pydantic_extra_types.payment

Represents and validates payment cards (such as a debit or credit card), including validation for payment card number and issuer.

PaymentCardBrand

Bases: str, Enum

Enumeration of payment card brands.

PaymentCardBrand can be one of the following based on the BIN:

• PaymentCardBrand.amex
• PaymentCardBrand.mastercard
• PaymentCardBrand.visa
• PaymentCardBrand.other

PaymentCardNumber

PaymentCardNumber(card_number)

Bases: str

A payment card number.

Attributes:

Name	Type	Description
strip_whitespace	bool	Whether to strip whitespace from the input value.
min_length	int	The minimum length of the card number.
max_length	int	The maximum length of the card number.
bin	str	The first 6 digits of the card number.
last4	str	The last 4 digits of the card number.
brand	PaymentCardBrand	The brand of the card.

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)

masked property

masked: str

The masked card number.

validate classmethod

validate(__input_value, _)

Validate the PaymentCardNumber instance.

Parameters:

Name	Type	Description	Default
__input_value	str	The input value to validate.	required
_	core_schema.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_brand staticmethod

validate_brand(card_number)

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.
    """
    if card_number[0] == '4':
        brand = PaymentCardBrand.visa
    elif 51 <= int(card_number[:2]) <= 55:
        brand = PaymentCardBrand.mastercard
    elif card_number[:2] in {'34', '37'}:
        brand = PaymentCardBrand.amex
    elif 2200 <= int(card_number[:4]) <= 2204:
        brand = PaymentCardBrand.mir
    else:
        brand = PaymentCardBrand.other

    required_length: None | int | str = None
    if brand in PaymentCardBrand.mastercard:
        required_length = 16
        valid = len(card_number) == required_length
    elif brand == PaymentCardBrand.visa:
        required_length = '13, 16 or 19'
        valid = len(card_number) in {13, 16, 19}
    elif brand == PaymentCardBrand.amex:
        required_length = 15
        valid = len(card_number) == required_length
    elif brand == PaymentCardBrand.mir:
        required_length = 'in range from 16 to 19'
        valid = len(card_number) in range(16, 20)
    else:
        valid = True

    if not valid:
        raise PydanticCustomError(
            'payment_card_number_brand',
            'Length for a {brand} card must be {required_length}',
            {'brand': brand, 'required_length': required_length},
        )
    return brand

validate_digits classmethod

validate_digits(card_number)

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.isdigit():
        raise PydanticCustomError('payment_card_number_digits', 'Card number is not all digits')

validate_luhn_check_digit classmethod

validate_luhn_check_digit(card_number)

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