Fetch Handler

Background

Incoming HTTP requests to a Worker are passed to the fetch() handler as a Request object. To respond to the request with a response, return a Response object:

JavaScript

export default {
  async fetch(request, env, ctx) {
    return new Response('Hello World!');
  },
};

Note

The Workers runtime does not support XMLHttpRequest (XHR). Learn the difference between XMLHttpRequest and fetch() in the MDN ↗ documentation.

Parameters

• request Request

  • The incoming HTTP request.

• env object

  • The bindings available to the Worker. As long as the environment has not changed, the same object (equal by identity) may be passed to multiple requests. You can also import env from cloudflare:workers to access bindings from anywhere in your code.

• ctx.waitUntil(promisePromise) : void

  • Refer to waitUntil.

• ctx.passThroughOnException() : void

  • Refer to passThroughOnException.