def from_string(cls, hash):
hash = to_unicode(hash, "ascii", "hash")
ident, data = hash[0:3], hash[3:]
if ident != cls.ident:
raise exc.InvalidHashError()
rounds, salt, chk = data[0], data[1:9], data[9:]
return cls(
rounds=h64.decode_int6(rounds.encode("ascii")),
salt=salt,
checksum=chk or None,
)
def from_string(cls, hash, **context):
# default from_string() which strips optional prefix,
# and passes rest unchanged as checksum value.
hash = to_unicode(hash, "ascii", "hash")
hash = cls._norm_hash(hash)
# could enable this for extra strictness
##pat = cls._hash_regex
##if pat and pat.match(hash) is None:
## raise ValueError("not a valid %s hash" % (cls.name,))
prefix = cls._hash_prefix
if prefix:
if hash.startswith(prefix):
hash = hash[len(prefix):]
else:
raise exc.InvalidHashError(cls)
# Decode the base64 stored actual hash
hash = unicode(base64.b64decode(hash))
return cls(checksum=hash, **context)