411 lines
16 KiB
Python
411 lines
16 KiB
Python
# Copyright (c) 2018 The Pooch Developers.
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# Distributed under the terms of the BSD 3-Clause License.
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# SPDX-License-Identifier: BSD-3-Clause
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#
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# This code is part of the Fatiando a Terra project (https://www.fatiando.org)
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#
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# pylint: disable=line-too-long
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"""
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Post-processing hooks
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"""
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import abc
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import os
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import bz2
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import gzip
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import lzma
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import shutil
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from zipfile import ZipFile
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from tarfile import TarFile
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from .utils import get_logger
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class ExtractorProcessor(abc.ABC): # pylint: disable=too-few-public-methods
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"""
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Abstract base class for extractions from compressed archives.
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Subclasses can be used with :meth:`pooch.Pooch.fetch` and
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:func:`pooch.retrieve` to unzip a downloaded data file into a folder in the
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local data store. :meth:`~pooch.Pooch.fetch` will return a list with the
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names of the extracted files instead of the archive.
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Parameters
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----------
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members : list or None
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If None, will unpack all files in the archive. Otherwise, *members*
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must be a list of file names to unpack from the archive. Only these
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files will be unpacked.
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extract_dir : str or None
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If None, files will be unpacked to the default location (a folder in
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the same location as the downloaded zip file, with a suffix added).
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Otherwise, files will be unpacked to ``extract_dir``, which is
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interpreted as a *relative path* (relative to the cache location
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provided by :func:`pooch.retrieve` or :meth:`pooch.Pooch.fetch`).
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"""
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def __init__(self, members=None, extract_dir=None):
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self.members = members
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self.extract_dir = extract_dir
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@property
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@abc.abstractmethod
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def suffix(self):
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"""
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String appended to unpacked archive folder name.
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Only used if extract_dir is None.
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MUST BE IMPLEMENTED BY CHILD CLASSES.
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"""
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@abc.abstractmethod
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def _all_members(self, fname):
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"""
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Return all the members in the archive.
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MUST BE IMPLEMENTED BY CHILD CLASSES.
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"""
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@abc.abstractmethod
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def _extract_file(self, fname, extract_dir):
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"""
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This method receives an argument for the archive to extract and the
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destination path.
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MUST BE IMPLEMENTED BY CHILD CLASSES.
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"""
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def __call__(self, fname, action, pooch):
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"""
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Extract all files from the given archive.
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Parameters
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----------
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fname : str
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Full path of the zipped file in local storage.
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action : str
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Indicates what action was taken by :meth:`pooch.Pooch.fetch` or
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:func:`pooch.retrieve`:
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* ``"download"``: File didn't exist locally and was downloaded
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* ``"update"``: Local file was outdated and was re-download
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* ``"fetch"``: File exists and is updated so it wasn't downloaded
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pooch : :class:`pooch.Pooch`
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The instance of :class:`pooch.Pooch` that is calling this.
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Returns
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-------
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fnames : list of str
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A list of the full path to all files in the extracted archive.
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"""
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if self.extract_dir is None:
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self.extract_dir = fname + self.suffix
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else:
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archive_dir = fname.rsplit(os.path.sep, maxsplit=1)[0]
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self.extract_dir = os.path.join(archive_dir, self.extract_dir)
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# Get a list of everyone who is supposed to be in the unpacked folder
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# so we can check if they are all there or if we need to extract new
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# files.
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if self.members is None or not self.members:
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members = self._all_members(fname)
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else:
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members = self.members
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if (
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(action in ("update", "download"))
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or (not os.path.exists(self.extract_dir))
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or not all(
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os.path.exists(os.path.join(self.extract_dir, m)) for m in members
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)
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):
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# Make sure that the folder with the extracted files exists
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os.makedirs(self.extract_dir, exist_ok=True)
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self._extract_file(fname, self.extract_dir)
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# Get a list of all file names (including subdirectories) in our folder
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# of unzipped files, filtered by the given members list
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fnames = []
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for path, _, files in os.walk(self.extract_dir):
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for filename in files:
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relpath = os.path.normpath(
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os.path.join(os.path.relpath(path, self.extract_dir), filename)
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)
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if self.members is None or any(
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relpath.startswith(os.path.normpath(m)) for m in self.members
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):
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fnames.append(os.path.join(path, filename))
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return fnames
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class Unzip(ExtractorProcessor): # pylint: disable=too-few-public-methods
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"""
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Processor that unpacks a zip archive and returns a list of all files.
