PHP流量控制令牌桶算法

<?php
class TrafficController {
    private $capacity; // 桶的容量
    private $rate; // 每秒产生的令牌数
    private $tokens; // 当前桶中的令牌数
    private $lastRefillTime; // 上次填充令牌的时间
    private $waitingRequests; // 等待的请求队列
    private $counters; // 用户访问计数器

    public function __construct($capacity, $rate) {
        $this->capacity = $capacity;
        $this->rate = $rate;
        $this->tokens = $capacity;
        $this->lastRefillTime = time();
        $this->waitingRequests = [];
        $this->counters = [];
    }

    public function allowRequest($userId) {
        $this->refillTokens();

        if ($this->tokens < 1 || $this->exceedsRateLimit($userId)) {
            $this->waitingRequests[$userId][] = time();
            return false; // 请求被限流
        }

        $this->tokens--;
        $this->counters[$userId]++;
        return true; // 可以处理请求
    }

    private function refillTokens() {
        $currentTime = time();
        $this->tokens = min(
            $this->capacity,
            $this->tokens + ($currentTime - $this->lastRefillTime) * $this->rate
        );
        $this->lastRefillTime = $currentTime;
    }

    private function exceedsRateLimit($userId) {
        $count = $this->counters[$userId] ?? 0;
        return $count >= $this->rate;
    }
}

// 使用示例
$trafficController = new TrafficController(10, 2); // 桶容量为10，每秒产生2个令牌

// 用户A发起请求
$userIdA = 1;
if ($trafficController->allowRequest($userIdA)) {
    // 处理请求
    echo "处理请求";
} else {
    // 请求被限流，返回错误信息
    echo "请求被限流";
}

// 用户B发起请求
$userIdB = 2;
if ($trafficController->allowRequest($userIdB)) {
    // 处理请求
    echo "处理请求";
} else {
    // 请求被限流，返回错误信息
    echo "请求被限流";
}
?>