require 'yaml'
require 'active_record/deprecated_finders'
module ActiveRecord #:nodoc:
class ActiveRecordError < StandardError #:nodoc:
end
class SubclassNotFound < ActiveRecordError #:nodoc:
end
class AssociationTypeMismatch < ActiveRecordError #:nodoc:
end
class SerializationTypeMismatch < ActiveRecordError #:nodoc:
end
class AdapterNotSpecified < ActiveRecordError # :nodoc:
end
class AdapterNotFound < ActiveRecordError # :nodoc:
end
class ConnectionNotEstablished < ActiveRecordError #:nodoc:
end
class ConnectionFailed < ActiveRecordError #:nodoc:
end
class RecordNotFound < ActiveRecordError #:nodoc:
end
class StatementInvalid < ActiveRecordError #:nodoc:
end
class PreparedStatementInvalid < ActiveRecordError #:nodoc:
end
class StaleObjectError < ActiveRecordError #:nodoc:
end
class ConfigurationError < StandardError #:nodoc:
end
class ReadOnlyRecord < StandardError #:nodoc:
end
class AttributeAssignmentError < ActiveRecordError #:nodoc:
attr_reader :exception, :attribute
def initialize(message, exception, attribute)
@exception = exception
@attribute = attribute
@message = message
end
end
class MultiparameterAssignmentErrors < ActiveRecordError #:nodoc:
attr_reader :errors
def initialize(errors)
@errors = errors
end
end
# 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/README.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 a 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 or an array 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. Examples:
#
# User < ActiveRecord::Base
# def self.authenticate_unsafely(user_name, password)
# find(:first, :conditions => "user_name = '#{user_name}' AND password = '#{password}'")
# end
#
# def self.authenticate_safely(user_name, password)
# find(:first, :conditions => [ "user_name = ? AND password = ?", user_name, password ])
# 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 a HTTP request. The <tt>authenticate_safely</tt> method,
# on the other hand, 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.find(:first, [
# "id = :id AND name = :name AND division = :division AND created_at > :accounting_date",
# { :id => 3, :name => "37signals", :division => "First", :accounting_date => '2005-01-01' }
# ])
#
# == Overwriting default accessors
#
# All column values are automatically available through basic accessors on the Active Record object, but some times you
# want to specialize this behavior. This can be done by either by overwriting the default accessors (using the same
# name as the attribute) calling read_attribute(attr_name) and write_attribute(attr_name, value) to actually change things.
# Example:
#
# class Song < ActiveRecord::Base
# # Uses an integer of seconds to hold the length of the song
#
# def length=(minutes)
# write_attribute(:length, minutes * 60)
# end
#
# def length
# read_attribute(:length) / 60
# end
# end
#
# You can alternatively use self[:attribute]=(value) and self[:attribute] instead of write_attribute(:attribute, vaule) and
# read_attribute(:attribute) as a shorter form.
#
# == 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 <attribute>_before_type_cast accessors that all attributes have. For example, if your Account model
# has a balance attribute, you can call account.balance_before_type_cast or account.id_before_type_cast.
#
# 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 objects by simple queries without turning to SQL. They work by
# appending the name of an attribute to <tt>find_by_</tt> or <tt>find_all_by_</tt>, so you get finders like Person.find_by_user_name,
# Person.find_all_by_last_name, Payment.find_by_transaction_id. So instead of writing
# <tt>Person.find(:first, ["user_name = ?", user_name])</tt>, you just do <tt>Person.find_by_user_name(user_name)</tt>.
# And instead of writing <tt>Person.find(:all, ["last_name = ?", last_name])</tt>, you just do <tt>Person.find_all_by_last_name(last_name)</tt>.
#
# It's also possible to use multiple attributes in the same find by separating them with "_and_", so you get finders like
# <tt>Person.find_by_user_name_and_password</tt> or even <tt>Payment.find_by_purchaser_and_state_and_country</tt>. So instead of writing
# <tt>Person.find(:first, ["user_name = ? AND password = ?", user_name, password])</tt>, you just do
# <tt>Person.find_by_user_name_and_password(user_name, password)</tt>.
#
# It's even possible to use all the additional parameters to find. For example, the full interface for Payment.find_all_by_amount
# is actually Payment.find_all_by_amount(amount, options). And the full interface to Person.find_by_user_name is
# actually Person.find_by_user_name(user_name, options). So you could call <tt>Payment.find_all_by_amount(50, :order => "created_on")</tt>.
#
# == 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. Example:
#
# 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
# descendent of a class not in the hierarchy. Example:
#
# class User < ActiveRecord::Base
# serialize :preferences, Hash
# end
#
# user = User.create(:preferences => %w( one two three ))
# User.find(user.id).preferences # raises SerializationTypeMismatch
#
# == Single table inheritance
#
# Active Record allows inheritance by storing the name of the class in a column that by default is called "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 Firm.create(:name => "37signals"), this record will be saved in the companies table with type = "Firm". You can then
# fetch this row again using Company.find(:first, "name = '37signals'") 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 a ActiveRecord::Base, but resides in a different database you can just say Course.establish_connection
# and Course *and all 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 a
# <tt>:adapter</tt> key.
# * +AdapterNotFound+ -- the <tt>:adapter</tt> key used in <tt>establish_connection</tt> specified an 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 object serialized 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.
# * +StatementInvalid+ -- the database server rejected the SQL statement. The precise error is added in the message.
# Either the record with the given ID doesn't exist or the record didn't meet the additional restrictions.
# * +MultiparameterAssignmentErrors+ -- collection of errors that occurred during a mass assignment using the
# +attributes=+ 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 +attributes=+ 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 Base.logger= which will then be used by all
# instances in the current object space.
class Base
# 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
# Returns the connection currently associated with the class. This can
# also be used to "borrow" the connection to do database work unrelated
# to any of the specific Active Records.
def self.connection
if allow_concurrency
retrieve_connection
else
@connection ||= retrieve_connection
end
end
# Returns the connection currently associated with the class. This can
# also be used to "borrow" the connection to do database work that isn't
# easily done without going straight to SQL.
def connection
self.class.connection
end
def self.inherited(child) #:nodoc:
@@subclasses[self] ||= []
@@subclasses[self] << child
super
end
# Allow all subclasses of AR::Base to be reloaded in dev mode, unless they
# explicitly decline the honor. USE WITH CAUTION. Only AR subclasses kept
# in the framework should use the flag, so #reset_subclasses and so forth
# leave it alone.
def self.reloadable? #:nodoc:
true
end
def self.reset_subclasses
nonreloadables = []
subclasses.each do |klass|
unless klass.reloadable?
