166 lines
6.4 KiB
Python
166 lines
6.4 KiB
Python
"""Utilities for extracting common archive formats"""
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__all__ = [
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"unpack_archive", "unpack_zipfile", "unpack_tarfile", "default_filter",
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"UnrecognizedFormat", "extraction_drivers", "unpack_directory",
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]
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import zipfile
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import tarfile
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import os
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import shutil
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import posixpath
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import contextlib
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from pkg_resources import ensure_directory, ContextualZipFile
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from distutils.errors import DistutilsError
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class UnrecognizedFormat(DistutilsError):
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"""Couldn't recognize the archive type"""
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def default_filter(src,dst):
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"""The default progress/filter callback; returns True for all files"""
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return dst
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def unpack_archive(filename, extract_dir, progress_filter=default_filter,
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drivers=None):
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"""Unpack `filename` to `extract_dir`, or raise ``UnrecognizedFormat``
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`progress_filter` is a function taking two arguments: a source path
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internal to the archive ('/'-separated), and a filesystem path where it
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will be extracted. The callback must return the desired extract path
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(which may be the same as the one passed in), or else ``None`` to skip
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that file or directory. The callback can thus be used to report on the
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progress of the extraction, as well as to filter the items extracted or
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alter their extraction paths.
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`drivers`, if supplied, must be a non-empty sequence of functions with the
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same signature as this function (minus the `drivers` argument), that raise
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``UnrecognizedFormat`` if they do not support extracting the designated
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archive type. The `drivers` are tried in sequence until one is found that
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does not raise an error, or until all are exhausted (in which case
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``UnrecognizedFormat`` is raised). If you do not supply a sequence of
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drivers, the module's ``extraction_drivers`` constant will be used, which
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means that ``unpack_zipfile`` and ``unpack_tarfile`` will be tried, in that
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order.
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"""
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for driver in drivers or extraction_drivers:
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try:
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driver(filename, extract_dir, progress_filter)
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except UnrecognizedFormat:
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continue
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else:
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return
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else:
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raise UnrecognizedFormat(
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"Not a recognized archive type: %s" % filename
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)
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def unpack_directory(filename, extract_dir, progress_filter=default_filter):
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""""Unpack" a directory, using the same interface as for archives
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Raises ``UnrecognizedFormat`` if `filename` is not a directory
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"""
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if not os.path.isdir(filename):
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raise UnrecognizedFormat("%s is not a directory" % (filename,))
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paths = {filename:('',extract_dir)}
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for base, dirs, files in os.walk(filename):
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src,dst = paths[base]
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for d in dirs:
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paths[os.path.join(base,d)] = src+d+'/', os.path.join(dst,d)
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for f in files:
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target = os.path.join(dst,f)
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target = progress_filter(src+f, target)
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if not target:
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continue # skip non-files
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ensure_directory(target)
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f = os.path.join(base,f)
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shutil.copyfile(f, target)
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shutil.copystat(f, target)
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def unpack_zipfile(filename, extract_dir, progress_filter=default_filter):
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"""Unpack zip `filename` to `extract_dir`
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Raises ``UnrecognizedFormat`` if `filename` is not a zipfile (as determined
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by ``zipfile.is_zipfile()``). See ``unpack_archive()`` for an explanation
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of the `progress_filter` argument.
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"""
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if not zipfile.is_zipfile(filename):
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raise UnrecognizedFormat("%s is not a zip file" % (filename,))
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with ContextualZipFile(filename) as z:
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for info in z.infolist():
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name = info.filename
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# don't extract absolute paths or ones with .. in them
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if name.startswith('/') or '..' in name.split('/'):
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continue
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target = os.path.join(extract_dir, *name.split('/'))
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target = progress_filter(name, target)
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if not target:
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continue
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if name.endswith('/'):
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# directory
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ensure_directory(target)
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else:
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# file
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ensure_directory(target)
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data = z.read(info.filename)
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f = open(target,'wb')
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try:
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f.write(data)
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finally:
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f.close()
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del data
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unix_attributes = info.external_attr >> 16
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if unix_attributes:
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os.chmod(target, unix_attributes)
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def unpack_tarfile(filename, extract_dir, progress_filter=default_filter):
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"""Unpack tar/tar.gz/tar.bz2 `filename` to `extract_dir`
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Raises ``UnrecognizedFormat`` if `filename` is not a tarfile (as determined
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by ``tarfile.open()``). See ``unpack_archive()`` for an explanation
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of the `progress_filter` argument.
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"""
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try:
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tarobj = tarfile.open(filename)
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except tarfile.TarError:
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raise UnrecognizedFormat(
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"%s is not a compressed or uncompressed tar file" % (filename,)
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)
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with contextlib.closing(tarobj):
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tarobj.chown = lambda *args: None # don't do any chowning!
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for member in tarobj:
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name = member.name
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# don't extract absolute paths or ones with .. in them
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if not name.startswith('/') and '..' not in name.split('/'):
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prelim_dst = os.path.join(extract_dir, *name.split('/'))
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# resolve any links and to extract the link targets as normal files
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while member is not None and (member.islnk() or member.issym()):
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linkpath = member.linkname
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if member.issym():
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linkpath = posixpath.join(posixpath.dirname(member.name), linkpath)
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linkpath = posixpath.normpath(linkpath)
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member = tarobj._getmember(linkpath)
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if member is not None and (member.isfile() or member.isdir()):
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final_dst = progress_filter(name, prelim_dst)
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if final_dst:
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if final_dst.endswith(os.sep):
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final_dst = final_dst[:-1]
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try:
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tarobj._extract_member(member, final_dst) # XXX Ugh
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except tarfile.ExtractError:
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pass # chown/chmod/mkfifo/mknode/makedev failed
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return True
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extraction_drivers = unpack_directory, unpack_zipfile, unpack_tarfile
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