Initial commit 🍀

src/api/limitter.ts

@@ -0,0 +1,69 @@
+import * as Limiter from 'ratelimiter';
+import limiterDB from '../db/redis';
+import { IEndpoint } from './endpoints';
+import { IAuthContext } from './authenticate';
+
+export default (endpoint: IEndpoint, ctx: IAuthContext) => new Promise((ok, reject) => {
+	const limitKey = endpoint.hasOwnProperty('limitKey')
+		? endpoint.limitKey
+		: endpoint.name;
+
+	const hasMinInterval =
+		endpoint.hasOwnProperty('minInterval');
+
+	const hasRateLimit =
+		endpoint.hasOwnProperty('limitDuration') &&
+		endpoint.hasOwnProperty('limitMax');
+
+	if (hasMinInterval) {
+		min();
+	} else if (hasRateLimit) {
+		max();
+	} else {
+		ok();
+	}
+
+	// Short-term limit
+	function min(): void {
+		const minIntervalLimiter = new Limiter({
+			id: `${ctx.user._id}:${limitKey}:min`,
+			duration: endpoint.minInterval,
+			max: 1,
+			db: limiterDB
+		});
+
+		minIntervalLimiter.get((limitErr, limit) => {
+			if (limitErr) {
+				reject('ERR');
+			} else if (limit.remaining === 0) {
+				reject('BRIEF_REQUEST_INTERVAL');
+			} else {
+				if (hasRateLimit) {
+					max();
+				} else {
+					ok();
+				}
+			}
+		});
+	}
+
+	// Long term limit
+	function max(): void {
+		const limiter = new Limiter({
+			id: `${ctx.user._id}:${limitKey}`,
+			duration: endpoint.limitDuration,
+			max: endpoint.limitMax,
+			db: limiterDB
+		});
+
+		limiter.get((limitErr, limit) => {
+			if (limitErr) {
+				reject('ERR');
+			} else if (limit.remaining === 0) {
+				reject('RATE_LIMIT_EXCEEDED');
+			} else {
+				ok();
+			}
+		});
+	}
+});