JS implementation

[jaimergp]

It should be possible to fetch .conda metadata (.tar.bz2 can't be streamed) with JS only. This works on the browser:

import { RemoteZipPointer } from "@basisai/remote-zip";

(async () => {
    const url = new URL("https://conda.anaconda.org/conda-forge/linux-64/des-fitvd-0.9.19-py39hf3d152e_2.conda");
    const remoteZip = await new RemoteZipPointer({ url }).populate();
    const fileListing = remoteZip.files(); // RemoteZipFile[]
    console.log(fileListing);
})();

Resulting in:

[
    {
        "filename": "metadata.json",
        "size": 31,
        "modified": "2024-02-06T18:29:10",
        "attributes": 25165824
    },
    {
        "filename": "pkg-des-fitvd-0.9.19-py39hf3d152e_2.tar.zst",
        "size": 93411,
        "modified": "1980-01-01T00:00:00",
        "attributes": 25165824
    },
    {
        "filename": "info-des-fitvd-0.9.19-py39hf3d152e_2.tar.zst",
        "size": 8325,
        "modified": "1980-01-01T00:00:00",
        "attributes": 25165824
    }
]

Paired with a zst library, we should be able to fetch the info/ bits like conda-package-streaming does. This could be implemented in the conda-forge.org website and only point here for the .tar.bz2 bits (which are provided by the OCI backend).