76 lines
1.9 KiB
TypeScript
76 lines
1.9 KiB
TypeScript
import { Elysia } from "elysia"
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type RateLimitEntry = {
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count: number
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resetAt: number
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}
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const store = new Map<string, RateLimitEntry>()
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// Clean up expired entries every 60 seconds
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setInterval(() => {
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const now = Date.now()
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for (const [key, entry] of store) {
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if (now > entry.resetAt) {
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store.delete(key)
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}
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}
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}, 60_000)
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function getClientIP(request: Request): string {
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const forwarded = request.headers.get("x-forwarded-for")
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if (forwarded) {
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return forwarded.split(",")[0].trim()
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}
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return "unknown"
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}
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function checkRateLimit(
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key: string,
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window: number,
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max: number,
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): { allowed: boolean; remaining: number; resetAt: number } {
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const now = Date.now()
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const entry = store.get(key)
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if (!entry || now > entry.resetAt) {
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const resetAt = now + window * 1000
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store.set(key, { count: 1, resetAt })
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return { allowed: true, remaining: max - 1, resetAt }
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}
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if (entry.count >= max) {
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return { allowed: false, remaining: 0, resetAt: entry.resetAt }
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}
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entry.count++
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return { allowed: true, remaining: max - entry.count, resetAt: entry.resetAt }
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}
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export const rateLimit = (
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window: number = 60,
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max: number = 100,
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) =>
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new Elysia({ name: "rate-limit" }).onRequest(({ request, set }) => {
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const ip = getClientIP(request)
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const path = new URL(request.url).pathname
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const key = `${ip}:${path}`
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const result = checkRateLimit(key, window, max)
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if (!result.allowed) {
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const retryAfter = Math.ceil((result.resetAt - Date.now()) / 1000)
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set.status = 429
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set.headers["Retry-After"] = String(retryAfter)
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return {
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error: "Too many requests",
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retryAfter,
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}
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}
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// These headers are informational — clients can use them to throttle
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set.headers["X-RateLimit-Limit"] = String(max)
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set.headers["X-RateLimit-Remaining"] = String(result.remaining)
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set.headers["X-RateLimit-Reset"] = String(Math.ceil(result.resetAt / 1000))
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})
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