JezK
Edit File: archive_util.py
"""Utilities for extracting common archive formats""" import zipfile import tarfile import os import shutil import posixpath import contextlib from distutils.errors import DistutilsError from pkg_resources import ensure_directory __all__ = [ "unpack_archive", "unpack_zipfile", "unpack_tarfile", "default_filter", "UnrecognizedFormat", "extraction_drivers", "unpack_directory", ] 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 zipfile.ZipFile(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