nonreloadables << klass
next
end
klass.instance_variables.each { |var| klass.send(:remove_instance_variable, var) }
klass.instance_methods(false).each { |m| klass.send :undef_method, m }
end
@@subclasses = {}
nonreloadables.each { |klass| (@@subclasses[klass.superclass] ||= []) << klass }
end
@@subclasses = {}
cattr_accessor :configurations
@@configurations = {}
# Accessor for the prefix type that will be prepended to every primary key column name. The options are :table_name and
# :table_name_with_underscore. If the first is specified, the Product class will look for "productid" instead of "id" as
# the primary column. If the latter is specified, the Product class will look for "product_id" instead of "id". Remember
# that this is a global setting for all Active Records.
cattr_accessor :primary_key_prefix_type
@@primary_key_prefix_type = nil
# Accessor for the name of the prefix string to prepend to every table name. So if set to "basecamp_", all
# table names will be named like "basecamp_projects", "basecamp_people", etc. This is a convenient way of creating a namespace
# for tables in a shared database. By default, the prefix is the empty string.
cattr_accessor :table_name_prefix
@@table_name_prefix = ""
# Works like +table_name_prefix+, but appends instead of prepends (set to "_basecamp" gives "projects_basecamp",
# "people_basecamp"). By default, the suffix is the empty string.
cattr_accessor :table_name_suffix
@@table_name_suffix = ""
# Indicates whether or not table names should be the pluralized versions of the corresponding class names.
# If true, the default table name for a +Product+ class will be +products+. If false, it would just be +product+.
# See table_name for the full rules on table/class naming. This is true, by default.
cattr_accessor :pluralize_table_names
@@pluralize_table_names = true
# Determines whether or not to use ANSI codes to colorize the logging statements committed by the connection adapter. These colors
# make it much easier to overview things during debugging (when used through a reader like +tail+ and on a black background), but
# may complicate matters if you use software like syslog. This is true, by default.
cattr_accessor :colorize_logging
@@colorize_logging = true
# 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
@@default_timezone = :local
# Determines whether or not to use a connection for each thread, or a single shared connection for all threads.
# Defaults to true; Railties' WEBrick server sets this to false.
cattr_accessor :allow_concurrency
@@allow_concurrency = true
# Determines whether to speed up access by generating optimized reader
# methods to avoid expensive calls to method_missing when accessing
# attributes by name. You might want to set this to false in development
# mode, because the methods would be regenerated on each request.
cattr_accessor :generate_read_methods
@@generate_read_methods = true
# 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
@@schema_format = :sql
class << self # Class methods
# Find operates with three different retrieval approaches:
#
# * Find by id: This can either be a specific id (1), a list of ids (1, 5, 6), or an array of ids ([5, 6, 10]).
# If no record can be found for all of the listed ids, then RecordNotFound will be raised.
# * Find first: This will return the first record matched by the options used. These options can either be specific
# conditions or merely an order. If no record can matched, nil is returned.
# * Find all: This will return all the records matched by the options used. If no records are found, an empty array is returned.
#
# All approaches accept an option hash as their last parameter. The options are:
#
# * <tt>:conditions</tt>: An SQL fragment like "administrator = 1" or [ "user_name = ?", username ]. See conditions in the intro.
# * <tt>:order</tt>: An SQL fragment like "created_at DESC, name".
# * <tt>:limit</tt>: An integer determining the limit on the number of rows that should be returned.
# * <tt>:offset</tt>: An integer determining the offset from where the rows should be fetched. So at 5, it would skip the first 4 rows.
# * <tt>:joins</tt>: An SQL fragment for additional joins like "LEFT JOIN comments ON comments.post_id = id". (Rarely needed).
# The records will be returned read-only since they will have attributes that do not correspond to the table's columns.
# Pass :readonly => false to override.
# * <tt>:include</tt>: Names associations that should be loaded alongside using LEFT OUTER JOINs. The symbols named refer
# to already defined associations. See eager loading under Associations.
# * <tt>:select</tt>: By default, this is * as in SELECT * FROM, but can be changed if you for example want to do a join, but not
# include the joined columns.
# * <tt>:readonly</tt>: Mark the returned records read-only so they cannot be saved or updated.
#
# Examples for find by id:
# Person.find(1) # returns the object for ID = 1
# Person.find(1, 2, 6) # returns an array for objects with IDs in (1, 2, 6)
# Person.find([7, 17]) # returns an array for objects with IDs in (7, 17)
# Person.find([1]) # returns an array for objects the object with ID = 1
# Person.find(1, :conditions => "administrator = 1", :order => "created_on DESC")
#
# Examples for find first:
# Person.find(:first) # returns the first object fetched by SELECT * FROM people
# Person.find(:first, :conditions => [ "user_name = ?", user_name])
# Person.find(:first, :order => "created_on DESC", :offset => 5)
#
# Examples for find all:
# Person.find(:all) # returns an array of objects for all the rows fetched by SELECT * FROM people
# Person.find(:all, :conditions => [ "category IN (?)", categories], :limit => 50)
# Person.find(:all, :offset => 10, :limit => 10)
# Person.find(:all, :include => [ :account, :friends ])
def find(*args)
options = extract_options_from_args!(args)
# :joins implies :readonly => true if unset.
if options[:joins] and !options.has_key?(:readonly)
options[:readonly] = true
end
case args.first
when :first
find(:all, options.merge(options[:include] ? { } : { :limit => 1 })).first
when :all
records = options[:include] ? find_with_associations(options) : find_by_sql(construct_finder_sql(options))
records.each { |record| record.readonly! } if options[:readonly]
records
else
return args.first if args.first.kind_of?(Array) && args.first.empty?
expects_array = args.first.kind_of?(Array)
conditions = " AND (#{sanitize_sql(options[:conditions])})" if options[:conditions]
ids = args.flatten.compact.uniq
case ids.size
when 0
raise RecordNotFound, "Couldn't find #{name} without an ID#{conditions}"
when 1
if result = find(:first, options.merge({ :conditions => "#{table_name}.#{primary_key} = #{sanitize(ids.first)}#{conditions}" }))
return expects_array ? [ result ] : result
else
raise RecordNotFound, "Couldn't find #{name} with ID=#{ids.first}#{conditions}"
end
else
# Find multiple ids
ids_list = ids.map { |id| sanitize(id) }.join(',')
result = find(:all, options.merge({ :conditions => "#{table_name}.#{primary_key} IN (#{ids_list})#{conditions}"}))
if result.size == ids.size
return result
else
raise RecordNotFound, "Couldn't find all #{name.pluralize} with IDs (#{ids_list})#{conditions}"
end
end
end
end
# Works like find(:all), but requires a complete SQL string. Examples:
# Post.find_by_sql "SELECT p.*, c.author FROM posts p, comments c WHERE p.id = c.post_id"
# Post.find_by_sql ["SELECT * FROM posts WHERE author = ? AND created > ?", author_id, start_date]
def find_by_sql(sql)
connection.select_all(sanitize_sql(sql), "#{name} Load").collect! { |record| instantiate(record) }
