Add rate limits

Co-authored-by: mrjvs <mistrjvs@gmail.com>

src/modules/ratelimits/index.ts

@@ -0,0 +1,24 @@
+import { conf } from '@/config';
+import { Limiter } from '@/modules/ratelimits/limiter';
+import { connectRedis } from '@/modules/ratelimits/redis';
+import { scopedLogger } from '@/services/logger';
+
+const log = scopedLogger('ratelimits');
+
+let limiter: null | Limiter = null;
+
+export function getLimiter() {
+  return limiter;
+}
+
+export async function setupRatelimits() {
+  if (!conf.ratelimits.enabled) {
+    log.warn('Ratelimits disabled!');
+    return;
+  }
+  const redis = await connectRedis();
+  limiter = new Limiter({
+    redis,
+  });
+  log.info('Ratelimits have been setup!');
+}

src/modules/ratelimits/limiter.ts

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+import Redis from 'ioredis';
+import RateLimiter from 'async-ratelimiter';
+import ms from 'ms';
+import { StatusError } from '@/services/error';
+
+export interface LimiterOptions {
+  redis: Redis;
+}
+
+interface LimitBucket {
+  limiter: RateLimiter;
+}
+
+interface BucketOptions {
+  id: string;
+  window: string;
+  max: number;
+  inc?: number;
+}
+
+export class Limiter {
+  private redis: Redis;
+  private buckets: Record<string, LimitBucket> = {};
+
+  constructor(ops: LimiterOptions) {
+    this.redis = ops.redis;
+  }
+
+  async bump(req: { ip: string }, ops: BucketOptions) {
+    const ip = req.ip;
+    if (!this.buckets[ops.id]) {
+      this.buckets[ops.id] = {
+        limiter: new RateLimiter({
+          db: this.redis,
+          namespace: `RATELIMIT_${ops.id}`,
+          duration: ms(ops.window),
+          max: ops.max,
+        }),
+      };
+    }
+
+    for (let i = 1; i < (ops.inc ?? 0); i++) {
+      await this.buckets[ops.id].limiter.get({
+        id: ip,
+      });
+    }
+    const currentLimit = await this.buckets[ops.id].limiter.get({
+      id: ip,
+    });
+
+    return {
+      hasBeenLimited: currentLimit.remaining <= 0,
+      limit: currentLimit,
+    };
+  }
+
+  async assertAndBump(req: { ip: string }, ops: BucketOptions) {
+    const { hasBeenLimited } = await this.bump(req, ops);
+    if (hasBeenLimited) {
+      throw new StatusError('Ratelimited', 429);
+    }
+  }
+}

src/modules/ratelimits/redis.ts

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+import { conf } from '@/config';
+import Redis from 'ioredis';
+
+export function connectRedis() {
+  if (!conf.ratelimits.redisUrl) throw new Error('missing redis URL');
+  return new Redis(conf.ratelimits.redisUrl);
+}