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"""
Read Exif metadata from tiff and jpeg files.
"""
import struct
from typing import BinaryIO
from exifread.exif_log import get_logger
from exifread.classes import ExifHeader
from exifread.tags import DEFAULT_STOP_TAG
from exifread.utils import ord_, make_string
from exifread.heic import HEICExifFinder
from exifread.jpeg import find_jpeg_exif
from exifread.exceptions import InvalidExif, ExifNotFound
__version__ = '3.0.0'
logger = get_logger()
def _find_tiff_exif(fh: BinaryIO) -> tuple:
logger.debug("TIFF format recognized in data[0:2]")
fh.seek(0)
endian = fh.read(1)
fh.read(1)
offset = 0
return offset, endian
def _find_webp_exif(fh: BinaryIO) -> tuple:
logger.debug("WebP format recognized in data[0:4], data[8:12]")
# file specification: https://developers.google.com/speed/webp/docs/riff_container
data = fh.read(5)
if data[0:4] == b'VP8X' and data[4] & 8:
# https://developers.google.com/speed/webp/docs/riff_container#extended_file_format
fh.seek(13, 1)
while True:
data = fh.read(8) # Chunk FourCC (32 bits) and Chunk Size (32 bits)
if len(data) != 8:
raise InvalidExif("Invalid webp file chunk header.")
if data[0:4] == b'EXIF':
offset = fh.tell()
endian = fh.read(1)
return offset, endian
size = struct.unpack('<L', data[4:8])[0]
fh.seek(size, 1)
raise ExifNotFound("Webp file does not have exif data.")
def _find_png_exif(fh: BinaryIO, data: bytes) -> tuple:
logger.debug("PNG format recognized in data[0:8]=%s", data[:8].hex())
fh.seek(8)
while True:
data = fh.read(8)
chunk = data[4:8]
logger.debug("PNG found chunk %s", chunk.decode("ascii"))
if chunk in (b'', b'IEND'):
break
if chunk == b'eXIf':
offset = fh.tell()
return offset, fh.read(1)
chunk_size = int.from_bytes(data[:4], "big")
fh.seek(fh.tell() + chunk_size + 4)
raise ExifNotFound("PNG file does not have exif data.")
def _get_xmp(fh: BinaryIO) -> bytes:
xmp_bytes = b''
logger.debug('XMP not in Exif, searching file for XMP info...')
xml_started = False
xml_finished = False
for line in fh:
open_tag = line.find(b'<x:xmpmeta')
close_tag = line.find(b'</x:xmpmeta>')
if open_tag != -1:
xml_started = True
line = line[open_tag:]
logger.debug('XMP found opening tag at line position %s', open_tag)
if close_tag != -1:
logger.debug('XMP found closing tag at line position %s', close_tag)
line_offset = 0
if open_tag != -1:
line_offset = open_tag
line = line[:(close_tag - line_offset) + 12]
xml_finished = True
if xml_started:
xmp_bytes += line
if xml_finished:
break
logger.debug('XMP Finished searching for info')
return xmp_bytes
def _determine_type(fh: BinaryIO) -> tuple:
# by default do not fake an EXIF beginning
fake_exif = 0
data = fh.read(12)
if data[0:2] in [b'II', b'MM']:
# it's a TIFF file
offset, endian = _find_tiff_exif(fh)
elif data[4:12] == b'ftypheic':
fh.seek(0)
heic = HEICExifFinder(fh)
offset, endian = heic.find_exif()
elif data[0:4] == b'RIFF' and data[8:12] == b'WEBP':
offset, endian = _find_webp_exif(fh)
elif data[0:2] == b'\xFF\xD8':
# it's a JPEG file
offset, endian, fake_exif = find_jpeg_exif(fh, data, fake_exif)
elif data[0:8] == b'\x89PNG\r\n\x1a\n':
offset, endian = _find_png_exif(fh, data)
else:
# file format not recognized
raise ExifNotFound("File format not recognized.")
return offset, endian, fake_exif
def process_file(fh: BinaryIO, stop_tag=DEFAULT_STOP_TAG,
details=True, strict=False, debug=False,
truncate_tags=True, auto_seek=True):
"""
Process an image file (expects an open file object).
This is the function that has to deal with all the arbitrary nasty bits
of the EXIF standard.
"""
if auto_seek:
fh.seek(0)
try:
offset, endian, fake_exif = _determine_type(fh)
except ExifNotFound as err:
logger.warning(err)
return {}
except InvalidExif as err:
logger.debug(err)
return {}
endian = chr(ord_(endian[0]))
# deal with the EXIF info we found
logger.debug("Endian format is %s (%s)", endian, {
'I': 'Intel',
'M': 'Motorola',
'\x01': 'Adobe Ducky',
'd': 'XMP/Adobe unknown'
}[endian])
hdr = ExifHeader(fh, endian, offset, fake_exif, strict, debug, details, truncate_tags)
ifd_list = hdr.list_ifd()
thumb_ifd = 0
ctr = 0
for ifd in ifd_list:
if ctr == 0:
ifd_name = 'Image'
elif ctr == 1:
ifd_name = 'Thumbnail'
thumb_ifd = ifd
else:
ifd_name = 'IFD %d' % ctr
logger.debug('IFD %d (%s) at offset %s:', ctr, ifd_name, ifd)
hdr.dump_ifd(ifd, ifd_name, stop_tag=stop_tag)
ctr += 1
# EXIF IFD
exif_off = hdr.tags.get('Image ExifOffset')
if exif_off:
logger.debug('Exif SubIFD at offset %s:', exif_off.values[0])
hdr.dump_ifd(exif_off.values[0], 'EXIF', stop_tag=stop_tag)
# deal with MakerNote contained in EXIF IFD
# (Some apps use MakerNote tags but do not use a format for which we
# have a description, do not process these).
if details and 'EXIF MakerNote' in hdr.tags and 'Image Make' in hdr.tags:
hdr.decode_maker_note()
# extract thumbnails
if details and thumb_ifd:
hdr.extract_tiff_thumbnail(thumb_ifd)
hdr.extract_jpeg_thumbnail()
# parse XMP tags (experimental)
if debug and details:
# Easy we already have them
xmp_tag = hdr.tags.get('Image ApplicationNotes')
if xmp_tag:
logger.debug('XMP present in Exif')
xmp_bytes = bytes(xmp_tag.values)
# We need to look in the entire file for the XML
else:
xmp_bytes = _get_xmp(fh)
if xmp_bytes:
hdr.parse_xmp(xmp_bytes)
return hdr.tags
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