Recursively Walk Into Directories and Archives

This module primarily provides the function unzipwalk(), which recursively walks into directories and compressed files and returns all files, directories, etc. found, together with binary file handles (file objects) for reading the files. Currently supported are ZIP, tar, tgz, and gz compressed files. File types are detected based on their extensions.

>>> from unzipwalk import unzipwalk
>>> results = []
>>> for result in unzipwalk('.'):
...     names = tuple( name.as_posix() for name in result.names )
...     if result.hnd:  # result is a file opened for reading (binary)
...         # could use result.hnd.read() here, or for line-by-line:
...         for line in result.hnd:
...             pass  # do something interesting with the data here
...     results.append(names + (result.typ.name,))
>>> print(sorted(results))
[('bar.zip', 'ARCHIVE'),
 ('bar.zip', 'bar.txt', 'FILE'),
 ('bar.zip', 'test.tar.gz', 'ARCHIVE'),
 ('bar.zip', 'test.tar.gz', 'hello.csv', 'FILE'),
 ('bar.zip', 'test.tar.gz', 'test', 'DIR'),
 ('bar.zip', 'test.tar.gz', 'test/cool.txt.gz', 'ARCHIVE'),
 ('bar.zip', 'test.tar.gz', 'test/cool.txt.gz', 'test/cool.txt', 'FILE'),
 ('foo.txt', 'FILE')]

Note that unzipwalk() automatically closes files as it goes from file to file. This means that you must use the handles as soon as you get them from the generator - something as seemingly simple as sorted(unzipwalk('.')) would cause the code above to fail, because all files will have been opened and closed during the call to sorted() and the handles to read the data would no longer be available in the body of the loop. This is why the above example first processes all the files before sorting the results. You can also use recursive_open() to open the files later.

The yielded file handles can be wrapped in io.TextIOWrapper to read them as text files. For example, to read all CSV files in the current directory and below, including within compressed files:

>>> from unzipwalk import unzipwalk, FileType
>>> from io import TextIOWrapper
>>> import csv
>>> for result in unzipwalk('.'):
...     if result.typ==FileType.FILE and result.names[-1].suffix.lower()=='.csv':
...         print([ name.as_posix() for name in result.names ])
...         with TextIOWrapper(result.hnd, encoding='UTF-8', newline='') as handle:
...             csv_rd = csv.reader(handle, strict=True)
...             for row in csv_rd:
...                 print(repr(row))
['bar.zip', 'test.tar.gz', 'hello.csv']
['Id', 'Name', 'Address']
['42', 'Hello', 'World']

API

unzipwalk.unzipwalk(paths: str | PathLike | bytes | Iterable[str | PathLike | bytes], *, matcher: Callable[[Sequence[PurePath]], bool] | None = None, raise_errors: bool = True)

This generator recursively walks into directories and compressed files and yields named tuples of type UnzipWalkResult.

• Parameters:
  • paths – A filename or iterable of filenames.
  • matcher – When you provide this optional argument, it must be a callable that accepts a sequence of paths as its only argument, and returns a boolean value whether this filename should be further processed or not. If a file is skipped, a UnzipWalkResult of type FileType.SKIP is yielded.
  • raise_errors – When this is turned on (the default), any errors are raised immediately, aborting the iteration. If this is turned off, when decompression errors occur, a UnzipWalkResult of type FileType.ERROR is yielded for those files instead. However, be aware that gzip.BadGzipFile errors are not raised until the file is actually read, so you’d need to add an exception handler around your read() call to handle such cases.

NOTE

Do not rely on the order of results!

class unzipwalk.UnzipWalkResult(names: tuple[PurePath, ...], typ: FileType, hnd: ReadOnlyBinary | None = None)

Return type for unzipwalk().

names : tuple[PurePath, ...]

A tuple of the filename(s) as pathlib objects. The first element is always the physical file in the file system. If the tuple has more than one element, then the yielded file is contained in a compressed file, possibly nested in other compressed file(s), and the last element of the tuple will contain the file’s actual name.

typ : FileType

A FileType value representing the type of the current file.

hnd : ReadOnlyBinary | None

When typ is FileType.FILE, this is a ReadOnlyBinary file handle (file object) for reading the file contents in binary mode. Otherwise, this is None. If this object was produced by from_checksum_line(), this handle will read the checksum of the data, not the data itself!

validate()

Validate whether the object’s fields are set properly and throw errors if not.

Intended for internal use, mainly when type checkers are not being used. unzipwalk() validates all the results it returns.

