Module: ActiveDenormalize::Associations::Extension

Defined in:
lib/active_denormalize/associations/extension.rb

Constant Summary collapse

OPTIONS = 
[:denormalize].freeze

Class Method Summary collapse

Class Method Details

.add_after_commit_callback(model, reflection) ⇒ Object 



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# File 'lib/active_denormalize/associations/extension.rb', line 78

def self.add_after_commit_callback(model, reflection)
  denormalized_column_prefix = model.model_name.singular
  denormalized_primary_key = "#{denormalized_column_prefix}_#{model.primary_key}"

  model.before_destroy do
    if (target = public_send(reflection.name))
      primary_key = public_send(self.class.primary_key)
      denormalized_primary_key_id = target.public_send(denormalized_primary_key)

      # The record being destroyed is currently denormalized on its association and needs to be replaced
      if denormalized_primary_key_id == primary_key
        replacement = target.association(model.model_name.collection).scope.denormalize.where.not(id: primary_key).order(created_at: :desc).first
        if replacement.present?
          replacement.denormalize(target)
        else
          target.public_send("clear_denormalized_#{denormalized_column_prefix}")
        end
      end
    end
  end

  model.after_create_commit do
    if denormalize? && (target = public_send(reflection.name))
      denormalize(target)
    end
  end

  model.after_update_commit do
    if (target = public_send(reflection.name))
      primary_key = public_send(self.class.primary_key)
      denormalized_primary_key_id = target.public_send(denormalized_primary_key)

      # After an update of a denormalized record, check the association to see if it is still the current denormalized record or if it has changed.
      denormalize(target) if denormalized_primary_key_id == primary_key
    end
  end
end

.build(model, reflection) ⇒ Object 



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# File 'lib/active_denormalize/associations/extension.rb', line 8

def self.build(model, reflection)
  return unless reflection.options[:denormalize]

  define_accessors(model, reflection)
  add_after_commit_callback(model, reflection)
end

.define_accessors(model, reflection) ⇒ Object 



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# File 'lib/active_denormalize/associations/extension.rb', line 19

def self.define_accessors(model, reflection)
  denormalized_column_prefix = model.model_name.singular
  target_mixin = reflection.klass.generated_association_methods

  target_mixin.class_eval do
    define_method("clear_denormalized_#{denormalized_column_prefix}") do
      denormalized_columns = model.denormalized_column_mapping.keys & self.class.column_names
      cleared_denormalized_attributes = denormalized_columns.index_with { |_column| nil }
      update!(cleared_denormalized_attributes)
    end
  end

  model.class_eval do
    # Needed to lookup the next valid record to denormalize when destroying the latest record.
    scope :denormalize, -> {}

    def denormalize?
      true
    end

    def denormalize(target)
      denormalized_columns = self.class.denormalized_column_mapping.keys & target.class.column_names
      attributes = denormalized_columns.to_h do |denormalized_column|
        column = self.class.denormalized_column_mapping[denormalized_column]

        if column == "denormalized_at"
          [denormalized_column, Time.zone.now]
        else
          value = send(column)
          if (enum_mapping = defined_enums[column])
            value = enum_mapping.fetch(value)
          end

          [denormalized_column, value]
        end
      end

      if attributes.empty?
        Rails.logger.debug { "No denormalized columns found for #{target.class}" }
      else
        Rails.logger.debug { "Denormalizing #{target.class} #{target.id} with #{attributes}" }
        target.update!(attributes)
      end
    end

    def self.denormalized_column_mapping
      @denormalized_column_mapping ||= begin
        prefix = model_name.singular

        mapping = column_names.index_by do |column_name|
          "#{prefix}_#{column_name}"
        end
        mapping["#{prefix}_denormalized_at"] = "denormalized_at"
        mapping
      end
    end
  end
end

.valid_options ⇒ Object 



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# File 'lib/active_denormalize/associations/extension.rb', line 15

def self.valid_options
  OPTIONS
end