end
# Returns true if the given +id+ represents the primary key of a record in the database, false otherwise.
# Example:
# Person.exists?(5)
def exists?(id)
!find(:first, :conditions => ["#{primary_key} = ?", id]).nil? rescue false
end
# Creates an object, instantly saves it as a record (if the validation permits it), and returns it. If the save
# fails under validations, the unsaved object is still returned.
def create(attributes = nil)
if attributes.is_a?(Array)
attributes.collect { |attr| create(attr) }
else
object = new(attributes)
object.save
object
end
end
# Finds the record from the passed +id+, instantly saves it with the passed +attributes+ (if the validation permits it),
# and returns it. If the save fails under validations, the unsaved object is still returned.
def update(id, attributes)
if id.is_a?(Array)
idx = -1
id.collect { |id| idx += 1; update(id, attributes[idx]) }
else
object = find(id)
object.update_attributes(attributes)
object
end
end
# Deletes the record with the given +id+ without instantiating an object first. If an array of ids is provided, all of them
# are deleted.
def delete(id)
delete_all([ "#{primary_key} IN (?)", id ])
end
# Destroys the record with the given +id+ by instantiating the object and calling #destroy (all the callbacks are the triggered).
# If an array of ids is provided, all of them are destroyed.
def destroy(id)
id.is_a?(Array) ? id.each { |id| destroy(id) } : find(id).destroy
end
# Updates all records with the SET-part of an SQL update statement in +updates+ and returns an integer with the number of rows updated.
# A subset of the records can be selected by specifying +conditions+. Example:
# Billing.update_all "category = 'authorized', approved = 1", "author = 'David'"
def update_all(updates, conditions = nil)
sql = "UPDATE #{table_name} SET #{sanitize_sql(updates)} "
add_conditions!(sql, conditions)
connection.update(sql, "#{name} Update")
end
# Destroys the objects for all the records that match the +condition+ by instantiating each object and calling
# the destroy method. Example:
# Person.destroy_all "last_login < '2004-04-04'"
def destroy_all(conditions = nil)
find(:all, :conditions => conditions).each { |object| object.destroy }
end
# Deletes all the records that match the +condition+ without instantiating the objects first (and hence not
# calling the destroy method). Example:
# Post.destroy_all "person_id = 5 AND (category = 'Something' OR category = 'Else')"
def delete_all(conditions = nil)
sql = "DELETE FROM #{table_name} "
add_conditions!(sql, conditions)
connection.delete(sql, "#{name} Delete all")
end
# Returns the number of records that meet the +conditions+. Zero is returned if no records match. Example:
# Product.count "sales > 1"
def count(conditions = nil, joins = nil)
sql = "SELECT COUNT(*) FROM #{table_name} "
sql << " #{joins} " if joins
add_conditions!(sql, conditions)
count_by_sql(sql)
end
# Returns the result of an SQL statement that should only include a COUNT(*) in the SELECT part.
# Product.count_by_sql "SELECT COUNT(*) FROM sales s, customers c WHERE s.customer_id = c.id"
def count_by_sql(sql)
sql = sanitize_conditions(sql)
connection.select_value(sql, "#{name} Count").to_i
end
# Increments the specified counter by one. So <tt>DiscussionBoard.increment_counter("post_count",
# discussion_board_id)</tt> would increment the "post_count" counter on the board responding to discussion_board_id.
# This is used for caching aggregate values, so that they don't need to be computed every time. Especially important
# for looping over a collection where each element require a number of aggregate values. Like the DiscussionBoard
# that needs to list both the number of posts and comments.
def increment_counter(counter_name, id)
update_all "#{counter_name} = #{counter_name} + 1", "#{primary_key} = #{quote(id)}"
end
# Works like increment_counter, but decrements instead.
def decrement_counter(counter_name, id)
update_all "#{counter_name} = #{counter_name} - 1", "#{primary_key} = #{quote(id)}"
end
# Attributes named in this macro are protected from mass-assignment, such as <tt>new(attributes)</tt> and
# <tt>attributes=(attributes)</tt>. Their assignment will simply be ignored. Instead, you can use the direct writer
# methods to do assignment. This is meant to protect sensitive attributes from being overwritten by URL/form hackers. Example:
#
# class Customer < ActiveRecord::Base
# attr_protected :credit_rating
# end
#
# customer = Customer.new("name" => David, "credit_rating" => "Excellent")
# customer.credit_rating # => nil
# customer.attributes = { "description" => "Jolly fellow", "credit_rating" => "Superb" }
# customer.credit_rating # => nil
#
# customer.credit_rating = "Average"
# customer.credit_rating # => "Average"
def attr_protected(*attributes)
write_inheritable_array("attr_protected", attributes - (protected_attributes || []))
end
# Returns an array of all the attributes that have been protected from mass-assignment.
def protected_attributes # :nodoc:
read_inheritable_attribute("attr_protected")
end
# If this macro is used, only those attributes named in it will be accessible for mass-assignment, such as
# <tt>new(attributes)</tt> and <tt>attributes=(attributes)</tt>. This is the more conservative choice for mass-assignment
# protection. If you'd rather start from an all-open default and restrict attributes as needed, have a look at
# attr_protected.
def attr_accessible(*attributes)
write_inheritable_array("attr_accessible", attributes - (accessible_attributes || []))
end
# Returns an array of all the attributes that have been made accessible to mass-assignment.
def accessible_attributes # :nodoc:
read_inheritable_attribute("attr_accessible")
end
# Specifies that the attribute by the name of +attr_name+ should be serialized before saving to the database and unserialized
# after loading from the database. The serialization is done through YAML. If +class_name+ is specified, the serialized
# object must be of that class on retrieval or +SerializationTypeMismatch+ will be raised.
def serialize(attr_name, class_name = Object)
serialized_attributes[attr_name.to_s] = class_name
end
# Returns a hash of all the attributes that have been specified for serialization as keys and their class restriction as values.
