Mimic 7zip with python

Question

I am using Python 3.6, and currently I subprocess out to my 7zip program to get the compression I need.

subprocess.call('7z a -t7z -ms=off {0} *'.format(filename))

I know the zipfile class has ‘ZIP_LZMA’ compression, but the application I am passing this too says the output file isn’t correct. So what else do I have to add to the ZipFile class to make it mimic the above command?

ZIP files are different from 7Z files. Even if ZIPs might support LZMA compression these days, the files are still different. See https://stackoverflow.com/questions/32797851/how-to-read-contents-of-7z-file-using-python maybe? — AKX, May 21 '18 at 13:15
@codebase5000, this library perhaps https://github.com/fancycode/pylzma ? — Tarun Lalwani, May 21 '18 at 15:35
@TarunLalwani So i tried pylzma, and can't seem to figure it out. Can you post a sample? — code base 5000, May 22 '18 at 14:03
@codebase5000, just figured it out, it is a read 7z file and not write 7z file. And I have tried digging but couldn't find one such reference to a library which writes to a 7z file — Tarun Lalwani, May 22 '18 at 14:05
Maybe I should increase the bounty, sounds like python really needs this functionality. — code base 5000, May 22 '18 at 14:06

score 2 · Accepted Answer · answered May 23 '18 at 21:10

2

If you do not care much for Windows, then perhaps libarchive could help. In Ubuntu, for example:

$ sudo apt install python3-libarchive-c

Then:

import libarchive
with libarchive.file_writer('test.7z', '7zip') as archive:
    archive.add_files('first.file', 'second.file', 'third.file')

Then there is the pylib7zip library, which wraps the existing 7z.dll and seems to offer a Windows-only alternative.

answered May 23 '18 at 21:10

KT.

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Also lib archive-c seems to fail on build – JabberJabber May 23 '18 at 23:43
Pylib7zip is a wrapper around 7z.dll, hence in theory one should be able to squeeze the compression out of it as well - the existence of the FileOutStream class does give some hope. – KT. May 23 '18 at 23:58
To build python_libarchive_c you'd probably need to install the necessary dependencies (e.g. libarchive-dev). The pre-built Ubuntu package somehow works, after all. – KT. May 24 '18 at 00:00

Mimic 7zip with python

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