def parse(cls: Type[Sscc], value: str) -> Sscc:
"""Parse the given value into a :class:`Sscc` object.
Args:
value: The value to parse.
Returns:
SSCC data structure with the successfully extracted data.
The checksum is guaranteed to be valid if an SSCC object is returned.
Raises:
ParseError: If the parsing fails.
"""
value = value.strip()
if len(value) != 18:
raise ParseError(f"Failed to parse {value!r} as SSCC: "
f"Expected 18 digits, got {len(value)}.")
if not value.isnumeric():
raise ParseError(
f"Failed to parse {value!r} as SSCC: Expected a numerical value."
)
value_without_extension_digit = value[1:]
prefix = GS1Prefix.extract(value_without_extension_digit)
extension_digit = int(value[0])
payload = value[:-1]
check_digit = int(value[-1])
calculated_check_digit = numeric_check_digit(payload)
if check_digit != calculated_check_digit:
raise ParseError(
f"Invalid SSCC check digit for {value!r}: "
f"Expected {calculated_check_digit!r}, got {check_digit!r}.")
return cls(
value=value,
prefix=prefix,
extension_digit=extension_digit,
payload=payload,
check_digit=check_digit,
)
def parse(
cls: Type[Gtin], value: str, *, rcn_region: Optional[RcnRegion] = None
) -> Gtin:
"""Parse the given value into a :class:`Gtin` object.
Both GTIN-8, GTIN-12, GTIN-13, and GTIN-14 are supported.
Args:
value: The value to parse.
rcn_region: The geographical region whose rules should be used to
interpret Restricted Circulation Numbers (RCN).
Needed to extract e.g. variable weight/price from GTIN.
Returns:
GTIN data structure with the successfully extracted data.
The checksum is guaranteed to be valid if a GTIN object is returned.
Raises:
ParseError: If the parsing fails.
"""
from biip.gtin import Rcn
value = value.strip()
if len(value) not in (8, 12, 13, 14):
raise ParseError(
f"Failed to parse {value!r} as GTIN: "
f"Expected 8, 12, 13, or 14 digits, got {len(value)}."
)
if not value.isnumeric():
raise ParseError(
f"Failed to parse {value!r} as GTIN: Expected a numerical value."
)
stripped_value = _strip_leading_zeros(value)
assert len(stripped_value) in (8, 12, 13, 14)
num_significant_digits = len(stripped_value)
gtin_format = GtinFormat(num_significant_digits)
payload = stripped_value[:-1]
check_digit = int(stripped_value[-1])
packaging_level: Optional[int] = None
if gtin_format == GtinFormat.GTIN_14:
packaging_level = int(stripped_value[0])
value_without_packaging_level = stripped_value[1:]
prefix = GS1Prefix.extract(value_without_packaging_level)
elif gtin_format == GtinFormat.GTIN_12:
# Add a zero to convert U.P.C. Company Prefix to GS1 Company Prefix
prefix = GS1Prefix.extract(stripped_value.zfill(13))
elif gtin_format == GtinFormat.GTIN_8:
prefix = GS1Prefix.extract(stripped_value.zfill(12))
else:
prefix = GS1Prefix.extract(stripped_value)
calculated_check_digit = numeric_check_digit(payload)
if check_digit != calculated_check_digit:
raise ParseError(
f"Invalid GTIN check digit for {value!r}: "
f"Expected {calculated_check_digit!r}, got {check_digit!r}."
)
gtin_type: Type[Union[Gtin, Rcn]]
if "Restricted Circulation Number" in prefix.usage:
gtin_type = Rcn
else:
gtin_type = Gtin
gtin = gtin_type(
value=value,
format=gtin_format,
prefix=prefix,
payload=payload,
check_digit=check_digit,
packaging_level=packaging_level,
)
if isinstance(gtin, Rcn) and rcn_region is not None:
gtin._parse_with_regional_rules(rcn_region)
return gtin
def test_is_hashable() -> None:
prefix = GS1Prefix.extract("978")
assert hash(prefix) is not None
def test_invalid_gs1_prefix(bad_value: str) -> None:
with pytest.raises(ParseError) as exc_info:
GS1Prefix.extract(bad_value)
assert str(exc_info.value) == f"Failed to get GS1 Prefix from {bad_value!r}."
def test_gs1_prefix(value: str, expected: GS1Prefix) -> None:
assert GS1Prefix.extract(value) == expected