private function register_fields_for_attachments() {

		register_rest_field(
			'attachment',
			'_llms_media_protection_product_id',
			array(
				'get_callback'    => function ( $object ) {
					return get_post_meta( $object['id'], '_llms_media_protection_product_id', true );
				},
				'update_callback' => function ( $value, $object ) {
					$settings = new LLMS_Admin_Media_Protection_Attachment_Settings();
					$protector = new LLMS_Media_Protector();

					if ( $protector->is_media_protected( $object->ID ) ) {
						update_post_meta( $object->ID, '_llms_media_protection_product_id', absint( $value ) );

						return;
					}

					if ( $settings->move_attachment_to_protected_dir( $object->ID ) ) {
						update_post_meta( $object->ID, '_llms_media_protection_product_id', absint( $value ) );
					}
				},
				'schema'          => array(
					'description' => __( 'The ID of the product that protects this media.', 'lifterlms' ),
					'type'        => 'integer',
					'context'     => array( 'view', 'edit' ),
				),
			)
		);
	}