse).
#
# When using multiple parameters in the conditions, it can easily become hard to read exactly
# what the fourth or fifth question mark is supposed to represent. In those cases, you can
# resort to named bind variables instead. That's done by replacing the question marks with
# symbols and supplying a hash with values for the matching symbol keys:
#
# Company.where(
# "id = :id AND name = :name AND division = :division AND created_at > :accounting_date",
# { :id => 3, :name => "37signals", :division => "First", :accounting_date => '2005-01-01' }
# ).first
#
# Similarly, a simple hash without a statement will generate conditions based on equality with the SQL AND
# operator. For instance:
#
# Student.where(:first_name => "Harvey", :status => 1)
# Student.where(params[:student])
#
# A range may be used in the hash to use the SQL BETWEEN operator:
#
# Student.where(:grade => 9..12)
#
# An array may be used in the hash to use the SQL IN operator:
#
# Student.where(:grade => [9,11,12])
#
# When joining tables, nested hashes or keys written in the form 'table_name.column_name'
# can be used to qualify the table name of a particular condition. For instance:
#
# Student.joins(:schools).where(:schools => { :category => 'public' })
# Student.joins(:schools).where('schools.category' => 'public' )
#
# == Overwriting default accessors
#
# All column values are automatically available through basic accessors on the Active Record
# object, but sometimes you want to specialize this behavior. This can be done by overwriting
# the default accessors (using the same name as the attribute) and calling
# <tt>read_attribute(attr_name)</tt> and <tt>write_attribute(attr_name, value)</tt> to actually
# change things.
#
# class Song < ActiveRecord::Base
# # Uses an integer of seconds to hold the length of the song
#
# def length=(minutes)
# write_attribute(:length, minutes.to_i * 60)
# end
#
# def length
# read_attribute(:length) / 60
# end
# end
#
# You can alternatively use <tt>self[:attribute]=(value)</tt> and <tt>self[:attribute]</tt>
# instead of <tt>write_attribute(:attribute, value)</tt> and <tt>read_attribute(:attribute)</tt>.
#
# == Attribute query methods
#
# In addition to the basic accessors, query methods are also automatically available on the Active Record object.
# Query methods allow you to test whether an attribute value is present.
#
# For example, an Active Record User with the <tt>name</tt> attribute has a <tt>name?</tt> method that you can call
# to determine whether the user has a name:
#
# user = User.new(:name => "David")
# user.name? # => true
#
# anonymous = User.new(:name => "")
# anonymous.name? # => false
#
# == Accessing attributes before they have been typecasted
#
# Sometimes you want to be able to read the raw attribute data without having the column-determined
# typecast run its course first. That can be done by using the <tt><attribute>_before_type_cast</tt>
# accessors that all attributes have. For example, if your Account model has a <tt>balance</tt> attribute,
# you can call <tt>account.balance_before_type_cast</tt> or <tt>account.id_before_type_cast</tt>.
#
# This is especially useful in validation situations where the user might supply a string for an
# integer field and you want to display the original string back in an error message. Accessing the
# attribute normally would typecast the string to 0, which isn't what you want.
#
# == Dynamic attribute-based finders
#
# Dynamic attribute-based finders are a cleaner way of getting (and/or creating) objects
# by simple queries without turning to SQL. They work by appending the name of an attribute
# to <tt>find_by_</tt>, <tt>find_last_by_</tt>, or <tt>find_all_by_</tt> and thus produces finders
# like <tt>Person.find_by_user_name</tt>, <tt>Person.find_all_by_last_name</tt>, and
# <tt>Payment.find_by_transaction_id</tt>. Instead of writing
# <tt>Person.where(:user_name => user_name).first</tt>, you just do <tt>Person.find_by_user_name(user_name)</tt>.
# And instead of writing <tt>Person.where(:last_name => last_name).all</tt>, you just do
# <tt>Person.find_all_by_last_name(last_name)</tt>.
#
# It's possible to add an exclamation point (!) on the end of the dynamic finders to get them to raise an
# <tt>ActiveRecord::RecordNotFound</tt> error if they do not return any records,
# like <tt>Person.find_by_last_name!</tt>.
#
# It's also possible to use multiple attributes in the same find by separating them with "_and_".
#
# Person.where(:user_name => user_name, :password => password).first
# Person.find_by_user_name_and_password(user_name, password) # with dynamic finder
#
# It's even possible to call these dynamic finder methods on relations and named scopes.
