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dsoprea / PyEasyArchive

A very intuitive and useful adapter to libarchive for universal archive access.
MIT License
96 stars 33 forks source link

RARV5 Support #46

Closed michaelcerne closed 4 years ago

michaelcerne commented 4 years ago

Hi,

Reading RAR5 files doesn't seem to work. I keep getting a libarchive.exception.ArchiveError: b'Unrecognized archive format' error. I tried manually specifying the format, but it looks like there isn't a ARCHIVE_FORMAT_RAR_V5 constant in libarchive.constants.

Is RARV5 supported? I see it here, but not in the Python bindings.

dsoprea commented 4 years ago

Please attach a sample archive.

dsoprea commented 4 years ago

Please add the constant and test. I'd appreciate you adding a unit-test, too, but, if not, I'll add one if you can attach a sample archive and/or detail how to produce a V5 archive.

https://github.com/libarchive/libarchive/blob/master/libarchive/archive.h#L343

michaelcerne commented 4 years ago

I'm afraid I'm away from my main computer right now, so the best I can do is attach a few samples for your reference.

I'll try to do more once I'm back.

GitHub doesn't support RAR attachments, so here's two links: 1 2

dsoprea commented 4 years ago

The issue is your library. If you want to support a newer format than you need to have a newer version of libarchive.

Supported was added in https://github.com/libarchive/libarchive/commit/7b3068c4bf7a217a1838db280072653197d30012 and it was included in https://github.com/libarchive/libarchive/releases/tag/v3.4.0 . Since I don't have an appropriate version of the library (3.1.2) nor have I been provided a procedure for making the archives nor has there been any previous request for this, I'm just closing this for now. Let me know if/when you upgrade your library and want to move forward.

michaelcerne commented 4 years ago

Duh, thanks. v3.4.0 is the version distributed in libarchive-dev as of Ubuntu 19.10.

It looks like the only way to actually create a RAR5 file is through WinRAR, as the format is somewhat proprietary, hence only read support existing in libarchive.

How do you handle the version requirement in this library? I have no problem adding the constant and unit test, I just want to make sure I understand how to make it fail properly on earlier versions (<3.4.0).

dsoprea commented 4 years ago

It will already fail when it doesn't recognize the format value.

The purpose of the library is simply to bridge to a third-party library and marshal the arguments and results. We can streamline some complex patterns as necessary but I don't want to impose any extra interpretations or soft restrictions when the library is already going to fail if it needs to. We can always funnel well-defined error messages into specific exceptions if that looks to be helpful for common error conditions that might be handled a certain way by the caller, but I don't interpret this as being such a case.