Watermarks

interface Env {
    BUCKET: R2Bucket,
    NAMESPACE: KVNamespace,
    IMAGES: ImagesBinding,
}
export default {
    async fetch(request, env, ctx): Promise<Response> {
        const watermarkKey = "my-watermark";
        const sourceKey = "my-source-image";

        const cache = await caches.open("transformed-images");
        const cacheKey = new URL(sourceKey + "/" + watermarkKey, request.url);
        const cacheResponse = await cache.match(cacheKey);

        if (cacheResponse) {
            return cacheResponse;
        }

        let watermark = await env.NAMESPACE.get(watermarkKey, "stream");
        let source = await env.BUCKET.get(sourceKey);

        if (!watermark || !source) {
            return new Response("Not found", { status: 404 });
        }

        const result = await env.IMAGES.input(source.body)
            .draw(watermark)
            .output({ format: "image/jpeg" });

        const response = result.response();

        ctx.waitUntil(cache.put(cacheKey, response.clone()));

        return result.response();
  },
} satisfies ExportedHandler<Env>;