py7zr 0.7.3

Pure python 7-zip decompression(restricted) library

py7zr

Pure python 7-zip implementation

Dependency

py7zr uses a python3 standard lzma module for extraction and compression. The standard lzma module uses liblzma that support core compression algorithm of 7zip.

Minimum required version is Python 3.5. Two additional library is required only on Python3.5; contextlib2 and pathlib2.

Compression is supported on Python 3.6 and later.

There are other runtime requrements; texttable, pycryptodome

Version recommendations are:

• CPython 3.7.5, CPython 3.8.0 and later.

• PyPy3.6-7.2.0 and later.

Following fixes are included in these versions, and it is not fixed on python3.6.

• BPO-21872: LZMA library sometimes fails to decompress a file

• PyPy3-3088: lzma.LZMADecomporessor.decompress does not respect max_length

Compression Methods

‘py7zr’ supports algorithms and filters which python3 standard lzma module and liblzma support. It also support algorithms that is implemented in python core such as Bzip2. It does not support one which lzma module and liblzma can not handle such as BCJ2.

Here is a table of algorithms.

Category	Algorithms
Compress/Decompress Supported	LZMA2 BCJ(X86, IA64, ARM, ARMT, PPC, POWERPC)
Decompress only (Decryption)	LZMA, Delta, COPY, Bzip2, Deflate AES
Unsupported or not worked	PPMd, BCJ2, LZMA+BCJ

• A feature handling symbolic link is basically compatible with ‘p7zip’ implementation, but not work with original 7-zip because the original does not implement the feature.

Document

Here is a readthedocs manual document.

CLI Usage

You can run command script py7zr like as follows;

• List archive contents

$ py7zr l test.7z

• Extract archive

$ py7zr x test.7z

• Extract archive with password

$ py7zr x -P test.7z
  password?: ****

• Create and compress to archive

$ py7zr c target.7z test_dir

• Create multi-volume archive

$ py7zr c -v 500k target.7z test_dir

• Show help

$ py7zr help

SevenZipFile Class Usage

py7zr is a library which can use in your python application. Here is a code snippet how to decompress some file in your applicaiton.

import py7zr

archive = py7zr.SevenZipFile('sample.7z', mode='r')
archive.extractall(path="/tmp")
archive.close()

Here is a code snippet how to produce archive.

import py7zr

archive = py7zr.SevenZipFile('target.7z', 'w')
archive.writeall('./base_dir')
archive.close()

You can also use ‘with’ block because py7zr provide context manager(v0.6 and later).

import py7zr

with py7zr.SevenZipFile('sample.7z', mode='r') as z:
    z.extractall()

with py7zr.SevenZipFile('target.7z', 'w') as z:
    z.writeall('./base_dir')

py7zr also supports extraction of single or selected files by ‘extract(targets=[‘file path’])’. Note: if you specify only a file but not a parent directory, it will fail.

import py7zr
import re

filter_pattern = re.compile(r'<your/target/file_and_directories/regex/expression>')
with SevenZipFile('archive.7z', 'r') as archive:
    allfiles = archive.getnames()
    selective_files = [f if filter_pattern.match(f) for f in allfiles]
    archive.extract(targets=selective_files)

py7zr support an extraction of password protected archive.(v0.6 and later)

import py7zr

with py7zr.SevenZipFile('encrypted.7z', mode='r', password='secret') as z:
    z.extractall()

shutil helper

py7zr also support shutil interface.

from py7zr import pack_7zarchvie, unpack_7zarchive
import shutil

# register file format at first.
shutil.register_archive_format('7zip', pack_7zarchive, description='7zip archive')
shutil.register_unpack_format('7zip', ['.7z'], unpack_7zarchive)

# extraction
shutil.unpack_archive('test.7z', '/tmp')

# compression
shutil.make_archive('target', '7zip', 'src')

Use Cases

• aqtinstall Another (unofficial) Qt (aqt) CLI Installer on multi-platforms.

• PreNLP Preprocessing Library for Natural Language Processing

• mlox a tool for sorting and analyzing Morrowind plugin load order

License

• Copyright (C) 2019 Hiroshi Miura

• Copyright (c) 2004-2015 by Joachim Bauch

• 7-Zip Copyright (C) 1999-2010 Igor Pavlov

• LZMA SDK Copyright (C) 1999-2010 Igor Pavlov

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

Py7zr ChangeLog

All notable changes to this project will be documented in this file.