#
# Payment.order("created_on").find_all_by_amount(50)
# Payment.pending.find_last_by_amount(100)
#
# The same dynamic finder style can be used to create the object if it doesn't already exist.
# This dynamic finder is called with <tt>find_or_create_by_</tt> and will return the object if
# it already exists and otherwise creates it, then returns it. Protected attributes won't be set
# unless they are given in a block.
#
# # No 'Summer' tag exists
# Tag.find_or_create_by_name("Summer") # equal to Tag.create(:name => "Summer")
#
# # Now the 'Summer' tag does exist
# Tag.find_or_create_by_name("Summer") # equal to Tag.find_by_name("Summer")
#
# # Now 'Bob' exist and is an 'admin'
# User.find_or_create_by_name('Bob', :age => 40) { |u| u.admin = true }
#
# Adding an exclamation point (!) on to the end of <tt>find_or_create_by_</tt> will
# raise an <tt>ActiveRecord::RecordInvalid</tt> error if the new record is invalid.
#
# Use the <tt>find_or_initialize_by_</tt> finder if you want to return a new record without
# saving it first. Protected attributes won't be set unless they are given in a block.
#
# # No 'Winter' tag exists
# winter = Tag.find_or_initialize_by_name("Winter")
# winter.persisted? # false
#
# To find by a subset of the attributes to be used for instantiating a new object, pass a hash instead of
# a list of parameters.
#
# Tag.find_or_create_by_name(:name => "rails", :creator => current_user)
#
# That will either find an existing tag named "rails", or create a new one while setting the
# user that created it.
#
# Just like <tt>find_by_*</tt>, you can also use <tt>scoped_by_*</tt> to retrieve data. The good thing about
# using this feature is that the very first time result is returned using <tt>method_missing</tt> technique
# but after that the method is declared on the class. Henceforth <tt>method_missing</tt> will not be hit.
#
# User.scoped_by_user_name('David')
#
# == Saving arrays, hashes, and other non-mappable objects in text columns
#
# Active Record can serialize any object in text columns using YAML. To do so, you must
# specify this with a call to the class method +serialize+.
# This makes it possible to store arrays, hashes, and other non-mappable objects without doing
# any additional work.
#
# class User < ActiveRecord::Base
# serialize :preferences
# end
#
# user = User.create(:preferences => { "background" => "black", "display" => large })
# User.find(user.id).preferences # => { "background" => "black", "display" => large }
#
# You can also specify a class option as the second parameter that'll raise an exception
# if a serialized object is retrieved as a descendant of a class not in the hierarchy.
#
# class User < ActiveRecord::Base
# serialize :preferences, Hash
# end
#
# user = User.create(:preferences => %w( one two three ))
# User.find(user.id).preferences # raises SerializationTypeMismatch
#
# When you specify a class option, the default value for that attribute will be a new
# instance of that class.
#
# class User < ActiveRecord::Base
# serialize :preferences, OpenStruct
# end
#
# user = User.new
# user.preferences.theme_color = "red"
#
#
# == Single table inheritance
#
# Active Record allows inheritance by storing the name of the class in a column that by
# default is named "type" (can be changed by overwriting <tt>Base.inheritance_column</tt>).
# This means that an inheritance looking like this:
#
# class Company < ActiveRecord::Base; end
# class Firm < Company; end
# class Client < Company; end
# class PriorityClient < Client; end
#
# When you do <tt>Firm.create(:name => "37signals")</tt>, this record will be saved in
# the companies table with type = "Firm". You can then fetch this row again using
# <tt>Company.where(:name => '37signals').first</tt> and it will return a Firm object.
#
# If you don't have a type column defined in your table, single-table inheritance won't
# be triggered. In that case, it'll work just like normal subclasses with no special magic
# for differentiating between them or reloading the right type with find.
#
# Note, all the attributes for all the cases are kept in the same table. Read more:
# http://www.martinfowler.com/eaaCatalog/singleTableInheritance.html
#
# == Connection to multiple databases in different models
#
# Connections are usually created through ActiveRecord::Base.establish_connection and retrieved
# by ActiveRecord::Base.connection. All classes inheriting from ActiveRecord::Base will use this
# connection. But you can also set a class-specific connection. For example, if Course is an
# ActiveRecord::Base, but resides in a different database, you can just say <tt>Course.establish_connection</tt>
# and Course and all of its subclasses will use this connection instead.
