pysimplemodel 0.2.0

Simple Models for Python

SimpleModel offers a simple way to handle data using classes instead of a plenty of lists and dicts.

It has simple objectives:

• Define your fields easily (just a tuple, not dicts or instances of type classes whatever)

• Support for field validation

• Serialize to dict

That’s it. If you want something more complex there are plenty of libraries and frameworks that does a lot of cool stuff.

How to install

pip install pysimplemodel

How to use

from simple_model import Model
from simple_model.exceptions import ValidationError


class Person(Model):
    fields = ('name', 'age', 'gender', 'height', 'weight')
    allow_empty = ('height', 'weight')

    def validate_age(self, value):
        if 0 > value > 150:
            raise ValidationError

    def validate_gender(self, value):
        if value not in ('M', 'F'):
            raise ValidationError

>> person = Person(name='John Doe', age=18, gender='M')
>> person.name
'John Doe'
>> person.validate()
>> person.serialize()
{'name': 'John Doe', 'age': 18, 'gender': 'M', 'height': '', 'weight': ''}

Validation

Model values aren’t validated until the validated method is called:

>> person = Person()  # no exception
>> person.validate()
...
EmptyField: name field cannot be empty
>> person = Person(name='Jane Doe', age=60, gender='F')
>> person.validate()  # now it's ok!

You may change the validate method to return a boolean instead of raising an exception:

>> person = Person()
>> person.validate(raise_exception=False)
False
>>> person = Person(name='Jane Doe', age=60, gender='F')
>>> person.validate(raise_exception=False)
True

Cleaning

Sometimes it is necessary to clean some values of your models, this can be easily done using simple-model:

class CleanPerson(Model):
    fields = ('name', 'gender')

    def clean_name(self, value):
        return value.strip()

    def clean_gender(self, value):
        return value.upper()

>> person = CleanPerson(name='John Doe  \n', gender='m')
>> person.name, person.gender
('John Doe  \n', 'm')
>> person.clean()
>> person.name, person.gender
('John Doe', 'M')

Serialization

Simple serialization is pretty straight-forward:

>> person = Person(name='Jane Doe', age=60, gender='F')
>> person.serialize()
{'age': 60, 'gender': 'F', 'height': None, 'name': 'Jane Doe', 'weight': None}

You may also hide some fields from serialization by passing a list to the serialize method:

>> person.serialize(exclude_fields=('gender', 'weight'))
{'age': 60, 'height': None, 'name': 'Jane Doe'}

Simple model also supports nested models:

class SocialPerson(Model):
    fields = ('name', 'friend')

>> person = Person(name='Jane Doe', age=60, gender='F')
>> other_person = SocialPerson(name='John Doe', friend=person)
>> other_person.serialize()
{'friend': {'age': 60, 'gender': 'F', 'height': None, 'name': 'Jane Doe', 'weight': None}, 'name': 'John Doe'}

It also supports nested models as lists:

class MoreSocialPerson(Model):
    fields = ('name', 'friends')

>> person = Person(name='Jane Doe', age=60, gender='F')
>> other_person = Person(name='John Doe', age=15, gender='M')
>> social_person = MoreSocialPerson(name='Foo Bar', friends=[person, other_person])
{
    'name': 'Foo Bar',
    'friends': [
        {
            'age': 60,
            'gender': 'F',
            'height': None,
            'name': 'Jane Doe',
            'weight': None
        },
        {
            'age': 15,
            'gender': 'M',
            'height': None,
            'name': 'John Doe',
            'weight': None
        }
    ]
}