Query D1 from SvelteKit

SvelteKit ↗ is a full-stack framework that combines the Svelte front-end framework with Vite for server-side capabilities and rendering. You can query D1 from SvelteKit by configuring a server endpoint ↗ with a binding to your D1 database(s).

To set up a new SvelteKit site on Cloudflare Pages that can query D1:

1. Refer to the SvelteKit guide and Svelte's Cloudflare adapter ↗.
2. Install the Cloudflare adapter within your SvelteKit project: npm i -D @sveltejs/adapter-cloudflare.
3. Bind a D1 database to your Pages Function.
4. Pass the --d1 BINDING_NAME=DATABASE_ID flag to wrangler dev when developing locally. BINDING_NAME should match what call in your code, and DATABASE_ID should match the database_id defined in your Wrangler configuration file: for example, --d1 DB=xxxx-xxxx-xxxx-xxxx-xxxx.

The following example shows you how to create a server endpoint configured to query D1.

• Bindings are available on the platform parameter passed to each endpoint, via platform.env.BINDING_NAME.
• With SvelteKit's file-based routing ↗, the server endpoint defined in src/routes/api/users/+server.ts is available at /api/users within your SvelteKit app.

The example also shows you how to configure both your app-wide types within src/app.d.ts to recognize your D1Database binding, import the @sveltejs/adapter-cloudflare adapter into svelte.config.js, and configure it to apply to all of your routes.

import type { RequestHandler } from "@sveltejs/kit";

export async function GET({ request, platform }) {
	try {
		let result = await platform.env.DB.prepare(
			"SELECT * FROM users LIMIT 5",
		).run();
		return new Response(JSON.stringify(result), {
			headers: { "Content-Type": "application/json" },
		});
	} catch (error) {
		return Response.json({ error: "Failed to fetch users" }, {
			status: 500
		});
	}
}

// See https://kit.svelte.dev/docs/types#app
// for information about these interfaces
declare global {
	namespace App {
		// interface Error {}
		// interface Locals {}
		// interface PageData {}
		interface Platform {
			env: {
				DB: D1Database;
			};
			context: {
				waitUntil(promise: Promise<any>): void;
			};
			caches: CacheStorage & { default: Cache };
		}
	}
}

export {};

import adapter from "@sveltejs/adapter-cloudflare";

export default {
	kit: {
		adapter: adapter({
			// See below for an explanation of these options
			routes: {
				include: ["/*"],
				exclude: ["<all>"],
			},
		}),
	},
};