Support rar archive file format extraction in keras.utils.get_file

[innat]

Currently, the keras.utils.get_file with extract supports zip and tar format. But not rar format.

url = 'https://www.crcv.ucf.edu/data/UCF101/UCF101.rar'
keras.utils.get_file(
    origin=url,
    cache_subdir='custom/',
    extract=True,
)
/tmp/ipykernel_34/1693670741.py:3: UserWarning: Could not extract archive.
  keras.utils.get_file(

[fchollet]

Thanks for the suggestion! It seems this requires an external library to handle rar files -- it cannot be done with the Python standard library. What's the most popular one? We could add it as an optional dependency. Are you willing to open a PR?

[innat]

it cannot be done with the Python standard library. What's the most popular one? We could add it as an optional dependency.

I often use linux cmd. For python API, this or this looks more popular. Here is another which uses subprocess.

Are you willing to open a PR?

No promise, but looking into this.