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php 实现网关限流

2026-02-15 15:18:30PHP

PHP 实现网关限流的方法

令牌桶算法实现

令牌桶算法是一种常用的限流方法，通过控制令牌的生成和消耗来实现限流。以下是一个简单的 PHP 实现：

class TokenBucket {
    private $capacity;
    private $tokens;
    private $lastTime;

    public function __construct($capacity) {
        $this->capacity = $capacity;
        $this->tokens = $capacity;
        $this->lastTime = time();
    }

    public function consume($tokens = 1) {
        $now = time();
        $elapsed = $now - $this->lastTime;
        $this->tokens = min($this->capacity, $this->tokens + $elapsed);
        $this->lastTime = $now;

        if ($this->tokens >= $tokens) {
            $this->tokens -= $tokens;
            return true;
        }
        return false;
    }
}

// 使用示例
$bucket = new TokenBucket(10); // 每秒最多10个请求
if (!$bucket->consume()) {
    http_response_code(429);
    exit('Too Many Requests');
}

漏桶算法实现

漏桶算法以固定速率处理请求，超出容量的请求会被丢弃或排队。PHP 实现如下：

class LeakyBucket {
    private $capacity;
    private $rate;
    private $water;
    private $lastTime;

    public function __construct($capacity, $rate) {
        $this->capacity = $capacity;
        $this->rate = $rate;
        $this->water = 0;
        $this->lastTime = time();
    }

    public function add() {
        $now = time();
        $leaked = ($now - $this->lastTime) * $this->rate;
        $this->water = max(0, $this->water - $leaked);
        $this->lastTime = $now;

        if ($this->water < $this->capacity) {
            $this->water++;
            return true;
        }
        return false;
    }
}

// 使用示例
$bucket = new LeakyBucket(10, 1); // 容量10，每秒漏出1个
if (!$bucket->add()) {
    http_response_code(429);
    exit('Rate Limit Exceeded');
}

Redis 分布式限流

对于分布式系统，可以使用 Redis 实现限流：

function checkRateLimit($key, $limit, $window) {
    $redis = new Redis();
    $redis->connect('127.0.0.1', 6379);

    $current = $redis->get($key);
    if ($current && $current >= $limit) {
        return false;
    }

    $redis->multi();
    $redis->incr($key);
    $redis->expire($key, $window);
    $redis->exec();
    return true;
}

// 使用示例
if (!checkRateLimit('user:123', 100, 60)) { // 每分钟100次
    http_response_code(429);
    exit('Rate Limit Exceeded');
}

Nginx 层限流

在网关层面可以使用 Nginx 的 limit_req 模块：

http {
    limit_req_zone $binary_remote_addr zone=mylimit:10m rate=10r/s;

    server {
        location /api/ {
            limit_req zone=mylimit burst=20 nodelay;
            proxy_pass http://backend;
        }
    }
}

中间件实现

在框架中可以使用中间件实现限流，例如 Laravel：

namespace App\Http\Middleware;

use Closure;
use Illuminate\Cache\RateLimiter;
use Symfony\Component\HttpFoundation\Response;

class ThrottleRequests {
    protected $limiter;

    public function __construct(RateLimiter $limiter) {
        $this->limiter = $limiter;
    }

    public function handle($request, Closure $next, $maxAttempts = 60, $decayMinutes = 1) {
        $key = $request->ip();

        if ($this->limiter->tooManyAttempts($key, $maxAttempts)) {
            return new Response('Too Many Attempts', 429);
        }

        $this->limiter->hit($key, $decayMinutes * 60);
        return $next($request);
    }
}