1 files changed, 83 insertions, 0 deletions
diff --git a/packages/backend/src/server/api/limiter.ts b/packages/backend/src/server/api/limiter.ts
new file mode 100644
index 0000000000..1e2fe5bcb3
--- /dev/null
+++ b/packages/backend/src/server/api/limiter.ts
@@ -0,0 +1,83 @@
+import * as Limiter from 'ratelimiter';
+import { redisClient } from '../../db/redis';
+import { IEndpoint } from './endpoints';
+import * as Acct from 'misskey-js/built/acct';
+import { User } from '@/models/entities/user';
+import Logger from '@/services/logger';
+
+const logger = new Logger('limiter');
+
+export default (endpoint: IEndpoint, user: User) => new Promise<void>((ok, reject) => {
+	const limitation = endpoint.meta.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: `${user.id}:${key}:min`,
+			duration: limitation.minInterval,
+			max: 1,
+			db: redisClient
+		});
+
+		minIntervalLimiter.get((err, info) => {
+			if (err) {
+				return reject('ERR');
+			}
+
+			logger.debug(`@${Acct.toString(user)} ${endpoint.name} min remaining: ${info.remaining}`);
+
+			if (info.remaining === 0) {
+				reject('BRIEF_REQUEST_INTERVAL');
+			} else {
+				if (hasLongTermLimit) {
+					max();
+				} else {
+					ok();
+				}
+			}
+		});
+	}
+
+	// Long term limit
+	function max() {
+		const limiter = new Limiter({
+			id: `${user.id}:${key}`,
+			duration: limitation.duration,
+			max: limitation.max,
+			db: redisClient
+		});
+
+		limiter.get((err, info) => {
+			if (err) {
+				return reject('ERR');
+			}
+
+			logger.debug(`@${Acct.toString(user)} ${endpoint.name} max remaining: ${info.remaining}`);
+
+			if (info.remaining === 0) {
+				reject('RATE_LIMIT_EXCEEDED');
+			} else {
+				ok();
+			}
+		});
+	}
+});