Add: New type ISBN

pydantic_extra_types/isbn.py

@@ -0,0 +1,131 @@
+"""
+The `pydantic_extra_types.isbn` module provides functionality to recieve and validate ISBN
+(International Standard Book Number) in 10-digit and 13-digit formats. The output is always ISBN-13.
+"""
+
+from __future__ import annotations
+
+from typing import Any
+
+from pydantic import GetCoreSchemaHandler
+from pydantic_core import PydanticCustomError, core_schema
+
+
+def isbn10_digit_calc(isbn: str) -> str:
+    """
+    Calc a ISBN-10 last digit from the provided str value. More information of validation algorithm on [Wikipedia](https://en.wikipedia.org/wiki/ISBN#Check_digits)
+
+    Args:
+        value: The str value representing the ISBN in 10 digits.
+
+    Returns:
+        The calculated last digit.
+    """
+    total = sum(int(digit) * (10 - idx) for idx, digit in enumerate(isbn[:9]))
+
+    for check_digit in range(1, 11):
+        if (total + check_digit) % 11 == 0:
+            valid_check_digit = 'X' if check_digit == 10 else str(check_digit)
+
+    return valid_check_digit
+
+
+def isbn13_digit_calc(isbn: str) -> str:
+    """
+    Calc a ISBN-13 last digit from the provided str value. More information of validation algorithm on [Wikipedia](https://en.wikipedia.org/wiki/ISBN#Check_digits)
+
+    Args:
+        value: The str value representing the ISBN in 13 digits.
+
+    Returns:
+        The calculated last digit.
+    """
+    total = sum(int(digit) * (1 if idx % 2 == 0 else 3) for idx, digit in enumerate(isbn[:12]))
+
+    check_digit = (10 - (total % 10)) % 10
+
+    return str(check_digit)
+
+
+class ISBN(str):
+    """Represents a ISBN and provides methods for conversion, validation, and serialization.
+
+    ```py
+    from pydantic import BaseModel
+
+    from pydantic_extra_types.isbn import ISBN
+
+
+    class Book(BaseModel):
+        isbn: ISBN
+
+    book = Book(isbn="8537809667")
+    print(book)
+    #> isbn='9788537809662'
+    ```
+    """
+
+    @classmethod
+    def __get_pydantic_core_schema__(cls, source: type[Any], handler: GetCoreSchemaHandler) -> core_schema.CoreSchema:
+        return core_schema.with_info_before_validator_function(
+            cls._validate,
+            core_schema.str_schema(),
+        )
+
+    @classmethod
+    def _validate(cls, __input_value: str, _: Any) -> str:
+        cls.validate_isbn_format(__input_value)
+
+        return cls.convert_isbn10_to_isbn13(__input_value)
+
+    @staticmethod
+    def validate_isbn_format(value: str) -> None:
+        """
+        Validate a ISBN format from the provided str value.
+
+        Args:
+            value: The str value representing the ISBN in 10 or 13 digits.
+
+        Raises:
+            PydanticCustomError: If the value is not a valid ISBN.
+        """
+
+        isbn_length = len(value)
+
+        if isbn_length not in (10, 13):
+            raise PydanticCustomError('isbn_length', f'Length for ISBN must be 10 or 13 digits, not {isbn_length}')
+
+        if isbn_length == 10:
+            if not value[:-1].isdigit() or ((value[-1] != 'X') and (not value[-1].isdigit())):
+                raise PydanticCustomError('isbn10_invalid_characters', 'First 9 digits of ISBN-10 must be integers')
+            if isbn10_digit_calc(value) != value[-1]:
+                raise PydanticCustomError('isbn_invalid_digit_check_isbn10', 'Provided digit is invalid for given ISBN')
+
+        if isbn_length == 13:
+            if not value.isdigit():
+                raise PydanticCustomError('isbn13_invalid_characters', 'All digits of ISBN-13 must be integers')
+            if value[:3] not in ('978', '979'):
+                raise PydanticCustomError(
+                    'isbn_invalid_early_characters', 'The first 3 digits of ISBN-13 must be 978 or 979'
+                )
+            if isbn13_digit_calc(value) != value[-1]:
+                raise PydanticCustomError('isbn_invalid_digit_check_isbn13', 'Provided digit is invalid for given ISBN')
+
+    @staticmethod
+    def convert_isbn10_to_isbn13(value: str) -> str:
+        """
+        Convert an ISBN-10 to ISBN-13.
+
+        Args:
+            value: The str value representing the ISBN.
+
+        Returns:
+            The converted ISBN or the original value if no conversion is necessary.
+        """
+
+        if len(value) == 10:
+            base_isbn = f'978{value[:-1]}'
+            isbn13_digit = isbn13_digit_calc(base_isbn)
+            return ISBN(f'{base_isbn}{isbn13_digit}')
+
+        return ISBN(value)

