cloudflare-bindings

Cloudflare Bindings

Patterns for Cloudflare Workers bindings in Hono.

Type Definitions

Define all bindings in a central type:

// types/bindings.ts
export type Env = {
  Bindings: {
    // D1 Database
    DB: D1Database

    // KV Namespace
    KV: KVNamespace

    // R2 Bucket
    BUCKET: R2Bucket

    // Durable Object
    COUNTER: DurableObjectNamespace

    // Environment Variables
    ENVIRONMENT: 'development' | 'staging' | 'production'
    API_KEY: string
    JWT_SECRET: string
  }
  Variables: {
    user: User
    requestId: string
  }
}

D1 Database

Basic Queries

app.get('/users', async (c) => {
  const db = c.env.DB

  // Select all
  const { results } = await db
    .prepare('SELECT * FROM users WHERE deleted_at IS NULL')
    .all()

  return c.json({ data: results })
})

app.get('/users/:id', async (c) => {
  const db = c.env.DB
  const id = c.req.param('id')

  // Select one
  const user = await db
    .prepare('SELECT * FROM users WHERE id = ?')
    .bind(id)
    .first()

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

  return c.json({ data: user })
})

Insert and Update

app.post('/users', async (c) => {
  const db = c.env.DB
  const { email, name } = c.req.valid('json')
  const id = crypto.randomUUID()

  const result = await db
    .prepare('INSERT INTO users (id, email, name) VALUES (?, ?, ?)')
    .bind(id, email, name)
    .run()

  return c.json({ data: { id, email, name } }, 201)
})

app.put('/users/:id', async (c) => {
  const db = c.env.DB
  const id = c.req.param('id')
  const { name } = c.req.valid('json')

  await db
    .prepare('UPDATE users SET name = ?, updated_at = datetime("now") WHERE id = ?')
    .bind(name, id)
    .run()

  return c.json({ data: { id, name } })
})

Transactions (Batch)

app.post('/transfer', async (c) => {
  const db = c.env.DB
  const { fromId, toId, amount } = c.req.valid('json')

  // D1 batch for transaction-like behavior
  const results = await db.batch([
    db.prepare('UPDATE accounts SET balance = balance - ? WHERE id = ?')
      .bind(amount, fromId),
    db.prepare('UPDATE accounts SET balance = balance + ? WHERE id = ?')
      .bind(amount, toId),
    db.prepare('INSERT INTO transfers (from_id, to_id, amount) VALUES (?, ?, ?)')
      .bind(fromId, toId, amount)
  ])

  return c.json({ success: true })
})