Support unauth datasets {files,download} in the CLI client.

[jmasukawa]

Description

Allow datasets download and datasets files to be called without authentication. These changes will not work without the corresponding DatasetsAnonymousDownloadsFromApi feature flag.

Other changes in this release:

• Fixes downloading a specific file from a dataset version. The version number was available on the API endpoint, but not being passed down to the request by the client logic.
• Allows --help -h and --version -v flags to work for all commands when unauthenticated.

Example commands while unauthenticated:

kaggle datasets files jessicali9530/animal-crossing-new-horizons-nookplaza-dataset

kaggle datasets download jessicali9530/animal-crossing-new-horizons-nookplaza-dataset

kaggle datasets download jessicali9530/animal-crossing-new-horizons-nookplaza-dataset/2 -f accessories.csv

(Note: Only Google / Kaggle employees have access to the below links)

Local testing

• With the FF enabled, valid unauth commands work as expected: screencast
• Without the FF enabled
  • Unauth commands on public datasets return "Unauthenticated": screenshot
  • Unauth commands on private datasets return "Permission denied": screenshot
• access to your private datasets via auth works as expected: screencast
• Design doc: http://go/kaggle-datasets-anon-downloads-for-apis

Previous equivalent PR (before kaggle-api was unified on the public repo): https://github.com/Kaggle/kaggleazure/pull/28453

http://b/325082647