284 lines
10 KiB
Python
284 lines
10 KiB
Python
import os
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import re
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import shutil
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import tempfile
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import datetime
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import zipfile
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import logging
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from typing import Dict, Set, Pattern
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try: # protect against DoS
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from defusedxml import ElementTree as ET # type: ignore
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except ImportError:
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import xml.etree.ElementTree as ET # type: ignore
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from . import abstract, parser_factory
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# Make pyflakes happy
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assert Set
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assert Pattern
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def _parse_xml(full_path: str):
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""" This function parse XML, with namespace support. """
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namespace_map = dict()
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for _, (key, value) in ET.iterparse(full_path, ("start-ns", )):
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namespace_map[key] = value
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ET.register_namespace(key, value)
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return ET.parse(full_path), namespace_map
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class ArchiveBasedAbstractParser(abstract.AbstractParser):
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""" Office files (.docx, .odt, …) are zipped files. """
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# Those are the files that have a format that _isn't_
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# supported by MAT2, but that we want to keep anyway.
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files_to_keep = set() # type: Set[str]
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# Those are the files that we _do not_ want to keep,
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# no matter if they are supported or not.
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files_to_omit = set() # type: Set[Pattern]
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def __init__(self, filename):
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super().__init__(filename)
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try: # better fail here than later
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zipfile.ZipFile(self.filename)
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except zipfile.BadZipFile:
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raise ValueError
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def _specific_cleanup(self, full_path: str) -> bool:
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""" This method can be used to apply specific treatment
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to files present in the archive."""
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# pylint: disable=unused-argument,no-self-use
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return True # pragma: no cover
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@staticmethod
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def _clean_zipinfo(zipinfo: zipfile.ZipInfo) -> zipfile.ZipInfo:
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zipinfo.create_system = 3 # Linux
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zipinfo.comment = b''
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zipinfo.date_time = (1980, 1, 1, 0, 0, 0) # this is as early as a zipfile can be
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return zipinfo
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@staticmethod
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def _get_zipinfo_meta(zipinfo: zipfile.ZipInfo) -> Dict[str, str]:
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metadata = {}
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if zipinfo.create_system == 3: # this is Linux
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pass
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elif zipinfo.create_system == 2:
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metadata['create_system'] = 'Windows'
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else:
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metadata['create_system'] = 'Weird'
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if zipinfo.comment:
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metadata['comment'] = zipinfo.comment # type: ignore
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if zipinfo.date_time != (1980, 1, 1, 0, 0, 0):
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metadata['date_time'] = str(datetime.datetime(*zipinfo.date_time))
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return metadata
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def remove_all(self) -> bool:
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with zipfile.ZipFile(self.filename) as zin,\
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zipfile.ZipFile(self.output_filename, 'w') as zout:
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temp_folder = tempfile.mkdtemp()
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for item in zin.infolist():
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if item.filename[-1] == '/': # `is_dir` is added in Python3.6
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continue # don't keep empty folders
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zin.extract(member=item, path=temp_folder)
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full_path = os.path.join(temp_folder, item.filename)
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if self._specific_cleanup(full_path) is False:
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shutil.rmtree(temp_folder)
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os.remove(self.output_filename)
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logging.warning("Something went wrong during deep cleaning of %s",
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item.filename)
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return False
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if item.filename in self.files_to_keep:
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# those files aren't supported, but we want to add them anyway
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pass
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elif any(map(lambda r: r.search(item.filename), self.files_to_omit)):
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continue
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else:
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# supported files that we want to clean then add
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tmp_parser, mtype = parser_factory.get_parser(full_path) # type: ignore
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if not tmp_parser:
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shutil.rmtree(temp_folder)
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os.remove(self.output_filename)
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logging.error("In file %s, element %s's format (%s) " +
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"isn't supported",
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self.filename, item.filename, mtype)
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return False
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tmp_parser.remove_all()
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os.rename(tmp_parser.output_filename, full_path)
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zinfo = zipfile.ZipInfo(item.filename) # type: ignore
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clean_zinfo = self._clean_zipinfo(zinfo)
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with open(full_path, 'rb') as f:
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zout.writestr(clean_zinfo, f.read())
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shutil.rmtree(temp_folder)
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return True
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class MSOfficeParser(ArchiveBasedAbstractParser):
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mimetypes = {
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'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
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'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
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'application/vnd.openxmlformats-officedocument.presentationml.presentation'
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}
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files_to_keep = {
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'[Content_Types].xml',
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'_rels/.rels',
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'word/_rels/document.xml.rels',
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'word/document.xml',
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'word/fontTable.xml',
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'word/settings.xml',
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'word/styles.xml',
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}
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files_to_omit = set(map(re.compile, { # type: ignore
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'^docProps/',
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}))
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@staticmethod
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def __remove_revisions(full_path: str) -> bool:
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""" In this function, we're changing the XML document in several
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different times, since we don't want to change the tree we're currently
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iterating on.