tests/test_isbn.py

@@ -0,0 +1,154 @@
+from typing import Any
+
+import pytest
+from pydantic import BaseModel, ValidationError
+
+from pydantic_extra_types.isbn import ISBN
+
+
+class Book(BaseModel):
+    isbn: ISBN
+
+
+isbn_length_test_cases = [
+    # Valid ISBNs
+    ('8537809667', '9788537809662', True),  # ISBN-10 as input
+    ('9788537809662', '9788537809662', True),  # ISBN-13 as input
+    ('080442957X', '9780804429573', True),  # ISBN-10 ending in "X" as input
+    ('9788584390670', '9788584390670', True),  # ISBN-13 Starting with 978
+    ('9790306406156', '9790306406156', True),  # ISBN-13 starting with 979
+    # Invalid ISBNs
+    ('97885843906701', None, False),  # Length: 14 (Higher)
+    ('978858439067', None, False),  # Length: 12 (In Between)
+    ('97885843906', None, False),  # Length: 11 (In Between)
+    ('978858439', None, False),  # Length: 9 (Lower)
+    ('', None, False),  # Length: 0 (Lower)
+]
+
+
+@pytest.mark.parametrize('input_isbn, output_isbn, valid', isbn_length_test_cases)
+def test_isbn_length(input_isbn: Any, output_isbn: str, valid: bool) -> None:
+    if valid:
+        assert Book(isbn=ISBN(input_isbn)).isbn == output_isbn
+    else:
+        with pytest.raises(ValidationError, match='isbn_length'):
+            Book(isbn=ISBN(input_isbn))
+
+
+isbn10_digits_test_cases = [
+    # Valid ISBNs
+    ('8537809667', '9788537809662', True),  # ISBN-10 as input
+    ('080442957X', '9780804429573', True),  # ISBN-10 ending in "X" as input
+    # Invalid ISBNs
+    ('@80442957X', None, False),  # Non Integer in [0] position
+    ('8@37809667', None, False),  # Non Integer in [1] position
+    ('85@7809667', None, False),  # Non Integer in [2] position
+    ('853@809667', None, False),  # Non Integer in [3] position
+    ('8537@09667', None, False),  # Non Integer in [4] position
+    ('85378@9667', None, False),  # Non Integer in [5] position
+    ('853780@667', None, False),  # Non Integer in [6] position
+    ('8537809@67', None, False),  # Non Integer in [7] position
+    ('85378096@7', None, False),  # Non Integer in [8] position
+    ('853780966@', None, False),  # Non Integer or X in [9] position
+]
+
+
+@pytest.mark.parametrize('input_isbn, output_isbn, valid', isbn10_digits_test_cases)
+def test_isbn10_digits(input_isbn: Any, output_isbn: str, valid: bool) -> None:
+    if valid:
+        assert Book(isbn=ISBN(input_isbn)).isbn == output_isbn
+    else:
+        with pytest.raises(ValidationError, match='isbn10_invalid_characters'):
+            Book(isbn=ISBN(input_isbn))
+
+
+isbn13_digits_test_cases = [
+    # Valid ISBNs
+    ('9788537809662', '9788537809662', True),  # ISBN-13 as input
+    ('9780306406157', '9780306406157', True),  # ISBN-13 as input
+    ('9788584390670', '9788584390670', True),  # ISBN-13 Starting with 978
+    ('9790306406156', '9790306406156', True),  # ISBN-13 starting with 979
+    # Invalid ISBNs
+    ('@788537809662', None, False),  # Non Integer in [0] position
+    ('9@88537809662', None, False),  # Non Integer in [1] position
+    ('97@8537809662', None, False),  # Non Integer in [2] position
+    ('978@537809662', None, False),  # Non Integer in [3] position
+    ('9788@37809662', None, False),  # Non Integer in [4] position
+    ('97885@7809662', None, False),  # Non Integer in [5] position
+    ('978853@809662', None, False),  # Non Integer in [6] position
+    ('9788537@09662', None, False),  # Non Integer in [7] position
+    ('97885378@9662', None, False),  # Non Integer in [8] position
+    ('978853780@662', None, False),  # Non Integer in [9] position
+    ('9788537809@62', None, False),  # Non Integer in [10] position
+    ('97885378096@2', None, False),  # Non Integer in [11] position
+    ('978853780966@', None, False),  # Non Integer in [12] position
