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import subprocess
import imghdr
import json
import os
import shutil
import tempfile
import re
from typing import Set
import cairo
import gi
gi.require_version('GdkPixbuf', '2.0')
from gi.repository import GdkPixbuf
from . import abstract, _get_exiftool_path
# Make pyflakes happy
assert Set
class _ImageParser(abstract.AbstractParser):
""" Since we use `exiftool` to get metadata from
all images fileformat, `get_meta` is implemented in this class,
and all the image-handling ones are inheriting from it."""
meta_whitelist = set() # type: Set[str]
@staticmethod
def __handle_problematic_filename(filename: str, callback) -> str:
""" This method takes a filename with a problematic name,
and safely applies it a `callback`."""
tmpdirname = tempfile.mkdtemp()
fname = os.path.join(tmpdirname, "temp_file")
shutil.copy(filename, fname)
out = callback(fname)
shutil.rmtree(tmpdirname)
return out
def get_meta(self):
""" There is no way to escape the leading(s) dash(es) of the current
self.filename to prevent parameter injections, so we need to take care
of this.
"""
fun = lambda f: subprocess.check_output([_get_exiftool_path(), '-json', f])
if re.search('^[a-z0-9/]', self.filename) is None:
out = self.__handle_problematic_filename(self.filename, fun)
else:
out = fun(self.filename)
meta = json.loads(out.decode('utf-8'))[0]
for key in self.meta_whitelist:
meta.pop(key, None)
return meta
class PNGParser(_ImageParser):
mimetypes = {'image/png', }
meta_whitelist = {'SourceFile', 'ExifToolVersion', 'FileName',
'Directory', 'FileSize', 'FileModifyDate',
'FileAccessDate', 'FileInodeChangeDate',
'FilePermissions', 'FileType', 'FileTypeExtension',
'MIMEType', 'ImageWidth', 'BitDepth', 'ColorType',
'Compression', 'Filter', 'Interlace', 'BackgroundColor',
'ImageSize', 'Megapixels', 'ImageHeight'}
def __init__(self, filename):
super().__init__(filename)
if imghdr.what(filename) != 'png':
raise ValueError
try: # better fail here than later
cairo.ImageSurface.create_from_png(self.filename)
except MemoryError:
raise ValueError
def remove_all(self):
surface = cairo.ImageSurface.create_from_png(self.filename)
surface.write_to_png(self.output_filename)
return True
class GdkPixbufAbstractParser(_ImageParser):
""" GdkPixbuf can handle a lot of surfaces, so we're rending images on it,
this has the side-effect of completely removing metadata.
"""
_type = ''
def remove_all(self):
_, extension = os.path.splitext(self.filename)
pixbuf = GdkPixbuf.Pixbuf.new_from_file(self.filename)
if extension.lower() == '.jpg':
extension = '.jpeg' # gdk is picky
pixbuf.savev(self.output_filename, extension[1:], [], [])
return True
def __init__(self, filename):
super().__init__(filename)
if imghdr.what(filename) != self._type: # better safe than sorry
raise ValueError
class JPGParser(GdkPixbufAbstractParser):
_type = 'jpeg'
mimetypes = {'image/jpeg'}
meta_whitelist = {'SourceFile', 'ExifToolVersion', 'FileName',
'Directory', 'FileSize', 'FileModifyDate',
'FileAccessDate', "FileInodeChangeDate",
'FilePermissions', 'FileType', 'FileTypeExtension',
'MIMEType', 'ImageWidth', 'ImageSize', 'BitsPerSample',
'ColorComponents', 'EncodingProcess', 'JFIFVersion',
'ResolutionUnit', 'XResolution', 'YCbCrSubSampling',
'YResolution', 'Megapixels', 'ImageHeight'}
class TiffParser(GdkPixbufAbstractParser):
_type = 'tiff'
mimetypes = {'image/tiff'}
meta_whitelist = {'Compression', 'ExifByteOrder', 'ExtraSamples',
'FillOrder', 'PhotometricInterpretation',
'PlanarConfiguration', 'RowsPerStrip', 'SamplesPerPixel',
'StripByteCounts', 'StripOffsets', 'BitsPerSample',
'Directory', 'ExifToolVersion', 'FileAccessDate',
'FileInodeChangeDate', 'FileModifyDate', 'FileName',
'FilePermissions', 'FileSize', 'FileType',
'FileTypeExtension', 'ImageHeight', 'ImageSize',
'ImageWidth', 'MIMEType', 'Megapixels', 'SourceFile'}
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