feat: 新增限流功能 (#718)

* 请求速率限制

* perf: 优化代码

---------

Co-authored-by: ChenZhaoYu <790348264@qq.com>

service/src/index.ts

@@ -2,6 +2,7 @@ import express from 'express'
 import type { ChatContext, ChatMessage } from './chatgpt'
 import { chatConfig, chatReplyProcess, currentModel } from './chatgpt'
 import { auth } from './middleware/auth'
+import { limiter } from './middleware/limiter'
 import { isNotEmptyString } from './utils/is'
 
 const app = express()
@@ -17,7 +18,7 @@ app.all('*', (_, res, next) => {
   next()
 })
 
-router.post('/chat-process', auth, async (req, res) => {
+router.post('/chat-process', [auth, limiter], async (req, res) => {
   res.setHeader('Content-type', 'application/octet-stream')
 
   try {

service/src/middleware/limiter.ts

@@ -0,0 +1,19 @@
+import { rateLimit } from 'express-rate-limit'
+import { isNotEmptyString } from '../utils/is'
+
+const MAX_REQUEST_PER_HOUR = process.env.MAX_REQUEST_PER_HOUR
+
+const maxCount = (isNotEmptyString(MAX_REQUEST_PER_HOUR) && !isNaN(Number(MAX_REQUEST_PER_HOUR)))
+  ? parseInt(MAX_REQUEST_PER_HOUR)
+  : 0 // 0 means unlimited
+
+const limiter = rateLimit({
+  windowMs: 60 * 60 * 1000, // Maximum number of accesses within an hour
+  max: maxCount,
+  statusCode: 200, // 200 means success，but the message is 'Too many request from this IP in 1 hour'
+  message: async (req, res) => {
+    res.send({ status: 'Fail', message: 'Too many request from this IP in 1 hour', data: null })
+  },
+})
+
+export { limiter }