Devine
/
pywidevine
mirror of https://github.com/devine-dl/pywidevine.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

PSSH: Merge get_as_box into the Constructor 

Also improves the code of it overall including documentation.

The _box class instance variable has been removed and the raw box is no longer kept.
This commit is contained in:
rlaphoenix 2022-08-05 05:32:41 +01:00
parent 1ea57865ad
commit fc47bbb436
3 changed files with 78 additions and 60 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
pywidevine/cdm.py
View File

@ -268,7 +268,7 @@ class Cdm:
if not init_data:
raise InvalidInitData("The init_data must not be empty.")
try:
init_data = PSSH.get_as_box(init_data).init_data
init_data = PSSH(init_data).init_data
except (ValueError, binascii.Error, DecodeError) as e:
raise InvalidInitData(str(e))

134
pywidevine/pssh.py
View File

@ -21,8 +21,82 @@ class PSSH:
Widevine = UUID(bytes=b"\xed\xef\x8b\xa9\x79\xd6\x4a\xce\xa3\xc8\x27\xdc\xd5\x1d\x21\xed")
PlayReady = UUID(bytes=b"\x9a\x04\xf0\x79\x98\x40\x42\x86\xab\x92\xe6\x5b\xe0\x88\x5f\x95")
def __init__(self, box: Container):
self._box = box
def __init__(self, data: Union[Container, str, bytes], strict: bool = False):
"""
Load a PSSH box or Widevine Cenc Header data as a new v0 PSSH box.
[Strict mode (strict=True)]
Supports the following forms of input data in either Base64 or Bytes form:
- Full PSSH mp4 boxes (as defined by pymp4 Box).
- Full Widevine Cenc Headers (as defined by WidevinePsshData proto).
[Lenient mode (strict=False, default)]
If the data is not supported in Strict mode, and is assumed not to be corrupt or
parsed incorrectly, the License Server likely accepts a custom init_data value
during a License Request call. This is uncommon behavior but not out of realm of
possibilities. For example, Netflix does this with it's MSL WidevineExchange
scheme.
Lenient mode will craft a new v0 PSSH box with the init_data field set to
the provided data as-is. The data will first be base64 decoded. This behavior
may not work in your scenario and if that's the case please manually craft
your own PSSH box with the init_data field to be used in License Requests.
Raises:
ValueError: If the data is empty.
TypeError: If the data is an unexpected type.
binascii.Error: If the data could not be decoded as Base64 if provided as a
string.
DecodeError: If the data could not be parsed as a PSSH mp4 box nor a Widevine
Cenc Header and strict mode is enabled.
"""
if not data:
raise ValueError("Data must not be empty.")
if isinstance(data, Container):
box = data
else:
if isinstance(data, str):
try:
data = base64.b64decode(data)
except (binascii.Error, binascii.Incomplete) as e:
raise binascii.Error(f"Could not decode data as Base64, {e}")
if not isinstance(data, bytes):
raise TypeError(f"Expected data to be a {Container}, bytes, or base64, not {data!r}")
try:
box = Box.parse(data)
except (IOError, construct.ConstructError): # not a box
try:
cenc_header = WidevinePsshData()
cenc_header.ParseFromString(data)
cenc_header = cenc_header.SerializeToString()
if cenc_header != data: # not actually a WidevinePsshData
raise DecodeError()
except DecodeError: # not a widevine cenc header
if strict:
raise DecodeError(f"Could not parse data as a {Container} nor a {WidevinePsshData}.")
# Data is not a Widevine Cenc Header, it's something custom.
# The license server likely has something custom to parse it.
# See doc-string about Lenient mode for more information.
cenc_header = data
box = Box.parse(Box.build(dict(
type=b"pssh",
version=0,
flags=0,
system_ID=PSSH.SystemId.Widevine,
init_data=cenc_header
)))
self.version = box.version
self.flags = box.flags
self.system_id = box.system_ID
self.key_ids = box.key_IDs
self.init_data = box.init_data
@staticmethod
def from_playready_pssh(box: Container) -> Container:
@ -78,62 +152,6 @@ class PSSH:
)))
return box
@staticmethod
def get_as_box(data: Union[Container, bytes, str], strict: bool = False) -> Container:
"""
Get possibly arbitrary data as a parsed PSSH mp4 box.
Parameters:
data: PSSH mp4 box, Widevine Cenc Header (init data), or arbitrary data to
parse or craft into a PSSH mp4 box.
strict: Do not return a PSSH box for arbitrary data. Require the data to be
at least a PSSH mp4 box, or a Widevine Cenc Header.
Raises:
ValueError: If the data is empty, or an unexpected type.
binascii.Error: If the data could not be decoded as Base64 if provided
as a string.
DecodeError: If the data could not be parsed as a PSSH mp4 box
nor a Widevine Cenc Header while strict=True.
"""
if not data:
raise ValueError("Data must not be empty.")
if isinstance(data, Container):
return data
if isinstance(data, str):
try:
data = base64.b64decode(data)
except (binascii.Error, binascii.Incomplete) as e:
raise binascii.Error(f"Could not decode data as Base64, {e}")
if isinstance(data, bytes):
try:
data = Box.parse(data)
except (IOError, construct.ConstructError):
if strict:
try:
cenc_header = WidevinePsshData()
if cenc_header.MergeFromString(data) < len(data):
raise DecodeError()
except DecodeError:
raise DecodeError(f"Could not parse data as a PSSH mp4 box nor a Widevine Cenc Header.")
else:
data = cenc_header.SerializeToString()
data = Box.parse(Box.build(dict(
type=b"pssh",
version=0,
flags=0,
system_ID=PSSH.SystemId.Widevine,
init_data=data
)))
else:
raise ValueError(f"Data is an unexpected type, expected bytes got {data!r}.")
return data
@staticmethod
def get_key_ids(box: Container) -> list[UUID]:
"""

2
pywidevine/remotecdm.py
View File

@ -164,7 +164,7 @@ class RemoteCdm(Cdm):
if not init_data:
raise InvalidInitData("The init_data must not be empty.")
try:
init_data = PSSH.get_as_box(init_data).init_data
init_data = PSSH(init_data).init_data
except (ValueError, binascii.Error, DecodeError) as e:
raise InvalidInitData(str(e))