1 # Copyright (c) 2005 Rick Olson
3 # Permission is hereby granted, free of charge, to any person obtaining
4 # a copy of this software and associated documentation files (the
5 # "Software"), to deal in the Software without restriction, including
6 # without limitation the rights to use, copy, modify, merge, publish,
7 # distribute, sublicense, and/or sell copies of the Software, and to
8 # permit persons to whom the Software is furnished to do so, subject to
9 # the following conditions:
11 # The above copyright notice and this permission notice shall be
12 # included in all copies or substantial portions of the Software.
14 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
15 # EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
16 # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
17 # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
18 # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
19 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
20 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
22 module ActiveRecord #:nodoc:
24 # Specify this act if you want to save a copy of the row in a versioned table. This assumes there is a
25 # versioned table ready and that your model has a version field. This works with optimistic locking if the lock_version
26 # column is present as well.
28 # The class for the versioned model is derived the first time it is seen. Therefore, if you change your database schema you have to restart
29 # your container for the changes to be reflected. In development mode this usually means restarting WEBrick.
31 # class Page < ActiveRecord::Base
32 # # assumes pages_versions table
38 # page = Page.create(:title => 'hello world!')
41 # page.title = 'hello world'
44 # page.versions.size # => 2
46 # page.revert_to(1) # using version number
47 # page.title # => 'hello world!'
49 # page.revert_to(page.versions.last) # using versioned instance
50 # page.title # => 'hello world'
52 # page.versions.earliest # efficient query to find the first version
53 # page.versions.latest # efficient query to find the most recently created version
56 # Simple Queries to page between versions
58 # page.versions.before(version)
59 # page.versions.after(version)
61 # Access the previous/next versions from the versioned model itself
63 # version = page.versions.latest
64 # version.previous # go back one version
65 # version.next # go forward one version
67 # See ActiveRecord::Acts::Versioned::ClassMethods#acts_as_versioned for configuration options
69 CALLBACKS = [:set_new_version, :save_version_on_create, :save_version?, :clear_altered_attributes]
70 def self.included(base) # :nodoc:
71 base.extend ClassMethods
75 # == Configuration options
77 # * <tt>class_name</tt> - versioned model class name (default: PageVersion in the above example)
78 # * <tt>table_name</tt> - versioned model table name (default: page_versions in the above example)
79 # * <tt>foreign_key</tt> - foreign key used to relate the versioned model to the original model (default: page_id in the above example)
80 # * <tt>inheritance_column</tt> - name of the column to save the model's inheritance_column value for STI. (default: versioned_type)
81 # * <tt>version_column</tt> - name of the column in the model that keeps the version number (default: version)
82 # * <tt>sequence_name</tt> - name of the custom sequence to be used by the versioned model.
83 # * <tt>limit</tt> - number of revisions to keep, defaults to unlimited
84 # * <tt>if</tt> - symbol of method to check before saving a new version. If this method returns false, a new version is not saved.
85 # For finer control, pass either a Proc or modify Model#version_condition_met?
87 # acts_as_versioned :if => Proc.new { |auction| !auction.expired? }
92 # def version_condition_met? # totally bypasses the <tt>:if</tt> option
97 # * <tt>if_changed</tt> - Simple way of specifying attributes that are required to be changed before saving a model. This takes
98 # either a symbol or array of symbols. WARNING - This will attempt to overwrite any attribute setters you may have.
99 # Use this instead if you want to write your own attribute setters (and ignore if_changed):
101 # def name=(new_name)
102 # write_changed_attribute :name, new_name
105 # * <tt>extend</tt> - Lets you specify a module to be mixed in both the original and versioned models. You can also just pass a block
106 # to create an anonymous mixin:
109 # acts_as_versioned do
118 # module AuctionExtension
124 # acts_as_versioned :extend => AuctionExtension
129 # @auction = Auction.find(1)
131 # @auction.versions.first.started?
135 # The model that you're versioning needs to have a 'version' attribute. The model is versioned
136 # into a table called #{model}_versions where the model name is singlular. The _versions table should
137 # contain all the fields you want versioned, the same version column, and a #{model}_id foreign key field.
139 # A lock_version field is also accepted if your model uses Optimistic Locking. If your table uses Single Table inheritance,
140 # then that field is reflected in the versioned model as 'versioned_type' by default.
