libarchive 0.4.7

Python adapter for universal, libarchive-based archive access.

Introduction

A ctypes-based adapter to libarchive. The source-code is written to be clear and intuitive.

Even 7-Zip is supported for both reading and writing.

I could definitely use some help, if any is available. Completeness will require a bit more work (see libarchive’s archive.h and archive_entry.h).

Installation

PyPI:

$ sudo pip install libarchive

Notes

• The Ubuntu libarchive package maintainer only provides a “libarchive.so” symlink in the dev package so you’ll have to install the libarchive-dev package.

  For example:

  apt-get install libarchive-dev

• Encryption is not currently supported since it’s not supported in the underlying library (libarchive). Note this inquiry and the wishlist item.

• OS X has a system version of libarchive that is very old. As a result, many users have encountered issues importing an alternate one. Specifically, often they install a different one via Brew but this will not be [sym]linked into the system like other packages. This is a precaution taken by Brew to prevent undefined behavior in the parts of OS X that depend on the factory version. In order to work around this, you should set LD_LIBRARY_PATH (or prepend if LD_LIBRARY_PATH is already defined) with the path of the location of the library version you want to use. You’ll want to set this from your user-profile script (unless your environment can not support this and you need to prepend something like “LD_LIBRARY_PATH=/some/path” to the front of the command-line or set it via os.environ above where you import this package). A tool has been provided that will print the path of the first version of libarchive installed via Brew. Just copy-and-paste it. Thanks to @SkyLeach for discussing the issue and treatments.

Task List

Done	Task
X	Read entries from physical file
X	Read entries from archive hosted in memory buffer
X	Write physical files from archive
X	Load memory buffer from archive
X	Populate physical archive from physical files
X	Populate archive hosted in memory buffer
_	Populate archive entries from memory buffers
_	Fill-out the entry object’s information/accessors

Examples

To extract to the current directory from a physical file (and print each relative filepath):

import libarchive.public

for entry in libarchive.public.file_pour('/tmp/test.zip'):
    print(entry)

To extract to the current directory from memory:

import libarchive.public

with open('/tmp/test.zip', 'rb') as f:
    for entry in libarchive.public.memory_pour(f.read()):
        print(entry)

To read files from a physical archive:

import libarchive.public

with libarchive.public.file_reader('test.7z') as e:
    for entry in e:
        with open('/tmp/' + str(entry), 'wb') as f:
            for block in entry.get_blocks():
                f.write(block)

To read files from memory:

import libarchive.public

with open('test.7z', 'rb') as f:
    buffer_ = f.read()
    with libarchive.public.memory_reader(buffer_) as e:
        for entry in e:
            with open('/tmp/' + str(entry), 'wb') as f:
                for block in entry.get_blocks():
                    f.write(block)

To specify a format and/or filter for reads (rather than detecting it):

import libarchive.public
import libarchive.constants

with open('test.7z', 'rb') as f:
    buffer_ = f.read()
    with libarchive.public.memory_reader(
            buffer_,
            format_code=libarchive.constants.ARCHIVE_FORMAT_TAR_USTAR,
            filter_code=libarchive.constants.ARCHIVE_FILTER_GZIP
        ) as e:
        for entry in e:
            with open('/tmp/' + str(entry), 'wb') as f:
                for block in entry.get_blocks():
                    f.write(block)

To read the “filetype” flag for each entry:

import libarchive.public

with open('test.7z', 'rb') as f:
    buffer_ = f.read()
    with libarchive.public.memory_reader(f.read()) as e:
        for entry in e:
            print(entry.filetype)

The output of this is:

EntryFileType(IFREG=True, IFLNK=True, IFSOCK=True, IFCHR=False, IFBLK=False, IFDIR=False, IFIFO=False)
EntryFileType(IFREG=True, IFLNK=True, IFSOCK=True, IFCHR=False, IFBLK=False, IFDIR=False, IFIFO=False)
EntryFileType(IFREG=True, IFLNK=True, IFSOCK=True, IFCHR=False, IFBLK=False, IFDIR=False, IFIFO=False)

To create a physical archive from physical files:

import libarchive.public
import libarchive.constants

libarchive.public.create_file(
    'create.7z',
    libarchive.constants.ARCHIVE_FORMAT_7ZIP,
    ['/etc/profile']):

The path of the file to add will be recorded verbatim.

To create an archive in memory from physical files:

import libarchive.public
import libarchive.constants

with open('/tmp/new.7z', 'wb') as f:
    def writer(buffer_, length):
        f.write(buffer_)
        return length

    libarchive.public.create_generic(
        writer,
        format_name=libarchive.constants.ARCHIVE_FORMAT_7ZIP,
        files=['/etc/profile']):

Testing

libarchive uses nose for testing:

tests$ ./run.py