113 lines
3.1 KiB
PHP
113 lines
3.1 KiB
PHP
<?php
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/*
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* This file is part of the Symfony package.
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*
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* (c) Fabien Potencier <fabien@symfony.com>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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namespace Symfony\Component\RateLimiter\Policy;
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use Symfony\Component\RateLimiter\LimiterStateInterface;
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/**
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* @author Wouter de Jong <wouter@wouterj.nl>
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*
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* @internal
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*/
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final class TokenBucket implements LimiterStateInterface
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{
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private string $id;
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private Rate $rate;
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private int $tokens;
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private int $burstSize;
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private float $timer;
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/**
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* @param string $id unique identifier for this bucket
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* @param int $initialTokens the initial number of tokens in the bucket (i.e. the max burst size)
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* @param Rate $rate the fill rate and time of this bucket
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* @param float|null $timer the current timer of the bucket, defaulting to microtime(true)
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*/
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public function __construct(string $id, int $initialTokens, Rate $rate, ?float $timer = null)
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{
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if ($initialTokens < 1) {
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throw new \InvalidArgumentException(\sprintf('Cannot set the limit of "%s" to 0, as that would never accept any hit.', TokenBucketLimiter::class));
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}
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$this->id = $id;
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$this->tokens = $this->burstSize = $initialTokens;
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$this->rate = $rate;
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$this->timer = $timer ?? microtime(true);
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}
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public function getId(): string
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{
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return $this->id;
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}
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public function setTimer(float $microtime): void
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{
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$this->timer = $microtime;
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}
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public function getTimer(): float
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{
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return $this->timer;
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}
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public function setTokens(int $tokens): void
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{
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$this->tokens = $tokens;
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}
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public function getAvailableTokens(float $now): int
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{
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$elapsed = max(0, $now - $this->timer);
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$newTokens = $this->rate->calculateNewTokensDuringInterval($elapsed);
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if ($newTokens > 0) {
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$this->timer += $this->rate->calculateRefillInterval($elapsed);
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}
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return min($this->burstSize, $this->tokens + $newTokens);
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}
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public function getExpirationTime(): int
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{
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return $this->rate->calculateTimeForTokens($this->burstSize);
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}
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public function __serialize(): array
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{
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return [
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pack('N', $this->burstSize).$this->id => $this->tokens,
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(string) $this->rate => $this->timer,
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];
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}
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public function __unserialize(array $data): void
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{
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// BC layer for old objects serialized via __sleep
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if (5 === \count($data)) {
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$data = array_values($data);
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$this->id = $data[0];
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$this->tokens = $data[1];
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$this->timer = $data[2];
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$this->burstSize = $data[3];
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$this->rate = Rate::fromString($data[4]);
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return;
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}
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[$this->tokens, $this->timer] = array_values($data);
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[$pack, $rate] = array_keys($data);
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$this->rate = Rate::fromString($rate);
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$this->burstSize = unpack('Na', $pack)['a'];
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$this->id = substr($pack, 4);
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}
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}
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