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