@deno/astro-adapter

This adapter allows Astro to deploy your SSR site to Deno targets.

Learn how to deploy your Astro site in our Deno Deploy deployment guide.

• Why Astro Deno
• Installation
• Usage
• Configuration
• Examples
• Contributing

Why Astro Deno

If you're using Astro as a static site builder—its behavior out of the box—you don't need an adapter.

If you wish to use server-side rendering (SSR), Astro requires an adapter that matches your deployment runtime.

You also need an adapter or server if you wish to deploy your site to Deno Deploy.

Deno is a runtime similar to Node, but with an API that's more similar to the browser's API. This adapter provides access to Deno's API and creates a script to run your project on a Deno server.

Installation

Add the Deno adapter to enable SSR in your Astro project with the following steps:

1. Install the Deno 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 @deno/astro-adapter

2. Update your astro.config.mjs project configuration file with the changes below.

   // astro.config.mjs
   import { defineConfig } from "astro/config";
   import deno from "@deno/astro-adapter";
   
   export default defineConfig({
     output: "server",
     adapter: deno(),
   });

Next, update your preview script in package.json to run deno:

// package.json
{
  // ...
  "scripts": {
    "dev": "astro dev",
    "start": "astro dev",
    "build": "astro build",
    "preview": "deno run --allow-net --allow-read --allow-env ./dist/server/entry.mjs"
  }
}

You can now use this command to preview your production Astro site locally with Deno.

npm run preview

Usage

After performing a build there will be a dist/server/entry.mjs module. You can start a server by importing this module in your Deno app:

import "./dist/server/entry.mjs";

See the start option below for how you can have more control over starting the Astro server.

You can also run the script directly using deno:

deno run --allow-net --allow-read --allow-env ./dist/server/entry.mjs

Configuration

To configure this adapter, pass an object to the deno() function call in astro.config.mjs.

// astro.config.mjs
import { defineConfig } from "astro/config";
import deno from "@deno/astro-adapter";

export default defineConfig({
  output: "server",
  adapter: deno({
    //options go here
  }),
});

start

This adapter automatically starts a server when it is imported. You can turn this off with the start option:

import { defineConfig } from "astro/config";
import deno from "@deno/astro-adapter";

export default defineConfig({
  output: "server",
  adapter: deno({
    start: false,
  }),
});

If you disable this, you need to write your own Deno web server. Import and call handle from the generated entry script to render requests:

import { handle } from "./dist/server/entry.mjs";

Deno.serve((req: Request) => {
  // Check the request, maybe do static file handling here.

  return handle(req);
});

port and hostname

You can set the port (default: 8085) and hostname (default: 0.0.0.0) for the deno server to use. If start is false, this has no effect; your own server must configure the port and hostname.

import { defineConfig } from "astro/config";
import deno from "@deno/astro-adapter";

export default defineConfig({
  output: "server",
  adapter: deno({
    port: 8081,
    hostname: "myhost",
  }),
});

esbuild options

You can customize esbuild options by passing an object to the esbuild option. This object is passed directly to esbuild's build function. See the esbuild documentation for more information.

import { defineConfig } from "astro/config";
import deno from "@deno/astro-adapter";

export default defineConfig({
  output: "server",
  adapter: deno({
    esbuild: {
      // options go here
    },
  }),
});

Examples

The Astro Deno example includes a preview command that runs the entry script directly. Run npm run build then npm run preview to run the production deno server.

Contributing

To configure your development environment, clone the repository and install pnpm. pnpm is a package manager that emphasizes disk space efficiency and is used for managing the dependencies of this project. Once installed, run pnpm i to install the dependencies.

git clone
cd astro-adapter
pnpm i

The Deno Astro Adapter is currently built and tested with Deno 2.x. To test your changes make sure you have Deno 2.x installed

pnpm run test

Finally, you can check your code formatting with: pnpm run fmt.

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