def serialized_attributes
read_inheritable_attribute("attr_serialized") or write_inheritable_attribute("attr_serialized", {})
end
# Guesses the table name (in forced lower-case) based on the name of the class in the inheritance hierarchy descending
# directly from ActiveRecord. So if the hierarchy looks like: Reply < Message < ActiveRecord, then Message is used
# to guess the table name from even when called on Reply. The rules used to do the guess are handled by the Inflector class
# in Active Support, which knows almost all common English inflections (report a bug if your inflection isn't covered).
#
# Additionally, the class-level table_name_prefix is prepended to the table_name and the table_name_suffix is appended.
# So if you have "myapp_" as a prefix, the table name guess for an Account class becomes "myapp_accounts".
#
# You can also overwrite this class method to allow for unguessable links, such as a Mouse class with a link to a
# "mice" table. Example:
#
# class Mouse < ActiveRecord::Base
# set_table_name "mice"
# end
def table_name
reset_table_name
end
def reset_table_name
name = "#{table_name_prefix}#{undecorated_table_name(class_name_of_active_record_descendant(self))}#{table_name_suffix}"
set_table_name name
name
end
# Defines the primary key field -- can be overridden in subclasses. Overwriting will negate any effect of the
# primary_key_prefix_type setting, though.
def primary_key
reset_primary_key
end
def reset_primary_key
key = 'id'
case primary_key_prefix_type
when :table_name
key = Inflector.foreign_key(class_name_of_active_record_descendant(self), false)
when :table_name_with_underscore
key = Inflector.foreign_key(class_name_of_active_record_descendant(self))
end
set_primary_key(key)
key
end
# Defines the column name for use with single table inheritance -- can be overridden in subclasses.
def inheritance_column
"type"
end
# Default sequence_name. Use set_sequence_name to override.
def sequence_name
connection.default_sequence_name(table_name, primary_key)
end
# Sets the table name to use to the given value, or (if the value
# is nil or false) to the value returned by the given block.
#
# Example:
#
# class Project < ActiveRecord::Base
# set_table_name "project"
# end
def set_table_name( value=nil, &block )
define_attr_method :table_name, value, &block
end
alias :table_name= :set_table_name
# Sets the name of the primary key column to use to the given value,
# or (if the value is nil or false) to the value returned by the given
# block.
#
# Example:
#
# class Project < ActiveRecord::Base
# set_primary_key "sysid"
# end
def set_primary_key( value=nil, &block )
define_attr_method :primary_key, value, &block
end
alias :primary_key= :set_primary_key
# Sets the name of the inheritance column to use to the given value,
# or (if the value # is nil or false) to the value returned by the
# given block.
#
# Example:
#
# class Project < ActiveRecord::Base
# set_inheritance_column do
# original_inheritance_column + "_id"
# end
# end
def set_inheritance_column( value=nil, &block )
define_attr_method :inheritance_column, value, &block
end
alias :inheritance_column= :set_inheritance_column
# Sets the name of the sequence to use when generating ids to the given
# value, or (if the value is nil or false) to the value returned by the
# given block. This is required for Oracle and is useful for any
# database which relies on sequences for primary key generation.
#
# Setting the sequence name when using other dbs will have no effect.
# If a sequence name is not explicitly set when using Oracle, it will
# default to the commonly used pattern of: #{table_name}_seq
#
# Example:
#
# class Project < ActiveRecord::Base
# set_sequence_name "projectseq" # default would have been "project_seq"
# end
def set_sequence_name( value=nil, &block )
define_attr_method :sequence_name, value, &block
end
alias :sequence_name= :set_sequence_name
# Turns the +table_name+ back into a class name following the reverse rules of +table_name+.
def class_name(table_name = table_name) # :nodoc:
# remove any prefix and/or suffix from the table name
class_name = table_name[table_name_prefix.length..-(table_name_suffix.length + 1)].camelize
class_name = class_name.singularize if pluralize_table_names
class_name
end
# Returns an array of column objects for the table associated with this class.
def columns
unless @columns
@columns = connection.columns(table_name, "#{name} Columns")
@columns.each {|column| column.primary = column.name == primary_key}
end
@columns
end
# Returns an array of column objects for the table associated with this class.
def columns_hash
@columns_hash ||= columns.inject({}) { |hash, column| hash[column.name] = column; hash }
end
def column_names
@column_names ||= columns.map { |column| column.name }
end
# Returns an array of column objects where the primary id, all columns ending in "_id" or "_count",
# and columns used for single table inheritance have been removed.
def content_columns
@content_columns ||= columns.reject { |c| c.primary || c.name =~ /(_id|_count)$/ || c.name == inheritance_column }
end
# Returns a hash of all the methods added to query each of the columns in the table with the name of the method as the key
# and true as the value. This makes it possible to do O(1) lookups in respond_to? to check if a given method for attribute
# is available.
def column_methods_hash
@dynamic_methods_hash ||= column_names.inject(Hash.new(false)) do |methods, attr|
attr_name = attr.to_s
methods[attr.to_sym] = attr_name
methods["#{attr}=".to_sym] = attr_name
methods["#{attr}?".to_sym] = attr_name
methods["#{attr}_before_type_cast".to_sym] = attr_name
methods
end
end
# Contains the names of the generated reader methods.
def read_methods
@read_methods ||= {}
end
# Resets all the cached information about columns, which will cause them to be reloaded on the next request.
def reset_column_information
read_methods.each_key {|name| undef_method(name)}
@column_names = @columns = @columns_hash = @content_columns = @dynamic_methods_hash = @read_methods = nil
end
def reset_column_information_and_inheritable_attributes_for_all_subclasses#:nodoc:
subclasses.each { |klass| klass.reset_inheritable_attributes; klass.reset_column_information }
end
# Transforms attribute key names into a more humane format, such as "First name" instead of "first_name". Example:
# Person.human_attribute_name("first_name") # => "First name"
# Deprecated in favor of just calling "first_name".humanize
def human_attribute_name(attribute_key_name) #:nodoc:
attribute_key_name.humanize
end
def descends_from_active_record? # :nodoc:
superclass == Base || !columns_hash.include?(inheritance_column)
end
def quote(object) #:nodoc:
connection.quote(object)
end
# Used to sanitize objects before they're used in an SELECT SQL-statement. Delegates to <tt>connection.quote</tt>.
def sanitize(object) #:nodoc:
connection.quote(object)
end
# Log and benchmark multiple statements in a single block. Example:
#
# Project.benchmark("Creating project") do
# project = Project.create("name" => "stuff")
# project.create_manager("name" => "David")
# project.milestones << Milestone.find(:all)
# end
#
# The benchmark is only recorded if the current level of the logger matches the <tt>log_level</tt>, which makes it
# easy to include benchmarking statements in production software that will remain inexpensive because the benchmark
# will only be conducted if the log level is low enough.
#
# The logging of the multiple statements is turned off unless <tt>use_silence</tt> is set to false.
def benchmark(title, log_level = Logger::DEBUG, use_silence = true)
if logger && logger.level == log_level
result = nil
seconds = Benchmark.realtime { result = use_silence ? silence { yield } : yield }
logger.add(log_level, "#{title} (#{'%.5f' % seconds})")
result
else
yield
end
end
# Silences the logger for the duration of the block.
def silence
old_logger_level, logger.level = logger.level, Logger::ERROR if logger
yield
ensure
logger.level = old_logger_level if logger
end
# Add constraints to all queries to the same model in the given block.
# Currently supported constraints are <tt>:conditions</tt> and <tt>:joins</tt>
#
# Article.constrain(:conditions => "blog_id = 1") do
# Article.find(1) # => SELECT * from articles WHERE blog_id = 1 AND id = 1
# end
def constrain(options = {}, &block)
begin
self.scope_constraints = options
block.call if block_given?
