# Create new project
npm create cloudflare@latest my-worker

# Initialize in existing directory
npx wrangler init

# Login
npx wrangler login
npx wrangler whoami

# Local development
npx wrangler dev
npx wrangler dev --remote    # Use remote bindings
npx wrangler dev --local     # Fully local

# Test cron trigger locally
curl "http://localhost:8787/__scheduled?cron=*+*+*+*+*"

# Deploy to production
npx wrangler deploy

# Deploy to environment
npx wrangler deploy --env staging

# List versions
npx wrangler versions list

# Rollback
npx wrangler rollback

# Create database
npx wrangler d1 create my-database

# Execute SQL
npx wrangler d1 execute my-database --local --file=schema.sql
npx wrangler d1 execute my-database --remote --command="SELECT * FROM users"

# Interactive shell
npx wrangler d1 execute my-database --local --command=".tables"

# Export
npx wrangler d1 export my-database --remote --output=backup.sql

# Create bucket
npx wrangler r2 bucket create my-bucket

# List buckets
npx wrangler r2 bucket list

# Upload/download
npx wrangler r2 object put my-bucket/file.txt --file=local.txt
npx wrangler r2 object get my-bucket/file.txt --file=download.txt

# Delete
npx wrangler r2 object delete my-bucket/file.txt

# Create namespace
npx wrangler kv namespace create MY_KV
npx wrangler kv namespace create MY_KV --preview  # Preview namespace

# List namespaces
npx wrangler kv namespace list

# Key operations
npx wrangler kv key put --binding MY_KV key "value"
npx wrangler kv key get --binding MY_KV key
npx wrangler kv key list --binding MY_KV
npx wrangler kv key delete --binding MY_KV key

# Bulk upload
npx wrangler kv bulk put --binding MY_KV data.json

# Set secret
npx wrangler secret put API_KEY
# (prompts for value)

# List secrets
npx wrangler secret list

# Delete secret
npx wrangler secret delete API_KEY

# Create queue
npx wrangler queues create my-queue

# List queues
npx wrangler queues list

# Create Hyperdrive config
npx wrangler hyperdrive create my-hyperdrive --connection-string="postgres://..."

# List configs
npx wrangler hyperdrive list

# Update
npx wrangler hyperdrive update my-hyperdrive --connection-string="postgres://..."

{
  "$schema": "./node_modules/wrangler/config-schema.json",
  "name": "my-worker",
  "main": "src/index.ts",
  "compatibility_date": "2024-01-01",
  "compatibility_flags": ["nodejs_compat"],

  // Account settings
  "account_id": "<optional-account-id>",

  // Build settings
  "minify": true,
  "node_compat": true,

  // Environment variables
  "vars": {
    "API_URL": "https://api.example.com"
  },

  // KV Namespaces
  "kv_namespaces": [
    {
      "binding": "MY_KV",
      "id": "<namespace-id>",
      "preview_id": "<preview-namespace-id>"
    }
  ],

  // R2 Buckets
  "r2_buckets": [
    {
      "binding": "MY_BUCKET",
      "bucket_name": "my-bucket",
      "preview_bucket_name": "my-bucket-preview",
      "jurisdiction": "eu"
    }
  ],

  // D1 Databases
  "d1_databases": [
    {
      "binding": "DB",
      "database_id": "<database-id>",
      "database_name": "my-database"
    }
  ],

  // Durable Objects
  "durable_objects": {
    "bindings": [
      {
        "name": "MY_DO",
        "class_name": "MyDurableObject"
      }
    ]
  },
  "migrations": [
    {
      "tag": "v1",
      "new_classes": ["MyDurableObject"]
    },
    {
      "tag": "v2",
      "new_sqlite_classes": ["MyDurableObjectWithSQL"]
    }
  ],

  // Queues
  "queues": {
    "producers": [
      {
        "binding": "MY_QUEUE",
        "queue": "my-queue"
      }
    ],
    "consumers": [
      {
        "queue": "my-queue",
        "max_batch_size": 10,
        "max_batch_timeout": 30,
        "max_retries": 3,
        "dead_letter_queue": "my-dlq"
      }
    ]
  },

  // Hyperdrive
  "hyperdrive": [
    {
      "binding": "MY_DB_POOL",
      "id": "<hyperdrive-config-id>"
    }
  ],

  // Workers AI
  "ai": {
    "binding": "AI"
  },

  // Vectorize
  "vectorize": [
    {
      "binding": "MY_VECTORS",
      "index_name": "my-index"
    }
  ],

  // Browser Rendering
  "browser": {
    "binding": "BROWSER"
  },

  // Service Bindings (Worker-to-Worker)
  "services": [
    {
      "binding": "OTHER_WORKER",
      "service": "other-worker-name"
    }
  ],