142 # Acts_as_versioned comes prepared with the ActiveRecord::Acts::Versioned::ActMethods::ClassMethods#create_versioned_table
143 # method, perfect for a migration. It will also create the version column if the main model does not already have it.
145 # class AddVersions < ActiveRecord::Migration
147 # # create_versioned_table takes the same options hash
148 # # that create_table does
149 # Post.create_versioned_table
153 # Post.drop_versioned_table
157 # == Changing What Fields Are Versioned
159 # By default, acts_as_versioned will version all but these fields:
161 # [self.primary_key, inheritance_column, 'version', 'lock_version', versioned_inheritance_column]
163 # You can add or change those by modifying #non_versioned_columns. Note that this takes strings and not symbols.
165 # class Post < ActiveRecord::Base
167 # self.non_versioned_columns << 'comments_count'
170 def acts_as_versioned(options = {}, &extension)
171 # don't allow multiple calls
172 return if self.included_modules.include?(ActiveRecord::Acts::Versioned::ActMethods)
174 send :include, ActiveRecord::Acts::Versioned::ActMethods
176 cattr_accessor :versioned_class_name, :versioned_foreign_key, :versioned_table_name, :versioned_inheritance_column,
177 :version_column, :max_version_limit, :track_altered_attributes, :version_condition, :version_sequence_name, :non_versioned_columns,
178 :version_association_options
181 alias_method :non_versioned_fields, :non_versioned_columns
182 alias_method :non_versioned_fields=, :non_versioned_columns=
185 alias_method :non_versioned_fields, :non_versioned_columns
186 alias_method :non_versioned_fields=, :non_versioned_columns=
189 send :attr_accessor, :altered_attributes
191 self.versioned_class_name = options[:class_name] || "Version"
192 self.versioned_foreign_key = options[:foreign_key] || self.to_s.foreign_key
193 self.versioned_table_name = options[:table_name] || "#{table_name_prefix}#{base_class.name.demodulize.underscore}_versions#{table_name_suffix}"
194 self.versioned_inheritance_column = options[:inheritance_column] || "versioned_#{inheritance_column}"
195 self.version_column = options[:version_column] || 'version'
196 self.version_sequence_name = options[:sequence_name]
197 self.max_version_limit = options[:limit].to_i
198 self.version_condition = options[:if] || true
199 self.non_versioned_columns = [self.primary_key, inheritance_column, 'version', 'lock_version', versioned_inheritance_column]
200 self.version_association_options = {
201 :class_name => "#{self.to_s}::#{versioned_class_name}",
202 :foreign_key => versioned_foreign_key,
203 :dependent => :delete_all
204 }.merge(options[:association_options] || {})
207 extension_module_name = "#{versioned_class_name}Extension"
209 self.const_set(extension_module_name, Module.new(&extension))
212 options[:extend] = self.const_get(extension_module_name)
216 has_many :versions, version_association_options do
217 # finds earliest version of this record
219 @earliest ||= find(:first, :order => 'version')
222 # find latest version of this record
224 @latest ||= find(:first, :order => 'version desc')
227 before_save :set_new_version
228 after_create :save_version_on_create
229 after_update :save_version
230 after_save :clear_old_versions
231 after_save :clear_altered_attributes
233 unless options[:if_changed].nil?
234 self.track_altered_attributes = true
235 options[:if_changed] = [options[:if_changed]] unless options[:if_changed].is_a?(Array)
236 options[:if_changed].each do |attr_name|
237 define_method("#{attr_name}=") do |value|
238 write_changed_attribute attr_name, value
243 include options[:extend] if options[:extend].is_a?(Module)
246 # create the dynamic versioned model
247 const_set(versioned_class_name, Class.new(ActiveRecord::Base)).class_eval do
248 def self.reloadable? ; false ; end
249 # find first version before the given version
250 def self.before(version)
251 find :first, :order => 'version desc',
252 :conditions => ["#{original_class.versioned_foreign_key} = ? and version < ?", version.send(original_class.versioned_foreign_key), version.version]
255 # find first version after the given version.