ensure
self.scope_constraints = nil
end
end
# Overwrite the default class equality method to provide support for association proxies.
def ===(object)
object.is_a?(self)
end
# Deprecated
def threaded_connections
allow_concurrency
end
# Deprecated
def threaded_connections=(value)
self.allow_concurrency = value
end
private
# Finder methods must instantiate through this method to work with the single-table inheritance model
# that makes it possible to create objects of different types from the same table.
def instantiate(record)
object =
if subclass_name = record[inheritance_column]
if subclass_name.empty?
allocate
else
require_association_class(subclass_name)
begin
compute_type(subclass_name).allocate
rescue NameError
raise SubclassNotFound,
"The single-table inheritance mechanism failed to locate the subclass: '#{record[inheritance_column]}'. " +
"This error is raised because the column '#{inheritance_column}' is reserved for storing the class in case of inheritance. " +
"Please rename this column if you didn't intend it to be used for storing the inheritance class " +
"or overwrite #{self.to_s}.inheritance_column to use another column for that information."
end
end
else
allocate
end
object.instance_variable_set("@attributes", record)
object
end
# Returns the name of the type of the record using the current module as a prefix. So descendents of
# MyApp::Business::Account would appear as "MyApp::Business::AccountSubclass".
def type_name_with_module(type_name)
self.name =~ /::/ ? self.name.scan(/(.*)::/).first.first + "::" + type_name : type_name
end
def construct_finder_sql(options)
sql = "SELECT #{options[:select] || '*'} FROM #{table_name} "
add_joins!(sql, options)
add_conditions!(sql, options[:conditions])
sql << " ORDER BY #{options[:order]} " if options[:order]
add_limit!(sql, options)
sql
end
def add_limit!(sql, options)
connection.add_limit_offset!(sql, options)
end
def add_joins!(sql, options)
join = scope_constraints[:joins] || options[:joins]
sql << " #{join} " if join
end
# Adds a sanitized version of +conditions+ to the +sql+ string. Note that the passed-in +sql+ string is changed.
def add_conditions!(sql, conditions)
condition_segments = [scope_constraints[:conditions]]
condition_segments << sanitize_sql(conditions) unless conditions.nil?
condition_segments << type_condition unless descends_from_active_record?
condition_segments.compact!
sql << "WHERE (#{condition_segments.join(") AND (")}) " unless condition_segments.empty?
end
def type_condition
type_condition = subclasses.inject("#{table_name}.#{inheritance_column} = '#{name.demodulize}' ") do |condition, subclass|
condition << "OR #{table_name}.#{inheritance_column} = '#{subclass.name.demodulize}' "
end
" (#{type_condition}) "
end
# Guesses the table name, but does not decorate it with prefix and suffix information.
def undecorated_table_name(class_name = class_name_of_active_record_descendant(self))
table_name = Inflector.underscore(Inflector.demodulize(class_name))
table_name = Inflector.pluralize(table_name) if pluralize_table_names
table_name
end
# Enables dynamic finders like find_by_user_name(user_name) and find_by_user_name_and_password(user_name, password) that are turned into
# find(:first, :conditions => ["user_name = ?", user_name]) and find(:first, :conditions => ["user_name = ? AND password = ?", user_name, password])
# respectively. Also works for find(:all), but using find_all_by_amount(50) that are turned into find(:all, :conditions => ["amount = ?", 50]).
#
# It's even possible to use all the additional parameters to find. For example, the full interface for find_all_by_amount
# is actually find_all_by_amount(amount, options).
def method_missing(method_id, *arguments)
method_name = method_id.id2name
if md = /find_(all_by|by)_([_a-zA-Z]\w*)/.match(method_id.to_s)
finder = md.captures.first == 'all_by' ? :all : :first
attributes = md.captures.last.split('_and_')
attributes.each { |attr_name| super unless column_methods_hash.include?(attr_name.to_sym) }
attr_index = -1
conditions = attributes.collect { |attr_name| attr_index += 1; "#{table_name}.#{attr_name} #{attribute_condition(arguments[attr_index])} " }.join(" AND ")
if arguments[attributes.length].is_a?(Hash)
find(finder, { :conditions => [conditions, *arguments[0...attributes.length]] }.update(arguments[attributes.length]))
else
# deprecated API
send("find_#{finder}", [conditions, *arguments[0...attributes.length]], *arguments[attributes.length..-1])
end
else
super
end
end
def attribute_condition(argument)
case argument
when nil then "IS ?"
when Array then "IN (?)"
else "= ?"
end
end
# Defines an "attribute" method (like #inheritance_column or
# #table_name). A new (class) method will be created with the
# given name. If a value is specified, the new method will
# return that value (as a string). Otherwise, the given block
# will be used to compute the value of the method.
#
# The original method will be aliased, with the new name being
# prefixed with "original_". This allows the new method to
# access the original value.
#
# Example:
#
# class A < ActiveRecord::Base
# define_attr_method :primary_key, "sysid"
# define_attr_method( :inheritance_column ) do
# original_inheritance_column + "_id"
# end
# end
def define_attr_method(name, value=nil, &block)
sing = class << self; self; end
sing.send :alias_method, "original_#{name}", name
if value
# use eval instead of a block to work around a memory leak in dev
# mode in fcgi
sing.class_eval "def #{name}; #{value.to_s.inspect}; end"
else
sing.send :define_method, name, &block
end
end
protected
def subclasses
@@subclasses[self] ||= []
@@subclasses[self] + extra = @@subclasses[self].inject([]) {|list, subclass| list + subclass.subclasses }
end
def scope_constraints
if allow_concurrency
Thread.current[:constraints] ||= {}
Thread.current[:constraints][self] ||= {}
else
@scope_constraints ||= {}
end
end
# backwards compatibility
alias_method :scope_constrains, :scope_constraints
def scope_constraints=(value)
if allow_concurrency
Thread.current[:constraints] ||= {}
Thread.current[:constraints][self] = value
else
@scope_constraints = value
end
end
# backwards compatibility
alias_method :scope_constrains=, :scope_constraints=
# Returns the class type of the record using the current module as a prefix. So descendents of
# MyApp::Business::Account would appear as MyApp::Business::AccountSubclass.
def compute_type(type_name)
type_name_with_module(type_name).split("::").inject(Object) do |final_type, part|
final_type.const_get(part)
end
end
# Returns the name of the class descending directly from ActiveRecord in the inheritance hierarchy.
def class_name_of_active_record_descendant(klass)
if klass.superclass == Base
klass.name
elsif klass.superclass.nil?
