169 lines
4.3 KiB
PHP
169 lines
4.3 KiB
PHP
<?php
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namespace app\common\library;
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/**
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* 雪花算法ID生成器
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* 不依赖数据库，通过配置或自动生成workerId
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* 64位ID结构：0(1位符号位) + 41位时间戳 + 10位工作机器ID + 12位序列号
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*/
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class Snowflake
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{
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// 起始时间戳（2023-01-01 00:00:00），可使用到2089年
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const EPOCH = 1672531200000;
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// 工作机器ID位数
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const WORKER_ID_BITS = 10;
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// 序列号位数
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const SEQUENCE_BITS = 12;
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// 最大工作机器ID
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const MAX_WORKER_ID = (1 << self::WORKER_ID_BITS) - 1;
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// 序列号掩码
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const SEQUENCE_MASK = (1 << self::SEQUENCE_BITS) - 1;
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// 工作机器ID左移位数
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const WORKER_ID_SHIFT = self::SEQUENCE_BITS;
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// 时间戳左移位数
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const TIMESTAMP_LEFT_SHIFT = self::SEQUENCE_BITS + self::WORKER_ID_BITS;
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// 工作机器ID（通过服务器IP生成）
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protected $workerId;
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// 序列号
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protected $sequence = 0;
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// 上次生成ID的时间戳
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protected $lastTimestamp = -1;
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// 单例实例
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protected static $instance = null;
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/**
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* 构造函数私有化，单例模式
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*/
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private function __construct()
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{
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$this->workerId = $this->generateWorkerId();
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}
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/**
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* 获取单例实例
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*/
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public static function getInstance()
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{
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if (self::$instance === null) {
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self::$instance = new self();
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}
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return self::$instance;
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}
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/**
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* 生成工作机器ID（基于服务器IP）
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*/
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protected function generateWorkerId()
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{
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// 方法1：从配置文件中读取
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if (config('snowflake.worker_id')) {
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return config('snowflake.worker_id') & self::MAX_WORKER_ID;
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}
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// 方法2：基于服务器IP生成（推荐）
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$serverIp = $_SERVER['SERVER_ADDR'] ?? '127.0.0.1';
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$ipParts = explode('.', $serverIp);
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// 使用IP后两段生成workerId
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if (count($ipParts) >= 4) {
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$workerId = ($ipParts[2] << 8) | $ipParts[3];
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} else {
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// 如果是IPv6或特殊情况，使用随机数
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$workerId = mt_rand(0, self::MAX_WORKER_ID);
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}
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return $workerId & self::MAX_WORKER_ID;
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}
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/**
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* 生成下一个ID
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*/
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public function nextId()
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{
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$timestamp = $this->getCurrentTimestamp();
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// 时钟回拨处理
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if ($timestamp < $this->lastTimestamp) {
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$diff = $this->lastTimestamp - $timestamp;
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throw new \Exception("时钟回拨了 {$diff} 毫秒");
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}
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// 同一毫秒内生成多个ID
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if ($this->lastTimestamp == $timestamp) {
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$this->sequence = ($this->sequence + 1) & self::SEQUENCE_MASK;
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if ($this->sequence == 0) {
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// 序列号用尽，等待下一毫秒
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$timestamp = $this->waitNextMillis($this->lastTimestamp);
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}
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} else {
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$this->sequence = 0;
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}
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$this->lastTimestamp = $timestamp;
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// 组合生成ID
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$id = (($timestamp - self::EPOCH) << self::TIMESTAMP_LEFT_SHIFT)
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| ($this->workerId << self::WORKER_ID_SHIFT)
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| $this->sequence;
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return (string)$id;
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}
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/**
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* 批量生成ID
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*/
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public function nextIds($count)
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{
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$ids = [];
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for ($i = 0; $i < $count; $i++) {
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$ids[] = $this->nextId();
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}
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return $ids;
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}
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/**
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* 获取当前毫秒时间戳
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*/
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protected function getCurrentTimestamp()
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{
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return (int)(microtime(true) * 1000);
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}
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/**
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* 等待到下一毫秒
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*/
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protected function waitNextMillis($lastTimestamp)
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{
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$timestamp = $this->getCurrentTimestamp();
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while ($timestamp <= $lastTimestamp) {
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usleep(100); // 休眠100微秒
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$timestamp = $this->getCurrentTimestamp();
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}
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return $timestamp;
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}
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/**
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* 解析雪花ID
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*/
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public static function parse($id)
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{
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$id = intval($id);
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return [
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'timestamp' => ($id >> self::TIMESTAMP_LEFT_SHIFT) + self::EPOCH,
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'worker_id' => ($id >> self::WORKER_ID_SHIFT) & self::MAX_WORKER_ID,
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'sequence' => $id & self::SEQUENCE_MASK,
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'generated_at' => date('Y-m-d H:i:s.v', (($id >> self::TIMESTAMP_LEFT_SHIFT) + self::EPOCH) / 1000)
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];
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}
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} |