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Handle DRMed EPUB files correctly when getting cover. Fixes #5304 (Adding an eBook (ePub) to Calibre...)

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This commit is contained in:
Kovid Goyal 2010-04-15 07:41:03 +05:30
parent bdc0a283a4
commit 4a13c31aca
1 changed files with 34 additions and 2 deletions
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36
src/calibre/ebooks/metadata/epub.py
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@ -51,6 +51,28 @@ class OCF(object):
def __init__(self): def __init__(self):
raise NotImplementedError('Abstract base class') raise NotImplementedError('Abstract base class')
class Encryption(object):
OBFUSCATION_ALGORITHMS = frozenset(['http://ns.adobe.com/pdf/enc#RC',
'http://www.idpf.org/2008/embedding'])
def __init__(self, raw):
from lxml import etree
self.root = etree.fromstring(raw) if raw else None
self.entries = {}
if self.root is not None:
for em in self.root.xpath('descendant::*[contains(name(), "EncryptionMethod")]'):
algorithm = em.get('Algorithm', '')
cr = em.getparent().xpath('descendant::*[contains(name(), "CipherReference")]')
if cr:
uri = cr[0].get('URI', '')
if uri and algorithm:
self.entries[uri] = algorithm
def is_encrypted(self, uri):
algo = self.entries.get(uri, None)
return algo is not None and algo not in self.OBFUSCATION_ALGORITHMS
class OCFReader(OCF): class OCFReader(OCF):
def __init__(self): def __init__(self):
@ -72,6 +94,11 @@ class OCFReader(OCF):
self.opf = OPF(f, self.root, populate_spine=False) self.opf = OPF(f, self.root, populate_spine=False)
except KeyError: except KeyError:
raise EPubException("missing OPF package file") raise EPubException("missing OPF package file")
try:
with closing(self.open(self.ENCRYPTION_PATH)) as f:
self.encryption_meta = Encryption(f.read())
except:
self.encryption_meta = Encryption(None)
class OCFZipReader(OCFReader): class OCFZipReader(OCFReader):
@ -98,7 +125,7 @@ class OCFDirReader(OCFReader):
def open(self, path, *args, **kwargs): def open(self, path, *args, **kwargs):
return open(os.path.join(self.root, path), *args, **kwargs) return open(os.path.join(self.root, path), *args, **kwargs)
def get_cover(opf, opf_path, stream): def get_cover(opf, opf_path, stream, reader=None):
import posixpath import posixpath
from calibre.ebooks import render_html_svg_workaround from calibre.ebooks import render_html_svg_workaround
from calibre.utils.logging import default_log from calibre.utils.logging import default_log
@ -106,6 +133,9 @@ def get_cover(opf, opf_path, stream):
stream.seek(0) stream.seek(0)
zf = ZipFile(stream) zf = ZipFile(stream)
if raster_cover: if raster_cover:
if reader is not None and \
reader.encryption_meta.is_encrypted(raster_cover):
return
base = posixpath.dirname(opf_path) base = posixpath.dirname(opf_path)
cpath = posixpath.normpath(posixpath.join(base, raster_cover)) cpath = posixpath.normpath(posixpath.join(base, raster_cover))
try: try:
@ -122,6 +152,8 @@ def get_cover(opf, opf_path, stream):
cpage = opf.first_spine_item() cpage = opf.first_spine_item()
if not cpage: if not cpage:
return return
if reader is not None and reader.encryption_meta.is_encrypted(cpage):
return
with TemporaryDirectory('_epub_meta') as tdir: with TemporaryDirectory('_epub_meta') as tdir:
with CurrentDir(tdir): with CurrentDir(tdir):
@ -139,7 +171,7 @@ def get_metadata(stream, extract_cover=True):
mi = MetaInformation(reader.opf) mi = MetaInformation(reader.opf)
if extract_cover: if extract_cover:
try: try:
cdata = get_cover(reader.opf, reader.opf_path, stream) cdata = get_cover(reader.opf, reader.opf_path, stream, reader=reader)
if cdata is not None: if cdata is not None:
mi.cover_data = ('jpg', cdata) mi.cover_data = ('jpg', cdata)
except: except: