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https://github.com/lamenezes/simple-model

data handling made easy
https://github.com/lamenezes/simple-model

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data handling made easy

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README 

        
============

Simple Model

============



.. image:: https://badge.fury.io/py/pysimplemodel.svg

    :target: https://pypi.org/project/pysimplemodel/



.. image:: https://img.shields.io/badge/python-3.6,3.7-blue.svg

    :target: https://github.com/lamenezes/simple-model



.. image:: https://img.shields.io/github/license/lamenezes/simple-model.svg

    :target: https://github.com/lamenezes/simple-model/blob/master/LICENSE



.. image:: https://circleci.com/gh/lamenezes/simple-model.svg?style=shield

    :target: https://circleci.com/gh/lamenezes/simple-model



.. image:: https://codecov.io/gh/lamenezes/simple-model/branch/master/graph/badge.svg

  :target: https://codecov.io/gh/lamenezes/simple-model



*SimpleModel* offers a simple way to handle data using classes instead of a

plenty of lists and dicts.



It has simple objectives:



- Define models and its fields easily using class attributes, type annotations or tuples (whatever suits your needs)

- Support for field validation, cleaning and type conversion

- Easy model conversion to dict



Quickstart

==========



Installing

----------



Open your favorite shell and run the following command:



.. code:: shell



    pip install pysimplemodel



Example

-------



Define your models using type annotations:



.. code:: python



    from simple_model import Model



    class Person(Model):

        age: int

        height: float

        is_active: bool = True

        name: str



Simple model automatically creates an initializer for your model and you all set

to create instances:



.. code:: python



    >> person = Person(age=18, height=1.67, name='John Doe')

    >> person.name

    'John Doe'



As you have noticed we haven't informed a value for field `is_active`, but the model

was still created. That's because we've set a default value of `True` for it and

the model takes care of assigning it automatically to the field:



.. code:: python



    >> person.is_active

    True



Simple model also offers model validation. Empty fields are considered invalid and will

raise errors upon validation. Let's perform some tests using the previous `Person` model:



.. code:: python



    >> person = Person()

    >> print(person.name)

    None

    >> person.validate()

    Traceback (most recent call last):

        ...

    EmptyField: 'height' field cannot be empty



Let's say we want the height and age fields to be optional, that can be achieved with

the following piece of code:



.. code:: python



    from simple_model import Model



    class Person(Model):

        age: int = None

        height: float = None

        is_active: bool = True

        name: str



Now let's test it:



.. code:: python



    >> person = Person(name='Jane Doe', is_active=False)

    >> person.is_active

    False

    >> person.validate()

    True



The last line won't raise an exception which means the model instance is valid!

In case you need the validation to return True or False instead of raising an

exception that's possible by doing the following:



.. code:: python



    >> person.validate(raise_exception=False)

    True



You can also add custom validations by writing class methods prefixed by `validate`

followed by the attribute name, e.g.



.. code:: python



    class Person:

        age: int

        height: float

        name: str



        def validate_age(self, age):

            if age < 0 or age > 150:

                raise ValidationError('Invalid value for age {!r}'.format(age))

            

            return age



        def validate_height(self, height):

            if height <= 0:

               raise ValidationError('Invalid value for height {!r}'.format(age))

            

            return height



Let's test it:



.. code:: python



    >> person = Person(name='John Doe', age=190)

    >> person.validate()

    Traceback (most recent call last):

        ...

    ValidationError: Invalid value for age 190

    >> other_person = Person(name='Jane Doe', height=-1.67)

    >> other_person.validate()

    Traceback (most recent call last):

        ...

    ValidationError: Invalid value for height -1.67



It is important to note that models don't validate types. Currently types are used

for field value conversion.



The `validate` method also supports cleaning the field values by defining custom transformations

in the `validate_` methods:



.. code:: python



    class Person:

        age: int

        name: str



        def validate_name(self, name):

            return name.strip()



    >>> person = Person(age=18.0, name='John Doe ')

    >>> person.name

    'John Doe '

    >> person.age

    18.0

    >>> person.validate()

    >>> person.name

    'John Doe'

    >>> person.age  # all attributes are converted to its type before cleaning

    18  # converted from float (18.0) to int (18)



Finally, simple model allows you to easily convert your model to dict type using the function `to_dict()`:



.. code:: python



    >>> to_dict(person)

    {

        'age': 18,

        'name': 'John Doe'

    }



Documentation

=============



Docs on simple-model.rtfd.io_



.. _simple-model.rtfd.io: https://simple-model.readthedocs.io/en/latest/