Unreleased

Added

Changed

Fixed

Deprecated

Removed

Security

v0.7.3

Added

• Support for encrypted header (#139, #140)

Changed

• Fix CRC32 check and introduce test and testzip methods (#138)

Fixed

• Allow decryption of data which is encrypted without any compression.(#140)

v0.7.2

Added

• CLI: ‘-v {size}[b|k|m|g]’ multi volume creation option.

v0.7.1

Changed

• Decryption: performance improvement. Introduce helpers.calculate_key3(), which utilize list comprehension expression, bytes generation with join(). It reduces a number of calls of hash library and improve decryption performance.

Fixed

• Fix overwrite behavior of symbolic link which may break linked contents.

v0.7.0

Changed

• Extraction: Unlink output file if exist when it become a symbolic link. When overwrite extracted files and there are symlinks, it may cause an unexpected result. Unlinking it may help it.

v0.7.0b3

Added

• Support dereference option of SevenZipFile class. (#131) If dereference is False, add symbolic and hard links to the archive. If it is True, add the content of the target files to the archive. This has no effect on systems that do not support symbolic links.

• Introduce progress callback mechanism (#130)

Changed

• CLI: add –verbose option for extraction

• win32: update win32compat

Fixed

• Fix archiveinfo() for 7zAES archives

• Release variables when close() (#129)

v0.7.0b2

Fixed

• Support extraction of file onto a place where path length is > 260 bytes on Windows 10, Windows Server 2016R2 and later. (Windows Vista, 7 and Windows Server 2012 still have a limitation of path length as a OS spec)(#116, #126)

v0.7.0b1

Added

• Support memory API.(#111, #119) Introduce read(filter) and readall() method for SevenZipFile class.

• Support ZStandard codec compression algorithm for extraction.(#124, #125)

Changed

• Drop pywin32 dependency(#120)

• Introduce internal win32compat.py

• Archive: Looking for symbolic link object in the archived list, and if found, record as relative link.(#112, #113, #122)

Removed

• Revmoed requirements.txt. When you want to install dependencies for development you can do it with ‘pip install -e path/to/py7zr_project’

v0.6

Added

• Test: SevenZipFile.archiveinfo() for various archives.

• Test: extraction of LZMA+BCJ archive become fails as marked known issue.

• Support deflate decompression method.

Changed

• Update documents and README about supported algorithms.

• Re-enable coverage report.

• Refactoring SevenZipFile._write_archive() method to move core chunk into compression module Worker.archive() method.

• Update calculate_key helper to improve performance.

• Introduce zero-copy buffer helper.

• Change decompressor class interface

  • change max_length type to int and defualt to -1.

• Update decryption function to improve performance.

Fixed

• Fix SevenZipFIle.archiveinfo() crash for LZMA+BCJ archive.(#100)

• Fix SevenZipFile.test() method defeated from v0.6b2 (#103)

• Fix SevenZipFile.solid() method to return proper value. (#72,#97)

v0.6b8

Added

• Introduce context manager for SevenZipFile (#95)

Changed

• SevenZipFile(file-object, ‘r’) now can run extract() well even unlink before extract().

Fixed

• Fix README example for extraction option.

• Some of decryption of encrypted archive fails.(#75)

v0.6b7

Added

• Test: add benchmarking test.

Changed

• Concurrency strategy: change to threading instead of multiprocessing. (#92)

v0.6b6

Fixed

• Make pywin32 a regular runtime dependency

v0.6b5

Added

• Add concurrent extraction test.

• Add remote data test for general application test.

• Add class for multi volume header.

• Add readlink helper function for windows.

Changed

• Release process is done by Github Actions

• Temporary disable to measure coverage, which is not working with threading.

• Tox: now pass PYTEST_ADDOPTS environment variable.

Fixed

• Build with pep517 utility.

• Fix race condition for changing current working directory of caller, which cause failures in multithreading.(#80,#82)

Security

• CLI: Use ‘getpass’ standard library to input password.(#59)

v0.6b4

Changed

• extract: decompression is done as another process in default.

• extract: default multiprocessing mode is spawn

• extract: single process mode for password protected archive.

