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Use SvelteKit with SST

Create and deploy a SvelteKit app to AWS with SST.

Prerequisites​

You'll need at least Node.js 18 and npm 7. You also need to have an AWS account and AWS credentials configured locally.

tip

If you are new to SST, we recommend you start with our latest version instead. Learn more about Ion.

1. Create a new app​

Create a new SvelteKit app.

npx create-svelte@latest

Now initialize SST in your project root.

npx create-sst@latest
Ready to deploy

Your SvelteKit app is now ready to be deployed to AWS! Just run — npx sst deploy. But let's take a second to look at how SST makes it easy to add other features to your app.

Start your local dev environment.

npx sst dev

Start Svelte​

npm run dev
info

When running sst dev, SST does not deploy your Svelte app. You are meant to run Svelte locally.

2. Add file uploads​

Let's add a file upload feature to our Svelte app.

Add an S3 bucket​

Add an S3 bucket to your sst.config.ts.

sst.config.ts
const bucket = new Bucket(stack, "public");

Bind it to your Svelte app.

sst.config.ts
const site = new SvelteKitSite(stack, "site", {
+ bind: [bucket],
});

Generate a presigned URL​

To upload a file to S3 we'll generate a presigned URL. Add this to src/routes/+page.server.ts.

src/routes/+page.server.ts
export const load = (async () => {
  const command = new PutObjectCommand({
    ACL: "public-read",
    Key: crypto.randomUUID(),
    Bucket: Bucket.public.bucketName,
  });
  const url = await getSignedUrl(new S3Client({}), command);

  return { url };
}) satisfies PageServerLoad;
tip

With SST we can access our infrastructure in a typesafe way — Bucket.public.bucketName. Learn more.

Add an upload form​

Let's add the form. Replace our src/routes/+page.svelte with.

src/routes/+page.svelte
<section>
  <form on:submit|preventDefault={handleSubmit}>
    <input name="file" type="file" accept="image/png, image/jpeg" />
    <button type="submit">Upload</button>
  </form>
</section>

Add the upload handler.

src/routes/+page.svelte
const handleSubmit = async (e: SubmitEvent) => {
  const formData = new FormData(e.target as HTMLFormElement);
  const file = formData.get("file") as File;

  const image = await fetch(data.url, {
    body: file,
    method: "PUT",
    headers: {
      "Content-Type": file.type,
      "Content-Disposition": `attachment; filename="${file.name}"`,
    },
  });

  window.location.href = image.url.split("?")[0];
};
note

We need to set prerender to false in src/routes/+page.ts since we want to generate the presigned URL on page load.

This will upload an image and redirect to it!

3. Add a cron job​

Next, we'll add a cron job to remove the uploaded files every day. Add this to sst.config.ts.

sst.config.ts
new Cron(stack, "cron", {
  schedule: "rate(1 day)",
  job: {
    function: {
      bind: [bucket],
      handler: "src/functions/delete.handler",
    },
  },
});

Just like our SvelteKit app, we are binding the S3 bucket to our cron job.

Add a cron function​

Add a function to src/functions/delete.ts that'll go through all the files in the bucket and remove them.

src/functions/delete.ts
export async function handler() {
  const client = new S3Client({});

  const list = await client.send(
    new ListObjectsCommand({
      Bucket: Bucket.public.bucketName,
    })
  );

  await Promise.all(
    (list.Contents || []).map((file) =>
      client.send(
        new DeleteObjectCommand({
          Key: file.Key,
          Bucket: Bucket.public.bucketName,
        })
      )
    )
  );
}

And that's it. We have a simple SvelteKit app that uploads files to S3 and runs a cron job to delete them!

4. Deploy to prod​

Let's end with deploying our app to production.

npx sst deploy --stage prod
info

View the source for this example on GitHub.

5. Manage in prod​

You can use the SST Console to view logs and issues in prod. Create a free account and connect it to AWS.

SvelteKit site in the SST Console

Next steps​

  1. Learn more about SST
  2. Ready to dive into the details of SST? Check out our guide.