astro/packages/integrations/cloudflare/README.md

# @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.

```sh
# 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:

```bash
npm install @astrojs/cloudflare
```

2. Add the following to your `astro.config.mjs` file:

```js ins={3, 6-7}
// 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 adapter default of `advanced` will be sufficient; the `dist` folder will contain your compiled project. Switching to directory mode allows you to use [pages plugins](https://developers.cloudflare.com/pages/platform/functions/plugins/) such as [Sentry](https://developers.cloudflare.com/pages/platform/functions/plugins/sentry/) or write custom code to enable logging.

In directory mode, the adapter will compile the client side part of your app the same way by default, but moves the worker script into a `functions` folder in the project root. In this case, the adapter 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.

With the build configuration `split: true`, the adapter instead compiles a separate bundle for each page. This option requires some manual maintenance of the `functions` folder. Files emitted by Astro will overwrite existing `functions` files with identical names, so you must choose unique file names for each file you manually add. Additionally, the adapter will never empty the `functions` folder of outdated files, so you must clean up the folder manually when you remove pages.

Note that this adapter does not support using [Cloudflare Pages Middleware](https://developers.cloudflare.com/pages/platform/functions/middleware/). Astro will bundle the [Astro middleware](https://docs.astro.build/en/guides/middleware/) into each page.

```ts
// directory mode
export default defineConfig({
  adapter: cloudflare({ mode: 'directory' }),
});
```

## Enabling Preview

In order for preview to work you must install `wrangler`

```sh
$ 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 to run your entire application locally with [Wrangler](https://github.com/cloudflare/wrangler2), which supports secrets, environment variables, KV namespaces, Durable Objects and [all other supported Cloudflare bindings](https://developers.cloudflare.com/pages/platform/functions/#adding-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.

```js
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.

## Environment Variables

See Cloudflare's documentation for [working with environment variables](https://developers.cloudflare.com/pages/platform/functions/bindings/#environment-variables).

```js
// 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](https://developers.cloudflare.com/pages/platform/headers/), configuring static [redirects](https://developers.cloudflare.com/pages/platform/redirects/) and defining which routes should [invoke functions](https://developers.cloudflare.com/pages/platform/functions/routing/#function-invocation-routes). 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](https://astro.build/chat). Our friendly Support Squad members are here to help!

You can also check our [Astro Integration Documentation][astro-integration] for more on integrations.

### Meaningful error messages

Currently, errors during running your application in Wrangler are not very useful, due to the minification of your code. For better debugging, you can add `vite.build.minify = false` setting to your `astro.config.js`

```js
export default defineConfig({
  adapter: cloudflare(),
  output: 'server',

  vite: {
    build: {
      minify: false,
    },
  },
});
```

## Contributing

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

[astro-integration]: https://docs.astro.build/en/guides/integrations-guide/