Module bookmeister.record

Record

Module collecting functions necessary to validate data from application form. Each of them raises ValueError when set value is not correct. Values are supposed to be stored in class Record which extends dictionary and maps proper validation function with expected database key. All database fields are added to FIELDS. datetime module is used to acquire current year during validation.

License

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

"""#### Record

Module collecting functions necessary to validate data from application form.
Each of them raises `ValueError` when set value is not correct. Values are
supposed to be stored in class `Record` which extends dictionary and maps
proper validation function with expected database key. All database fields are
added to `FIELDS`. `datetime` module is used to acquire current year during
validation.


#### License
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
"""

from datetime import datetime

FIELDS = ('Title', 'Author', 'Type', 'Publisher', 'ISBN', 'Release',
          'Language', 'Pages', 'Quantity', 'Price', 'Discount')


def check_length(text, minimum=1, maximum=100):
    """Check if length of passed text is between set values.

    Parameters
    ----------
    text : str
        string to check if its length is in set range
    minimum : int, optional
        minimum value for text length, default is 1
    maximum : int, optional
        maximum value for text length, default is 100

    Raises
    ------
    ValueError
        when text length is not in range
    """
    if not minimum <= len(text) <= maximum:
        raise ValueError(f'Text length must be {minimum} to {maximum} '
                         'characters.')


def check_number(value, minimum=0, maximum=9999):
    """Check if passed string is integer between set values.

    Parameters
    ----------
    value : str
        string to check if it is integer in set range
    minimum : int, optional
        minimum value for accepted number, default is 0
    maximum : int, optional
        maximum value for accepted number, default is 9999

    Raises
    ------
    ValueError
        when value cannot be converted to `int` or is not in range
    """
    try:
        number = int(value)
    except ValueError:
        raise ValueError('It must be integer.')

    if not minimum <= number <= maximum:
        raise ValueError(f'Number must be in range {minimum} to {maximum}.')


def check_isbn(number):
    """Check if ISBN-13 number is correct.

    Check if passed value is digit and its length is equal to 13. Then run
    calculations to compare result with checksum. If conditions are not met
    raise ValueError.

    Parameters
    ----------
    number : str
        string to check if it is correct ISBN-13 number

    Raises
    ------
    ValueError
        when value for ISBN-13 is not correct
    """
    if number.isdigit() and len(number) == 13:
        n = [int(char) for char in number]
        control = (10 - ((n[0] + n[2] + n[4] + n[6] + n[8] + n[10] + 3 * (
                n[1] + n[3] + n[5] + n[7] + n[9] + n[11])) % 10)) % 10
        if n[12] == control:
            return
    raise ValueError('Number must be valid ISBN-13 code.')


def check_lang_code(code):
    """Check if language code has two letters.

    Parameters
    ----------
    code : str
        string to check if it is correct language code

    Raises
    ------
    ValueError
        when value for language code is not correct
    """
    if not code.isalpha() or not len(code) == 2:
        raise ValueError('Language code must be two characters. '
                         'Check ISO 639-1 for more details.')


def check_price(value):
    """Check if passed string is price.

    Parameters
    ----------
    value : str
        string to check if it is int or float number with proper precision

    Raises
    ------
    ValueError
        when value contains letters or has too many digits after dot
    """
    price = value.split('.')
    try:
        if len(price) > 2:
            raise ValueError
        check_number(price[0])
        check_number(price[1], 0, 99)
    except IndexError:
        pass
    except ValueError:
        raise ValueError('Price must be a number with maximum two digits after'
                         ' dot, e.g. "125.75".')


class Record(dict):
    """
    Create customized dictionary.

