fix(#19): Implement rate limiting for auth and write-heavy endpoints

backend/src/__tests__/rateLimit.test.js

@@ -0,0 +1,65 @@
+import { rateLimit, authRateLimit } from '../middleware/rateLimit.js';
+import express from 'express';
+import request from 'supertest';
+
+describe('Rate Limit Middleware', () => {
+  let app;
+
+  beforeEach(() => {
+    app = express();
+    app.use(express.json());
+  });
+
+  it('should allow requests within limit', (done) => {
+    const middleware = rateLimit({ max: 2, windowMs: 1000 });
+    
+    app.get('/test', middleware, (req, res) => {
+      res.status(200).json({ message: 'OK' });
+    });
+
+    request(app)
+      .get('/test')
+      .expect(200)
+      .end(done);
+  });
+
+  it('should block requests exceeding limit', (done) => {
+    const middleware = rateLimit({ max: 1, windowMs: 1000 });
+    
+    app.get('/test', middleware, (req, res) => {
+      res.status(200).json({ message: 'OK' });
+    });
+
+    // Erster Request sollte erfolgreich sein
+    request(app)
+      .get('/test')
+      .expect(200)
+      .end(() => {
+        // Zweiter Request sollte blockiert werden
+        request(app)
+          .get('/test')
+          .expect(429)
+          .end(done);
+      });
+  });
+
+  it('should apply auth rate limiting correctly', (done) => {
+    const middleware = authRateLimit({ max: 1, windowMs: 1000 });
+    
+    app.get('/auth-test', middleware, (req, res) => {
+      res.status(200).json({ message: 'OK' });
+    });
+
+    // Erster Request sollte erfolgreich sein
+    request(app)
+      .get('/auth-test')
+      .expect(200)
+      .end(() => {
+        // Zweiter Request sollte blockiert werden
+        request(app)
+          .get('/auth-test')
+          .expect(429)
+          .end(done);
+      });
+  });
+});

backend/src/middleware/rateLimit.js

@@ -0,0 +1,52 @@
+// Einfache Rate-Limiting-Middleware ohne externe Abhängigkeiten
+
+// Konfigurierbare Limits über Umgebungsvariablen
+const DEFAULT_WINDOW_MS = parseInt(process.env.RATE_LIMIT_WINDOW_MS) || 15 * 60 * 1000; // 15 Minuten
+const DEFAULT_MAX_REQUESTS = parseInt(process.env.RATE_LIMIT_MAX_REQUESTS) || 100;
+const DEFAULT_AUTH_WINDOW_MS = parseInt(process.env.RATE_LIMIT_AUTH_WINDOW_MS) || 5 * 60 * 1000; // 5 Minuten
+const DEFAULT_AUTH_MAX_REQUESTS = parseInt(process.env.RATE_LIMIT_AUTH_MAX_REQUESTS) || 5;
+
+// Speicher für IP-Adressen und Request-Zähler
+const rateLimits = new Map();
+
+const rateLimit = (options = {}) => {
+  const windowMs = options.windowMs || DEFAULT_WINDOW_MS;
+  const maxRequests = options.max || DEFAULT_MAX_REQUESTS;
+
+  return (req, res, next) => {
+    const key = req.ip; // IP-Adresse als Schlüssel
+    const now = Date.now();
+    
+    if (!rateLimits.has(key)) {
+      rateLimits.set(key, { count: 1, windowStart: now });
+    } else {
+      const data = rateLimits.get(key);
+      if (now - data.windowStart > windowMs) {
+        // Fenster abgelaufen, neues Fenster starten
+        rateLimits.set(key, { count: 1, windowStart: now });
+      } else {
+        // Prüfen, ob Limit erreicht wurde
+        if (data.count >= maxRequests) {
+          return res.status(429).json({
+            error: 'Too many requests',
+            retryAfter: Math.ceil((windowMs - (now - data.windowStart)) / 1000)
+          });
+        }
+        // Zähler erhöhen
+        rateLimits.set(key, { count: data.count + 1, windowStart: data.windowStart });
+      }
+    }
+    
+    next();
+  };
+};
+
+// Spezielle Middleware für Auth-Endpunkte mit kürzerem Fenster und niedrigerem Limit
+const authRateLimit = (options = {}) => {
+  const windowMs = options.windowMs || DEFAULT_AUTH_WINDOW_MS;
+  const maxRequests = options.max || DEFAULT_AUTH_MAX_REQUESTS;
+
+  return rateLimit({ windowMs, max: maxRequests });
+};
+
+module.exports = { rateLimit, authRateLimit };

backend/src/server.js

@@ -8,6 +8,7 @@ import addressRoutes from './routes/addresses.js';
 import contactRoutes from './routes/contacts.js';
 import profileRoutes from './routes/profile.js';
 import logger from './middleware/logger.js';
+const { rateLimit, authRateLimit } = require('./middleware/rateLimit.js');
 
 dotenv.config();
 
@@ -33,13 +34,16 @@ app.get('/metrics', (_req, res) => {
   });
 });
 
-app.use('/auth', authRoutes);
-app.use('/requests', helpRequestRoutes);
-app.use('/offers', offerRoutes);
-app.use('/reviews', reviewRoutes);
-app.use('/addresses', addressRoutes);
-app.use('/contacts', contactRoutes);
-app.use('/profile', profileRoutes);
+// Rate limiting für Auth-Endpunkte
+app.use('/auth', authRateLimit(), authRoutes);
+
+// Rate limiting für write-heavy Endpunkte
+app.use('/requests', rateLimit({ max: 50 }), helpRequestRoutes);
+app.use('/offers', rateLimit({ max: 50 }), offerRoutes);
+app.use('/reviews', rateLimit({ max: 50 }), reviewRoutes);
+app.use('/addresses', rateLimit({ max: 50 }), addressRoutes);
+app.use('/contacts', rateLimit({ max: 50 }), contactRoutes);
+app.use('/profile', rateLimit({ max: 50 }), profileRoutes);
 
 const port = Number(process.env.PORT || 3000);
 app.listen(port, () => {