#
# This feature is implemented by keeping a connection pool in ActiveRecord::Base that is
# a Hash indexed by the class. If a connection is requested, the retrieve_connection method
# will go up the class-hierarchy until a connection is found in the connection pool.
#
# == Exceptions
#
# * ActiveRecordError - Generic error class and superclass of all other errors raised by Active Record.
# * AdapterNotSpecified - The configuration hash used in <tt>establish_connection</tt> didn't include an
# <tt>:adapter</tt> key.
# * AdapterNotFound - The <tt>:adapter</tt> key used in <tt>establish_connection</tt> specified a
# non-existent adapter
# (or a bad spelling of an existing one).
# * AssociationTypeMismatch - The object assigned to the association wasn't of the type
# specified in the association definition.
# * SerializationTypeMismatch - The serialized object wasn't of the class specified as the second parameter.
# * ConnectionNotEstablished+ - No connection has been established. Use <tt>establish_connection</tt>
# before querying.
# * RecordNotFound - No record responded to the +find+ method. Either the row with the given ID doesn't exist
# or the row didn't meet the additional restrictions. Some +find+ calls do not raise this exception to signal
# nothing was found, please check its documentation for further details.
# * StatementInvalid - The database server rejected the SQL statement. The precise error is added in the message.
# * MultiparameterAssignmentErrors - Collection of errors that occurred during a mass assignment using the
# <tt>attributes=</tt> method. The +errors+ property of this exception contains an array of
# AttributeAssignmentError
# objects that should be inspected to determine which attributes triggered the errors.
# * AttributeAssignmentError - An error occurred while doing a mass assignment through the
# <tt>attributes=</tt> method.
# You can inspect the +attribute+ property of the exception object to determine which attribute
# triggered the error.
#
# *Note*: The attributes listed are class-level attributes (accessible from both the class and instance level).
# So it's possible to assign a logger to the class through <tt>Base.logger=</tt> which will then be used by all
# instances in the current object space.
class Base
##
# :singleton-method:
# Accepts a logger conforming to the interface of Log4r or the default Ruby 1.8+ Logger class,
# which is then passed on to any new database connections made and which can be retrieved on both
# a class and instance level by calling +logger+.
cattr_accessor :logger, :instance_writer => false
##
# :singleton-method:
# Contains the database configuration - as is typically stored in config/database.yml -
# as a Hash.
#
# For example, the following database.yml...
#
# development:
# adapter: sqlite3
# database: db/development.sqlite3
#
# production:
# adapter: sqlite3
# database: db/production.sqlite3
#
# ...would result in ActiveRecord::Base.configurations to look like this:
#
# {
# 'development' => {
# 'adapter' => 'sqlite3',
# 'database' => 'db/development.sqlite3'
# },
# 'production' => {
# 'adapter' => 'sqlite3',
# 'database' => 'db/production.sqlite3'
# }
# }
cattr_accessor :configurations, :instance_writer => false
@@configurations = {}
##
# :singleton-method:
# Determines whether to use Time.local (using :local) or Time.utc (using :utc) when pulling
# dates and times from the database. This is set to :local by default.
cattr_accessor :default_timezone, :instance_writer => false
@@default_timezone = :local
##
# :singleton-method:
# Specifies the format to use when dumping the database schema with Rails'
# Rakefile. If :sql, the schema is dumped as (potentially database-
# specific) SQL statements. If :ruby, the schema is dumped as an
# ActiveRecord::Schema file which can be loaded into any database that
# supports migrations. Use :ruby if you want to have different database
# adapters for, e.g., your development and test environments.
cattr_accessor :schema_format , :instance_writer => false
@@schema_format = :ruby
##
# :singleton-method:
# Specify whether or not to use timestamps for migration versions
cattr_accessor :timestamped_migrations , :instance_writer => false
@@timestamped_migrations = true
class << self # Class methods
def inherited(child_class) #:nodoc:
child_class.initialize_generated_modules
super
end
def initialize_generated_modules #:nodoc:
@attribute_methods_mutex = Mutex.new
# force attribute methods to be higher in inheritance hierarchy than other generated methods
generated_attribute_methods
generated_feature_methods
end
def generated_feature_methods
@generated_feature_methods ||= begin
mod = const_set(:GeneratedFeatureMethods, Module.new)
include mod
mod
end
end
# Returns a string like 'Post(id:integer, title:string, body:text)'
def inspect
if self == Base
super
elsif abstract_class?
