backend-patterns

Files (1)

• SKILL.md

SKILL.md (first lines)

# Backend Development Patterns

Backend architecture patterns and best practices for scalable server-side applications.

## API Design Patterns

### RESTful API Structure

```typescript
// ✅ Resource-based URLs
GET    /api/markets                 # List resources
GET    /api/markets/:id             # Get single resource
POST   /api/markets                 # Create resource
PUT    /api/markets/:id             # Replace resource
PATCH  /api/markets/:id             # Update resource
DELETE /api/markets/:id             # Delete resource

// ✅ Query parameters for filtering, sorting, pagination
GET /api/markets?status=active&sort=volume&limit=20&offset=0
```

### Repository Pattern

```typescript
// Abstract data access logic
interface MarketRepository {
  findAll(filters?: MarketFilters): Promise<Market[]>
  findById(id: string): Promise<Market | null>
  create(data: CreateMarketDto): Promise<Market>
  update(id: string, data: UpdateMarketDto): Promise<Market>
  delete(id: string): Promise<void>
}

import { eq } from 'drizzle-orm'
import { db } from '@/db'
import { markets } from '@/db/schema'

class PostgresMarketRepository implements MarketRepository {
  async findAll(filters?: MarketFilters): Promise<Market[]> {
    let query = db.select().from(markets)

    if (filters?.status) {
      query = query.where(eq(markets.status, filters.status))
    }

    if (filters?.limit) {
      query = query.limit(filters.limit)
    }

    return await query
  }

  // Other methods...
}
```

### Service Layer Pattern

```typescript
// Business logic separated from data access
class MarketService {
  constructor(private marketRepo: MarketRepository) {}

  async searchMarkets(query: string, limit: number = 10): Promise<Market[]> {
    // Business logic
    const embedding = await generateEmbedding(query)
    const results = await this.vectorSearch(embedding, limit)

    // Fetch full data
    const markets = await this.marketRepo.findByIds(results.map(r => r.id))

    // Sort by similarity
    return markets.sort((a, b) => {
      const scoreA = results.find(r => r.id === a.id)?.score || 0
      const scoreB = results.find(r => r.id === b.id)?.score || 0
      return scoreA - scoreB
    })
  }

  private async vectorSearch(embedding: number[], limit: number) {
    // Vector search implementation
  }
}
```

### Middleware Pattern

```typescript
import { Hono } from 'hono'
import { verifyToken } from '@/lib/auth'

const app = new Hono()

// Request/response processing pipeline
app.use('*', async (c, next) => {
  const token = c.req.header('Authorization')?.replace('Bearer ', '')

  if (!token) {
    return c.json({ error: 'Unauthorized' }, 401)
  }

  try {
    const user = await verifyToken(token)
    c.set('user', user)
    await next()
  } catch (error) {
    return c.json({ error: 'Invalid token' }, 401)
  }
})

app.get('/protected', (c) => {
  const user = c.get('user')
  return c.json({ ok: true, user })
})
```

## Database Patterns

### Query Optimization

From ComeOnOliver/skillshub, MIT.

More from ComeOnOliver/skillshub