50 lines
2.0 KiB
PHP
50 lines
2.0 KiB
PHP
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<?php
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declare(strict_types=1);
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/** Fixed-window rate limiter backed by the database (works on shared hosting without Redis). */
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final class RateLimit
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{
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/**
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* @return array{allowed:bool, retryAfter:int}
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*/
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public static function hit(string $bucket, int $limit, int $windowSeconds): array
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{
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$pdo = Db::pdo();
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$now = time();
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$pdo->beginTransaction();
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try {
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$st = $pdo->prepare('SELECT hits, window_start FROM rate_limits WHERE bucket = ?');
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$st->execute([$bucket]);
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$row = $st->fetch();
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if (!$row || ($now - (int)$row['window_start']) >= $windowSeconds) {
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if (Db::isSqlite()) {
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$pdo->prepare('INSERT OR REPLACE INTO rate_limits (bucket, hits, window_start) VALUES (?, 1, ?)')->execute([$bucket, $now]);
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} else {
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$pdo->prepare('REPLACE INTO rate_limits (bucket, hits, window_start) VALUES (?, 1, ?)')->execute([$bucket, $now]);
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}
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$pdo->commit();
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return ['allowed' => true, 'retryAfter' => 0];
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}
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$hits = (int)$row['hits'] + 1;
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$pdo->prepare('UPDATE rate_limits SET hits = ? WHERE bucket = ?')->execute([$hits, $bucket]);
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$pdo->commit();
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if ($hits > $limit) {
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return ['allowed' => false, 'retryAfter' => max(1, $windowSeconds - ($now - (int)$row['window_start']))];
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}
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return ['allowed' => true, 'retryAfter' => 0];
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} catch (Throwable $e) {
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if ($pdo->inTransaction()) {
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$pdo->rollBack();
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}
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Log::warn('Rate limit storage failed; allowing request', ['error' => $e->getMessage()]);
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return ['allowed' => true, 'retryAfter' => 0];
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}
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}
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/** Stable, non-reversible bucket key for an IP. */
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public static function ipBucket(string $prefix, string $ip): string
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{
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return $prefix . ':' . substr(hash('sha256', $ip . '|' . (Config::get('HASH_SALT') ?? 'visit')), 0, 32);
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}
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}
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