32 lines
840 B
TypeScript
32 lines
840 B
TypeScript
import type { NextFunction, Request, Response } from 'express';
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type Bucket = {
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count: number;
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windowStart: number;
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};
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const buckets = new Map<string, Bucket>();
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export const rateLimit = (options: { keyPrefix: string; windowMs: number; max: number }) => {
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return (req: Request, res: Response, next: NextFunction): void => {
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const key = `${options.keyPrefix}:${req.ip ?? 'unknown'}`;
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const now = Date.now();
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const current = buckets.get(key);
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if (!current || now - current.windowStart > options.windowMs) {
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buckets.set(key, { count: 1, windowStart: now });
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next();
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return;
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}
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if (current.count >= options.max) {
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res.status(429).json({ message: 'Rate limit exceeded. Try again later.' });
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return;
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}
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current.count += 1;
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buckets.set(key, current);
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next();
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};
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};
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