authlib/jose/util.py
import binascii
from authlib.common.encoding import urlsafe_b64decode, json_loads, to_unicode
from authlib.jose.errors import DecodeError
def extract_header(header_segment, error_cls):
header_data = extract_segment(header_segment, error_cls, 'header')
try:
header = json_loads(header_data.decode('utf-8'))
except ValueError as e:
raise error_cls(f'Invalid header string: {e}')
if not isinstance(header, dict):
raise error_cls('Header must be a json object')
return header
def extract_segment(segment, error_cls, name='payload'):
try:
return urlsafe_b64decode(segment)
except (TypeError, binascii.Error):
msg = f'Invalid {name} padding'
raise error_cls(msg)
def ensure_dict(s, structure_name):
if not isinstance(s, dict):
try:
s = json_loads(to_unicode(s))
except (ValueError, TypeError):
raise DecodeError(f'Invalid {structure_name}')
if not isinstance(s, dict):
raise DecodeError(f'Invalid {structure_name}')
return s