256 def self.after(version)
257 find :first, :order => 'version',
258 :conditions => ["#{original_class.versioned_foreign_key} = ? and version > ?", version.send(original_class.versioned_foreign_key), version.version]
262 self.class.before(self)
266 self.class.after(self)
274 versioned_class.cattr_accessor :original_class
275 versioned_class.original_class = self
276 versioned_class.set_table_name versioned_table_name
277 versioned_class.belongs_to self.to_s.demodulize.underscore.to_sym,
278 :class_name => "::#{self.to_s}",
279 :foreign_key => versioned_foreign_key
280 versioned_class.send :include, options[:extend] if options[:extend].is_a?(Module)
281 versioned_class.set_sequence_name version_sequence_name if version_sequence_name
286 def self.included(base) # :nodoc:
287 base.extend ClassMethods
290 # Finds a specific version of this record
291 def find_version(version = nil)
292 self.class.find_version(id, version)
295 # Saves a version of the model if applicable
297 save_version_on_create if save_version?
300 # Saves a version of the model in the versioned table. This is called in the after_save callback by default
301 def save_version_on_create
302 rev = self.class.versioned_class.new
303 self.clone_versioned_model(self, rev)
304 rev.version = send(self.class.version_column)
305 rev.send("#{self.class.versioned_foreign_key}=", self.id)
309 # Clears old revisions if a limit is set with the :limit option in <tt>acts_as_versioned</tt>.
310 # Override this method to set your own criteria for clearing old versions.
311 def clear_old_versions
312 return if self.class.max_version_limit == 0
313 excess_baggage = send(self.class.version_column).to_i - self.class.max_version_limit
314 if excess_baggage > 0
315 sql = "DELETE FROM #{self.class.versioned_table_name} WHERE version <= #{excess_baggage} AND #{self.class.versioned_foreign_key} = #{self.id}"
316 self.class.versioned_class.connection.execute sql
324 # Reverts a model to a given version. Takes either a version number or an instance of the versioned model
325 def revert_to(version)
326 if version.is_a?(self.class.versioned_class)
327 return false unless version.send(self.class.versioned_foreign_key) == self.id and !version.new_record?
329 return false unless version = versions.find_by_version(version)
331 self.clone_versioned_model(version, self)
332 self.send("#{self.class.version_column}=", version.version)
336 # Reverts a model to a given version and saves the model.
337 # Takes either a version number or an instance of the versioned model
338 def revert_to!(version)
339 revert_to(version) ? save_without_revision : false
342 # Temporarily turns off Optimistic Locking while saving. Used when reverting so that a new version is not created.
343 def save_without_revision
344 save_without_revision!
350 def save_without_revision!
358 # Returns an array of attribute keys that are versioned. See non_versioned_columns
359 def versioned_attributes
360 self.attributes.keys.select { |k| !self.class.non_versioned_columns.include?(k) }
363 # If called with no parameters, gets whether the current model has changed and needs to be versioned.
364 # If called with a single parameter, gets whether the parameter has changed.
365 def changed?(attr_name = nil)
367 (!self.class.track_altered_attributes || (altered_attributes && altered_attributes.length > 0)) :
368 (altered_attributes && altered_attributes.include?(attr_name.to_s))
371 # keep old dirty? method
372 alias_method :dirty?, :changed?
374 # Clones a model. Used when saving a new version or reverting a model's version.
375 def clone_versioned_model(orig_model, new_model)
376 self.versioned_attributes.each do |key|
377 new_model.send("#{key}=", orig_model.send(key)) if orig_model.has_attribute?(key)
380 if orig_model.is_a?(self.class.versioned_class)
381 new_model[new_model.class.inheritance_column] = orig_model[self.class.versioned_inheritance_column]
382 elsif new_model.is_a?(self.class.versioned_class)
383 new_model[self.class.versioned_inheritance_column] = orig_model[orig_model.class.inheritance_column]
387 # Checks whether a new version shall be saved or not. Calls <tt>version_condition_met?</tt> and <tt>changed?</tt>.
389 version_condition_met? && changed?
392 # Checks condition set in the :if option to check whether a revision should be created or not. Override this for
393 # custom version condition checking.
394 def version_condition_met?
396 when version_condition.is_a?(Symbol)
397 send(version_condition)
398 when version_condition.respond_to?(:call) && (version_condition.arity == 1 || version_condition.arity == -1)
399 version_condition.call(self)
405 # Executes the block with the versioning callbacks disabled.
