Leon Serfaty
45 lines
1.6 KiB
TypeScript
45 lines
1.6 KiB
TypeScript
import { RateLimiterMemory } from "rate-limiter-flexible";
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// In-memory limiters (no Redis). Fine for a single-instance Plesk deployment;
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// swap for RateLimiterPostgres if the app is ever scaled to multiple nodes.
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const limiters = new Map<string, RateLimiterMemory>();
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function getLimiter(name: string, points: number, durationSec: number): RateLimiterMemory {
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let limiter = limiters.get(name);
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if (!limiter) {
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limiter = new RateLimiterMemory({ points, duration: durationSec });
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limiters.set(name, limiter);
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}
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return limiter;
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}
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export interface RateLimitResult {
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ok: boolean;
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retryAfterSec?: number;
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}
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/** Consume one unit for `key` under a named bucket; returns ok=false when throttled. */
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export async function rateLimit(
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bucket: string,
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key: string,
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opts: { points: number; durationSec: number }
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): Promise<RateLimitResult> {
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const limiter = getLimiter(bucket, opts.points, opts.durationSec);
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try {
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await limiter.consume(key);
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return { ok: true };
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} catch (res) {
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const retryAfterSec = Math.ceil((res as { msBeforeNext?: number }).msBeforeNext ?? 1000) / 1000;
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return { ok: false, retryAfterSec: Math.ceil(retryAfterSec) };
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}
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}
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// Common presets.
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export const LIMITS = {
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generation: { points: 10, durationSec: 60 }, // 10 generations / min / user
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repurpose: { points: 15, durationSec: 60 },
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api: { points: 60, durationSec: 60 }, // 60 API calls / min / key (writes)
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read: { points: 120, durationSec: 60 }, // 120 read/list calls / min / key
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stream: { points: 30, durationSec: 60 }, // SSE (re)connects / min / user
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} as const;
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