raise ActiveRecordError, "#{name} doesn't belong in a hierarchy descending from ActiveRecord"
else
class_name_of_active_record_descendant(klass.superclass)
end
end
# Accepts an array or string. The string is returned untouched, but the array has each value
# sanitized and interpolated into the sql statement.
# ["name='%s' and group_id='%s'", "foo'bar", 4] returns "name='foo''bar' and group_id='4'"
def sanitize_sql(ary)
return ary unless ary.is_a?(Array)
statement, *values = ary
if values.first.is_a?(Hash) and statement =~ /:\w+/
replace_named_bind_variables(statement, values.first)
elsif statement.include?('?')
replace_bind_variables(statement, values)
else
statement % values.collect { |value| connection.quote_string(value.to_s) }
end
end
alias_method :sanitize_conditions, :sanitize_sql
def replace_bind_variables(statement, values)
raise_if_bind_arity_mismatch(statement, statement.count('?'), values.size)
bound = values.dup
statement.gsub('?') { quote_bound_value(bound.shift) }
end
def replace_named_bind_variables(statement, bind_vars)
raise_if_bind_arity_mismatch(statement, statement.scan(/:(\w+)/).uniq.size, bind_vars.size)
statement.gsub(/:(\w+)/) do
match = $1.to_sym
if bind_vars.include?(match)
quote_bound_value(bind_vars[match])
else
raise PreparedStatementInvalid, "missing value for :#{match} in #{statement}"
end
end
end
def quote_bound_value(value)
if (value.respond_to?(:map) && !value.is_a?(String))
value.map { |v| connection.quote(v) }.join(',')
else
connection.quote(value)
end
end
def raise_if_bind_arity_mismatch(statement, expected, provided)
unless expected == provided
raise PreparedStatementInvalid, "wrong number of bind variables (#{provided} for #{expected}) in: #{statement}"
end
end
def extract_options_from_args!(args)
options = args.last.is_a?(Hash) ? args.pop : {}
validate_find_options(options)
options
end
def validate_find_options(options)
options.assert_valid_keys [:conditions, :include, :joins, :limit, :offset, :order, :select, :readonly]
end
def encode_quoted_value(value)
quoted_value = connection.quote(value)
quoted_value = "'#{quoted_value[1..-2].gsub(/\'/, "\\\\'")}'" if quoted_value.include?("\\\'") # (for ruby mode) "
quoted_value
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.
def initialize(attributes = nil)
@attributes = attributes_from_column_definition
@new_record = true
ensure_proper_type
self.attributes = attributes unless attributes.nil?
yield self if block_given?
end
# Every Active Record class must use "id" as their primary ID. This getter overwrites the native
# id method, which isn't being used in this context.
def id
attr_name = self.class.primary_key
column = column_for_attribute(attr_name)
raise ActiveRecordError, "No such primary key column #{attr_name} for table #{table_name}" if column.nil?
define_read_method(:id, attr_name, column) if self.class.generate_read_methods
(value = @attributes[attr_name]) && column.type_cast(value)
end
# Enables Active Record objects to be used as URL parameters in Action Pack automatically.
alias_method :to_param, :id
def id_before_type_cast #:nodoc:
read_attribute_before_type_cast(self.class.primary_key)
end
def quoted_id #:nodoc:
quote(id, column_for_attribute(self.class.primary_key))
end
# Sets the primary ID.
def id=(value)
write_attribute(self.class.primary_key, value)
end
# Returns true if this object hasn't been saved yet -- that is, a record for the object doesn't exist yet.
def new_record?
@new_record
end
# * No record exists: Creates a new record with values matching those of the object attributes.
# * A record does exist: Updates the record with values matching those of the object attributes.
def save
raise ActiveRecord::ReadOnlyRecord if readonly?
create_or_update
end
# Deletes the record in the database and freezes this instance to reflect that no changes should
# be made (since they can't be persisted).
def destroy
unless new_record?
connection.delete <<-end_sql, "#{self.class.name} Destroy"
DELETE FROM #{self.class.table_name}
WHERE #{self.class.primary_key} = #{quoted_id}
end_sql
end
freeze
end
# Returns a clone of the record that hasn't been assigned an id yet and is treated as a new record.
def clone
attrs = self.attributes_before_type_cast
attrs.delete(self.class.primary_key)
self.class.new do |record|
record.send :instance_variable_set, '@attributes', attrs
end
end
# Updates a single attribute and saves the record. This is especially useful for boolean flags on existing records.
# Note: This method is overwritten by the Validation module that'll make sure that updates made with this method
# doesn't get subjected to validation checks. Hence, attributes can be updated even if the full object isn't valid.
def update_attribute(name, value)
send(name.to_s + '=', value)
save
end
# Updates all the attributes from the passed-in Hash and saves the record. If the object is invalid, the saving will
# fail and false will be returned.
def update_attributes(attributes)
self.attributes = attributes
save
end
# Initializes the +attribute+ to zero if nil and adds one. Only makes sense for number-based attributes. Returns self.
def increment(attribute)
self[attribute] ||= 0
self[attribute] += 1
self
end
# Increments the +attribute+ and saves the record.
def increment!(attribute)
increment(attribute).update_attribute(attribute, self[attribute])
end
# Initializes the +attribute+ to zero if nil and subtracts one. Only makes sense for number-based attributes. Returns self.
def decrement(attribute)
self[attribute] ||= 0
self[attribute] -= 1
self
end
# Decrements the +attribute+ and saves the record.
def decrement!(attribute)
decrement(attribute).update_attribute(attribute, self[attribute])
end
# Turns an +attribute+ that's currently true into false and vice versa. Returns self.
def toggle(attribute)
self[attribute] = !send("#{attribute}?")
self
end
# Toggles the +attribute+ and saves the record.
def toggle!(attribute)
toggle(attribute).update_attribute(attribute, self[attribute])
end
# Reloads the attributes of this object from the database.
def reload
clear_association_cache
@attributes.update(self.class.find(self.id).instance_variable_get('@attributes'))
self
end
# Returns the value of the attribute identified by <tt>attr_name</tt> 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 <tt>attr_name</tt> with the specified +value+.