+]
+
+
+@pytest.mark.parametrize('input_isbn, output_isbn, valid', isbn13_digits_test_cases)
+def test_isbn13_digits(input_isbn: Any, output_isbn: str, valid: bool) -> None:
+    if valid:
+        assert Book(isbn=ISBN(input_isbn)).isbn == output_isbn
+    else:
+        with pytest.raises(ValidationError, match='isbn13_invalid_characters'):
+            Book(isbn=ISBN(input_isbn))
+
+
+isbn13_early_digits_test_cases = [
+    # Valid ISBNs
+    ('9780306406157', '9780306406157', True),  # ISBN-13 as input
+    ('9788584390670', '9788584390670', True),  # ISBN-13 Starting with 978
+    ('9790306406156', '9790306406156', True),  # ISBN-13 starting with 979
+    # Invalid ISBNs
+    ('1788584390670', None, False),  # Does not start with 978 or 979
+    ('9288584390670', None, False),  # Does not start with 978 or 979
+    ('9738584390670', None, False),  # Does not start with 978 or 979
+]
+
+
+@pytest.mark.parametrize('input_isbn, output_isbn, valid', isbn13_early_digits_test_cases)
+def test_isbn13_early_digits(input_isbn: Any, output_isbn: str, valid: bool) -> None:
+    if valid:
+        assert Book(isbn=ISBN(input_isbn)).isbn == output_isbn
+    else:
+        with pytest.raises(ValidationError, match='isbn_invalid_early_characters'):
+            Book(isbn=ISBN(input_isbn))
+
+
+isbn_last_digit_test_cases = [
+    # Valid ISBNs
+    ('8537809667', '9788537809662', True),  # ISBN-10 as input
+    ('9788537809662', '9788537809662', True),  # ISBN-13 as input
+    ('080442957X', '9780804429573', True),  # ISBN-10 ending in "X" as input
+    ('9788584390670', '9788584390670', True),  # ISBN-13 Starting with 978
+    ('9790306406156', '9790306406156', True),  # ISBN-13 starting with 979
+    # Invalid ISBNs
+    ('8537809663', None, False),  # ISBN-10 as input with wrong last digit
+    ('9788537809661', None, False),  # ISBN-13 as input with wrong last digit
+    ('080442953X', None, False),  # ISBN-10 ending in "X" as input with wrong last digit
+    ('9788584390671', None, False),  # ISBN-13 Starting with 978 with wrong last digit
+    ('9790306406155', None, False),  # ISBN-13 starting with 979 with wrong last digit
+]
+
+
+@pytest.mark.parametrize('input_isbn, output_isbn, valid', isbn_last_digit_test_cases)
+def test_isbn_last_digit(input_isbn: Any, output_isbn: str, valid: bool) -> None:
+    if valid:
+        assert Book(isbn=ISBN(input_isbn)).isbn == output_isbn
+    else:
+        with pytest.raises(ValidationError, match='isbn_invalid_digit_check_isbn'):
+            Book(isbn=ISBN(input_isbn))
+
+
+isbn_conversion_test_cases = [
+    # Valid ISBNs
+    ('8537809667', '9788537809662'),
+    ('080442957X', '9780804429573'),
+    ('9788584390670', '9788584390670'),
+    ('9790306406156', '9790306406156'),
+]
+
+
+@pytest.mark.parametrize('input_isbn, output_isbn', isbn_conversion_test_cases)
+def test_isbn_conversion(input_isbn: Any, output_isbn: str) -> None:
+    assert Book(isbn=ISBN(input_isbn)).isbn == output_isbn

tests/test_json_schema.py

@@ -10,6 +10,7 @@
     CountryOfficialName,
     CountryShortName,
 )
+from pydantic_extra_types.isbn import ISBN
 from pydantic_extra_types.mac_address import MacAddress
 from pydantic_extra_types.payment import PaymentCardNumber
 from pydantic_extra_types.ulid import ULID
@@ -185,6 +186,20 @@
                 'type': 'object',
             },
         ),
+        (
+            ISBN,
+            {
+                'properties': {
+                    'x': {
+                        'title': 'X',
+                        'type': 'string',
+                    }
+                },
+                'required': ['x'],
+                'title': 'Model',
+                'type': 'object',
+            },
+        ),
     ],
 )
 def test_json_schema(cls, expected):