cozip

JavaScript reader for Cloud-Optimized ZIP archives. It reads the small index and archive tail, verifies their integrity hash, then fetches the manifest without scanning the ZIP Central Directory.

Install

npm install @asterisk-labs/cozip

Usage

import { read } from "@asterisk-labs/cozip";

const manifest = await read("https://example.com/dataset.zip");
const train = manifest.filter((row) => row.split === "train");

manifest is an array of row objects: name, offset, size, cozip:location, and the writer's extras.

columns: [...] picks extras. location: false drops cozip:location.

read() supports only Flat-profile archives (profile = 1). TACO archives (profile = 2) and every other profile are rejected with UNKNOWN_PROFILE.

const manifest = await read(url, {
  columns: ["cloud_pct", "split"],
  location: false,
});

Only non-empty ASCII http:// and https:// URLs are supported. For cloud storage, use a presigned HTTP URL or a CORS-enabled proxy. The server must support range requests (Accept-Ranges: bytes) and, in browsers, allow the Range header through CORS.

Spec

See SPEC.md for the on-disk format.

License

MIT. See LICENSE.