    It validates new elements if their keys are stored in `FIELDS`. Method
    `check` binds proper function needed for validation. It extends `dict`.
    """

    def __setitem__(self, key, value):
        """Extend `__setitem__` method by value check for `FIELDS` elements."""
        if key in FIELDS and isinstance(value, str):
            self.check(key, value)
        super(Record, self).__setitem__(key, value)

    @staticmethod
    def check(key, value):
        """Map functions which check field value with expected key."""
        if key in ('Title', 'Author', 'Type', 'Publisher'):
            check_length(value)
        elif key in ('Release', 'Pages', 'Quantity', 'Discount'):
            args = []
            if key == 'Release':
                args.extend((1800, datetime.now().year + 1))
            if key == 'Discount':
                args.extend((0, 99))
            check_number(value, *args)
        else:
            {'ISBN': check_isbn,
             'Language': check_lang_code,
             'Price': check_price}[key](value)

    def cast(self):
        """Cast `Record` values to type expected in database."""
        try:
            self['Price'] = float(self['Price'])
        except (KeyError, ValueError):
            pass

        for field in ('ISBN', 'Release', 'Pages', 'Quantity', 'Discount'):
            try:
                self[field] = int(self[field])
            except (KeyError, ValueError):
                pass

Functions

def check_isbn(number)

Check if ISBN-13 number is correct.

Check if passed value is digit and its length is equal to 13. Then run calculations to compare result with checksum. If conditions are not met raise ValueError.

Parameters

number : str

string to check if it is correct ISBN-13 number

Raises

ValueError

when value for ISBN-13 is not correct

Expand source code Browse git

def check_isbn(number):
    """Check if ISBN-13 number is correct.

    Check if passed value is digit and its length is equal to 13. Then run
    calculations to compare result with checksum. If conditions are not met
    raise ValueError.

    Parameters
    ----------
    number : str
        string to check if it is correct ISBN-13 number

    Raises
    ------
    ValueError
        when value for ISBN-13 is not correct
    """
    if number.isdigit() and len(number) == 13:
        n = [int(char) for char in number]
        control = (10 - ((n[0] + n[2] + n[4] + n[6] + n[8] + n[10] + 3 * (
                n[1] + n[3] + n[5] + n[7] + n[9] + n[11])) % 10)) % 10
        if n[12] == control:
            return
    raise ValueError('Number must be valid ISBN-13 code.')

def check_lang_code(code)

Check if language code has two letters.

Parameters

code : str

string to check if it is correct language code

Raises

ValueError

when value for language code is not correct

Expand source code Browse git

def check_lang_code(code):
    """Check if language code has two letters.

    Parameters
    ----------
    code : str
        string to check if it is correct language code

    Raises
    ------
    ValueError
        when value for language code is not correct
    """
    if not code.isalpha() or not len(code) == 2:
        raise ValueError('Language code must be two characters. '
                         'Check ISO 639-1 for more details.')

def check_length(text, minimum=1, maximum=100)

Check if length of passed text is between set values.

Parameters

text : str

string to check if its length is in set range

minimum : int, optional

minimum value for text length, default is 1

maximum : int, optional

maximum value for text length, default is 100

Raises

ValueError

when text length is not in range

Expand source code Browse git

def check_length(text, minimum=1, maximum=100):
    """Check if length of passed text is between set values.

    Parameters
    ----------
    text : str
        string to check if its length is in set range
    minimum : int, optional
        minimum value for text length, default is 1
    maximum : int, optional
        maximum value for text length, default is 100

    Raises
    ------
    ValueError
        when text length is not in range
    """
    if not minimum <= len(text) <= maximum:
        raise ValueError(f'Text length must be {minimum} to {maximum} '
                         'characters.')

def check_number(value, minimum=0, maximum=9999)

Check if passed string is integer between set values.

Parameters

value : str

string to check if it is integer in set range

minimum : int, optional

minimum value for accepted number, default is 0

maximum : int, optional

maximum value for accepted number, default is 9999

Raises

ValueError

when value cannot be converted to int or is not in range

Expand source code Browse git

def check_number(value, minimum=0, maximum=9999):
    """Check if passed string is integer between set values.