"#{super}(abstract)"
elsif table_exists?
attr_list = columns.map { |c| "#{c.name}: #{c.type}" } * ', '
"#{super}(#{attr_list})"
else
"#{super}(Table doesn't exist)"
end
end
# Overwrite the default class equality method to provide support for association proxies.
def ===(object)
object.is_a?(self)
end
def arel_table
@arel_table ||= Arel::Table.new(table_name, arel_engine)
end
def arel_engine
@arel_engine ||= begin
if self == ActiveRecord::Base
ActiveRecord::Base
else
connection_handler.retrieve_connection_pool(self) ? self : superclass.arel_engine
end
end
end
private
def relation #:nodoc:
relation = Relation.new(self, arel_table)
if finder_needs_type_condition?
relation.where(type_condition).create_with(inheritance_column.to_sym => sti_name)
else
relation
end
end
end
public
# New objects can be instantiated as either empty (pass no construction parameter) or pre-set with
# attributes but not yet saved (pass a hash with key names matching the associated table column names).
# In both instances, valid attribute keys are determined by the column names of the associated table --
# hence you can't have attributes that aren't part of the table columns.
#
# +initialize+ respects mass-assignment security and accepts either +:as+ or +:without_protection+ options
# in the +options+ parameter.
#
# ==== Examples
# # Instantiates a single new object
# User.new(:first_name => 'Jamie')
#
# # Instantiates a single new object using the :admin mass-assignment security role
# User.new({ :first_name => 'Jamie', :is_admin => true }, :as => :admin)
#
# # Instantiates a single new object bypassing mass-assignment security
# User.new({ :first_name => 'Jamie', :is_admin => true }, :without_protection => true)
def initialize(attributes = nil, options = {})
defaults = Hash[self.class.column_defaults.map { |k, v| [k, v.duplicable? ? v.dup : v] }]
@attributes = self.class.initialize_attributes(defaults)
@association_cache = {}
@aggregation_cache = {}
@attributes_cache = {}
@new_record = true
@readonly = false
@destroyed = false
@marked_for_destruction = false
@previously_changed = {}
@changed_attributes = {}
ensure_proper_type
populate_with_current_scope_attributes
assign_attributes(attributes, options) if attributes
yield self if block_given?
run_callbacks :initialize
end
# Initialize an empty model object from +coder+. +coder+ must contain
# the attributes necessary for initializing an empty model object. For
# example:
#
# class Post < ActiveRecord::Base
# end
#
# post = Post.allocate
# post.init_with('attributes' => { 'title' => 'hello world' })
# post.title # => 'hello world'
def init_with(coder)
@attributes = self.class.initialize_attributes(coder['attributes'])
@relation = nil
@attributes_cache, @previously_changed, @changed_attributes = {}, {}, {}
@association_cache = {}
@aggregation_cache = {}
@readonly = @destroyed = @marked_for_destruction = false
@new_record = false
run_callbacks :find
run_callbacks :initialize
self
end
# Duped objects have no id assigned and are treated as new records. Note
# that this is a "shallow" copy as it copies the object's attributes
# only, not its associations. The extent of a "deep" copy is application
# specific and is therefore left to the application to implement according
# to its need.
# The dup method does not preserve the timestamps (created|updated)_(at|on).
def initialize_dup(other)
cloned_attributes = other.clone_attributes(:read_attribute_before_type_cast)
self.class.initialize_attributes(cloned_attributes, :serialized => false)
cloned_attributes.delete(self.class.primary_key)
@attributes = cloned_attributes
_run_after_initialize_callbacks if respond_to?(:_run_after_initialize_callbacks)
@changed_attributes = {}
self.class.column_defaults.each do |attr, orig_value|
@changed_attributes[attr] = orig_value if _field_changed?(attr, orig_value, @attributes[attr])
end
@aggregation_cache = {}
@association_cache = {}
@attributes_cache = {}
@new_record = true
ensure_proper_type
super
end
# Backport dup from 1.9 so that initialize_dup() gets called
unless Object.respond_to?(:initialize_dup, true)
def dup # :nodoc:
copy = super
copy.initialize_dup(self)
