cakephp/src/Auth/FallbackPasswordHasher.php

<?php
/**
 * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
 * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 *
 * Licensed under The MIT License
 * For full copyright and license information, please see the LICENSE.txt
 * Redistributions of files must retain the above copyright notice.
 *
 * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 * @link          http://cakephp.org CakePHP(tm) Project
 * @since         3.0.0
 * @license       http://www.opensource.org/licenses/mit-license.php MIT License
 */
namespace Cake\Auth;

use Cake\Auth\AbstractPasswordHasher;

/**
 * A password hasher that can use multiple different hashes where only
 * one is the preferred one. This is useful when trying to migrate an
 * existing database of users from one password type to another.
 *
 */
class FallbackPasswordHasher extends AbstractPasswordHasher {

/**
 * Default config for this object.
 *
 * @var array
 */
	protected $_defaultConfig = [
		'hashers' => []
	];

/**
 * Holds the list of password hasher objects that will be used
 *
 * @var array
 */
	protected $_hashers = [];

/**
 * Constructor
 *
 * @param array $config configuration options for this object. Requires the
 * `hashers` key to be present in the array with a list of other hashers to be
 * used
 */
	public function __construct(array $config = array()) {
		parent::__construct($config);
		foreach ($this->_config['hashers'] as $hasher) {
			$this->_hashers[] = PasswordHasherFactory::build($hasher);
		}
	}

/**
 * Generates password hash.
 *
 * Uses the first password hasher in the list to generate the hash
 *
 * @param string $password Plain text password to hash.
 * @return string Password hash
 */
	public function hash($password) {
		return $this->_hashers[0]->hash($password);
	}

/**
 * Verifies that the provided password corresponds to its hashed version
 *
 * This will iterate over all configured hashers until one of them returns
 * true.
 *
 * @param string $password Plain text password to hash.
 * @param string $hashedPassword Existing hashed password.
 * @return bool True if hashes match else false.
 */
	public function check($password, $hashedPassword) {
		foreach ($this->_hashers as $hasher) {
			if ($hasher->check($password, $hashedPassword)) {
				return true;
			}
		}
		return false;
	}

/**
 * Returns true if the password need to be rehashed, with the first hasher present
 * in the list of hashers
 *
 * @param string $password The password to verify
 * @return bool
 */
	public function needsRehash($password) {
		return $this->_hashers[0]->needsRehash($password);
	}

}