backend-patterns

# Backend Patterns

Comprehensive patterns for API design, database operations, error handling, and backend architecture.

## When to Use

- Creating API endpoints
- Designing database schemas
- Implementing business logic
- Error handling and logging
- Background jobs and queues
- Caching strategies

## API Design Patterns

### RESTful API Structure

```typescript
// app/api/users/route.ts
export async function GET(request: Request) {
  const { searchParams } = new URL(request.url)
  const page = parseInt(searchParams.get('page') || '1')
  const limit = parseInt(searchParams.get('limit') || '10')

  const users = await db.users.findMany({
    skip: (page - 1) * limit,
    take: limit
  })

  return NextResponse.json({
    success: true,
    data: users,
    pagination: {
      page,
      limit,
      total: await db.users.count()
    }
  })
}

export async function POST(request: Request) {
  const body = await request.json()

  // Validate input
  const validated = CreateUserSchema.parse(body)

  const user = await db.users.create({ data: validated })

  return NextResponse.json(
    { success: true, data: user },
    { status: 201 }
  )
}

// app/api/users/[id]/route.ts
export async function GET(
  request: Request,
  { params }: { params: { id: string } }
) {
  const user = await db.users.findUnique({
    where: { id: params.id }
  })

  if (!user) {
    return NextResponse.json(
      { error: 'User not found' },
      { status: 404 }
    )
  }

  return NextResponse.json({ success: true, data: user })
}

export async function PATCH(
  request: Request,
  { params }: { params: { id: string } }
) {
  const body = await request.json()
  const validated = UpdateUserSchema.parse(body)

  const user = await db.users.update({
    where: { id: params.id },
    data: validated
  })

  return NextResponse.json({ success: true, data: user })
}

export async function DELETE(
  request: Request,
  { params }: { params: { id: string } }
) {
  await db.users.delete({ where: