unify "tar.gz" and "zip" access methods using shutil

[chfin]

shutil can unpack archives in different formats including zip and tar.gz. We could use this to unify these to an "archive" access method, which would provide support for other archive formats supported by shutil for free.

[chfin]

The same might be possible for single files using e.g. xopen.

[robert-lieck]

Sounds good to me 👍 Especially, because shutil is not a third-party library, so it does not add new dependencies. The only question that might come up is how to best specify combination of archive and compression. But maybe that is a limited number of cases or it is already supported by shutil out of the box.

Concerning xopen, I am in favour of using std libs whenever possible, to reduce dependencies and make the lib more robust. So I hope that there are std libs for handling this, but I haven't checked.

[chfin]

If I understand correctly, shutil indeed automatically detects the archive type, so you don't have to specify it.

For single files, python doesn't provide this abstraction (shutil only works for archives). However, there are individual std libs for gz, bz2, and xz. The question is only whether (a) to summarize them into a "file" access method that (in analogy to "archive") guesses the right decompression algorithm (e.g. from the url) and just copies the file if it is not compressed, or (b) to have individual access methods "file", "gz", etc, or (c) to just distinguish "file" and "compressed-file". (a) would be the most convenient and opinionated option, but (c) would give most control.