  // Cron Triggers
  "triggers": {
    "crons": ["0 * * * *", "0 6 * * *"]
  },

  // Routes
  "routes": [
    {
      "pattern": "example.com/*",
      "zone_name": "example.com"
    }
  ],

  // Observability
  "observability": {
    "logs": {
      "enabled": true,
      "invocation_logs": true,
      "head_sampling_rate": 1
    }
  },

  // Environments
  "env": {
    "staging": {
      "name": "my-worker-staging",
      "vars": {
        "API_URL": "https://staging-api.example.com"
      }
    },
    "production": {
      "name": "my-worker-production",
      "routes": [
        {
          "pattern": "api.example.com/*",
          "zone_name": "example.com"
        }
      ]
    }
  }
}

interface Env {
  MY_KV: KVNamespace;
}

// Write operations
await env.MY_KV.put("key", "string value");
await env.MY_KV.put("key", JSON.stringify(object));
await env.MY_KV.put("key", arrayBuffer);

// With TTL (seconds)
await env.MY_KV.put("session", data, { expirationTtl: 3600 });

// With absolute expiration
await env.MY_KV.put("session", data, { expiration: Math.floor(Date.now() / 1000) + 3600 });

// With metadata
await env.MY_KV.put("user:123", userData, {
  metadata: { type: "user", version: 2 }
});

// Read operations
const value = await env.MY_KV.get("key");  // Returns string or null
const json = await env.MY_KV.get("key", "json");  // Parses JSON
const buffer = await env.MY_KV.get("key", "arrayBuffer");
const stream = await env.MY_KV.get("key", "stream");

// With metadata
const { value, metadata } = await env.MY_KV.getWithMetadata("key");

// List keys
const list = await env.MY_KV.list();
const filtered = await env.MY_KV.list({ prefix: "user:", limit: 100 });
// Pagination: use list.cursor for next page

// Delete
await env.MY_KV.delete("key");

interface Env {
  MY_BUCKET: R2Bucket;
}

// Put object
await env.MY_BUCKET.put("path/to/file.json", JSON.stringify(data), {
  httpMetadata: {
    contentType: "application/json",
    cacheControl: "max-age=3600",
  },
  customMetadata: {
    uploadedBy: "worker",
    version: "1.0",
  },
});

// Put with checksums
await env.MY_BUCKET.put("file.bin", data, {
  md5: expectedMd5,  // Validates on upload
  sha256: expectedSha256,
});

// Get object
const object = await env.MY_BUCKET.get("path/to/file.json");
if (object) {
  const text = await object.text();
  const json = await object.json();
  const buffer = await object.arrayBuffer();
  const blob = await object.blob();
  const stream = object.body;  // ReadableStream

  // Metadata
  console.log(object.key, object.size, object.etag);
  console.log(object.httpMetadata.contentType);
  console.log(object.customMetadata.uploadedBy);
}

// Head (metadata only)
const head = await env.MY_BUCKET.head("path/to/file.json");

// List objects
const list = await env.MY_BUCKET.list();
const filtered = await env.MY_BUCKET.list({
  prefix: "uploads/",
  delimiter: "/",
  limit: 1000,
});

// Delete
await env.MY_BUCKET.delete("path/to/file.json");
await env.MY_BUCKET.delete(["file1.json", "file2.json"]);  // Batch delete

// Multipart upload (for files > 5GB)
const upload = await env.MY_BUCKET.createMultipartUpload("large-file.zip");
const part1 = await upload.uploadPart(1, chunk1);
const part2 = await upload.uploadPart(2, chunk2);
await upload.complete([part1, part2]);

// Or abort
await upload.abort();

interface Env {
  DB: D1Database;
}

// Prepared statements (recommended)
const stmt = env.DB.prepare("SELECT * FROM users WHERE id = ?");
const { results } = await stmt.bind(userId).all();
const user = await stmt.bind(userId).first();
const value = await stmt.bind(userId).first("name");  // Single column

// Insert/Update
const { meta } = await env.DB.prepare(
  "INSERT INTO users (name, email) VALUES (?, ?)"
).bind(name, email).run();
console.log(meta.last_row_id, meta.changes);

// Batch operations (single transaction)
const results = await env.DB.batch([
  env.DB.prepare("INSERT INTO users (name) VALUES (?)").bind("Alice"),
  env.DB.prepare("INSERT INTO users (name) VALUES (?)").bind("Bob"),
  env.DB.prepare("UPDATE counters SET value = value + 1 WHERE name = 'users'"),
]);

// Raw execution
await env.DB.exec("PRAGMA table_info(users)");

// Transaction pattern (using batch)
await env.DB.batch([
  env.DB.prepare("UPDATE accounts SET balance = balance - ? WHERE id = ?").bind(100, fromId),
  env.DB.prepare("UPDATE accounts SET balance = balance + ? WHERE id = ?").bind(100, toId),
]);

