Class: ActiveSnapshot::Snapshot

Inherits:
ActiveRecord::Base
  • Object
show all
Defined in:
lib/active_snapshot/models/snapshot.rb

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.build_snapshot(resource, identifier: nil, user: nil, metadata: nil) ⇒ Object 



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# File 'lib/active_snapshot/models/snapshot.rb', line 19

def build_snapshot(resource, identifier: nil, user: nil, metadata: nil)
  snapshot = resource.snapshots.build({
    identifier: identifier,
    user_id: (user.id if user),
    user_type: (user.class.name if user),
    metadata: (metadata || {}),
  })

  snapshot.build_snapshot_item(resource)

  snapshot_children = resource.children_to_snapshot

  snapshot_children&.each do |child_group_name, h|
    h[:records].each do |child_item|
      snapshot.build_snapshot_item(child_item, child_group_name: child_group_name)
    end
  end

  snapshot
end

.diff(from, to) ⇒ Object 



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# File 'lib/active_snapshot/models/snapshot.rb', line 40

def diff(from, to)
  if !from.is_a?(Snapshot)
    raise ArgumentError.new("'from' must be an ActiveSnapshot::Snapshot")
  end

  to_item_id, to_item_type = to.is_a?(Snapshot) ? [to.item_id, to.item_type] : [to.id, to.class.polymorphic_name]

  if from.item_id != to_item_id || from.item_type != to_item_type
    raise ArgumentError.new("Both records must reference the same item")
  end

  if to.is_a?(Snapshot) && from.created_at > to.created_at
    raise ArgumentError.new("'to' must be a newer snapshot than 'from'")
  end

  from_snapshot = from
  to_snapshot = to.is_a?(Snapshot) ? to : build_snapshot(to)

  from_snapshot_items = from_snapshot.snapshot_items
  to_snapshot_items = to_snapshot.snapshot_items

  diffs = []

  from_snapshot_items.each do |from_snapshot_item|
    to_snapshot_item = to_snapshot_items.find do |item|
      item.item_id == from_snapshot_item.item_id && item.item_type == from_snapshot_item.item_type
    end

    if to_snapshot_item.nil?
      diffs << {
        action: :destroy,
        item_id: from_snapshot_item.item_id,
        item_type: from_snapshot_item.item_type,
        changes: snapshot_item_changes(from_snapshot_item, nil)
      }
    else
      changes = snapshot_item_changes(from_snapshot_item, to_snapshot_item)

      next if changes.empty?

      diffs << {
        action: :update,
        item_id: from_snapshot_item.item_id,
        item_type: from_snapshot_item.item_type,
        changes: changes
      }
    end
  end

  to_snapshot_items.each do |to_snapshot_item|
    from_snapshot_item = from_snapshot_items.find do |item|
      item.item_id == to_snapshot_item.item_id && item.item_type == to_snapshot_item.item_type
    end

    next if from_snapshot_item.present?

    diffs << {
      action: :create,
      item_id: to_snapshot_item.item_id,
      item_type: to_snapshot_item.item_type,
      changes: snapshot_item_changes(nil, to_snapshot_item)
    }
  end

  diffs
end

Instance Method Details

#build_snapshot_item(instance, child_group_name: nil) ⇒ Object 



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# File 'lib/active_snapshot/models/snapshot.rb', line 167

def build_snapshot_item(instance, child_group_name: nil)
  attrs = instance.attributes_for_database

  self.snapshot_items.new({
    object: attrs,
    item_id: instance.id,
    item_type: instance.class.name,
    child_group_name: child_group_name,
  })
end

#fetch_reified_items(readonly: true) ⇒ Object 



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# File 'lib/active_snapshot/models/snapshot.rb', line 220

def fetch_reified_items(readonly: true)
  reified_children_hash = {}.with_indifferent_access

  reified_parent = nil

  snapshot_items.each do |si|
    item_class = si.item_type.constantize
    reified_item = item_class.new

    si.object.each do |k,v|
      if reified_item.respond_to?("#{k}=")
        reified_item[k] = ActiveSnapshot.get_deserialized_value(item_class, key: k, value: v)
      else
        # database column was likely dropped since the snapshot was created
      end
    end

    if readonly
      reified_item.readonly!
    end

    key = si.child_group_name

    if key
      reified_children_hash[key] ||= []

      reified_children_hash[key] << reified_item

    elsif self.item_id == si.item_id && (self.item_type == si.item_type || si.item_type.constantize.new.is_a?(self.item_type.constantize))
      reified_parent = reified_item
    end
  end

  return [reified_parent, reified_children_hash]
end

#metadata ⇒ Object 



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# File 'lib/active_snapshot/models/snapshot.rb', line 133

def metadata
  return @metadata if @metadata

  if ActiveSnapshot.config.storage_method_serialized_json?
    # for legacy active_snapshot configurations only
    @metadata = JSON.parse(self[:metadata])
  elsif ActiveSnapshot.config.storage_method_yaml?
    # for legacy active_snapshot configurations only
    yaml_method = "unsafe_load"

    if !YAML.respond_to?("unsafe_load")
      yaml_method = "load"
    end

    @metadata = YAML.send(yaml_method, self[:metadata])
  else
    @metadata = self[:metadata]
  end
end

#metadata=(h) ⇒ Object 



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# File 'lib/active_snapshot/models/snapshot.rb', line 153

def metadata=(h)
  @metadata = nil

  if ActiveSnapshot.config.storage_method_serialized_json?
    # for legacy active_snapshot configurations only
    self[:metadata] = h.to_json
  elsif ActiveSnapshot.config.storage_method_yaml?
    # for legacy active_snapshot configurations only
    self[:metadata] = YAML.dump(h)
  else
    self[:metadata] = h
  end
end

#restore! ⇒ Object 



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# File 'lib/active_snapshot/models/snapshot.rb', line 178

def restore!
  ActiveRecord::Base.transaction do
    ### Cache the child snapshots in a variable for re-use
    cached_snapshot_items = snapshot_items.includes(:item)

    existing_snapshot_children = item ? item.children_to_snapshot : []

    if existing_snapshot_children.any?
      children_to_keep = Set.new

      cached_snapshot_items.each do |snapshot_item|
        key = "#{snapshot_item.item_type} #{snapshot_item.item_id}"

        children_to_keep << key
      end

      ### Destroy or Detach Items not included in this Snapshot's Items
      ### We do this first in case you later decide to validate children in ItemSnapshot#restore_item! method
      existing_snapshot_children.each do |child_group_name, h|
        delete_method = h[:delete_method] || ->(child_record){ child_record.destroy! }

        h[:records].each do |child_record|
          child_record_id = child_record.send(child_record.class.send(:primary_key))

          key = "#{child_record.class.name} #{child_record_id}"

          if children_to_keep.exclude?(key)
            delete_method.call(child_record)
          end
        end
      end
    end

    ### Create or Update Items from Snapshot Items
    cached_snapshot_items.each do |snapshot_item|
      snapshot_item.restore_item!
    end
  end

  return true
end