add rate limiter for endpoints

Author: commit111

samples/agentic-langgraph/app/package-lock.json

@@ -15,6 +15,7 @@
     "@langchain/openai": "^0.6.3",
     "@langchain/tavily": "^0.1.4",
     "express": "^4.21.2",
+    "express-rate-limit": "^8.0.1",
     "ts-node": "^10.9.2"
   },
   "devDependencies": {

samples/agentic-langgraph/app/package.json

@@ -1,10 +1,20 @@
 import express from "express";
 import { getAgentOutputAsString } from "./agent.mts";
 import path from "path";
+import rateLimit from "express-rate-limit";
 
 const app = express();
+
+const limiter = rateLimit({
+  windowMs: 60 * 1000, // 1 minute
+  max: 30, // limit each IP to 30 requests per windowMs
+  standardHeaders: true,
+  legacyHeaders: false,
+});
+
 app.use(express.json());
 app.use(express.static(path.join(process.cwd(), "public")));
+app.use(limiter);
 
 app.post("/agent", async (req, res) => {
   const input = req.body.input;