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Use with :meth:`pooch.Pooch.fetch` or :func:`pooch.retrieve` to unzip a
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downloaded data file into a folder in the local data store. The
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method/function will return a list with the names of the unzipped files
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instead of the zip archive.
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The output folder is ``{fname}.unzip``.
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Parameters
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----------
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members : list or None
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If None, will unpack all files in the zip archive. Otherwise, *members*
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must be a list of file names to unpack from the archive. Only these
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files will be unpacked.
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extract_dir : str or None
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If None, files will be unpacked to the default location (a folder in
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the same location as the downloaded zip file, with the suffix
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``.unzip`` added). Otherwise, files will be unpacked to
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``extract_dir``, which is interpreted as a *relative path* (relative to
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the cache location provided by :func:`pooch.retrieve` or
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:meth:`pooch.Pooch.fetch`).
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"""
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@property
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def suffix(self):
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"""
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String appended to unpacked archive folder name.
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Only used if extract_dir is None.
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"""
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return ".unzip"
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def _all_members(self, fname):
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"""Return all members from a given archive."""
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with ZipFile(fname, "r") as zip_file:
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return zip_file.namelist()
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def _extract_file(self, fname, extract_dir):
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"""
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This method receives an argument for the archive to extract and the
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destination path.
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"""
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with ZipFile(fname, "r") as zip_file:
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if self.members is None:
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get_logger().info(
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"Unzipping contents of '%s' to '%s'", fname, extract_dir
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)
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# Unpack all files from the archive into our new folder
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zip_file.extractall(path=extract_dir)
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else:
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for member in self.members:
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get_logger().info(
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"Extracting '%s' from '%s' to '%s'", member, fname, extract_dir
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)
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# If the member is a dir, we need to get the names of the
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# elements it contains for extraction (ZipFile does not
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# support dirs on .extract). If it's not a dir, this will
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# only include the member itself.
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# Based on:
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# https://stackoverflow.com/questions/8008829/extract-only-a-single-directory-from-tar
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subdir_members = [
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name
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for name in zip_file.namelist()
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if os.path.normpath(name).startswith(os.path.normpath(member))
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]
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# Extract the data file from within the archive
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zip_file.extractall(members=subdir_members, path=extract_dir)
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class Untar(ExtractorProcessor): # pylint: disable=too-few-public-methods
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"""
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Processor that unpacks a tar archive and returns a list of all files.
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Use with :meth:`pooch.Pooch.fetch` or :func:`pooch.retrieve` to untar a
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downloaded data file into a folder in the local data store. The
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method/function will return a list with the names of the extracted files
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instead of the archive.
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The output folder is ``{fname}.untar``.
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Parameters
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----------
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members : list or None
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If None, will unpack all files in the archive. Otherwise, *members*
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must be a list of file names to unpack from the archive. Only these
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files will be unpacked.
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extract_dir : str or None
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If None, files will be unpacked to the default location (a folder in
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the same location as the downloaded tar file, with the suffix
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``.untar`` added). Otherwise, files will be unpacked to
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``extract_dir``, which is interpreted as a *relative path* (relative to
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the cache location provided by :func:`pooch.retrieve` or
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:meth:`pooch.Pooch.fetch`).
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"""
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@property
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def suffix(self):
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"""
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String appended to unpacked archive folder name.
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Only used if extract_dir is None.
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"""
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return ".untar"
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def _all_members(self, fname):
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"""Return all members from a given archive."""
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with TarFile.open(fname, "r") as tar_file:
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return [info.name for info in tar_file.getmembers()]
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def _extract_file(self, fname, extract_dir):
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"""
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This method receives an argument for the archive to extract and the
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destination path.
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"""
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with TarFile.open(fname, "r") as tar_file:
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if self.members is None:
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get_logger().info(
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"Untarring contents of '%s' to '%s'", fname, extract_dir
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)
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# Unpack all files from the archive into our new folder
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tar_file.extractall(path=extract_dir)
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else:
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for member in self.members:
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get_logger().info(
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"Extracting '%s' from '%s' to '%s'", member, fname, extract_dir
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)
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# If the member is a dir, we need to get the names of the
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# elements it contains for extraction (TarFile does not
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# support dirs on .extract). If it's not a dir, this will
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# only include the member itself.