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"""
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try:
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tree, namespace = _parse_xml(full_path)
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except ET.ParseError:
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return False
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# Revisions are either deletions (`w:del`) or
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# insertions (`w:ins`)
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del_presence = tree.find('.//w:del', namespace)
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ins_presence = tree.find('.//w:ins', namespace)
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if del_presence is None and ins_presence is None:
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return True # No revisions are present
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parent_map = {c:p for p in tree.iter() for c in p}
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elements = list()
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for element in tree.iterfind('.//w:del', namespace):
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elements.append(element)
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for element in elements:
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parent_map[element].remove(element)
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elements = list()
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for element in tree.iterfind('.//w:ins', namespace):
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for position, item in enumerate(tree.iter()): #pragma: no cover
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if item == element:
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for children in element.iterfind('./*'):
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elements.append((element, position, children))
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break
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for (element, position, children) in elements:
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parent_map[element].insert(position, children)
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parent_map[element].remove(element)
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tree.write(full_path, xml_declaration=True)
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return True
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def _specific_cleanup(self, full_path: str) -> bool:
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if full_path.endswith('/word/document.xml'):
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# this file contains the revisions
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return self.__remove_revisions(full_path)
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return True
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def get_meta(self) -> Dict[str, str]:
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"""
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Yes, I know that parsing xml with regexp ain't pretty,
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be my guest and fix it if you want.
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"""
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metadata = {}
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zipin = zipfile.ZipFile(self.filename)
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for item in zipin.infolist():
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if item.filename.startswith('docProps/') and item.filename.endswith('.xml'):
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try:
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content = zipin.read(item).decode('utf-8')
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results = re.findall(r"<(.+)>(.+)</\1>", content, re.I|re.M)
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for (key, value) in results:
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metadata[key] = value
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except (TypeError, UnicodeDecodeError): # We didn't manage to parse the xml file
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metadata[item.filename] = 'harmful content'
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for key, value in self._get_zipinfo_meta(item).items():
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metadata[key] = value
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zipin.close()
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return metadata
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class LibreOfficeParser(ArchiveBasedAbstractParser):
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mimetypes = {
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'application/vnd.oasis.opendocument.text',
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'application/vnd.oasis.opendocument.spreadsheet',
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'application/vnd.oasis.opendocument.presentation',
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'application/vnd.oasis.opendocument.graphics',
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'application/vnd.oasis.opendocument.chart',
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'application/vnd.oasis.opendocument.formula',
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'application/vnd.oasis.opendocument.image',
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}
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files_to_keep = {
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'META-INF/manifest.xml',
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'content.xml',
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'manifest.rdf',
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'mimetype',
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'settings.xml',
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'styles.xml',
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}
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files_to_omit = set(map(re.compile, { # type: ignore
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r'^meta\.xml$',
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'^Configurations2/',
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'^Thumbnails/',
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}))
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@staticmethod
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def __remove_revisions(full_path: str) -> bool:
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try:
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tree, namespace = _parse_xml(full_path)
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except ET.ParseError:
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return False
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if 'office' not in namespace.keys(): # no revisions in the current file
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return True
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for text in tree.getroot().iterfind('.//office:text', namespace):
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for changes in text.iterfind('.//text:tracked-changes', namespace):
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text.remove(changes)
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tree.write(full_path, xml_declaration=True)
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return True
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def _specific_cleanup(self, full_path: str) -> bool:
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if os.path.basename(full_path) == 'content.xml':
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return self.__remove_revisions(full_path)
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return True
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def get_meta(self) -> Dict[str, str]:
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"""
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Yes, I know that parsing xml with regexp ain't pretty,
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be my guest and fix it if you want.
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"""
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metadata = {}
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zipin = zipfile.ZipFile(self.filename)
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for item in zipin.infolist():
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if item.filename == 'meta.xml':
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try:
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content = zipin.read(item).decode('utf-8')
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results = re.findall(r"<((?:meta|dc|cp).+?)>(.+)</\1>", content, re.I|re.M)
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for (key, value) in results:
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metadata[key] = value
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except (TypeError, UnicodeDecodeError): # We didn't manage to parse the xml file
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metadata[item.filename] = 'harmful content'
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for key, value in self._get_zipinfo_meta(item).items():
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metadata[key] = value
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zipin.close()
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return metadata
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