# (Alias for the protected write_attribute method).
def []=(attr_name, value)
write_attribute(attr_name, value)
end
# Allows you to set all the attributes at once by passing in a hash with keys
# matching the attribute names (which again matches the column names). Sensitive attributes can be protected
# from this form of mass-assignment by using the +attr_protected+ macro. Or you can alternatively
# specify which attributes *can* be accessed in with the +attr_accessible+ macro. Then all the
# attributes not included in that won't be allowed to be mass-assigned.
def attributes=(attributes)
return if attributes.nil?
attributes.stringify_keys!
multi_parameter_attributes = []
remove_attributes_protected_from_mass_assignment(attributes).each do |k, v|
k.include?("(") ? multi_parameter_attributes << [ k, v ] : send(k + "=", v)
end
assign_multiparameter_attributes(multi_parameter_attributes)
end
# Returns a hash of all the attributes with their names as keys and clones of their objects as values.
def attributes
clone_attributes :read_attribute
end
# Returns a hash of cloned attributes before typecasting and deserialization.
def attributes_before_type_cast
clone_attributes :read_attribute_before_type_cast
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.blank? or value == 0
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 sorted alphabetically.
def attribute_names
@attributes.keys.sort
end
# Returns the column object for the named attribute.
def column_for_attribute(name)
self.class.columns_hash[name.to_s]
end
# Returns true if the +comparison_object+ is the same object, or is of the same type and has the same id.
def ==(comparison_object)
comparison_object.equal?(self) ||
(comparison_object.instance_of?(self.class) &&
comparison_object.id == id &&
!comparison_object.new_record?)
end
# Delegates to ==
def eql?(comparison_object)
self == (comparison_object)
end
# 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
# For checking respond_to? without searching the attributes (which is faster).
alias_method :respond_to_without_attributes?, :respond_to?
# 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.
def respond_to?(method, include_priv = false)
if attr_name = self.class.column_methods_hash[method.to_sym]
return true if @attributes.include?(attr_name) || attr_name == self.class.primary_key
return false if self.class.read_methods.include?(attr_name)
elsif @attributes.include?(method_name = method.to_s)
return true
elsif md = /(=|\?|_before_type_cast)$/.match(method_name)
return true if @attributes.include?(md.pre_match)
end
# super must be called at the end of the method, because the inherited respond_to?
# would return true for generated readers, even if the attribute wasn't present
super
end
# Just freeze the attributes hash, such that associations are still accessible even on destroyed records.
def freeze
@attributes.freeze; self
end
def frozen?
@attributes.frozen?
end
def readonly?
@readonly == true
end
def readonly!
@readonly = true
end
private
def create_or_update
if new_record? then create else update end
end
# Updates the associated record with values matching those of the instance attributes.
def update
connection.update(
"UPDATE #{self.class.table_name} " +
"SET #{quoted_comma_pair_list(connection, attributes_with_quotes(false))} " +
"WHERE #{self.class.primary_key} = #{quote(id)}",
"#{self.class.name} Update"
)
end
# Creates a new record with values matching those of the instance attributes.
def create
self.id = connection.insert(
"INSERT INTO #{self.class.table_name} " +
"(#{quoted_column_names.join(', ')}) " +
"VALUES(#{attributes_with_quotes.values.join(', ')})",
"#{self.class.name} Create",
self.class.primary_key, self.id, self.class.sequence_name
)
@new_record = false
end
# Sets the attribute used for single table inheritance to this class name if this is not the ActiveRecord descendent.
# Considering the hierarchy Reply < Message < ActiveRecord, this makes it possible to do Reply.new without having to
# set Reply[Reply.inheritance_column] = "Reply" yourself. No such attribute would be set for objects of the
# Message class in that example.
def ensure_proper_type
unless self.class.descends_from_active_record?
write_attribute(self.class.inheritance_column, Inflector.demodulize(self.class.name))
end
end
# Allows access to the object attributes, which are held in the @attributes hash, as were
# they first-class methods. So a Person class with a name attribute can use Person#name and
# Person#name= and never directly use the attributes hash -- except for multiple assigns with
# ActiveRecord#attributes=. A Milestone class can also ask Milestone#completed? to test that
# the completed attribute is not nil or 0.
#
# It's also possible to instantiate related objects, so a Client class belonging to the clients
# table with a master_id foreign key can instantiate master through Client#master.
def method_missing(method_id, *args, &block)
method_name = method_id.to_s
if @attributes.include?(method_name)
define_read_methods if self.class.read_methods.empty? && self.class.generate_read_methods
read_attribute(method_name)
elsif self.class.primary_key.to_s == method_name
id
elsif md = /(=|\?|_before_type_cast)$/.match(method_name)
attribute_name, method_type = md.pre_match, md.to_s
if @attributes.include?(attribute_name)
case method_type
when '='
write_attribute(attribute_name, args.first)
when '?'
query_attribute(attribute_name)
when '_before_type_cast'
read_attribute_before_type_cast(attribute_name)
end
else
super
end
else
super
end
end
# Returns the value of the attribute identified by <tt>attr_name</tt> 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)).
def read_attribute(attr_name)
attr_name = attr_name.to_s
if !(value = @attributes[attr_name]).nil?
if column = column_for_attribute(attr_name)
if unserializable_attribute?(attr_name, column)
unserialize_attribute(attr_name)
else
column.type_cast(value)
end
else
value
end
else
nil
end
end
def read_attribute_before_type_cast(attr_name)
@attributes[attr_name]
end
# Called on first read access to any given column and generates reader
# methods for all columns in the columns_hash if
# ActiveRecord::Base.generate_read_methods is set to true.
def define_read_methods
self.class.columns_hash.each do |name, column|
unless self.class.serialized_attributes[name] || respond_to_without_attributes?(name)
define_read_method(name.to_sym, name, column)
end
end
end
# Define a column type specific reader method.
def define_read_method(symbol, attr_name, column)
cast_code = column.type_cast_code('v')
access_code = cast_code ? "(v=@attributes['#{attr_name}']) && #{cast_code}" : "@attributes['#{attr_name}']"
unless attr_name.to_s == self.class.primary_key.to_s
access_code = access_code.insert(0, "raise NoMethodError, 'missing attribute: #{attr_name}', caller unless @attributes.has_key?('#{attr_name}'); ")
end
self.class.class_eval("def #{symbol}; #{access_code}; end")
self.class.read_methods[attr_name] = true unless symbol == :id
end
# Returns true if the attribute is of a text column and marked for serialization.
def unserializable_attribute?(attr_name, column)
column.text? && self.class.serialized_attributes[attr_name]
end
# Returns the unserialized object of the attribute.
def unserialize_attribute(attr_name)
unserialized_object = object_from_yaml(@attributes[attr_name])
if unserialized_object.is_a?(self.class.serialized_attributes[attr_name])
@attributes[attr_name] = unserialized_object
else
raise SerializationTypeMismatch,
"#{attr_name} was supposed to be a #{self.class.serialized_attributes[attr_name]}, but was a #{unserialized_object.class.to_s}"
end
end
# Updates the attribute identified by <tt>attr_name</tt> with the specified +value+. Empty strings for fixnum and float
# columns are turned into nil.
def write_attribute(attr_name, value)
attr_name = attr_name.to_s
if (column = column_for_attribute(attr_name)) && column.number?
