Current File : //usr/lib/calibre/calibre/ebooks/oeb/transforms/data_url.py
#!/usr/bin/env python3
__license__ = 'GPL v3'
__copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
import re
from calibre.ebooks.oeb.base import XPath, urlunquote
from polyglot.builtins import as_bytes
class DataURL:
def __call__(self, oeb, opts):
from calibre.utils.imghdr import what
self.log = oeb.log
attr_path = XPath('//h:img[@src]')
for item in oeb.spine:
root = item.data
if not hasattr(root, 'xpath'):
continue
for img in attr_path(root):
raw = img.get('src', '')
if not raw.startswith('data:'):
continue
header, data = raw.partition(',')[0::2]
if not header.startswith('data:image/') or not data:
continue
if ';base64' in header:
data = re.sub(r'\s+', '', data)
from polyglot.binary import from_base64_bytes
try:
data = from_base64_bytes(data)
except Exception:
self.log.error('Found invalid base64 encoded data URI, ignoring it')
continue
else:
data = urlunquote(data)
data = as_bytes(data)
fmt = what(None, data)
if not fmt:
self.log.warn('Image encoded as data URL has unknown format, ignoring')
continue
img.set('src', item.relhref(self.convert_image_data_uri(data, fmt, oeb)))
def convert_image_data_uri(self, data, fmt, oeb):
self.log('Found image encoded as data URI converting it to normal image')
from calibre import guess_type
item_id, item_href = oeb.manifest.generate('data-url-image', 'data-url-image.' + fmt)
oeb.manifest.add(item_id, item_href, guess_type(item_href)[0], data=data)
return item_href
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