Application example Bindings

Use R2 in a real application path

R2 is Cloudflare object storage for files, uploads, generated assets, and private objects.

This example uses one private bucket and one route, which is still the cleanest default shape for many real apps.

A good first R2 example teaches both the binding and the delivery boundary: the worker decides what the browser gets.

Config focus: Direct bucket naming
Runtime shape: Get an object from R2 and stream it through a route
Best use: Private file delivery or media endpoints

Start by wiring the binding clearly in config

Minimal R2 config

import { defineConfig } from 'devflare/config'

export default defineConfig({

name: 'r2-example',

files: {

fetch: 'src/fetch.ts'

bindings: {

r2: {

FILES: 'private-files'

}

})

Build the application flow around the binding

Treat this as the app-level R2 path: the route, event handler, or service module receives a real request and uses the binding to do useful work.

Keep product limits, remote ownership, and fallback behavior visible in the code around the binding instead of hiding everything behind a vague utility too early.

This route pattern keeps auth, caching, and content-type decisions in your app instead of in an assumed bucket URL contract.
If you later choose a public bucket, make that an explicit architecture decision rather than a hidden side effect.

Serve an object through the worker

import { env } from 'devflare/runtime'

export async function fetch(request: Request): Promise<Response> {

const url = new URL(request.url)

const key = url.pathname.replace(/^\/files\//, '')

const object = await env.FILES.get(key)

if (!object) {

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

}

return new Response(object.body, {

headers: {

'content-type': object.httpMetadata?.contentType ?? 'application/octet-stream'

}

})

}

Keep production boundaries visible

Config focus: Direct bucket naming.
Runtime shape: Get an object from R2 and stream it through a route.
Best use: Private file delivery or media endpoints.

A better first instinct than “just use the bucket URL”

Routing through the worker teaches the real boundary between stored objects and browser-facing responses.

Testing R2

R2 is local-friendly, which means you can test real object operations without inventing a storage adapter just to get off the ground.

Durable Objects

The fast Devflare payoff is simple: put one counter object in a file, call it from the worker, and call the same object directly in tests.