-- Create indexes for WHERE clause columns
CREATE INDEX idx_users_email ON users(email);

-- Use EXPLAIN QUERY PLAN to verify index usage
EXPLAIN QUERY PLAN SELECT * FROM users WHERE email = 'test@example.com';

-- Batch large migrations
DELETE FROM logs WHERE created_at < '2024-01-01' LIMIT 1000;

-- Run after schema changes
PRAGMA optimize;

// Durable Object class
export class Counter {
  state: DurableObjectState;
  value: number = 0;

  constructor(state: DurableObjectState, env: Env) {
    this.state = state;
    // Restore state from storage
    this.state.blockConcurrencyWhile(async () => {
      this.value = (await this.state.storage.get("value")) || 0;
    });
  }

  async fetch(request: Request): Promise<Response> {
    const url = new URL(request.url);

    switch (url.pathname) {
      case "/increment":
        this.value++;
        await this.state.storage.put("value", this.value);
        return Response.json({ value: this.value });

      case "/value":
        return Response.json({ value: this.value });

      default:
        return new Response("Not found", { status: 404 });
    }
  }
}

// Worker that uses the Durable Object
export default {
  async fetch(request: Request, env: Env) {
    const id = env.COUNTER.idFromName("global");
    const stub = env.COUNTER.get(id);
    return stub.fetch(request);
  },
};

export class ChatRoom {
  state: DurableObjectState;

  constructor(state: DurableObjectState, env: Env) {
    this.state = state;
  }

  async fetch(request: Request): Promise<Response> {
    if (request.headers.get("Upgrade") === "websocket") {
      const pair = new WebSocketPair();
      const [client, server] = Object.values(pair);

      // Use Hibernation API
      this.state.acceptWebSocket(server);

      return new Response(null, { status: 101, webSocket: client });
    }
    return new Response("Expected WebSocket", { status: 400 });
  }

  // Called when hibernated DO receives WebSocket message
  async webSocketMessage(ws: WebSocket, message: string | ArrayBuffer) {
    // Broadcast to all connected clients
    for (const client of this.state.getWebSockets()) {
      if (client !== ws && client.readyState === WebSocket.READY_STATE_OPEN) {
        client.send(message);
      }
    }
  }

  async webSocketClose(ws: WebSocket, code: number, reason: string) {
    // Handle disconnect
  }

  async webSocketError(ws: WebSocket, error: unknown) {
    // Handle error
    ws.close(1011, "Internal error");
  }
}

// Producer
interface Env {
  MY_QUEUE: Queue;
}

export default {
  async fetch(request: Request, env: Env) {
    // Send single message
    await env.MY_QUEUE.send({ type: "email", to: "user@example.com" });

    // Send with options
    await env.MY_QUEUE.send(
      { type: "process", id: 123 },
      { contentType: "json" }
    );

    // Batch send
    await env.MY_QUEUE.sendBatch([
      { body: { id: 1 } },
      { body: { id: 2 } },
      { body: { id: 3 } },
    ]);

    return new Response("Queued");
  },
};

// Consumer
interface QueueMessage {
  type: string;
  id?: number;
  to?: string;
}

export default {
  async queue(batch: MessageBatch<QueueMessage>, env: Env): Promise<void> {
    for (const message of batch.messages) {
      try {
        console.log(`Processing: ${JSON.stringify(message.body)}`);
        await processMessage(message.body);
        message.ack();  // Mark as processed
      } catch (e) {
        console.error(`Failed: ${e}`);
        message.retry();  // Will retry (up to max_retries)
      }
    }
  },
};

interface Env {
  AI: Ai;
}

// Text generation
const response = await env.AI.run("@cf/meta/llama-3.3-70b-instruct-fp8-fast", {
  messages: [
    { role: "system", content: "You are a helpful assistant." },
    { role: "user", content: "What is Cloudflare?" },
  ],
  max_tokens: 512,
  temperature: 0.7,
});

// Streaming
const stream = await env.AI.run("@cf/meta/llama-3.3-70b-instruct-fp8-fast", {
  messages: [...],
  stream: true,
});
return new Response(stream, {
  headers: { "Content-Type": "text/event-stream" },
});

// Text-to-Speech
const audio = await env.AI.run("@deepgram/aura-2-en", {
  text: "Hello, this is a test.",
});
return new Response(audio, {
  headers: { "Content-Type": "audio/wav" },
});

// Speech-to-Text
const transcript = await env.AI.run("@cf/openai/whisper-large-v3-turbo", {
  audio: audioArrayBuffer,
});
// Returns { text: "...", segments: [...] }

