/worker-examples

Examples of Javascript you can run on Cloudflare’s worldwide network

MIT LicenseMIT

Cloudflare Workers | Recipes

This repository contains examples of how Workers can be used to accomplish common tasks. You are welcome to use, modify, and extend this code! Pull requests are encourged.

In-Browser Editor | Official Workers Documentation | Community

⚡️

What is Workers?

Workers make it possible to write serverless JavaScript applications and run them on Cloudflare's global cloud network of 165 data centers. Workers ...

  • run on Chrome V8 and uses standard JavaScript API's
  • can also be written in languages like Rust and C# then compiled via WebAssembly
  • are used to achieve a wide array of goals, from trivializing small tasks like intercepting requests to an origin server:
addEventListener('fetch', event => {
  event.respondWith(handleRequest(event))
})

/*
 * Add an extra header to the client request
 */
async function handleRequest (event) {
  let request = new Request(event.request)
  request.headers.append('X-My-Request-Header', 'was set in Workers')
  const response = await fetch(request)
  console.log(`Got status: ${response.status} ${response.statusText}`)
  return response
}

... to developing full stack Internet-scale applications using Cloudflare's globally-distributed object storage, Workers KV Store:

addEventListener('fetch', event => {
 event.respondWith(readFromStorage(event))
})

/* 
 * Retrieve some JSON data from KV Store 
 */
async function readFromStorage (event) {
  // const writeKey = await FIRST_KV_NAMESPACE.put('first-key', '{ "foo": "bar" }')
  const value = await FIRST_KV_NAMESPACE.get('first-key')
  return new Response(value, { headers: 'Content-Type': 'application/json' })
}

You can use Workers to perform cryptographic operations using the WebCrypto API, rewrite HTML response streams on-the-fly and serve dynamic content to visitors halfway around the world in milliseconds!

Questions

Questions about Workers can be addressed on our community site.