I'm very excited to share a guest post I wrote for the Hugging Face 🤗 blog! The post is called 👉 Experimenting with the proposed Cross-Origin Storage API in Transformers.js 👈! This proposed new browser API, navigator.crossOriginStorage.requestFileHandle(hash), has the potential of revolutionizing the Web, a little bit at least. Learn more by reading the Explainer for the Cross-Origin Storage (COS) API.

And Transformers.js aren't alone with experimenting with this, they're joined by WebLLM (docs), wllama (code), Flutter (code), and Emscripten (docs).

In a nutshell, this is the usual flow of using the API:

const hash = {
  algorithm: 'SHA-256',
  value: '8f434346648f6b96df89dda901c5176b10a6d83961dd3c1ac88b59b2dc327aa4',
};

try {
  const handle = await navigator.crossOriginStorage.requestFileHandle(hash);
  // Cache hit! Get the file as a Blob and use it directly.
  const fileBlob = await handle.getFile();
} catch {
  // Cache miss. Download from network, then store for next time.
  const fileBlob = await fetch('https://cdn.jsdelivr.net/.../ort-wasm-simd-threaded.asyncify.wasm')
    .then(r => r.blob());
  const handle = await navigator.crossOriginStorage.requestFileHandle(
    hash,
    { create: true, origins: '*' },
  );
  const writableStream = await handle.createWritable();
  await writableStream.write(fileBlob);
  await writableStream.close();  
}