59 lines
1.3 KiB
JavaScript
59 lines
1.3 KiB
JavaScript
const { sendError } = require("../utils/http");
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const buckets = new Map();
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function pruneExpired(now) {
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for (const [key, value] of buckets.entries()) {
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if (value.resetAt <= now) {
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buckets.delete(key);
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}
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}
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}
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function getClientIp(req) {
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const forwardedFor = req.headers["x-forwarded-for"];
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if (typeof forwardedFor === "string" && forwardedFor.trim()) {
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return forwardedFor.split(",")[0].trim();
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}
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return req.ip || req.socket?.remoteAddress || "unknown";
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}
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function createRateLimit({ keyPrefix, windowMs, max, message }) {
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return (req, res, next) => {
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const now = Date.now();
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if (buckets.size > 5000) {
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pruneExpired(now);
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}
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const key = `${keyPrefix}:${getClientIp(req)}`;
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const existing = buckets.get(key);
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const bucket =
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!existing || existing.resetAt <= now
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? { count: 0, resetAt: now + windowMs }
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: existing;
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bucket.count += 1;
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buckets.set(key, bucket);
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if (bucket.count > max) {
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const retryAfterSeconds = Math.max(
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1,
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Math.ceil((bucket.resetAt - now) / 1000)
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);
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res.setHeader("Retry-After", String(retryAfterSeconds));
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return sendError(
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res,
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429,
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message || "Too many requests. Please try again later."
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);
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}
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return next();
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};
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}
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module.exports = {
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createRateLimit,
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};
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