Payment

The pydantic_extra_types.payment module provides the PaymentCardNumber data type.

PaymentCardBrand

Bases: str, Enum

Payment card brands supported by the PaymentCardNumber.

PaymentCardNumber

PaymentCardNumber(card_number: str)

Bases: str

A payment card number.

Source code in pydantic_extra_types/payment.py

def __init__(self, card_number: str):
    self.validate_digits(card_number)

    card_number = self.validate_luhn_check_digit(card_number)

    self.bin = card_number[:6]
    self.last4 = card_number[-4:]
    self.brand = self.validate_brand(card_number)

strip_whitespace class-attribute

strip_whitespace: bool = True

Whether to strip whitespace from the input value.

min_length class-attribute

min_length: int = 12

The minimum length of the card number.

max_length class-attribute

max_length: int = 19

The maximum length of the card number.

bin instance-attribute

bin: str = card_number[:6]

The first 6 digits of the card number.

last4 instance-attribute

last4: str = card_number[-4:]

The last 4 digits of the card number.

brand instance-attribute

brand: PaymentCardBrand = validate_brand(card_number)

The brand of the card.

masked property

masked: str

The masked card number.

validate classmethod

validate(
    __input_value: str, _: ValidationInfo
) -> PaymentCardNumber

Validate the PaymentCardNumber instance.

Parameters:

Name	Type	Description	Default
__input_value	str	The input value to validate.	required
_	ValidationInfo	The validation info.	required

Returns:

Type	Description
PaymentCardNumber	The validated PaymentCardNumber instance.

Source code in pydantic_extra_types/payment.py

@classmethod
def validate(cls, __input_value: str, _: core_schema.ValidationInfo) -> PaymentCardNumber:
    """Validate the `PaymentCardNumber` instance.

    Args:
        __input_value: The input value to validate.
        _: The validation info.

    Returns:
        The validated `PaymentCardNumber` instance.
    """
    return cls(__input_value)

validate_digits classmethod

validate_digits(card_number: str) -> None

Validate that the card number is all digits.

Parameters:

Name	Type	Description	Default
card_number	str	The card number to validate.	required

Raises:

Type	Description
PydanticCustomError	If the card number is not all digits.

Source code in pydantic_extra_types/payment.py

@classmethod
def validate_digits(cls, card_number: str) -> None:
    """Validate that the card number is all digits.

    Args:
        card_number: The card number to validate.

    Raises:
        PydanticCustomError: If the card number is not all digits.
    """
    if not card_number or not all('0' <= c <= '9' for c in card_number):
        raise PydanticCustomError('payment_card_number_digits', 'Card number is not all digits')

validate_luhn_check_digit classmethod

validate_luhn_check_digit(card_number: str) -> str

Validate the payment card number. Based on the Luhn algorithm.

Parameters:

Name	Type	Description	Default
card_number	str	The card number to validate.	required

Returns:

Type	Description
str	The validated card number.

Raises:

Type	Description
PydanticCustomError	If the card number is not valid.

Source code in pydantic_extra_types/payment.py

@classmethod
def validate_luhn_check_digit(cls, card_number: str) -> str:
    """Validate the payment card number.
    Based on the [Luhn algorithm](https://en.wikipedia.org/wiki/Luhn_algorithm).

    Args:
        card_number: The card number to validate.

    Returns:
        The validated card number.

    Raises:
        PydanticCustomError: If the card number is not valid.
    """
    sum_ = int(card_number[-1])
    length = len(card_number)
    parity = length % 2
    for i in range(length - 1):
        digit = int(card_number[i])
        if i % 2 == parity:
            digit *= 2
        if digit > 9:
            digit -= 9
        sum_ += digit
    valid = sum_ % 10 == 0
    if not valid:
        raise PydanticCustomError('payment_card_number_luhn', 'Card number is not luhn valid')
    return card_number

validate_brand staticmethod

validate_brand(card_number: str) -> PaymentCardBrand

Validate length based on BIN for major brands.

Parameters:

Name	Type	Description	Default
card_number	str	The card number to validate.	required

Returns:

Type	Description
PaymentCardBrand	The validated card brand.

Raises:

Type	Description
PydanticCustomError	If the card number is not valid.

Source code in pydantic_extra_types/payment.py

@staticmethod
def validate_brand(card_number: str) -> PaymentCardBrand:
    """Validate length based on
    [BIN](https://en.wikipedia.org/wiki/Payment_card_number#Issuer_identification_number_(IIN))
    for major brands.

    Args:
        card_number: The card number to validate.

    Returns:
        The validated card brand.

    Raises:
        PydanticCustomError: If the card number is not valid.
    """
    brand = PaymentCardBrand.other

    if card_number[0] == '4':
        brand = PaymentCardBrand.visa
        required_length = [13, 16, 19]
    elif 51 <= int(card_number[:2]) <= 55:
        brand = PaymentCardBrand.mastercard
        required_length = [16]
    elif card_number[:2] in {'34', '37'}:
        brand = PaymentCardBrand.amex
        required_length = [15]
    elif 2200 <= int(card_number[:4]) <= 2204:
        brand = PaymentCardBrand.mir
        required_length = list(range(16, 20))
    elif card_number[:4] in {'5018', '5020', '5038', '5893', '6304', '6759', '6761', '6762', '6763'} or card_number[
        :6
    ] in (
        '676770',
        '676774',
    ):
        brand = PaymentCardBrand.maestro
        required_length = list(range(12, 20))
    elif card_number.startswith('65') or 644 <= int(card_number[:3]) <= 649 or card_number.startswith('6011'):
        brand = PaymentCardBrand.discover
        required_length = list(range(16, 20))
    elif (
        506099 <= int(card_number[:6]) <= 506198
        or 650002 <= int(card_number[:6]) <= 650027
        or 507865 <= int(card_number[:6]) <= 507964
    ):
        brand = PaymentCardBrand.verve
        required_length = [16, 18, 19]
    elif card_number[:4] in {'5019', '4571'}:
        brand = PaymentCardBrand.dankort
        required_length = [16]
    elif card_number.startswith('9792'):
        brand = PaymentCardBrand.troy
        required_length = [16]
    elif card_number[:2] in {'62', '81'}:
        brand = PaymentCardBrand.unionpay
        required_length = [16, 19]
    elif 3528 <= int(card_number[:4]) <= 3589:
        brand = PaymentCardBrand.jcb
        required_length = [16, 19]

    valid = len(card_number) in required_length if brand != PaymentCardBrand.other else True

    if not valid:
        raise PydanticCustomError(
            'payment_card_number_brand',
            f'Length for a {brand} card must be {" or ".join(map(str, required_length))}',
            {'brand': brand, 'required_length': required_length},
        )

    return brand