class PaperTrail::Events::Base

We refer to times in the lifecycle of a record as “events”. There are three events:

The value inserted into the `event` column of the versions table can also be overridden by the user, with `paper_trail_event`.

@api private

Constants

RAILS_GTE_5_1

Public Class Methods

new(record, in_after_callback) click to toggle source

@api private

# File lib/mongo_trails/events/base.rb, line 28
def initialize(record, in_after_callback)
  @record = record
  @in_after_callback = in_after_callback
end

Public Instance Methods

changed_notably?() click to toggle source

Determines whether it is appropriate to generate a new version instance. A timestamp-only update (e.g. only `updated_at` changed) is considered notable unless an ignored attribute was also changed.

@api private

# File lib/mongo_trails/events/base.rb, line 38
def changed_notably?
  if ignored_attr_has_changed?
    timestamps = @record.send(:timestamp_attributes_for_update_in_model).map(&:to_s)
    (notably_changed - timestamps).any?
  else
    notably_changed.any?
  end
end

Private Instance Methods

attribute_changed_in_latest_version?(attr_name) click to toggle source

Rails 5.1 changed the API of `ActiveRecord::Dirty`. See github.com/paper-trail-gem/mongo_trails/pull/899

@api private

# File lib/mongo_trails/events/base.rb, line 53
def attribute_changed_in_latest_version?(attr_name)
  if @in_after_callback && RAILS_GTE_5_1
    @record.saved_change_to_attribute?(attr_name.to_s)
  else
    @record.attribute_changed?(attr_name.to_s)
  end
end
attribute_in_previous_version(attr_name, is_touch) click to toggle source

Rails 5.1 changed the API of `ActiveRecord::Dirty`. See github.com/paper-trail-gem/mongo_trails/pull/899

Event can be any of the three (create, update, destroy).

@api private

# File lib/mongo_trails/events/base.rb, line 93
def attribute_in_previous_version(attr_name, is_touch)
  if RAILS_GTE_5_1
    if @in_after_callback && !is_touch
      # For most events, we want the original value of the attribute, before
      # the last save.
      @record.attribute_before_last_save(attr_name.to_s)
    else
      # We are either performing a `record_destroy` or a
      # `record_update(is_touch: true)`.
      @record.attribute_in_database(attr_name.to_s)
    end
  else
    @record.attribute_was(attr_name.to_s)
  end
end
cache_changed_attributes() { || ... } click to toggle source

Rails 5.1 changed the API of `ActiveRecord::Dirty`. @api private

# File lib/mongo_trails/events/base.rb, line 76
def cache_changed_attributes
  if RAILS_GTE_5_1
    # Everything works fine as it is
    yield
  else
    # Any particular call to `changed_attributes` produces the huge memory allocation.
    # Lets use the generic AR workaround for that.
    @record.send(:cache_changed_attributes) { yield }
  end
end
calculated_ignored_array() click to toggle source

@api private

# File lib/mongo_trails/events/base.rb, line 110
def calculated_ignored_array
  ignore = @record.paper_trail_options[:ignore].dup
  # Remove Hash arguments and then evaluate whether the attributes (the
  # keys of the hash) should also get pushed into the collection.
  ignore.delete_if do |obj|
    obj.is_a?(Hash) &&
      obj.each { |attr, condition|
        ignore << attr if condition.respond_to?(:call) && condition.call(@record)
      }
  end
end
changed_and_not_ignored() click to toggle source

@api private

# File lib/mongo_trails/events/base.rb, line 123
def changed_and_not_ignored
  skip = @record.paper_trail_options[:skip]
  (changed_in_latest_version - calculated_ignored_array) - skip
end
changed_in_latest_version() click to toggle source

@api private

# File lib/mongo_trails/events/base.rb, line 129
def changed_in_latest_version
  # Memoized to reduce memory usage
  @changed_in_latest_version ||= changes_in_latest_version.keys
end
changes_in_latest_version() click to toggle source

Rails 5.1 changed the API of `ActiveRecord::Dirty`. See github.com/paper-trail-gem/mongo_trails/pull/899

@api private

# File lib/mongo_trails/events/base.rb, line 138
def changes_in_latest_version
  # Memoized to reduce memory usage
  @changes_in_latest_version ||= begin
    if @in_after_callback && RAILS_GTE_5_1
      @record.saved_changes
    else
      @record.changes
    end
  end
end
ignored_attr_has_changed?() click to toggle source

An attributed is “ignored” if it is listed in the `:ignore` option and/or the `:skip` option. Returns true if an ignored attribute has changed.

@api private

# File lib/mongo_trails/events/base.rb, line 154
def ignored_attr_has_changed?
  ignored = calculated_ignored_array + @record.paper_trail_options[:skip]
  ignored.any? && (changed_in_latest_version & ignored).any?
end
merge_item_subtype_into(data) click to toggle source

PT 10 has a new optional column, `item_subtype`

@api private

# File lib/mongo_trails/events/base.rb, line 162
def merge_item_subtype_into(data)
  if @record.class.paper_trail.version_class.fields.key?("item_subtype")
    data.merge!(item_subtype: @record.class.name)
  end
end
merge_metadata_from_controller_into(data) click to toggle source

Updates `data` from `controller_info`.

@api private

# File lib/mongo_trails/events/base.rb, line 181
def merge_metadata_from_controller_into(data)
  data.merge(PaperTrail.request.controller_info || {})
end
merge_metadata_from_model_into(data) click to toggle source

Updates `data` from the model's `meta` option.

