Helmet, CORS, Rate Limiting — security hardening cho NestJS API?

Helmet: HTTP security headers middleware — ngăn chặn XSS, clickjacking, sniffing:

import helmet from 'helmet';
app.use(helmet()); // Thêm vào main.ts

CORS: chỉ allow origins cụ thể:

app.enableCors({
  origin: ['https://yourdomain.com'],
  credentials: true,
  methods: ['GET', 'POST', 'PUT', 'DELETE'],
});

Rate Limiting với @nestjs/throttler:

ThrottlerModule.forRoot([
  { name: 'short', ttl: 1000, limit: 3 },     // 3 req/s
  { name: 'medium', ttl: 10000, limit: 20 },  // 20 req/10s
  { name: 'long', ttl: 60000, limit: 100 },   // 100 req/min
])

Input sanitization: class-validator + ValidationPipe với whitelist: true ngăn chặn mass assignment.

Dùng sanitize-html cho user-generated content. SQL Injection: TypeORM parameterized queries tự động escape — không bao giờ dùng raw string interpolation trong queries.

Helmet: HTTP security headers — prevents XSS, clickjacking: app.use(helmet())

CORS: allow specific origins:

app.enableCors({ origin: ['https://yourdomain.com'], credentials: true });

Rate Limiting with @nestjs/throttler:

ThrottlerModule.forRoot([
  { name: 'short', ttl: 1000, limit: 3 },
  { name: 'long', ttl: 60000, limit: 100 },
])

Input sanitization: ValidationPipe with whitelist: true prevents mass assignment.

TypeORM parameterized queries prevent SQL injection — never use raw string interpolation.