1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179

#!/usr/bin/env python3
# Copyright c 2012-13 Qtrac Ltd. All rights reserved.
# This program or module is free software: you can redistribute it
# and/or modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version. It is provided for
# educational purposes and 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
# General Public License for more details.

import contextlib
import gzip
import os
import re
import string
import tarfile
import zipfile


class Archive:

    def __init__(self, filename):
        self._names = None
        self._unpack = None
        self._file = None
        self.filename = filename


    @property
    def filename(self):
        return self.__filename


    @filename.setter
    def filename(self, name):
        self.close()
        self.__filename = name


    def close(self):
        if self._file is not None:
            self._file.close()
        self._names = self._unpack = self._file = None


    def names(self):
        if self._file is None:
            self._prepare()
        return self._names()


    def unpack(self):
        if self._file is None:
            self._prepare()
        self._unpack()


    def _prepare(self):
        if self.filename.endswith((".tar.gz", ".tar.bz2", ".tar.xz",
                ".zip")):
            self._prepare_tarball_or_zip()
        elif self.filename.endswith(".gz"):
            self._prepare_gzip()
        else:
            raise ValueError("unreadable: {}".format(self.filename))


    def _prepare_tarball_or_zip(self):
        def safe_extractall():
            unsafe = []
            for name in self.names():
                if not self.is_safe(name):
                    unsafe.append(name)
            if unsafe:
                raise ValueError("unsafe to unpack: {}".format(unsafe))
            self._file.extractall()
        if self.filename.endswith(".zip"):
            self._file = zipfile.ZipFile(self.filename)
            self._names = self._file.namelist
            self._unpack = safe_extractall
        else: # Ends with .tar.gz, .tar.bz2, or .tar.xz
            suffix = os.path.splitext(self.filename)[1]
            self._file = tarfile.open(self.filename, "r:" + suffix[1:])
            self._names = self._file.getnames
            self._unpack = safe_extractall


    def _prepare_gzip(self):
        self._file = gzip.open(self.filename)
        filename = self.filename[:-3]
        self._names = lambda: [filename]
        def extractall():
            with open(filename, "wb") as file:
                file.write(self._file.read())
        self._unpack = extractall


    def is_safe(self, filename):
        return not (filename.startswith(("/", "\\")) or
            (len(filename) > 1 and filename[1] == ":" and
             filename[0] in string.ascii_letter) or
            re.search(r"[.][.][/\\]", filename))


    def __enter__(self):
        return self


    def __exit__(self, exc_type, exc_value, traceback):
        self.close()


    def __str__(self):
        return "{}({})".format(self.filename, self._file is not None)


if __name__ == "__main__":
    # This code is designed to work with 3.1+, so can't use
    # os.makedirs()'s exist_ok keyword argument, can't use
    # zipfile.ZipFile as a context manager, and can't use text mode for
    # gzip.
    import errno
    import os
    import shutil
    import tempfile
    fromPath = os.path.dirname(os.path.abspath(__file__))
    toPath = os.path.join(tempfile.gettempdir(), "unpack")
    try:
        os.makedirs(toPath)
    except OSError as err:
        if err.errno != errno.EEXIST:
            raise
    zipFilename = os.path.join(toPath, "test.zip")
    zipNames = ["Bag1.py", "Bag2.py", "Bag3.py"]
    tarFilename = os.path.join(toPath, "test.tar.gz")
    tarNames = ["genome1.py", "genome2.py", "genome3.py"]
    gzFilename = os.path.join(toPath, "hello.pyw.gz")
    gzName = "hello.pyw"
    file = None
    try:
        file = zipfile.ZipFile(zipFilename, "w", zipfile.ZIP_DEFLATED)
        for name in zipNames:
            file.write(name)
    finally:
        if file is not None:
            file.close()
    file = None
    try:
        file = tarfile.open(tarFilename, "w:gz")
        for name in tarNames:
            file.add(name)
    finally:
        if file is not None:
            file.close()
    file = None
    try:
        file = gzip.open(gzFilename, "w")
        with open(gzName, "rb") as infile:
            file.write(infile.read())
    finally:
        if file is not None:
            file.close()

    os.chdir(toPath)
    with Archive(zipFilename) as archive:
        print(archive.names())
        assert archive.names() == zipNames
        archive.unpack()

        archive.filename = tarFilename
        print(archive.names())
        assert archive.names() == tarNames
        archive.unpack()

        archive.filename = gzFilename
        archive.unpack()
    # print(toPath)
    # shutil.rmtree(toPath)