pyvalid 0.3

How to install

• With PyPI: pip install -U pyvalid

• Manually: python setup.py install

Example of usage

Function calc in example below has next limitations:

• Can return only int or float value;

• First parameter must be only of type str;

• Second parameter must be of type int or equals to 2.0;

• Third parameter must be of type int or float.

from pyvalid import accepts, returns


@returns(int, float)
@accepts(str, (int, 2.0), (int, float))
def calc(operator, val1, val2, val3):
    expression = '{v1} {op} {v2} {op} {v3}'.format(
        op=operator,
        v1=val1, v2=val2, v3=val3
    )
    return eval(expression)


# Returns int value: 24.
print(calc('*', 2, 3, 4))

# Returns float value: 24.0.
print(calc(operator='*', val1=2, val2=3.0, val3=4))

# Returns float value: 24.0.
print(calc('*', 2.0, 3, 4))

# Raise pyvalid.ArgumentValidationError exception,
# because second argument has unsupported value.
print(calc('*', 3.14, 3, 4))


# Raise pyvalid.InvalidReturnType exception,
# because returns value is of type str.
print(calc('*', 2, 3, '"4"'))

Here is an example of usage pyvalid module in context of classes.

from pyvalid import accepts, returns
from collections import Iterable

class SqlDriver(object):

    @returns(bool)
    @accepts(object, str, int, str, str, str)
    def connect(self, host, port, user, password, database):
        return True

    @returns(bool)
    def close(self):
        return True

    @returns(None, dict)
    @accepts(object, str, Iterable)
    def query(self, sql, params=None):
        return None

sql_driver = SqlDriver()

sql_driver.connect('8.8.8.8', 1433, 'admin', 'password', 'programming')

sql = r'SELECT * FROM ProgrammingLang'
pl = sql_driver.query(sql)

sql = r'SELECT * FROM ProgrammingLang WHERE name=?'
python_pl = sql_driver.query(sql, ('Python',))

sql_driver.close()