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https://github.com/pluvial/svelte-adapter-deno

A SvelteKit adapter for Deno
https://github.com/pluvial/svelte-adapter-deno

deno svelte sveltekit sveltekit-adapter

Last synced: 3 months ago
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A SvelteKit adapter for Deno

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README 

        
# svelte-adapter-deno



[Adapter](https://kit.svelte.dev/docs/adapters) for SvelteKit apps that generates a standalone Deno server.



## Usage



Install with `npm i -D svelte-adapter-deno`, then add the adapter to your `svelte.config.js`:



```js

// svelte.config.js

import adapter from 'svelte-adapter-deno';



export default {

  kit: {

    adapter: adapter()

  }

};

```



After building the server (`npm run build`), use the following command to start:



```sh

# with the default build directory

deno run --allow-env --allow-read --allow-net build/index.js



# with a custom build directory

deno run --allow-env --allow-read --allow-net path/to/build/index.js

```



You can use the [deployctl](https://github.com/denoland/deployctl/blob/main/action/README.md) GitHub Action to automatically deploy your app in Deno Deploy:



.github/workflows/ci.yml



```yml

name: ci



on:

  push:

    branches:

      - main

  pull_request:

    branches:

      - main



jobs:

  deploy:

    name: deploy

    runs-on: ubuntu-latest

    permissions:

      id-token: write

      contents: read



    steps:

      - name: Clone repository

        uses: actions/checkout@v2



      - name: Install Node

        uses: actions/setup-node@v2

        with:

          node-version: 16



      - name: Cache pnpm modules

        uses: actions/cache@v2

        with:

          path: ~/.pnpm-store

          key: ${{ runner.os }}-${{ hashFiles('**/pnpm-lock.yaml') }}

          restore-keys: |

            ${{ runner.os }}-



      - name: Install pnpm and node_modules

        uses: pnpm/action-setup@v2

        with:

          version: latest

          run_install: true



      - name: Build site

        run: pnpm build

        working-directory: '' # if necessary, should contain {out}



      - name: Deploy to Deno Deploy

        uses: denoland/deployctl@v1

        with:

          project: 

          entrypoint: '{out}/index.js' # same as `out` option in config

          root: '' # if necessary

```



The server needs at least the following permissions to run:



- `allow-env` - allow environment access, to support runtime configuration via runtime variables (can be further restricted to include just the necessary variables)

- `allow-read` - allow file system read access (can be further restricted to include just the necessary directories)

- `allow-net` - allow network access (can be further restricted to include just the necessary domains)



In the documentation `deno run -A` is used for simplicity rather than as a recommendation, use only the necessary permissions in general use.



## Environment variables



### `PORT` and `HOST`



By default, the server will accept connections on `0.0.0.0` using port 3000. These can be customised with the `PORT` and `HOST` environment variables:



```

HOST=127.0.0.1 PORT=4000 deno run --allow-env --allow-read --allow-net build/server.js

```



### `ADDRESS_HEADER` and `XFF_DEPTH`



The [RequestEvent](types#public-types-requestevent) object passed to hooks and endpoints includes an `event.getClientAddress()` function that returns the client's IP address. By default this is the connecting `remoteAddress`. If your server is behind one or more proxies (such as a load balancer), this value will contain the innermost proxy's IP address rather than the client's, so we need to specify an `ADDRESS_HEADER` to read the address from:



```

ADDRESS_HEADER=True-Client-IP node build

```



> Headers can easily be spoofed. As with `PROTOCOL_HEADER` and `HOST_HEADER`, you should [know what you're doing](https://adam-p.ca/blog/2022/03/x-forwarded-for/) before setting these.



If the `ADDRESS_HEADER` is `X-Forwarded-For`, the header value will contain a comma-separated list of IP addresses. The `XFF_DEPTH` environment variable should specify how many trusted proxies sit in front of your server. E.g. if there are three trusted proxies, proxy 3 will forward the addresses of the original connection and the first two proxies:



```

, , 

```



Some guides will tell you to read the left-most address, but this leaves you [vulnerable to spoofing](https://adam-p.ca/blog/2022/03/x-forwarded-for/):



```

, , , 

```



We instead read from the _right_, accounting for the number of trusted proxies. In this case, we would use `XFF_DEPTH=3`.



> If you need to read the left-most address instead (and don't care about spoofing) — for example, to offer a geolocation service, where it's more important for the IP address to be _real_ than _trusted_, you can do so by inspecting the `x-forwarded-for` header within your app.



## Options



The adapter can be configured with various options:



```js

/// file: svelte.config.js

import adapter from '@sveltejs/adapter-node';



export default {

  kit: {

    adapter: adapter({

      // default options are shown

      out: 'build',

      precompress: false,

      envPrefix: '',

      deps: './deps.ts' // (relative to adapter-deno package)

    })

  }

};

```



### out



The directory to build the server to. It defaults to `build` — i.e. `deno run -A build/index.js` would start the server locally after it has been created.



### precompress



Enables precompressing using gzip and brotli for assets and prerendered pages. It defaults to `false`.



### envPrefix



If you need to change the name of the environment variables used to configure the deployment (for example, to deconflict with environment variables you don't control), you can specify a prefix:



```js

envPrefix: 'MY_CUSTOM_';

```



```

MY_CUSTOM_HOST=127.0.0.1 \

MY_CUSTOM_PORT=4000 \

MY_CUSTOM_ORIGIN=https://my.site \

deno run -A build/index.js

```



### deps



The file re-exporting external runtime dependencies (`deps.ts` by convention in Deno). It defaults to the `deps.ts` file included in the package.



## Custom server



The adapter creates two files in your build directory — `index.js` and `handler.js`. Running `index.js` — e.g. `deno run -A build/index.js`, if you use the default build directory — will start a server on the configured port.



Alternatively, you can import the `handler.js` file, which exports a handler suitable for use with [Oak](https://github.com/oakserver/oak) and set up your own server:



```js

/// file: my-server.js

import { Application, Router } from 'https://deno.land/x/[email protected]/mod.ts';

import { handler } from './build/handler.js';



const app = new Application();



// add a route that lives separately from the SvelteKit app

const router = new Router();

router.get('/healthcheck', (ctx) => {

  ctx.response.body = 'ok';

});

app.use(router.routes());

app.use(router.allowedMethods());



// let SvelteKit handle everything else, including serving prerendered pages and static assets

app.use(handler);



app.addEventListener('listen', () => {

  console.log('listening on port 3000');

});

await app.listen({ port: 3000 });

```



## License



[MIT](LICENSE)