public function get_fields_for_response( $request ) {
    $schema     = $this->WP_REST_Controller::get_item_schema();
    $properties = isset( $schema['properties'] ) ? $schema['properties'] : array();

    $additional_fields = $this->WP_REST_Controller::get_additional_fields();

    foreach ( $additional_fields as $field_name => $field_options ) {
      /*
			 * For back-compat, include any field with an empty schema
			 * because it won't be present in $this->get_item_schema().
			 */
      if ( is_null( $field_options['schema'] ) ) {
        $properties[ $field_name ] = $field_options;
      }
    }

    // Exclude fields that specify a different context than the request context.
    $context = $request['context'];
    if ( $context ) {
      foreach ( $properties as $name => $options ) {
        if ( ! empty( $options['context'] ) && ! in_array( $context, $options['context'], true ) ) {
          unset( $properties[ $name ] );
        }
      }
    }

    $fields = array_keys( $properties );

    /*
		 * '_links' and '_embedded' are not typically part of the item schema,
		 * but they can be specified in '_fields', so they are added here as a
		 * convenience for checking with rest_is_field_included().
		 */
    $fields[] = '_links';
    if ( $request->has_param( '_embed' ) ) {
      $fields[] = '_embedded';
    }

    $fields = array_unique( $fields );

    if ( ! isset( $request['_fields'] ) ) {
      return $fields;
    }
    $requested_fields = wp_parse_list( $request['_fields'] );
    if ( 0 === count( $requested_fields ) ) {
      return $fields;
    }
    // Trim off outside whitespace from the comma delimited list.
    $requested_fields = array_map( 'trim', $requested_fields );
    // Always persist 'id', because it can be needed for add_additional_fields_to_object().
    if ( in_array( 'id', $fields, true ) ) {
      $requested_fields[] = 'id';
    }
    // Return the list of all requested fields which appear in the schema.
    return array_reduce(
      $requested_fields,
      static function( $response_fields, $field ) use ( $fields ) {
        if ( in_array( $field, $fields, true ) ) {
          $response_fields[] = $field;
          return $response_fields;
        }
        // Check for nested fields if $field is not a direct match.
        $nested_fields = explode( '.', $field );
        /*
				 * A nested field is included so long as its top-level property
				 * is present in the schema.
				 */
        if ( in_array( $nested_fields[0], $fields, true ) ) {
          $response_fields[] = $field;
        }
        return $response_fields;
      },
      array()
    );
  }