nextcloud/apps/files_encryption/ajax/userrecovery.php

<?php
/**
 * Copyright (c) 2013, Sam Tuke <samtuke@owncloud.com>
 * This file is licensed under the Affero General Public License version 3 or later.
 * See the COPYING-README file.
 *
 * @brief Script to handle admin settings for encrypted key recovery
 */

use OCA\Encryption;

\OCP\JSON::checkLoggedIn();
\OCP\JSON::checkAppEnabled( 'files_encryption' );
\OCP\JSON::callCheck();

if ( 
	isset( $_POST['userEnableRecovery'] ) 
	&& ( 0 == $_POST['userEnableRecovery'] || 1 == $_POST['userEnableRecovery'] )
) {

	$userId = \OCP\USER::getUser();
	$view = new \OC_FilesystemView( '/' );
	$util = new \OCA\Encryption\Util( $view, $userId );
	
	// Save recovery preference to DB
	$return = $util->setRecoveryForUser( $_POST['userEnableRecovery'] );
	
} else {

	$return = false;
	
}

// Return success or failure
( $return ) ? \OCP\JSON::success() : \OCP\JSON::error();