Source of file IDGenerator.php

<?php

/**

 * @author Marwan Al-Soltany <MarwanAlsoltany@gmail.com>

 * @copyright Marwan Al-Soltany 2020

 * For the full copyright and license information, please view

 * the LICENSE file that was distributed with this source code.

 */

declare(strict_types=1);

namespace MAKS\AmqpAgent\Helper;

/**

 * A class containing functions for generating unique IDs and Tokens.

 * @since 2.0.0

 */

final class IDGenerator

{

    /**

     * Generates an md5 hash from microtime and uniqid.

     * @param string $entropy [optional] Additional entropy.

     * @return string

     */

    public static function generateHash(string $entropy = 'maks-amqp-agent-id'): string

    {

        $prefix = sprintf('-%s-[%d]-', $entropy, rand());

        $symbol = microtime(true) . uniqid($prefix, true);

        return md5($symbol);

    }

    /**

     * Generates a crypto safe unique token. Note that this function is pretty expensive.

     * @param int $length The length of the token. If the token is hashed this will not be the length of the returned string.

     * @param string|null $charset [optional] A string of characters to generate the token from. Defaults to alphanumeric.

     * @param string|null $hashing [optional] A name of hashing algorithm to hash the generated token with. Defaults to no hashing.

     * @return string

     */

    public static function generateToken(int $length = 32, ?string $charset = null, ?string $hashing = null): string

    {

        $token = '';

        $charset = $charset ?? (

            implode(range('A', 'Z')) .

            implode(range('a', 'z')) .

            implode(range(0, 9))

        );

        $max = strlen($charset);

        for ($i = 0; $i < $length; $i++) {

            $token .= $charset[

                self::generateCryptoSecureRandom(0, $max - 1)

            ];

        }

        return $hashing ? hash($hashing, $token) : $token;

    }

    /**

     * Generates a crypto secure random number.

     * @param int $min

     * @param int $max

     * @return int

     */

    protected static function generateCryptoSecureRandom(int $min, int $max): int

    {

        $range = $max - $min;

        if ($range < 1) {

            return $min;

        }

        $log = ceil(log($range, 2));

        $bytes = (int)(($log / 8) + 1); // length in bytes

        $bits = (int)($log + 1); // length in bits

        $filter = (int)((1 << $bits) - 1); // set all lower bits to 1

        do {

            $random = PHP_VERSION >= 7

                ? random_bytes($bytes)

                : openssl_random_pseudo_bytes($bytes);

            $random = hexdec(bin2hex($random));

            $random = $random & $filter; // discard irrelevant bits

        } while ($random > $range);

        return $min + $random;

    }

}