@api private

# File lib/mongo_trails/events/base.rb, line 188
def merge_metadata_from_model_into(data)
  @record.paper_trail_options[:meta].each do |k, v|
    data[k] = model_metadatum(v, data[:event])
  end
end
merge_metadata_into(data) click to toggle source

Updates `data` from the model's `meta` option and from `controller_info`. Metadata is always recorded; that means all three events (create, update, destroy) and `update_columns`.

@api private

# File lib/mongo_trails/events/base.rb, line 173
def merge_metadata_into(data)
  merge_metadata_from_model_into(data)
  merge_metadata_from_controller_into(data)
end
model_metadatum(value, event) click to toggle source

Given a `value` from the model's `meta` option, returns an object to be persisted. The `value` can be a simple scalar value, but it can also be a symbol that names a model method, or even a Proc.

@api private

# File lib/mongo_trails/events/base.rb, line 199
def model_metadatum(value, event)
  if value.respond_to?(:call)
    value.call(@record)
  elsif value.is_a?(Symbol) && @record.respond_to?(value, true)
    # If it is an attribute that is changing in an existing object,
    # be sure to grab the current version.
    if event != "create" &&
        @record.has_attribute?(value) &&
        attribute_changed_in_latest_version?(value)
      attribute_in_previous_version(value, false)
    else
      @record.send(value)
    end
  else
    value
  end
end
nonskipped_attributes_before_change(is_touch) click to toggle source

@api private

# File lib/mongo_trails/events/base.rb, line 62
def nonskipped_attributes_before_change(is_touch)
  cache_changed_attributes do
    record_attributes = @record.attributes.except(*@record.paper_trail_options[:skip])

    record_attributes.each_key do |k|
      if @record.class.column_names.include?(k)
        record_attributes[k] = attribute_in_previous_version(k, is_touch)
      end
    end
  end
end
notable_changes() click to toggle source

@api private

# File lib/mongo_trails/events/base.rb, line 218
def notable_changes
  changes_in_latest_version.delete_if { |k, _v|
    !notably_changed.include?(k)
  }
end
notably_changed() click to toggle source

@api private

# File lib/mongo_trails/events/base.rb, line 225
def notably_changed
  # Memoized to reduce memory usage
  @notably_changed ||= begin
    only = @record.paper_trail_options[:only].dup
    # Remove Hash arguments and then evaluate whether the attributes (the
    # keys of the hash) should also get pushed into the collection.
    only.delete_if do |obj|
      obj.is_a?(Hash) &&
        obj.each { |attr, condition|
          only << attr if condition.respond_to?(:call) && condition.call(@record)
        }
    end
    only.empty? ? changed_and_not_ignored : (changed_and_not_ignored & only)
  end
end
object_attrs_for_paper_trail(is_touch) click to toggle source

Returns hash of attributes (with appropriate attributes serialized), omitting attributes to be skipped.

@api private

# File lib/mongo_trails/events/base.rb, line 245
def object_attrs_for_paper_trail(is_touch)
  attrs = nonskipped_attributes_before_change(is_touch)
  AttributeSerializers::ObjectAttribute.new(@record.class).serialize(attrs)
  attrs
end
prepare_object_changes(changes) click to toggle source

@api private

# File lib/mongo_trails/events/base.rb, line 252
def prepare_object_changes(changes)
  changes = serialize_object_changes(changes)
  recordable_object_changes(changes)
end
record_object?() click to toggle source

Returns a boolean indicating whether to store the original object during save.

@api private

# File lib/mongo_trails/events/base.rb, line 292
def record_object?
  @record.class.paper_trail.version_class.fields.keys.include?("object")
end
record_object_changes?() click to toggle source

Returns a boolean indicating whether to store serialized version diffs in the `object_changes` column of the version record.

@api private

# File lib/mongo_trails/events/base.rb, line 285
def record_object_changes?
  @record.class.paper_trail.version_class.fields.keys.include?("object_changes")
end
recordable_object(is_touch) click to toggle source

Returns an object which can be assigned to the `object` attribute of a nascent version record. If the `object` column is a postgres `json` column, then a hash can be used in the assignment, otherwise the column is a `text` column, and we must perform the serialization here, using `PaperTrail.serializer`.

@api private

# File lib/mongo_trails/events/base.rb, line 303
def recordable_object(is_touch)
  if @record.class.paper_trail.version_class.object_col_is_json?
    object_attrs_for_paper_trail(is_touch)
  else
    PaperTrail.serializer.dump(object_attrs_for_paper_trail(is_touch))
  end
end
recordable_object_changes(changes) click to toggle source

Returns an object which can be assigned to the `object_changes` attribute of a nascent version record. If the `object_changes` column is a postgres `json` column, then a hash can be used in the assignment, otherwise the column is a `text` column, and we must perform the serialization here, using `PaperTrail.serializer`.

@api private @param changes HashWithIndifferentAccess

# File lib/mongo_trails/events/base.rb, line 265
def recordable_object_changes(changes)
  if PaperTrail.config.object_changes_adapter&.respond_to?(:diff)
    # We'd like to avoid the `to_hash` here, because it increases memory
    # usage, but that would be a breaking change because
    # `object_changes_adapter` expects a plain `Hash`, not a
    # `HashWithIndifferentAccess`.
    changes = PaperTrail.config.object_changes_adapter.diff(changes.to_hash)
  end

  if @record.class.paper_trail.version_class.object_changes_col_is_json?
    changes
  else
    PaperTrail.serializer.dump(changes)
  end
end
serialize_object_changes(changes) click to toggle source

@api private

# File lib/mongo_trails/events/base.rb, line 312
def serialize_object_changes(changes)
  AttributeSerializers::ObjectChangesAttribute.
    new(@record.class).
    serialize(changes)

  # We'd like to convert this `HashWithIndifferentAccess` to a plain
  # `Hash`, but we don't, to save memory.
  changes
end