fix: adds rate limit

Author: velopert

src/server/CacheManager.ts

@@ -1,7 +1,7 @@
 import Redis from 'ioredis';
 import checkCacheRule from './checkCacheRule';
 
-const redis = new Redis({
+export const redis = new Redis({
   host: process.env.REACT_APP_REDIS_HOST || 'localhost',
 });
 

src/server/rateLimitMiddleware.ts

@@ -0,0 +1,37 @@
+import { Middleware } from 'koa';
+import { redis } from './CacheManager';
+
+const rateLimitMiddleware: Middleware = async (ctx, next) => {
+  const ip = ctx.request.ips.slice(-1)[0] || ctx.request.ip;
+
+  const key = `${ip}:pageview`;
+  const blockedKey = `${ip}:blocked`;
+
+  const blocked = await redis.get(blockedKey);
+
+  if (blocked) {
+    ctx.status = 429;
+    ctx.body = { msg: 'Too many request' };
+    return;
+  }
+  const exists = await redis.get(key);
+
+  if (typeof exists === 'number' && exists > 100) {
+    await redis.set(blockedKey, 1);
+    await redis.expire(blockedKey, 300);
+    ctx.status = 429;
+    ctx.body = { msg: 'Too many request' };
+    return;
+  }
+
+  if (exists === null) {
+    await redis.set(key, 1);
+    await redis.expire(key, 60);
+  } else {
+    console.log(`${ip} - ${exists}`);
+    await redis.incr(key);
+  }
+  return next();
+};
+
+export default rateLimitMiddleware;