@attributes[attr_name] = convert_number_column_value(value)
else
@attributes[attr_name] = value
end
end
def convert_number_column_value(value)
case value
when FalseClass: 0
when TrueClass: 1
when '': nil
else value
end
end
def query_attribute(attr_name)
attribute = @attributes[attr_name]
if attribute.kind_of?(Fixnum) && attribute == 0
false
elsif attribute.kind_of?(String) && attribute == "0"
false
elsif attribute.kind_of?(String) && attribute.empty?
false
elsif attribute.nil?
false
elsif attribute == false
false
elsif attribute == "f"
false
elsif attribute == "false"
false
else
true
end
end
def remove_attributes_protected_from_mass_assignment(attributes)
if self.class.accessible_attributes.nil? && self.class.protected_attributes.nil?
attributes.reject { |key, value| attributes_protected_by_default.include?(key.gsub(/\(.+/, "")) }
elsif self.class.protected_attributes.nil?
attributes.reject { |key, value| !self.class.accessible_attributes.include?(key.gsub(/\(.+/, "").intern) || attributes_protected_by_default.include?(key.gsub(/\(.+/, "")) }
elsif self.class.accessible_attributes.nil?
attributes.reject { |key, value| self.class.protected_attributes.include?(key.gsub(/\(.+/,"").intern) || attributes_protected_by_default.include?(key.gsub(/\(.+/, "")) }
end
end
# The primary key and inheritance column can never be set by mass-assignment for security reasons.
def attributes_protected_by_default
default = [ self.class.primary_key, self.class.inheritance_column ]
default << 'id' unless self.class.primary_key.eql? 'id'
default
end
# Returns copy of the attributes hash where all the values have been safely quoted for use in
# an SQL statement.
def attributes_with_quotes(include_primary_key = true)
attributes.inject({}) do |quoted, (name, value)|
if column = column_for_attribute(name)
quoted[name] = quote(value, column) unless !include_primary_key && column.primary
end
quoted
end
end
# Quote strings appropriately for SQL statements.
def quote(value, column = nil)
self.class.connection.quote(value, column)
end
# Interpolate custom sql string in instance context.
# Optional record argument is meant for custom insert_sql.
def interpolate_sql(sql, record = nil)
instance_eval("%@#{sql.gsub('@', '\@')}@")
end
# Initializes the attributes array with keys matching the columns from the linked table and
# the values matching the corresponding default value of that column, so
# that a new instance, or one populated from a passed-in Hash, still has all the attributes
# that instances loaded from the database would.
def attributes_from_column_definition
self.class.columns.inject({}) do |attributes, column|
attributes[column.name] = column.default unless column.name == self.class.primary_key
attributes
end
end
# Instantiates objects for all attribute classes that needs more than one constructor parameter. This is done
# by calling new on the column type or aggregation type (through composed_of) object with these parameters.
# So having the pairs written_on(1) = "2004", written_on(2) = "6", written_on(3) = "24", will instantiate
# written_on (a date type) with Date.new("2004", "6", "24"). You can also specify a typecast character in the
# parentheses to have the parameters typecasted before they're used in the constructor. Use i for Fixnum, f for Float,
# s for String, and a for Array. If all the values for a given attribute is empty, the attribute will be set to nil.
def assign_multiparameter_attributes(pairs)
execute_callstack_for_multiparameter_attributes(
extract_callstack_for_multiparameter_attributes(pairs)
)
end
# Includes an ugly hack for Time.local instead of Time.new because the latter is reserved by Time itself.
def execute_callstack_for_multiparameter_attributes(callstack)
errors = []
callstack.each do |name, values|
klass = (self.class.reflect_on_aggregation(name) || column_for_attribute(name)).klass
if values.empty?
send(name + "=", nil)
else
begin
send(name + "=", Time == klass ? klass.local(*values) : klass.new(*values))
rescue => ex
errors << AttributeAssignmentError.new("error on assignment #{values.inspect} to #{name}", ex, name)
end
end
end
unless errors.empty?
raise MultiparameterAssignmentErrors.new(errors), "#{errors.size} error(s) on assignment of multiparameter attributes"
end
end
def extract_callstack_for_multiparameter_attributes(pairs)
attributes = { }
for pair in pairs
multiparameter_name, value = pair
attribute_name = multiparameter_name.split("(").first
attributes[attribute_name] = [] unless attributes.include?(attribute_name)
unless value.empty?
attributes[attribute_name] <<
[ find_parameter_position(multiparameter_name), type_cast_attribute_value(multiparameter_name, value) ]
end
end
attributes.each { |name, values| attributes[name] = values.sort_by{ |v| v.first }.collect { |v| v.last } }
end
def type_cast_attribute_value(multiparameter_name, value)
multiparameter_name =~ /\([0-9]*([a-z])\)/ ? value.send("to_" + $1) : value
end
def find_parameter_position(multiparameter_name)
multiparameter_name.scan(/\(([0-9]*).*\)/).first.first
end
# Returns a comma-separated pair list, like "key1 = val1, key2 = val2".
def comma_pair_list(hash)
hash.inject([]) { |list, pair| list << "#{pair.first} = #{pair.last}" }.join(", ")
end
def quoted_column_names(attributes = attributes_with_quotes)
attributes.keys.collect do |column_name|
self.class.connection.quote_column_name(column_name)
end
end
def quote_columns(quoter, hash)
hash.inject({}) do |quoted, (name, value)|
quoted[quoter.quote_column_name(name)] = value
quoted
end
end
def quoted_comma_pair_list(quoter, hash)
comma_pair_list(quote_columns(quoter, hash))
end
def object_from_yaml(string)
return string unless string.is_a?(String)
YAML::load(string) rescue string
end
def clone_attributes(reader_method = :read_attribute, attributes = {})
self.attribute_names.inject(attributes) do |attributes, name|
attributes[name] = clone_attribute_value(reader_method, name)
attributes
end
end
def clone_attribute_value(reader_method, attribute_name)
value = send(reader_method, attribute_name)
value.clone
rescue TypeError, NoMethodError
value
end
end
end
