kaxuna1/express

Express Skill

Express backend for Luxia e-commerce uses a service layer pattern with modular routing. Routes handle HTTP concerns, services contain business logic, and middleware manages cross-cutting concerns like auth and rate limiting.

Quick Start

Creating a Route

// backend/src/routes/exampleRoutes.ts
import { Router } from 'express';
import { body, validationResult } from 'express-validator';
import { authenticate } from '../middleware/authMiddleware';
import { exampleService } from '../services/exampleService';

const router = Router();

router.post(
  '/',
  authenticate,
  [body('name').notEmpty(), body('email').isEmail()],
  async (req, res) => {
    const errors = validationResult(req);
    if (!errors.isEmpty()) {
      return res.status(400).json({ errors: errors.array() });
    }
    try {
      const result = await exampleService.create(req.body);
      res.status(201).json(result);
    } catch (error: any) {
      console.error('Error:', error);
      res.status(500).json({ message: error.message });
    }
  }
);

export default router;

Creating a Service

// backend/src/services/exampleService.ts
import { pool } from '../db/client';

export const exampleService = {
  async create(payload: { name: string; email: string }) {
    const result = await pool.query(
      'INSERT INTO examples (name, email) VALUES ($1, $2) RETURNING *',
      [payload.name, payload.email]
    );
    return result.rows[0];
  },

  async findById(id: number) {
    const result = await pool.query(
      'SELECT * FROM examples WHERE id = $1',
      [id]
    );
    return result.rows[0] || null;
  }
};

Key Concepts

| Concept | Usage | Example | |---------|-------|---------| | Route | HTTP endpoint definition | router.get('/items', handler) | | Service | Business logic encapsulation | itemService.findById(id) | | Middleware | Request preprocessing | authenticate, rateLimiter | | Validator | Input validation | body('email').isEmail() | | Pool | Database connection | pool.query(sql, params) |

Common Patterns

Protected Admin Route

router.use(authenticate);  // All routes below require auth

router.get('/', async (req, res) => {
  const adminId = (req as AuthenticatedRequest).adminId;
  // ...
});

Optional Authentication

router.get('/public', optionalAuth, async (req, res) => {
  const userId = (req as AuthenticatedRequest).userId; // May be undefined
  // ...
});

File Upload with Processing

router.post('/', authenticate, upload.single('image'), async (req, res) => {
  if (!req.file) {
    return res.status(400).json({ message: 'No file provided' });
  }
  const processed = await sharp(req.file.buffer).webp().toBuffer();
  // ...
});

See Also

• routes - Route organization and patterns
• services - Service layer architecture
• database - PostgreSQL query patterns
• auth - JWT authentication flow
• errors - Error handling patterns

Related Skills

• See the postgresql skill for database schema and query optimization
• See the typescript skill for type safety patterns
• See the node skill for Node.js runtime patterns
• See the zod skill for runtime validation (alternative to express-validator)