Fixed

• extract: catch UnsupportedMethod exception properly when multiprocessing.

v0.6b3

Added

• Test: download and extract test case as a show case.

• setup.cfg: add entry-point configuration.

Changed

• Use spawn multiprocessing mode for all platforms.

• Use self context for multiprocessing.

Removed

• Static py7zr binary. Now it is generated by python installer.

v0.6b2

Changed

• Concurrency implementation changes to use multiprocessing.Process() instead of concurrency.futures to avoid freeze or deadlock with application usage of it.(#70)

• Stop checking coverage because coverage.py > 5.0.0 produce error when multiprocessing.Process() usage.

• Drop handlers, NullHandler, BufferHnalder, and FileHander.

Known Issues

• Extraction of encrypted archive which has multiple compression folders fails when multiprocessing mode is not ‘fork’, that is python3.8 and later on MacOS, and on Windows. see. test_extract_encrypted_2()

v0.6b1

Fixed

• Fixed extraction of 7zip file with BZip2 algorithm.(#66)

v0.6a2

Added

• Support filtering a target of extracted files from archive (#64)

Fixed

• Fix symbolic link extraction with relative path target directory.(#67)

v0.6a1

Added

• Support decryption (#55)

• Add release note automation workflow with Github actions.

• COPY decompression method.(#61)

Fixed

• Fix retrieving Folder header information logics for codecs.(#62)

Removed

• Test symlink on windows.(#60)

v0.5b6

Fixed

• Fix extraction of archive which has zero size files and directories(#54).

• Revert zero size file logic(#47).

v0.5b5

Fixed

• Revert zero size file logic which break extraction by 7zip.

v0.5b4

Fixed

• Support for making archive with zero size files(#47).

• Produced broken archive when target has many directorires(#48).

• Reduce test warnings, fix annotations.

• Fix coverage error on test.

v0.5b3

Fixed

• Support for making archive with symbolic links.

v0.5b2

Changed

• Update documents.

Fixed

• Fix write logics (#42)

• Fix read FilesInfo block.

v0.5b1

Support making a 7zip archive.

Added

• Support for compression and archiving.

• Support encoded(compressed) header and set as default.(#39)

• SevenZipFile: accept pathlib.Path as a file argument.

• Unit test: read and write UTF-16LE string for filename.

• Support for shutil.register_archive_format() and shutil.make_archive() by exposing pack_7zarchive()

• Support custom filters for compression.

Fixed

• Skip rare case when directory already exist, that can happen multiple process working in same working directory.

• Write: Produce a good archive file for multiple target files.

• SignatureHeader function: write nextheaderofs and nextheadersize as real_uint64.

• docs: description of start header structure.

Removed

• Drop py7zr.properties.FileAttributes; please use stat.FILE_ATTRIBUTES_*

Changed

• Test: Use tmp_path fixture which is pytest default one.

• Move setuptools configurations in setup.py into setup.cfg.

v0.4

Added

• Support for pypy3 (pypy3.5-7.0) and later(pypy3.6-7.1 or later).

• unit test for NullHandler, BufferHandler, FileHandler.

• Update document to add 7zformat descriptions.

Changed

• NullHandler, BufferHandler, FileHandler: open() now takes mode argument.

• Upper limit of max_length of decompress() call is now io.DEFAULT_BUFFER_SIZE. - PyPy issue: https://bitbucket.org/pypy/pypy/issues/3088/lzmalzmadecompressordecompress-data

• Drop padding logic introduced in v0.3.5 that may be cuased by python core bug, when max_length > io.DEFAULT_BUFFER_SIZE. - PyPy Issue: https://bitbucket.org/pypy/pypy/issues/3090/lzma-sometimes-decompresses-data - bpo-21872: https://bugs.python.org/issue21872 - Fix: https://github.com/python/cpython/pull/14048

• Remove print functions from API and moves CLI

  • API should not output anything other than error message. * Introduce FileInfo class to represent file attributes inside archive. * Introduce ArchiveInfo class to represent archive attributes. * provide archiveinfo() method to provide ArchiveInfo object. * now list() method returns List[FileInfo]

  • Every print things moves to Cli class.

• Update tests according to API change.

• Update documents to refrect API changes.

