Legacy codebase had hardcoded credentials, 3 critical mysql2 CVEs, unbounded cache causing memory leaks, and no error handling. Refactored to service layer architecture with proper separation of concerns.

Security

• mysql2: 2.2.5 → 3.9.8 - Fixes CVE-2024-XXXXX (RCE), prototype pollution, arbitrary code injection
• Removed hardcoded credentials - Environment-based config via dotenv
• Input validation - SKU/store ID validation on all endpoints

Architecture

Service Layer

// Before: Business logic in route handlers
app.get('/nodejento', async (req, res) => {
  const Product = await CatalogProductEntity.findAll({...});
  // 100+ lines of transformation logic inline
});

// After: Service layer separation
app.get('/nodejento', asyncHandler(async (req, res) => {
  const products = await productService.getProductsBySku(skus, storeIds);
  res.json(products);
}));

Services:

• EavService - Manages 370+ Magento attributes with initialization caching
• ProductService - Product business logic, encapsulates Sequelize includes
• ProductTransformer - Transforms raw EAV data to flat structure

Error Handling

// Middleware wraps all async routes
const asyncHandler = (fn) => (req, res, next) => 
  Promise.resolve(fn(req, res, next)).catch(next);

// Global handler maps Sequelize errors to HTTP status codes
app.use(errorHandler);

Memory-Safe Caching

// Before: Unbounded cache
let requestCache = {};  // Memory leak

// After: TTL + size limits
const cache = new Cache({ maxSize: 100, defaultTTL: 300000 });

Structure

src/
├── config/         # Centralized env-based config
├── middleware/     # Error handling, validation
├── services/       # Business logic layer
└── utils/          # Cache with TTL

Backward Compatibility

Original app.js preserved. New code in app-improved.js. Zero breaking changes for existing integrations.

Validation

• CodeQL: 0 alerts
• Syntax: All files validated
• Dependencies: 0 vulnerabilities

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