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'''
Parent class of all parser
'''
import hachoir_core
import hachoir_editor
import os
import mat
NOMETA = ('.bmp', # image
'.rdf', # text
'.txt', # plain text
'.xml', # formated text (XML)
'.rels', # openXML formated text
)
FIELD = object()
class GenericParser(object):
'''
Parent class of all parsers
'''
def __init__(self, filename, parser, mime, backup, **kwargs):
self.filename = ''
self.parser = parser
self.mime = mime
self.backup = backup
self.editor = hachoir_editor.createEditor(parser)
self.realname = filename
try:
self.filename = hachoir_core.cmd_line.unicodeFilename(filename)
except TypeError: # get rid of "decoding Unicode is not supported"
self.filename = filename
basename, ext = os.path.splitext(filename)
self.output = basename + '.cleaned' + ext
self.basename = os.path.basename(filename) # only filename
def is_clean(self):
'''
Check if the file is clean from harmful metadatas
'''
for field in self.editor:
if self._should_remove(field):
return self._is_clean(self.editor)
return True
def _is_clean(self, fieldset):
for field in fieldset:
remove = self._should_remove(field)
if remove is True:
return False
if remove is FIELD:
if not self._is_clean(field):
return False
return True
def remove_all(self):
'''
Remove all compromising fields
'''
state = self._remove_all(self.editor)
hachoir_core.field.writeIntoFile(self.editor, self.output)
self.do_backup()
return state
def _remove_all(self, fieldset):
'''
Recursive way to handle tree metadatas
'''
try:
for field in fieldset:
remove = self._should_remove(field)
if remove is True:
self._remove(fieldset, field.name)
if remove is FIELD:
self._remove_all(field)
return True
except:
return False
def _remove(self, fieldset, field):
'''
Delete the given field
'''
del fieldset[field]
def get_meta(self):
'''
Return a dict with all the meta of the file
'''
metadata = {}
self._get_meta(self.editor, metadata)
return metadata
def _get_meta(self, fieldset, metadata):
'''
Recursive way to handle tree metadatas
'''
for field in fieldset:
remove = self._should_remove(field)
if remove:
try:
metadata[field.name] = field.value
except:
metadata[field.name] = 'harmful content'
if remove is FIELD:
self._get_meta(field, None)
def _should_remove(self, key):
'''
return True if the field is compromising
abstract method
'''
raise NotImplementedError
def do_backup(self):
'''
Do a backup of the file if asked,
and change his creation/access date
'''
if not self.backup:
mat.secure_remove(self.filename)
os.rename(self.output, self.filename)
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