407 # @foo.without_revision do
411 def without_revision(&block)
412 self.class.without_revision(&block)
415 # Turns off optimistic locking for the duration of the block
417 # @foo.without_locking do
421 def without_locking(&block)
422 self.class.without_locking(&block)
425 def empty_callback() end #:nodoc:
428 # sets the new version before saving, unless you're using optimistic locking. In that case, let it take care of the version.
430 self.send("#{self.class.version_column}=", self.next_version) if new_record? || (!locking_enabled? && save_version?)
433 # Gets the next available version for the current record, or 1 for a new record
435 return 1 if new_record?
436 (versions.calculate(:max, :version) || 0) + 1
439 # clears current changed attributes. Called after save.
440 def clear_altered_attributes
441 self.altered_attributes = []
444 def write_changed_attribute(attr_name, attr_value)
445 # Convert to db type for comparison. Avoids failing Float<=>String comparisons.
446 attr_value_for_db = self.class.columns_hash[attr_name.to_s].type_cast(attr_value)
447 (self.altered_attributes ||= []) << attr_name.to_s unless self.changed?(attr_name) || self.send(attr_name) == attr_value_for_db
448 write_attribute(attr_name, attr_value_for_db)
452 # Finds a specific version of a specific row of this model
453 def find_version(id, version = nil)
454 return find(id) unless version
456 conditions = ["#{versioned_foreign_key} = ? AND version = ?", id, version]
457 options = { :conditions => conditions, :limit => 1 }
459 if result = find_versions(id, options).first
462 raise RecordNotFound, "Couldn't find #{name} with ID=#{id} and VERSION=#{version}"
466 # Finds versions of a specific model. Takes an options hash like <tt>find</tt>
467 def find_versions(id, options = {})
468 versioned_class.find :all, {
469 :conditions => ["#{versioned_foreign_key} = ?", id],
470 :order => 'version' }.merge(options)
473 # Returns an array of columns that are versioned. See non_versioned_columns
474 def versioned_columns
475 self.columns.select { |c| !non_versioned_columns.include?(c.name) }
478 # Returns an instance of the dynamic versioned model
480 const_get versioned_class_name
483 # Rake migration task to create the versioned table using options passed to acts_as_versioned
484 def create_versioned_table(create_table_options = {})
485 # create version column in main table if it does not exist
486 if !self.content_columns.find { |c| %w(version lock_version).include? c.name }
487 self.connection.add_column table_name, :version, :integer
490 self.connection.create_table(versioned_table_name, create_table_options) do |t|
491 t.column versioned_foreign_key, :integer
492 t.column :version, :integer
496 self.versioned_columns.each do |col|
497 updated_col = col if !updated_col && %(updated_at updated_on).include?(col.name)
498 self.connection.add_column versioned_table_name, col.name, col.type,
500 :default => col.default,
502 :precision => col.precision
505 if type_col = self.columns_hash[inheritance_column]
506 self.connection.add_column versioned_table_name, versioned_inheritance_column, type_col.type,
507 :limit => type_col.limit,
508 :default => type_col.default,
509 :scale => type_col.scale,
510 :precision => type_col.precision
514 self.connection.add_column versioned_table_name, :updated_at, :timestamp
518 # Rake migration task to drop the versioned table
519 def drop_versioned_table
520 self.connection.drop_table versioned_table_name
523 # Executes the block with the versioning callbacks disabled.
525 # Foo.without_revision do
529 def without_revision(&block)
531 CALLBACKS.each do |attr_name|
532 alias_method "orig_#{attr_name}".to_sym, attr_name
533 alias_method attr_name, :empty_callback
539 CALLBACKS.each do |attr_name|
540 alias_method attr_name, "orig_#{attr_name}".to_sym
545 # Turns off optimistic locking for the duration of the block
547 # Foo.without_locking do
551 def without_locking(&block)
552 current = ActiveRecord::Base.lock_optimistically
553 ActiveRecord::Base.lock_optimistically = false if current
555 ActiveRecord::Base.lock_optimistically = true if current
564 ActiveRecord::Base.send :include, ActiveRecord::Acts::Versioned