copy
end
end
# Populate +coder+ with attributes about this record that should be
# serialized. The structure of +coder+ defined in this method is
# guaranteed to match the structure of +coder+ passed to the +init_with+
# method.
#
# Example:
#
# class Post < ActiveRecord::Base
# end
# coder = {}
# Post.new.encode_with(coder)
# coder # => { 'id' => nil, ... }
def encode_with(coder)
coder['attributes'] = attributes
end
# Returns true if +comparison_object+ is the same exact object, or +comparison_object+
# is of the same type and +self+ has an ID and it is equal to +comparison_object.id+.
#
# Note that new records are different from any other record by definition, unless the
# other record is the receiver itself. Besides, if you fetch existing records with
# +select+ and leave the ID out, you're on your own, this predicate will return false.
#
# Note also that destroying a record preserves its ID in the model instance, so deleted
# models are still comparable.
def ==(comparison_object)
super ||
comparison_object.instance_of?(self.class) &&
id.present? &&
comparison_object.id == id
end
alias :eql? :==
# Delegates to id in order to allow two records of the same type and id to work with something like:
# [ Person.find(1), Person.find(2), Person.find(3) ] & [ Person.find(1), Person.find(4) ] # => [ Person.find(1) ]
def hash
id.hash
end
# Freeze the attributes hash such that associations are still accessible, even on destroyed records.
def freeze
@attributes.freeze; self
end
# Returns +true+ if the attributes hash has been frozen.
def frozen?
@attributes.frozen?
end
# Allows sort on objects
def <=>(other_object)
if other_object.is_a?(self.class)
self.to_key <=> other_object.to_key
else
nil
end
end
# Returns +true+ if the record is read only. Records loaded through joins with piggy-back
# attributes will be marked as read only since they cannot be saved.
def readonly?
@readonly
end
# Marks this record as read only.
def readonly!
@readonly = true
end
# Returns the contents of the record as a nicely formatted string.
def inspect
inspection = if @attributes
self.class.column_names.collect { |name|
if has_attribute?(name)
"#{name}: #{attribute_for_inspect(name)}"
end
}.compact.join(", ")
else
"not initialized"
end
"#<#{self.class} #{inspection}>"
end
# Hackery to accomodate Syck. Remove for 4.0.
def to_yaml(opts = {}) #:nodoc:
if YAML.const_defined?(:ENGINE) && !YAML::ENGINE.syck?
super
else
coder = {}
encode_with(coder)
YAML.quick_emit(self, opts) do |out|
out.map(taguri, to_yaml_style) do |map|
coder.each { |k, v| map.add(k, v) }
end
end
end
end
# Hackery to accomodate Syck. Remove for 4.0.
def yaml_initialize(tag, coder) #:nodoc:
init_with(coder)
end
private
# Under Ruby 1.9, Array#flatten will call #to_ary (recursively) on each of the elements
# of the array, and then rescues from the possible NoMethodError. If those elements are
# ActiveRecord::Base's, then this triggers the various method_missing's that we have,
# which significantly impacts upon performance.
#
# So we can avoid the method_missing hit by explicitly defining #to_ary as nil here.
#
# See also http://tenderlovemaking.com/2011/06/28/til-its-ok-to-return-nil-from-to_ary/
def to_ary # :nodoc:
nil
end
include ActiveRecord::Persistence
extend ActiveModel::Naming
extend QueryCache::ClassMethods
extend ActiveSupport::Benchmarkable
extend ActiveSupport::DescendantsTracker
extend Querying
include ReadonlyAttributes
include ModelSchema
extend Translation
include Inheritance
include Scoping
extend DynamicMatchers
include Sanitization
include AttributeAssignment
include ActiveModel::Conversion
include Integration
include Validations
extend CounterCache
include Locking::Optimistic, Locking::Pessimistic
include AttributeMethods
include Callbacks, ActiveModel::Observing, Timestamp
include Associations
include IdentityMap
include ActiveModel::SecurePassword
extend Explain
# AutosaveAssociation needs to be included before Transactions, because we want
# #save_with_autosave_associations to be wrapped inside a transaction.
include AutosaveAssociation, NestedAttributes
include Aggregations, Transactions, Reflection, Serialization, Store
end
end
require 'active_record/connection_adapters/abstract/connection_specification'
ActiveSupport.run_load_hooks(:active_record, ActiveRecord::Base)
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