Validation

Here we validate that a message has acceptable headers and body.

from pilo import Form
from pilo.fields import Dict, String


class Message(Form):
    headers = Dict(String(choices=['to', 'from', 'content-type']), String())
    body = String(max_length=20)


>>> print Message(headers={'to': 'William III'}, body='ha'*10)
{'body': 'hahahahahahahahahaha', 'headers': {'to': 'William III'}}

>>> print Message(headers={'send-to': 'William III'}, body='ha'*10)
Invalid: headers - "send-to" is not one of "to", "from", "content-type"

>>> print Message(headers={'to': 'William III'}, body='ha'*11)
Invalid: body - "hahahahahahahahahahaha" must have length <= 20

Hooks

Override-able mechanism allowing users to inject functions to customize these behaviors:

• compute

• resolve

• parse

• default

• munge

• filter

• validate

e.g.:

import pilo


class ExtraCurricular(pilo.Form):

   category = pilo.fields.String(
       choices=['athletics', 'academics', 'social', 'service']
   )

   name = pilo.fields.String(max_length=40)

   description = pilo.fields.String(max_length=140)

   role = pilo.fields.String(choices=['member', 'leader'])


class CollegeApplication(pilo.Form):

    high_school_name = pilo.fields.String()

    sat_score = pilo.fields.Integer()

    gpa = pilo.fields.Float()

    extra_curriculars = pilo.fields.List(pilo.fields.SubForm(ExtraCurricular))

    score = pilo.fields.Float(default=pilo.NONE)

    accepted = pilo.fields.Bool(default=False)

    @score.compute
    def score(self):
        leadership_roles = [
            ec for ec in self.extra_curriculars if ec.role == 'leader'
        ]
        relevant_extra_curriculars =[
            ec for ec in self.extra_curriculars
            if ec.category in ['academics', 'service']
        ]
        score = (
            10 * (self.sat_score / 1600.0) +
            10 * (self.gpa / 4.0) +
             5 * len(leadership_roles) +
             5 * len(relevant_extra_curriculars)
        )
        return score

    @accepted.compute
    def accepted(self):
        if self.score > 30:
            return True
        return False

    @high_school_name.munge
    def high_school_name(self, value):
        return value.upper()


application = CollegeApplication(
    high_school_name='Bodega High',
    sat_score=1400,
    gpa=4.0,
    extra_curriculars=[
        dict(category='athletics', role='leader', name='hockey', description=''),
        dict(category='academics', role='member', name='chess club', description=''),
    ]
)


>>> print application.high_school_name
BODEGA HIGH

>>> print application.score
28.75

>>> print application.accepted
False

Form polymorphism and type downcasting

In the following example, a user has an address, but the address schema is polymorphic on the country abbreviation.

import pilo
import uuid


class Address(pilo.Form):

    guid = pilo.fields.UUID(default=uuid.uuid4)
    country = pilo.fields.Type.abstract()


class UnitedKingdomAddress(Address):

    country = pilo.fields.Type.constant('UK')
    name = pilo.fields.String()
    street = pilo.fields.String()
    locality = pilo.fields.String()
    post_town = pilo.fields.String()
    postcode = pilo.fields.String()


class UnitedStatesAddress(Address):

    country = pilo.fields.Type.constant('USA')
    name = pilo.fields.String()
    street = pilo.fields.String()
    unit = pilo.fields.String(default=None)
    city = pilo.fields.String()
    state = pilo.fields.String()
    zip = pilo.fields.String(length=5)


class User(pilo.Form):

     guid = pilo.fields.UUID(default=uuid.uuid4)
     name = pilo.fields.String()
     address = pilo.fields.PolymorphicSubForm(Address.country)


mikey_representation = dict(
    name='Michael Pikey',
    address=dict(
        country='UK',
        name='Mikey Pikey',
        street='351 Meagre Lane',
        locality='Hedge End',
        post_town='Southampton',
        postcode='SO31 4NG',
    )
)


bart_representation = dict(
    name='Bartholomew Simpson',
    address=dict(
        country='USA',
        name='Bite Me',
        street='742 Evergreen Terrace',
        city='Springfield',
        state='???',
        zip='12345',
    )
)


mikey = User(**mikey_representation)


bart = User(**bart_representation)


>>> print dict(mikey)
{
    'address': {
        'country': 'UK',
        'guid': UUID('8c73752c-69a2-4832-99f8-c5354cbeec59'),
        'locality': 'Hedge End',
        'name': 'Mikey Pikey',
        'post_town': 'Southampton',
        'postcode': 'SO31 4NG',
        'street': '351 Meagre Lane'
    },
    'guid': UUID('eee0953c-1b5a-4bd0-893d-f513b1cf24f4'),
    'name': 'Michael Pikey'
}

>>> print dict(bart)
{
    'address': {
        'city': 'Springfield',
        'country': 'USA',
        'guid': UUID('a321bedd-8b94-46b8-830e-ea137b08a608'),
        'name': 'Bite Me',
        'state': '???',
        'street': '742 Evergreen Terrace',
        'unit': None,
        'zip': '12345'
    },
    'guid': UUID('3155a3dd-4b5a-4990-aaea-439359bb36a9'),
    'name': 'Bartholomew Simpson'
}

>>> print mikey.address.postcode
SO31 4NG

>>> print bart.address.zip
12345

>>> print type(mikey.address).__name__
UnitedKingdomAddress

>>> print type(bart.address).__name__
UnitedStatesAddress