webui: Provide rate limit feature to prevent DOS attack

webui/package.json

@@ -44,6 +44,7 @@
         "clipboard-copy": "^4.0.1",
         "clsx": "^1.2.1",
         "dompurify": "^3.0.4",
+        "express-rate-limit": "^7.2.0",
         "fetch-retry": "^5.0.6",
         "lodash": "^4.17.21",
         "markdown-it": "^13.0.1",

webui/src/default/server.ts

@@ -10,9 +10,39 @@
 
 import * as express from 'express';
 import * as path from 'path';
+import { rateLimit } from 'express-rate-limit';
 
 const app = express();
 
+const args = process.argv.slice(2);
+if (args.indexOf('-ratelimit') != -1) {
+    const proxiesIndex = args.indexOf('-ratelimit-proxies');
+    if (proxiesIndex != -1) {
+        app.set('trust proxy', Number(args[proxiesIndex + 1]));
+    }
+
+    let windowMs = 15 * 60 * 1000; // 15 minutes
+    const rateLimitWindowIndex = args.indexOf('-ratelimit-window-seconds');
+    if (rateLimitWindowIndex != -1) {
+        windowMs = Number(args[rateLimitWindowIndex + 1]) * 1000;
+    }
+
+    let limit = 100; // Limit each IP to 100 requests per windowMs
+    const rateLimitAmountIndex = args.indexOf('-ratelimit-limit');
+    if (rateLimitAmountIndex != -1) {
+        limit = Number(args[rateLimitAmountIndex + 1]);
+    }
+
+    // Apply rate limiter to all requests
+    const limiter = rateLimit({
+        windowMs,
+        limit,
+        standardHeaders: 'draft-7',
+        legacyHeaders: false
+    });
+    app.use(limiter);
+}
+
 // Serve static resources
 const staticPath = path.join(__dirname, '..', '..', 'static');
 app.use(express.static(staticPath));

webui/yarn.lock

@@ -2840,6 +2840,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"express-rate-limit@npm:^7.2.0":
+  version: 7.2.0
+  resolution: "express-rate-limit@npm:7.2.0"
+  peerDependencies:
+    express: 4 || 5 || ^5.0.0-beta.1
+  checksum: 10/1cd33daeeeb3428f8990718512e8c803ca3406d1e99cbc38bcda12056a42ea51319a7bbc357bdc02d79b7f2b508c743895e8805118115cc637e180eb420e643f
+  languageName: node
+  linkType: hard
+
 "express@npm:^4.18.2":
   version: 4.18.2
   resolution: "express@npm:4.18.2"
@@ -4648,6 +4657,7 @@ __metadata:
     eslint: "npm:^8.44.0"
     eslint-plugin-react: "npm:^7.32.2"
     express: "npm:^4.18.2"
+    express-rate-limit: "npm:^7.2.0"
     fetch-retry: "npm:^5.0.6"
     lodash: "npm:^4.17.21"
     markdown-it: "npm:^13.0.1"