92 lines
2.5 KiB
TypeScript
92 lines
2.5 KiB
TypeScript
import { Context, Next } from "koa";
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import { defaults } from "lodash";
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import RateLimiter from "@server/RateLimiter";
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import env from "@server/env";
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import { RateLimitExceededError } from "@server/errors";
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import Metrics from "@server/logging/metrics";
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import Redis from "@server/redis";
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/**
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* Middleware that limits the number of requests that are allowed within a given
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* window. Should only be applied once to a server – do not use on individual
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* routes.
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*
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* @returns The middleware function.
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*/
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export function defaultRateLimiter() {
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return async function rateLimiterMiddleware(ctx: Context, next: Next) {
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if (!env.RATE_LIMITER_ENABLED) {
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return next();
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}
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const key = RateLimiter.hasRateLimiter(ctx.path)
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? `${ctx.path}:${ctx.ip}`
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: `${ctx.ip}`;
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const limiter = RateLimiter.getRateLimiter(ctx.path);
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try {
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await limiter.consume(key);
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} catch (rateLimiterRes) {
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ctx.set("Retry-After", `${rateLimiterRes.msBeforeNext / 1000}`);
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ctx.set("RateLimit-Limit", `${limiter.points}`);
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ctx.set("RateLimit-Remaining", `${rateLimiterRes.remainingPoints}`);
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ctx.set(
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"RateLimit-Reset",
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`${new Date(Date.now() + rateLimiterRes.msBeforeNext)}`
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);
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Metrics.increment("rate_limit.exceeded", {
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path: ctx.path,
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});
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throw RateLimitExceededError();
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}
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return next();
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};
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}
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type RateLimiterConfig = {
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/** The window for which this rate limiter is considered (defaults to 60s) */
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duration?: number;
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/** The number of requests per IP address that are allowed within the window */
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requests: number;
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};
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/**
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* Middleware that limits the number of requests per IP address that are allowed
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* within a window, overrides default middleware when used on a route.
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*
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* @returns The middleware function.
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*/
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export function rateLimiter(config: RateLimiterConfig) {
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return async function registerRateLimiterMiddleware(
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ctx: Context,
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next: Next
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) {
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if (!env.RATE_LIMITER_ENABLED) {
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return next();
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}
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if (!RateLimiter.hasRateLimiter(ctx.path)) {
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RateLimiter.setRateLimiter(
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ctx.path,
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defaults(
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{
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...config,
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points: config.requests,
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},
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{
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duration: 60,
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points: env.RATE_LIMITER_REQUESTS,
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keyPrefix: RateLimiter.RATE_LIMITER_REDIS_KEY_PREFIX,
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storeClient: Redis.defaultClient,
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}
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)
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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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