astro-workers-for-platforms-adapter

Custom Astro adapter for Cloudflare Workers for Platforms.

How it works

Request → Dispatch Worker → User Worker (worker-entry.mjs) → env.ASSETS.fetch()

This adapter ensures Astro always emits a worker entry, even for fully static sites. While static assets could be uploaded to R2 and served by the dispatch worker. Workers for Platforms supports a native Static Assets binding (env.ASSETS) that serves files from the edge with per-tenant isolation — no R2 needed.

Running astro build produces two outputs: a bundled worker at dist/server/entry.mjs and static assets in dist/client/. The adapter sets ssr.noExternal: true so Vite inlines all dependencies into a single file with no external imports.

Deployment uses the Workers for Platforms asset upload API in three steps: create session, upload asset buckets, then deploy the worker with a completion token.

Why not @astrojs/cloudflare?

The official @astrojs/cloudflare adapter cannot be used here because:

• It requires wrangler as a peer dependency (we deploy programmatically via the API, not with wrangler)
• As of Astro 6, it deletes _worker.js for fully static sites — Workers for Platforms always needs a worker entry

Getting started

npm install @recranet/astro-workers-for-platforms-adapter

// astro.config.mjs
import { defineConfig } from 'astro/config';
import astroWorkersForPlatformsAdapter from '@recranet/astro-workers-for-platforms-adapter';

export default defineConfig({
  adapter: astroWorkersForPlatformsAdapter(),
});

References

• Cloudflare VibeSDK