    Parameters
    ----------
    value : str
        string to check if it is integer in set range
    minimum : int, optional
        minimum value for accepted number, default is 0
    maximum : int, optional
        maximum value for accepted number, default is 9999

    Raises
    ------
    ValueError
        when value cannot be converted to `int` or is not in range
    """
    try:
        number = int(value)
    except ValueError:
        raise ValueError('It must be integer.')

    if not minimum <= number <= maximum:
        raise ValueError(f'Number must be in range {minimum} to {maximum}.')

def check_price(value)

Check if passed string is price.

Parameters

value : str

string to check if it is int or float number with proper precision

Raises

ValueError

when value contains letters or has too many digits after dot

Expand source code Browse git

def check_price(value):
    """Check if passed string is price.

    Parameters
    ----------
    value : str
        string to check if it is int or float number with proper precision

    Raises
    ------
    ValueError
        when value contains letters or has too many digits after dot
    """
    price = value.split('.')
    try:
        if len(price) > 2:
            raise ValueError
        check_number(price[0])
        check_number(price[1], 0, 99)
    except IndexError:
        pass
    except ValueError:
        raise ValueError('Price must be a number with maximum two digits after'
                         ' dot, e.g. "125.75".')

Classes

class Record (...)

Create customized dictionary.

It validates new elements if their keys are stored in FIELDS. Method check binds proper function needed for validation. It extends dict.

Expand source code Browse git

class Record(dict):
    """
    Create customized dictionary.

    It validates new elements if their keys are stored in `FIELDS`. Method
    `check` binds proper function needed for validation. It extends `dict`.
    """

    def __setitem__(self, key, value):
        """Extend `__setitem__` method by value check for `FIELDS` elements."""
        if key in FIELDS and isinstance(value, str):
            self.check(key, value)
        super(Record, self).__setitem__(key, value)

    @staticmethod
    def check(key, value):
        """Map functions which check field value with expected key."""
        if key in ('Title', 'Author', 'Type', 'Publisher'):
            check_length(value)
        elif key in ('Release', 'Pages', 'Quantity', 'Discount'):
            args = []
            if key == 'Release':
                args.extend((1800, datetime.now().year + 1))
            if key == 'Discount':
                args.extend((0, 99))
            check_number(value, *args)
        else:
            {'ISBN': check_isbn,
             'Language': check_lang_code,
             'Price': check_price}[key](value)

    def cast(self):
        """Cast `Record` values to type expected in database."""
        try:
            self['Price'] = float(self['Price'])
        except (KeyError, ValueError):
            pass

        for field in ('ISBN', 'Release', 'Pages', 'Quantity', 'Discount'):
            try:
                self[field] = int(self[field])
            except (KeyError, ValueError):
                pass

Ancestors

• builtins.dict

Static methods

def check(key, value)

Map functions which check field value with expected key.

Expand source code Browse git

@staticmethod
def check(key, value):
    """Map functions which check field value with expected key."""
    if key in ('Title', 'Author', 'Type', 'Publisher'):
        check_length(value)
    elif key in ('Release', 'Pages', 'Quantity', 'Discount'):
        args = []
        if key == 'Release':
            args.extend((1800, datetime.now().year + 1))
        if key == 'Discount':
            args.extend((0, 99))
        check_number(value, *args)
    else:
        {'ISBN': check_isbn,
         'Language': check_lang_code,
         'Price': check_price}[key](value)

Methods

def cast(self)

Cast Record values to type expected in database.

Expand source code Browse git

def cast(self):
    """Cast `Record` values to type expected in database."""
    try:
        self['Price'] = float(self['Price'])
    except (KeyError, ValueError):
        pass

    for field in ('ISBN', 'Release', 'Pages', 'Quantity', 'Discount'):
        try:
            self[field] = int(self[field])
        except (KeyError, ValueError):
            pass