98 lines
2.4 KiB
TypeScript
98 lines
2.4 KiB
TypeScript
import { headers } from "next/headers";
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import { resolveClientIp, UNKNOWN_CLIENT_IP } from "@/lib/client-ip";
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import { logger } from "@/lib/logger";
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import { redis } from "@/lib/redis";
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type Bucket = { count: number; resetAt: number };
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const buckets = new Map<string, Bucket>();
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export interface RateLimitResult {
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ok: boolean;
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retryAfter: number;
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}
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const CLEANUP_INTERVAL_MS = 300_000;
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const MAX_BUCKETS = 10_000;
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let lastCleanup = Date.now();
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let redisFailWarned = false;
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function cleanup(): void {
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const now = Date.now();
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if (now - lastCleanup < CLEANUP_INTERVAL_MS) return;
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lastCleanup = now;
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for (const [k, b] of buckets) {
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if (now >= b.resetAt) buckets.delete(k);
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}
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if (buckets.size > MAX_BUCKETS) {
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const sorted = [...buckets.entries()].sort(
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(a, b) => a[1].resetAt - b[1].resetAt,
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);
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const keysToRemove = sorted
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.slice(0, Math.floor(sorted.length * 0.2))
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.map((entry) => entry[0]);
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for (const key of keysToRemove) buckets.delete(key);
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}
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}
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export async function rateLimit(
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key: string,
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limit: number,
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windowMs: number,
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): Promise<RateLimitResult> {
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const now = Date.now();
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if (redis) {
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try {
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const windowKey = `ratelimit:${key}`;
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const current = await redis.incr(windowKey);
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if (current === 1) await redis.pexpire(windowKey, windowMs);
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const ttl =
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current === 1 ? windowMs : Math.max(0, await redis.pttl(windowKey));
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if (current > limit) {
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return { ok: false, retryAfter: Math.ceil(ttl / 1000) };
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}
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return { ok: true, retryAfter: 0 };
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} catch {
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// Redis unavailable — fall through to in-memory
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if (process.env.NODE_ENV === "production" && !redisFailWarned) {
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redisFailWarned = true;
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logger.error(
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"[rate-limit] Redis error — falling back to in-process buckets. Limits are not shared across instances until Redis recovers.",
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);
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}
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}
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}
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cleanup();
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const windowKey = `mem:${key}`;
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const bucket = buckets.get(windowKey);
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if (!bucket || now >= bucket.resetAt) {
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buckets.set(windowKey, { count: 1, resetAt: now + windowMs });
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return { ok: true, retryAfter: 0 };
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}
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const newCount = bucket.count + 1;
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if (newCount > limit) {
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return {
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ok: false,
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retryAfter: Math.max(1, Math.ceil((bucket.resetAt - now) / 1000)),
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};
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}
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bucket.count = newCount;
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return { ok: true, retryAfter: 0 };
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}
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export async function clientIp(): Promise<string> {
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try {
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return resolveClientIp(await headers());
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} catch {
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return UNKNOWN_CLIENT_IP;
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}
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}
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