compute-starter-kit-javascript-default

Compute@Edge starter kit for JavaScript

Experiment with running JavaScript in the Fastly Compute@Edge environment with a basic starter that demonstrates rudimentary request handling.

For more details about other starter kits for Compute@Edge, see the Fastly developer hub

Features

• Handling incoming requests via a handler for the fetch event
• Getting the incoming request via event.request
• Basic handling of requests, including
  • reading headers and request bodies using request.text(), request.arrayBuffer(), request.json()
  • reading request headers using request.headers
• Setting response bodies via the Response constructor (but not the body setter)
• Setting response headers via the Response#headers getter
• Sending async upstream requests using fetch(request, { backend: "backend_name" })
• Reading values from Edge Dictionaries using the Dictionary builtin
• Getting the client's IP address via event.client.address
• Getting the client's geolocation data via event.client.geo
• Getting geolocation data for any IP address via getGeolocationForIpAddress

Understanding the code

The code in src/index.js registers a handler for the fetch event that takes an event object with the downstream request as a request property, and shows how to read the URL, request body and headers, and send a response.

The template uses webpack to bundle index.js and its imports into a single JS file, bin/index.js, which is then wrapped into a .wasm file, bin/index.wasm using the js-compute-runtime CLI tool bundled with the @fastly/js-compute npm package, and bundled into a .tar.gz file ready for deployment to Compute@Edge.

After deployment, your Compute@Edge service will simply return an iframe with instructions on how to get started with C@E. For more complex examples of what can be done within a Compute@Edge program, see the usage guide for JavaScript or our library of code examples.

Security issues

Please see our SECURITY.md for guidance on reporting security-related issues.