// Image generation
const image = await env.AI.run("@cf/black-forest-labs/flux-1-schnell", {
  prompt: "A futuristic cityscape at sunset",
  num_steps: 4,
});
return new Response(image, {
  headers: { "Content-Type": "image/png" },
});

// Embeddings
const embeddings = await env.AI.run("@cf/baai/bge-large-en-v1.5", {
  text: ["Hello world", "Cloudflare Workers"],
});
// Returns { data: [{ embedding: [...] }, { embedding: [...] }] }

// Image captioning
const caption = await env.AI.run("@cf/meta/llama-3.2-11b-vision-instruct", {
  image: imageArrayBuffer,
  prompt: "Describe this image in detail.",
});

# Create Hyperdrive config
npx wrangler hyperdrive create my-db \
  --connection-string="postgres://user:pass@host:5432/database"

# Add to wrangler.jsonc

import { Client } from "pg";

interface Env {
  MY_DB: Hyperdrive;
}

export default {
  async fetch(request: Request, env: Env) {
    // Connect using Hyperdrive connection string
    const client = new Client({
      connectionString: env.MY_DB.connectionString,
    });

    await client.connect();
    const result = await client.query("SELECT * FROM users WHERE id = $1", [1]);

    // No need to call client.end() - Hyperdrive manages pooling
    return Response.json(result.rows);
  },
};

Worker -> TCP handshake (1 RTT)
       -> TLS negotiation (3 RTTs)
       -> DB authentication (3 RTTs)
       -> Query (1 RTT)
Total: 8 round-trips before first query

Worker -> Hyperdrive pool (cached connection)
       -> Query (1 RTT to pool, reuses DB connection)
Total: 1 round-trip to query

# macOS
brew install cloudflared

# Windows
winget install Cloudflare.cloudflared

# Linux
curl -L https://github.com/cloudflare/cloudflared/releases/latest/download/cloudflared-linux-amd64 -o cloudflared
sudo chmod +x cloudflared && sudo mv cloudflared /usr/local/bin/

# Login
cloudflared tunnel login

# Create tunnel
cloudflared tunnel create my-tunnel

# Create config file (~/.cloudflared/config.yml)
cat << EOF > ~/.cloudflared/config.yml
tunnel: <tunnel-id>
credentials-file: $HOME/.cloudflared/<tunnel-id>.json

ingress:
  - hostname: app.example.com
    service: http://localhost:3000
  - hostname: api.example.com
    service: http://localhost:8080
  - service: http_status:404
EOF

# Add DNS
cloudflared tunnel route dns my-tunnel app.example.com

# Run
cloudflared tunnel run my-tunnel

# Linux
sudo cloudflared service install
sudo systemctl enable cloudflared
sudo systemctl start cloudflared

# macOS
sudo cloudflared service install
sudo launchctl load /Library/LaunchDaemons/com.cloudflare.cloudflared.plist

Application:
  name: Internal App
  type: Self-hosted
  domain: app.example.com

Policy:
  name: Allow Company
  action: Allow
  include:
    - email_domain: company.com
  require:
    - country: US

import { McpServer } from "@cloudflare/mcp-server";

interface Env {
  DB: D1Database;
}

const server = new McpServer({
  name: "my-mcp-server",
  version: "1.0.0",
});

// Define tools
server.addTool({
  name: "query_database",
  description: "Query the D1 database",
  parameters: {
    type: "object",
    properties: {
      query: { type: "string", description: "SQL query to execute" },
    },
    required: ["query"],
  },
  handler: async ({ query }, { env }) => {
    const result = await env.DB.prepare(query).all();
    return {
      content: [{ type: "text", text: JSON.stringify(result.results) }],
    };
  },
});

// Define resources
server.addResource({
  uri: "db://tables",
  name: "Database Tables",
  description: "List of all tables",
  handler: async ({ env }) => {
    const tables = await env.DB.prepare(
      "SELECT name FROM sqlite_master WHERE type='table'"
    ).all();
    return {
      contents: [{ uri: "db://tables", text: JSON.stringify(tables.results) }],
    };
  },
});

export default {
  async fetch(request: Request, env: Env) {
    return server.handleRequest(request, env);
  },
};

{
  "mcpServers": {
    "cloudflare": {
      "url": "https://mcp.cloudflare.com/sse",
      "transport": "sse"
    }
  }
}

name: Deploy Worker

on:
  push:
    branches: [main]

jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Setup Node.js
        uses: actions/setup-node@v4
        with:
          node-version: "20"

      - name: Install dependencies
        run: npm ci

      - name: Run tests
        run: npm test

      - name: Deploy to Cloudflare
        uses: cloudflare/wrangler-action@v3
        with:
          apiToken: ${{ secrets.CLOUDFLARE_API_TOKEN }}
          accountId: ${{ secrets.CLOUDFLARE_ACCOUNT_ID }}