• Returns: The object itself, for method chaining.
• Raises: ValueError, TypeError – If the object is invalid.

checksum_line(hash_algo: str, *, raise_errors: bool = True)

Encodes this object into a line of text suitable for use as a checksum line.

Intended mostly for internal use by the --checksum CLI option. See from_checksum_line() for the inverse operation.

WARNING

Requires that the file handle be open (for files), and will read from it to generate the checksum!

• Parameters: hash_algo – The hashing algorithm to use, as recognized by hashlib.new().
• Returns: The checksum line, without trailing newline.

classmethod from_checksum_line(line: str, *, windows: bool = False)

Decodes a checksum line as produced by checksum_line().

Intended as a utility function for use when reading files produced by the --checksum CLI option.

WARNING

The hnd of the returned object will not be a handle to the data from the file, instead it will be a handle to read the checksum of the file! (You could use recursive_open() to open the files themselves.)

• Parameters:
  • line – The line to parse.
  • windows – Set this to True if the pathname in the line is in Windows format, otherwise it is assumed the filename is in POSIX format.
• Returns: The UnzipWalkResult object, or None for empty or comment lines.
• Raises: ValueError – If the line could not be parsed.

class unzipwalk.FileType(value)

Used in UnzipWalkResult to indicate the type of the file.

WARNING

Don’t rely on the numeric value of the enum elements, they are automatically generated and may change!

FILE = 1

A regular file.

ARCHIVE = 2

An archive file, will be descended into.

DIR = 3

A directory.

SYMLINK = 4

A symbolic link.

OTHER = 5

Some other file type (e.g. FIFO).

SKIP = 6

A file was skipped due to the matcher filter.

ERROR = 7

An error was encountered with this file, when the raise_errors option is off.

unzipwalk.recursive_open(fns: Sequence[str | PathLike], encoding=None, errors=None, newline=None)

This context manager allows opening files nested inside archives directly.

unzipwalk() automatically closes files as it iterates through directories and archives; this function exists to allow you to open the returned files after the iteration.

If any of encoding, errors, or newline is specified, the returned file is wrapped in io.TextIOWrapper!

If the last file in the list of files is an archive file, then it won’t be decompressed, instead you’ll be able to read the archive’s raw compressed data from the handle.

In this example, we open a gzip-compressed file, stored inside a tgz archive, which in turn is stored in a Zip file:

>>> from unzipwalk import recursive_open
>>> with recursive_open(('bar.zip', 'test.tar.gz', 'test/cool.txt.gz', 'test/cool.txt'), encoding='UTF-8') as fh:
...     print(fh.read())
Hi, I'm a compressed file!

class unzipwalk.ReadOnlyBinary(*args, **kwargs)

Interface for the file handle (file object) used in UnzipWalkResult.

The interface is the intersection of typing.BinaryIO, gzip.GzipFile, and zipfile.ZipExtFile. Because gzip.GzipFile doesn’t implement .tell(), that method isn’t available here. Whether the handle supports seeking depends on the underlying library.

Note unzipwalk() automatically closes files.

property name : str

close()

property closed : bool

readable()

read(n: int = -1)

readline(limit: int = -1)

seekable()

seek(offset: int, whence: int = 0)

Command-Line Interface

usage: unzipwalk [-h] [-a] [-d | -c ALGO] [-e EXCLUDE] [-r] [-o OUTFILE]
                 [PATH ...]

Recursively walk into directories and archives

positional arguments:
  PATH                  paths to process (default is current directory)

optional arguments:
  -h, --help            show this help message and exit
  -a, --all-files       also list dirs, symlinks, etc.
  -d, --dump            also dump file contents
  -c ALGO, --checksum ALGO
                        generate a checksum for each file**
  -e EXCLUDE, --exclude EXCLUDE
                        filename globs to exclude*
  -r, --raise-errors    raise errors instead of reporting them in output
  -o OUTFILE, --outfile OUTFILE
                        output filename

* Note --exclude currently only matches against the final name in the
sequence, excluding path names, but this interface may change in future
versions. For more control, use the library instead of this command-line tool.
** Possible values for ALGO: blake2b, blake2s, md5, md5-sha1, sha1, sha224,
sha256, sha384, sha3_224, sha3_256, sha3_384, sha3_512, sha512, sha512_224,
sha512_256, shake_128, shake_256, sm3

The available checksum algorithms may vary depending on your system and Python version. Run the command with --help to see the list of currently available algorithms.

Author, Copyright, and License

Copyright (c) 2022-2024 Hauke Dämpfling (haukex@zero-g.net) at the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany, https://www.igb-berlin.de/

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 3 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 program. If not, see https://www.gnu.org/licenses/