197 lines
7.5 KiB
Ruby
197 lines
7.5 KiB
Ruby
module PaperTrail
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class Version < ::ActiveRecord::Base
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belongs_to :item, :polymorphic => true
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validates_presence_of :event
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attr_accessible :item_type, :item_id, :event, :whodunnit, :object, :object_changes if PaperTrail.active_record_protected_attributes?
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after_create :enforce_version_limit!
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def self.with_item_keys(item_type, item_id)
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where :item_type => item_type, :item_id => item_id
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end
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def self.creates
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where :event => 'create'
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end
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def self.updates
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where :event => 'update'
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end
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def self.destroys
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where :event => 'destroy'
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end
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def self.not_creates
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where 'event <> ?', 'create'
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end
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# These methods accept a timestamp or a version and returns other versions that come before or after
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scope :subsequent, lambda { |obj|
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obj = obj.send(PaperTrail.timestamp_field) if obj.is_a?(self)
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where("#{PaperTrail.timestamp_field} > ?", obj).order("#{PaperTrail.timestamp_field} ASC")
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}
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scope :preceding, lambda { |obj|
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obj = obj.send(PaperTrail.timestamp_field) if obj.is_a?(self)
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where("#{PaperTrail.timestamp_field} < ?", obj).order("#{PaperTrail.timestamp_field} DESC")
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}
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scope :between, lambda { |start_time, end_time|
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where("#{PaperTrail.timestamp_field} > ? AND #{PaperTrail.timestamp_field} < ?", start_time, end_time).
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order("#{PaperTrail.timestamp_field} ASC")
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}
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# Restore the item from this version.
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#
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# This will automatically restore all :has_one associations as they were "at the time",
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# if they are also being versioned by PaperTrail. NOTE: this isn't always guaranteed
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# to work so you can either change the lookback period (from the default 3 seconds) or
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# opt out.
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#
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# Options:
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# :has_one set to `false` to opt out of has_one reification.
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# set to a float to change the lookback time (check whether your db supports
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# sub-second datetimes if you want them).
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def reify(options = {})
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without_identity_map do
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options[:has_one] = 3 if options[:has_one] == true
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options.reverse_merge! :has_one => false
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unless object.nil?
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attrs = PaperTrail.serializer.load object
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# Normally a polymorphic belongs_to relationship allows us
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# to get the object we belong to by calling, in this case,
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# `item`. However this returns nil if `item` has been
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# destroyed, and we need to be able to retrieve destroyed
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# objects.
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#
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# In this situation we constantize the `item_type` to get hold of
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# the class...except when the stored object's attributes
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# include a `type` key. If this is the case, the object
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# we belong to is using single table inheritance and the
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# `item_type` will be the base class, not the actual subclass.
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# If `type` is present but empty, the class is the base class.
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if item
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model = item
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# Look for attributes that exist in the model and not in this version. These attributes should be set to nil.
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(model.attribute_names - attrs.keys).each { |k| attrs[k] = nil }
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else
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inheritance_column_name = item_type.constantize.inheritance_column
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class_name = attrs[inheritance_column_name].blank? ? item_type : attrs[inheritance_column_name]
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klass = class_name.constantize
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model = klass.new
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end
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model.class.unserialize_attributes_for_paper_trail attrs
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# Set all the attributes in this version on the model
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attrs.each do |k, v|
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if model.respond_to?("#{k}=")
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model[k.to_sym] = v
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else
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logger.warn "Attribute #{k} does not exist on #{item_type} (Version id: #{id})."
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end
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end
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model.send "#{model.class.version_association_name}=", self
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unless options[:has_one] == false
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reify_has_ones model, options[:has_one]
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end
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model
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end
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end
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end
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# Returns what changed in this version of the item. Cf. `ActiveModel::Dirty#changes`.
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# Returns nil if your `versions` table does not have an `object_changes` text column.
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def changeset
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return nil unless self.class.column_names.include? 'object_changes'
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@changeset ||= HashWithIndifferentAccess.new(PaperTrail.serializer.load(object_changes)).tap do |changes|
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item_type.constantize.unserialize_attribute_changes(changes)
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end rescue {}
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end
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# Returns who put the item into the state stored in this version.
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def originator
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@originator ||= previous.whodunnit rescue nil
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end
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# Returns who changed the item from the state it had in this version.
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# This is an alias for `whodunnit`.
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def terminator
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@terminator ||= whodunnit
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end
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alias_method :version_author, :terminator
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def sibling_versions(reload = false)
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@sibling_versions = nil if reload == true
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@sibling_versions ||= self.class.with_item_keys(item_type, item_id)
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end
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def next
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@next ||= sibling_versions.subsequent(self).first
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end
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def previous
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@previous ||= sibling_versions.preceding(self).first
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end
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def index
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@index ||= sibling_versions.select([PaperTrail.timestamp_field, self.class.primary_key.to_sym]).
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order("#{PaperTrail.timestamp_field} ASC").index(self)
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end
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private
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# In Rails 3.1+, calling reify on a previous version confuses the
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# IdentityMap, if enabled. This prevents insertion into the map.
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def without_identity_map(&block)
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if defined?(::ActiveRecord::IdentityMap) && ::ActiveRecord::IdentityMap.respond_to?(:without)
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::ActiveRecord::IdentityMap.without(&block)
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else
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block.call
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end
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end
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# Restore the `model`'s has_one associations as they were when this version was
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# superseded by the next (because that's what the user was looking at when they
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# made the change).
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#
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# The `lookback` sets how many seconds before the model's change we go.
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def reify_has_ones(model, lookback)
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model.class.reflect_on_all_associations(:has_one).each do |assoc|
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child = model.send assoc.name
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if child.respond_to? :version_at
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# N.B. we use version of the child as it was `lookback` seconds before the parent was updated.
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# Ideally we want the version of the child as it was just before the parent was updated...
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# but until PaperTrail knows which updates are "together" (e.g. parent and child being
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# updated on the same form), it's impossible to tell when the overall update started;
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# and therefore impossible to know when "just before" was.
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if (child_as_it_was = child.version_at(send(PaperTrail.timestamp_field) - lookback.seconds))
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child_as_it_was.attributes.each do |k,v|
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model.send(assoc.name).send :write_attribute, k.to_sym, v rescue nil
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end
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else
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model.send "#{assoc.name}=", nil
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end
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end
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end
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end
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# checks to see if a value has been set for the `version_limit` config option, and if so enforces it
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def enforce_version_limit!
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return unless PaperTrail.config.version_limit.is_a? Numeric
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previous_versions = sibling_versions.not_creates
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return unless previous_versions.size > PaperTrail.config.version_limit
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excess_previous_versions = previous_versions - previous_versions.last(PaperTrail.config.version_limit)
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excess_previous_versions.map(&:destroy)
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end
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end
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end
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