Introduce processor

src/server/api/limitter.ts

@@ -0,0 +1,83 @@
+import * as Limiter from 'ratelimiter';
+import * as debug from 'debug';
+import limiterDB from '../../db/redis';
+import { Endpoint } from './endpoints';
+import { IAuthContext } from './authenticate';
+import getAcct from '../common/user/get-acct';
+
+const log = debug('misskey:limitter');
+
+export default (endpoint: Endpoint, ctx: IAuthContext) => new Promise((ok, reject) => {
+	const limitation = endpoint.limit;
+
+	const key = limitation.hasOwnProperty('key')
+		? limitation.key
+		: endpoint.name;
+
+	const hasShortTermLimit =
+		limitation.hasOwnProperty('minInterval');
+
+	const hasLongTermLimit =
+		limitation.hasOwnProperty('duration') &&
+		limitation.hasOwnProperty('max');
+
+	if (hasShortTermLimit) {
+		min();
+	} else if (hasLongTermLimit) {
+		max();
+	} else {
+		ok();
+	}
+
+	// Short-term limit
+	function min() {
+		const minIntervalLimiter = new Limiter({
+			id: `${ctx.user._id}:${key}:min`,
+			duration: limitation.minInterval,
+			max: 1,
+			db: limiterDB
+		});
+
+		minIntervalLimiter.get((err, info) => {
+			if (err) {
+				return reject('ERR');
+			}
+
+			log(`@${getAcct(ctx.user)} ${endpoint.name} min remaining: ${info.remaining}`);
+
+			if (info.remaining === 0) {
+				reject('BRIEF_REQUEST_INTERVAL');
+			} else {
+				if (hasLongTermLimit) {
+					max();
+				} else {
+					ok();
+				}
+			}
+		});
+	}
+
+	// Long term limit
+	function max() {
+		const limiter = new Limiter({
+			id: `${ctx.user._id}:${key}`,
+			duration: limitation.duration,
+			max: limitation.max,
+			db: limiterDB
+		});
+
+		limiter.get((err, info) => {
+			if (err) {
+				return reject('ERR');
+			}
+
+			log(`@${getAcct(ctx.user)} ${endpoint.name} max remaining: ${info.remaining}`);
+
+			if (info.remaining === 0) {
+				reject('RATE_LIMIT_EXCEEDED');
+			} else {
+				ok();
+			}
+		});
+	}
+});