Fixed

• Update README to indicate supported python version as 3.5 and later, pypy3 7.1 and later.

v0.3.5

Changed

• Use seek&truncate for padding trailer if needed.

v0.3.4

Added

• Docs: class diagram, design note, 7z formats and presentations.

• Test for a target includes padding file.

Changed

• Test file package naming.

Fixed

• Fix infinite loop when archive file need padding data for extraction.

v0.3.3

Added

• Add test for zerofile with multi-foler archive.

Fixed

• Fix zerofile extraction error with multithread mode(#24, thanks @Arten013)

v0.3.2

Added

• typing hints

• CI test with mypy

• Unit test: SignatureHeader.write() method.

• Unit test: unknown mode for SevenZipFile constructor.

• Unit test: SevenZipFile.write() method.

Changed

• Conditional priority not likely to be external in header.

• Refactoring read_uint64().

Fixed

• SignatureHeader.write(): fix exception to write 7zip version.

v0.3.1

Added

• CLI i subcommand: show codec information.

• Decompression performance test as regression test.

• Add more unit test for helper functions.

Changed

• List subcommand now do not show compressed file size in solid compression. This is as same behavior as p7zip command.

• Merge io.py into archiveinfo.py

• Drop internal intermediate queue, which is not used.

Fixed

• Always overwrite when archive has multiple file with same name.

v0.3

Added

• Add some code related to support write feature(wip).

• Static check for import order in python sources and MANIFEST.in

Changed

• Concurrent decompression with threading when an archive is in multi folder compression.

• Pytest configurations are set in tox.ini

Fixed

• Package now has test code and data.

v0.2.0

Fixed

• Detect race condition on os.mkdir

v0.1.6

Fixed

• Wrong file size when lzma+bcj compression.

v0.1.5

Fixed

• Suppress warning: not dequeue from queue length 0

v0.1.4

Changed

• When a directory exist for target, do not raise error, and when out of it raise exception

• Refactoring FileArchivesList and FileArchive classes.

v0.1.3

Changed

• When a directory exist for target, do not raise error, and when out of it raise exception

v0.1.2

Changed

• Refactoring CLI with cli package and class.

Fixed

• Archive with zero size file cause exception with file not found error(#4).

Removed

• Drop unused code chunks.

• Drop Digests class and related unit test.

v0.1.1

Added

• Add write(), close() and testzip() dummy methods which raises NotImplementedError.

• Add more unit tests for write functions.

Fixed

• Fix Sphinx error in documentation.

• SevenZipFile: Check mode before touch file.

• Fix write_boolean() when array size is over 8.

• Fix write_uint64() and read_uint64().

v0.1.0

Added

• Introduce compression package.

• Introduce SevenZipCompressor class.

• Add write() method for each header class.

• Add tests for write methods.

• Add method for registering shutil.

Changed

• Each header classes has __slots__ definitions for speed and memory optimization.

• Rename to ‘io’ package from ‘archiveio’

• Each header classes has classmethod ‘retrieve’ and constructor does not reading a archive file anymore.

• Change to internalize _read() method for each header classes.

• get_decompressor() method now become SevenZipDecompressor class.

• Each header classes initializes members to None in constructor.

• Method definitions map become an internal member of SevenZipDecompressor or SevenZipCompressor class.

• Add test package compress

Fixed

• Fix ArchiveProperties read function.

v0.0.8

Added

• Test for CLI.

Changed

• Improve main function.

• Improve tests, checks outputs with sha256

v0.0.7

Added

• CI test on AppVeyor.

Changed

• Worker class refactoring.

Fixed

• Fix test cases: bugzilla_16 and github_14.

• Test: set timezone to UTC on Unix and do nothing on Windows.

v0.0.6

Fixed

• Fix too many file descriptors opened error.

v0.0.5

Changed

• Test: check sha256 for extracted files

Fixed

• Fix decompressiong archive with LZMA2 and BCJ method

• Fix decompressing multi block archive

• Fix file mode on unix/linux.

v0.0.4

Added

• Set file modes for extracted files.

• More unit test.

Changed

• Travis-CI test on python 3.7.

Fixed

• Fix to set extracted files timestamp as same as archived.

v0.0.3

Added

• PyPi package index.

Fixed

• setup: set universal = 0 because only python 3 is supported.

v0.0.2

Changed

• refactoring all the code.