Initial commit: PodcastYes — AI podcast platform

lib/ratelimit/index.ts

@@ -0,0 +1,42 @@
+import { RateLimiterMemory } from "rate-limiter-flexible";
+
+// In-memory limiters (no Redis). Fine for a single-instance Plesk deployment;
+// swap for RateLimiterPostgres if the app is ever scaled to multiple nodes.
+const limiters = new Map<string, RateLimiterMemory>();
+
+function getLimiter(name: string, points: number, durationSec: number): RateLimiterMemory {
+  let limiter = limiters.get(name);
+  if (!limiter) {
+    limiter = new RateLimiterMemory({ points, duration: durationSec });
+    limiters.set(name, limiter);
+  }
+  return limiter;
+}
+
+export interface RateLimitResult {
+  ok: boolean;
+  retryAfterSec?: number;
+}
+
+/** Consume one unit for `key` under a named bucket; returns ok=false when throttled. */
+export async function rateLimit(
+  bucket: string,
+  key: string,
+  opts: { points: number; durationSec: number }
+): Promise<RateLimitResult> {
+  const limiter = getLimiter(bucket, opts.points, opts.durationSec);
+  try {
+    await limiter.consume(key);
+    return { ok: true };
+  } catch (res) {
+    const retryAfterSec = Math.ceil((res as { msBeforeNext?: number }).msBeforeNext ?? 1000) / 1000;
+    return { ok: false, retryAfterSec: Math.ceil(retryAfterSec) };
+  }
+}
+
+// Common presets.
+export const LIMITS = {
+  generation: { points: 10, durationSec: 60 }, // 10 generations / min / user
+  repurpose: { points: 15, durationSec: 60 },
+  api: { points: 60, durationSec: 60 }, // 60 API calls / min / key
+} as const;