Cloudflare

Edge computing platform with CDN, Workers, and security.

When to Use

• CDN and caching
• Edge computing (Workers)
• Static site hosting (Pages)
• DDoS protection and WAF

Quick Start

// Cloudflare Worker
export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    const url = new URL(request.url);

    if (url.pathname === "/api/hello") {
      return Response.json({ message: "Hello from the edge!" });
    }

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

Core Concepts

Workers with KV

export interface Env {
  MY_KV: KVNamespace;
  MY_DO: DurableObjectNamespace;
}

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    // Read from KV
    const cached = await env.MY_KV.get("key", "json");
    if (cached) return Response.json(cached);

    // Fetch and cache
    const data = await fetchData();
    await env.MY_KV.put("key", JSON.stringify(data), {
      expirationTtl: 3600,
    });

    return Response.json(data);
  },
};

Durable Objects

export class Counter implements DurableObject {
  state: DurableObjectState;

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

  async fetch(request: Request): Promise<Response> {
    let count = (await this.state.storage.get<number>("count")) || 0;

    if (request.method === "POST") {
      count++;
      await this.state.storage.put("count", count);
    }

    return Response.json({ count });
  }
}

Common Patterns

Pages Deployment

# wrangler.toml
name = "my-app"
compatibility_date = "2024-01-01"

[site]
bucket = "./dist"

[[kv_namespaces]]
binding = "CACHE"
id = "abc123"

# Deploy
npx wrangler deploy

# Pages
npx wrangler pages deploy dist

Best Practices

Do:

• Use KV for caching
• Implement proper error handling
• Use Durable Objects for state
• Configure proper cache headers

Don’t:

• Block the event loop
• Make too many subrequests
• Store large data in KV values
• Ignore execution time limits

Troubleshooting

References

• Cloudflare Workers Docs
• Cloudflare Pages