FormSession.php

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<?php
declare(strict_types = 1);
namespace ‪TYPO3\CMS\Form\Domain\Runtime\FormRuntime;
 
/*
 * This file is part of the TYPO3 CMS project.
 *
 * It is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, either version 2
 * of the License, or any later version.
 *
 * For the full copyright and license information, please read the
 * LICENSE.txt file that was distributed with this source code.
 *
 * The TYPO3 project - inspiring people to share!
 */
 
use ‪TYPO3\CMS\Core\Crypto\Random;
use ‪TYPO3\CMS\Core\Error\Http\BadRequestException;
use ‪TYPO3\CMS\Core\Utility\GeneralUtility;
use ‪TYPO3\CMS\Extbase\Security\Cryptography\HashService;
use ‪TYPO3\CMS\Extbase\Security\Exception\InvalidArgumentForHashGenerationException;
use ‪TYPO3\CMS\Extbase\Security\Exception\InvalidHashException;
 
class ‪FormSession
{
    protected ‪$identifier;
 
    public function ‪__construct(string $authenticatedIdentifier = null)
    {
        if ($authenticatedIdentifier === null) {
            $this->identifier = $this->‪generateIdentifier();
        } else {
            $this->identifier = $this->‪validateIdentifier($authenticatedIdentifier);
        }
    }
 
    public function ‪getIdentifier(): string
    {
        return ‪$this->identifier;
    }
 
    public function ‪getAuthenticatedIdentifier(): string
    {
        return GeneralUtility::makeInstance(HashService::class)
            // restrict string expansion by adding some char ('|')
            ->appendHmac($this->identifier . '|');
    }
 
    protected function ‪generateIdentifier(): string
    {
        return GeneralUtility::makeInstance(Random::class)->generateRandomHexString(40);
    }
 
    protected function ‪validateIdentifier(string $authenticatedIdentifier): string
    {
        try {
            ‪$identifier = GeneralUtility::makeInstance(HashService::class)
                ->validateAndStripHmac($authenticatedIdentifier);
            return rtrim(‪$identifier, '|');
        } catch (‪InvalidHashException | ‪InvalidArgumentForHashGenerationException $e) {
            throw new ‪BadRequestException('The HMAC of the form session could not be validated.', 1613300274);
        }
    }
}