Marek Miklewicz
53 lines
1.6 KiB
PHP
53 lines
1.6 KiB
PHP
<?php
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declare(strict_types=1);
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final class RateLimiter
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{
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public function __construct(private string $dir)
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{
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}
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public function assertAllowed(string $bucket, int $limit, int $windowSeconds): void
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{
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if ($limit < 1) {
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throw new RuntimeException('Rate limit is invalid');
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}
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if (!is_dir($this->dir)) {
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mkdir($this->dir, 0700, true);
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}
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$file = $this->dir . '/' . preg_replace('/[^A-Za-z0-9._-]/', '_', $bucket) . '.json';
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$handle = fopen($file, 'c+');
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if ($handle === false) {
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throw new RuntimeException('Cannot open rate limit bucket');
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}
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if (!flock($handle, LOCK_EX)) {
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fclose($handle);
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throw new RuntimeException('Cannot lock rate limit bucket');
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}
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$now = time();
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$events = [];
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$contents = stream_get_contents($handle);
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$decoded = json_decode(is_string($contents) ? $contents : '', true);
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if (is_array($decoded)) {
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foreach ($decoded as $event) {
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if (is_int($event) && $event > $now - $windowSeconds) {
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$events[] = $event;
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}
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}
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}
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if (count($events) >= $limit) {
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flock($handle, LOCK_UN);
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fclose($handle);
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throw new RuntimeException('Rate limit exceeded');
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}
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$events[] = $now;
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ftruncate($handle, 0);
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rewind($handle);
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fwrite($handle, json_encode($events) ?: '[]');
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fflush($handle);
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flock($handle, LOCK_UN);
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fclose($handle);
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@chmod($file, 0600);
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}
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}
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