@astrojs/cloudflare

@astrojs/cloudflare

An SSR adapter for use with Cloudflare Pages Functions targets. Write your code in Astro/Javascript and deploy to Cloudflare Pages.

Install

Add the Cloudflare adapter to enable SSR in your Astro project with the following astro add command. This will install the adapter and make the appropriate changes to your astro.config.mjs file in one step.

# Using NPM
npx astro add cloudflare
# Using Yarn
yarn astro add cloudflare
# Using PNPM
pnpm astro add cloudflare

If you prefer to install the adapter manually instead, complete the following two steps:

1. Add the Cloudflare adapter to your project's dependencies using your preferred package manager. If you’re using npm or aren’t sure, run this in the terminal:

npm install @astrojs/cloudflare

1. Add the following to your astro.config.mjs file:

// astro.config.mjs
import { defineConfig } from 'astro/config';
import cloudflare from '@astrojs/cloudflare';

export default defineConfig({
  output: 'server',
  adapter: cloudflare()
});

Options

Mode

mode: "advanced" | "directory"

default "advanced"

Cloudflare Pages has 2 different modes for deploying functions, advanced mode which picks up the _worker.js in dist, or a directory mode where pages will compile the worker out of a functions folder in the project root.

For most projects the adaptor default of advanced will be sufficient; the dist folder will contain your compiled project. Switching to directory mode allows you to use pages plugins such as Sentry or write custom code to enable logging.

In directory mode the adaptor will compile the client side part of you app the same way, but moves the worker script into a functions folder in the project root. The adaptor will only ever place a [[path]].js in that folder, allowing you to add additional plugins and pages middleware which can be checked into version control. Cloudflare documentation contains more information about writing custom functions.

// directory mode
export default defineConfig({
  adapter: cloudflare({ mode: "directory" }),
});

Enabling Preview

In order for preview to work you must install wrangler

$ pnpm install wrangler --save-dev

It's then possible to update the preview script in your package.json to "preview": "wrangler pages dev ./dist". This will allow you run your entire application locally with Wrangler, which supports secrets, environment variables, KV namespaces, Durable Objects and all other supported Cloudflare bindings.

Access to the Cloudflare runtime

You can access all the Cloudflare bindings and environment variables from Astro components and API routes through the adapter API.

import { getRuntime } from "@astrojs/cloudflare/runtime";

getRuntime(Astro.request);

Depending on your adapter mode (advanced = worker, directory = pages), the runtime object will look a little different due to differences in the Cloudflare API.

Streams

Some integrations such as React rely on web streams. Currently Cloudflare Pages Functions require enabling a flag to support Streams.

To do this:

• go to the Cloudflare Pages project
• click on Settings in the top bar, then Functions in the sidebar
• scroll down to Compatibility Flags, click Configure Production Compatibility Flags, and add streams_enable_constructors
• do this for both the Production Compatibility Flags and Preview Compatibility Flags

Environment Variables

As Cloudflare Pages Functions provides environment variables per request, you can only access private environment variables when a request has happened. Usually, this means moving environment variable access inside a function.

// pages/[id].json.js

export function get({ params }) {
  // Access environment variables per request inside a function
  const serverUrl = import.meta.env.SERVER_URL;
  const result = await fetch(serverUrl + "/user/" + params.id);
  return {
    body: await result.text(),
  };
}

Headers, Redirects and function invocation routes

Cloudflare has support for adding custom headers, configuring static redirects and defining which routes should invoke functions. Cloudflare looks for _headers, _redirects, and _routes.json files in your build output directory to configure these features. This means they should be placed in your Astro project’s public/ directory.

Custom _routes.json

By default, @astrojs/cloudflare will generate a _routes.json file that lists all files from your dist/ folder and redirects from the _redirects file in the exclude array. This will enable Cloudflare to serve files and process static redirects without a function invocation. Creating a custom _routes.json will override this automatic optimization and, if not configured manually, cause function invocations that will count against the request limits of your Cloudflare plan.

Troubleshooting

For help, check out the #support channel on Discord. Our friendly Support Squad members are here to help!

You can also check our Astro Integration Documentation for more on integrations.

Contributing

This package is maintained by Astro's Core team. You're welcome to submit an issue or PR!