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# Based on:
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# https://stackoverflow.com/questions/8008829/extract-only-a-single-directory-from-tar
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# Can't use .getnames because extractall expects TarInfo
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# objects.
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subdir_members = [
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info
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for info in tar_file.getmembers()
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if os.path.normpath(info.name).startswith(
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os.path.normpath(member)
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)
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]
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# Extract the data file from within the archive
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tar_file.extractall(members=subdir_members, path=extract_dir)
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class Decompress: # pylint: disable=too-few-public-methods
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"""
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Processor that decompress a file and returns the decompressed version.
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Use with :meth:`pooch.Pooch.fetch` or :func:`pooch.retrieve` to decompress
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a downloaded data file so that it can be easily opened. Useful for data
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files that take a long time to decompress (exchanging disk space for
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speed).
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Supported decompression methods are LZMA (``.xz``), bzip2 (``.bz2``), and
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gzip (``.gz``).
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File names with the standard extensions (see above) can use
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``method="auto"`` to automatically determine the compression method. This
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can be overwritten by setting the *method* argument.
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.. note::
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To unpack zip and tar archives with one or more files, use
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:class:`pooch.Unzip` and :class:`pooch.Untar` instead.
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The output file is ``{fname}.decomp`` by default but it can be changed by
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setting the ``name`` parameter.
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.. warning::
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Passing in ``name`` can cause existing data to be lost! For example, if
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a file already exists with the specified name it will be overwritten
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with the new decompressed file content. **Use this option with
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caution.**
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Parameters
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----------
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method : str
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Name of the compression method. Can be "auto", "lzma", "xz", "bzip2",
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or "gzip".
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name : None or str
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Defines the decompressed file name. The file name will be
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``{fname}.decomp`` if ``None`` (default) or the given name otherwise.
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Note that the name should **not** include the full (or relative) path,
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it should be just the file name itself.
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"""
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modules = {"auto": None, "lzma": lzma, "xz": lzma, "gzip": gzip, "bzip2": bz2}
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extensions = {".xz": "lzma", ".gz": "gzip", ".bz2": "bzip2"}
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def __init__(self, method="auto", name=None):
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self.method = method
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self.name = name
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def __call__(self, fname, action, pooch):
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"""
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Decompress the given file.
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The output file will be either ``{fname}.decomp`` or the given *name*
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class attribute.
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Parameters
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----------
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fname : str
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Full path of the compressed file in local storage.
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action : str
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Indicates what action was taken by :meth:`pooch.Pooch.fetch` or
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:func:`pooch.retrieve`:
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- ``"download"``: File didn't exist locally and was downloaded
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- ``"update"``: Local file was outdated and was re-download
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- ``"fetch"``: File exists and is updated so it wasn't downloaded
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pooch : :class:`pooch.Pooch`
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The instance of :class:`pooch.Pooch` that is calling this.
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Returns
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-------
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fname : str
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The full path to the decompressed file.
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"""
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if self.name is None:
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decompressed = fname + ".decomp"
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else:
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decompressed = os.path.join(os.path.dirname(fname), self.name)
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if action in ("update", "download") or not os.path.exists(decompressed):
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get_logger().info(
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"Decompressing '%s' to '%s' using method '%s'.",
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fname,
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decompressed,
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self.method,
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)
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module = self._compression_module(fname)
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with open(decompressed, "w+b") as output:
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with module.open(fname) as compressed:
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shutil.copyfileobj(compressed, output)
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return decompressed
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def _compression_module(self, fname):
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"""
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Get the Python module compatible with fname and the chosen method.
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If the *method* attribute is "auto", will select a method based on the
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extension. If no recognized extension is in the file name, will raise a
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ValueError.
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"""
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error_archives = "To unpack zip/tar archives, use pooch.Unzip/Untar instead."
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if self.method not in self.modules:
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message = (
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f"Invalid compression method '{self.method}'. "
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f"Must be one of '{list(self.modules.keys())}'."
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)
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if self.method in {"zip", "tar"}:
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message = " ".join([message, error_archives])
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raise ValueError(message)
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if self.method == "auto":
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ext = os.path.splitext(fname)[-1]
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if ext not in self.extensions:
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message = (
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f"Unrecognized file extension '{ext}'. "
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f"Must be one of '{list(self.extensions.keys())}'."
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)
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if ext in {".zip", ".tar"}:
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message = " ".join([message, error_archives])
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raise ValueError(message)
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return self.modules[self.extensions[ext]]
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return self.modules[self.method]
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