crx-extract

#!/usr/bin/env python3.7
#
# Copyright (C) 2017-2018 The University of Sheffield, UK
#
# This program 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.
#
# This program 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.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
#
# SPDX-License-Identifier: GPL-3.0-or-later
"""Tool for extracting crx file from a tar archive."""

import os
import sys
import glob
import getopt
import tarfile
import datetime
import dateutil
import dateutil.parser
from ExtensionCrawler.archive import last_crx, get_local_archive_dir
from ExtensionCrawler.config import const_basedir


def helpmsg():
    """Print help message."""
    print("crx-extract [OPTION] extid")
    print("    -h        print this help text")
    print("    -s        silent (no log messages)")
    print("    -e        use etag instead of date in outoput")
    print("    -w        avoid ':' in filenames (useful on Windows)")
    print("    -d=<DATE> date")
    print("    -o=<DIR>  output directory")
    print("    -a=<DIR>  archive directory")


def get_tarinfo(members, name, winfs=False, etag=None):
    """Select tarinfo object with a specified path/name."""
    for tarinfo in members:
        if tarinfo.name == name:
            if winfs:
                tarinfo.name = name.replace(":", "-")
            if etag is not None:
                (path, crx) = os.path.split(tarinfo.name)
                (path, _) = os.path.split(path)
                tarinfo.name = os.path.join(path, etag, crx)
            yield tarinfo


def main(argv):
    """Main function of the extension crawler."""
    basedir = const_basedir()
    verbose = True
    date = None
    useetag = False
    output = ""
    winfs = False
    try:
        opts, args = getopt.getopt(argv, "hsed:a:o:w",
                                   ["date=", "archive=", "output="])
    except getopt.GetoptError:
        helpmsg()
        sys.exit(2)
    for opt, arg in opts:
        if opt == '-h':
            helpmsg()
            sys.exit()
        elif opt in ("-a", "--archive"):
            basedir = arg
        elif opt in ("-d", "--date"):
            date = arg
        elif opt in ("-o", "--output"):
            output = arg
        elif opt in ("-w", "--winfs"):
            winfs = True
        elif opt in ("-e", "--etag"):
            useetag = True
        elif opt == '-s':
            verbose = False

    if len(args) > 0:
        extid = args[0]
    else:
        helpmsg()
        sys.exit()

    if date is not None:
        dateobj = dateutil.parser.parse(date)
        if dateobj.tzinfo is None or dateobj.tzinfo.utcoffset(dateobj) is None:
            dateobj = dateobj.replace(tzinfo=datetime.timezone.utc)
        last, etag = last_crx(os.path.join(basedir, "data"), extid, dateobj)
    else:
        last, etag = last_crx(os.path.join(basedir, "data"), extid)

    if not useetag:
        etag = None
    basetar = os.path.join(basedir, "data",
                       get_local_archive_dir(extid), extid)
    tar = basetar+".tar"
   
    if last != "":
        if os.path.exists(tar):
            files = None
            if verbose:
                print("Extracting " + os.path.join(output, last) + " from " + tar)
            with tarfile.open(tar, 'r') as archive:
                files = archive.extractall(
                            path=output,
                            members=get_tarinfo(archive, last, winfs, etag))
            archivetars = sorted(glob.glob(basetar+".[0-9][0-9][0-9].tar.xz"))
            while (not files and  archivetars):
                tar = archivetars.pop()
                if verbose:
                    print("Extracting " + os.path.join(output, last) + " from " + tar)
                with tarfile.open(tar, 'r:xz') as archive:
                    files = archive.extractall(
                                path=output,
                                members=get_tarinfo(archive, last, winfs, etag))
        elif verbose:
            print("Cannot find archive " + tar)
    elif verbose:
        if os.path.exists(tar):
            print("CRX not in archive" + tar)
        else:
            print("CRX does not exist: cannot find archive " + tar)


if __name__ == "__main__":
    main(sys.argv[1:])