django-extra-field-validation
Table of Contents
Background
This package aims to provide tools needed to define custom field validation logic which can be used independently or with django forms, test cases, API implementation or any model operation that requires saving data to the database.
This can also be extended by defining check constraints if needed but currently validation will only be handled at the model level.
Installation
```shell script pip install django-extra-field-validation
## Usage
### Require all fields
```py
from django.db import models
from extra_validator import FieldValidationMixin
class TestModel(FieldValidationMixin, models.Model):
amount = models.DecimalField(max_digits=5, decimal_places=2, null=True, blank=True)
fixed_price = models.DecimalField(max_digits=7, decimal_places=2, null=True, blank=True)
percentage = models.DecimalField(max_digits=3, decimal_places=0, null=True, blank=True)
REQUIRED_FIELDS = ['amount'] # Always requires an amount to create the instance.
Example
In [1]: from decimal import Decimal
In [2]: from demo.models import TestModel
In [3]: TestModel.objects.create(fixed_price=Decimal('3.00'))
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
...
ValueError: {'amount': ValidationError([u'Please provide a value for: "amount".'])}
Require at least one field in a collection
from django.db import models
from extra_validator import FieldValidationMixin
class TestModel(FieldValidationMixin, models.Model):
amount = models.DecimalField(max_digits=5, decimal_places=2, null=True, blank=True)
fixed_price = models.DecimalField(max_digits=7, decimal_places=2, null=True, blank=True)
percentage = models.DecimalField(max_digits=3, decimal_places=0, null=True, blank=True)
REQUIRED_TOGGLE_FIELDS = [
['amount', 'fixed_price', 'percentage'], # Require only one of the following fields.
]
Example
In [1]: from decimal import Decimal
In [2]: from demo.models import TestModel
In [3]: TestModel.objects.create(amount=Decimal('2.50'), fixed_price=Decimal('3.00'))
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
...
ValueError: {'fixed_price': ValidationError([u'Please provide only one of: Amount, Fixed price, Percentage'])}
Optionally require at least one field in a collection
from django.db import models
from extra_validator import FieldValidationMixin
class TestModel(FieldValidationMixin, models.Model):
amount = models.DecimalField(max_digits=5, decimal_places=2, null=True, blank=True)
fixed_price = models.DecimalField(max_digits=7, decimal_places=2, null=True, blank=True)
percentage = models.DecimalField(max_digits=3, decimal_places=0, null=True, blank=True)
OPTIONAL_TOGGLE_FIELDS = [
['fixed_price', 'percentage'] # Optionally validates that only fixed price/percentage are provided when present.
]
Example
In [1]: from decimal import Decimal
In [2]: from demo.models import TestModel
In [3]: first_obj = TestModel.objects.create(amount=Decimal('2.0'))
In [4]: second_obj = TestModel.objects.create(amount=Decimal('2.0'), fixed_price=Decimal('3.00'))
In [5]: third_obj = TestModel.objects.create(amount=Decimal('2.0'), fixed_price=Decimal('3.00'), percentage=Decimal('10.0'))
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
...
ValueError: {'percentage': ValidationError([u'Please provide only one of: Fixed price, Percentage'])}
Conditionally require all fields
from django.db import models
from django.conf import settings
from extra_validator import FieldValidationMixin
class TestModel(FieldValidationMixin, models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL)
amount = models.DecimalField(max_digits=5, decimal_places=2, null=True, blank=True)
fixed_price = models.DecimalField(max_digits=7, decimal_places=2, null=True, blank=True)
percentage = models.DecimalField(max_digits=3, decimal_places=0, null=True, blank=True)
CONDITIONAL_REQUIRED_FIELDS = [
(
lambda instance: instance.user.is_active, ['amount', 'percentage'],
),
]
Example
In [1]: from decimal import Decimal
in [2]: from django.contrib.auth import get_user_model
In [3]: from demo.models import TestModel
In [4]: user = get_user_model().objects.create(username='test', is_active=True)
In [5]: first_obj = TestModel.objects.create(user=user, amount=Decimal('2.0'))
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
...
ValueError: {u'percentage': ValidationError([u'Please provide a value for: "percentage"'])}
Conditionally require at least one field in a collection
from django.db import models
from django.conf import settings
from extra_validator import FieldValidationMixin
class TestModel(FieldValidationMixin, models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL)
amount = models.DecimalField(max_digits=5, decimal_places=2, null=True, blank=True)
fixed_price = models.DecimalField(max_digits=7, decimal_places=2, null=True, blank=True)
percentage = models.DecimalField(max_digits=3, decimal_places=0, null=True, blank=True)
CONDITIONAL_REQUIRED_TOGGLE_FIELDS = [
(
lambda instance: instance.user.is_active, ['fixed_price', 'percentage', 'amount'],
),
]
Example
In [1]: from decimal import Decimal
in [2]: from django.contrib.auth import get_user_model
In [3]: from demo.models import TestModel
In [4]: user = get_user_model().objects.create(username='test', is_active=True)
In [5]: first_obj = TestModel.objects.create(user=user)
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
...
ValueError: {'__all__': ValidationError([u'Please provide a valid value for any of the following fields: Fixed price, Percentage, Amount'])}
In [6]: second_obj = TestModel.objects.create(user=user, amount=Decimal('2'), fixed_price=Decimal('2'))
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
...
ValueError: {'__all__': ValidationError([u'Please provide only one of the following fields: Fixed price, Percentage, Amount'])}
Model Attributes
This is done using model attributes below.
# A list of required fields
REQUIRED_FIELDS = []
# A list of fields with at most one required.
REQUIRED_TOGGLE_FIELDS = []
# A list of field with at least one required.
REQUIRED_MIN_FIELDS = []
# Optional list of fields with at most one required.
OPTIONAL_TOGGLE_FIELDS = []
# Conditional field required list of tuples the condition a boolean or a callable.
# [(lambda user: user.is_admin, ['first_name', 'last_name'])] : Both 'first_name' or 'last_name'
# If condition is True ensure that all fields are set
CONDITIONAL_REQUIRED_FIELDS = []
# [(lambda user: user.is_admin, ['first_name', 'last_name'])] : Either 'first_name' or 'last_name'
# If condition is True ensure that at most one field is set
CONDITIONAL_REQUIRED_TOGGLE_FIELDS = []
# [(lambda user: user.is_admin, ['first_name', 'last_name'])] : At least 'first_name' or 'last_name' provided or both
# If condition is True ensure that at least one field is set
CONDITIONAL_REQUIRED_MIN_FIELDS = []
# [(lambda user: user.is_admin, ['first_name', 'last_name'])] : Both 'first_name' and 'last_name' isn't provided
# If condition is True ensure none of the fields are provided
CONDITIONAL_REQUIRED_EMPTY_FIELDS = []
License
django-extra-field-validation is distributed under the terms of both
at your option.
TODO's
- [ ] Support
CONDITIONAL_NON_REQUIRED_TOGGLE_FIELDS - [ ] Support
CONDITIONAL_NON_REQUIRED_FIELDS - [ ] Move to support class and function based validators that use the instance object this should enable cross field model validation.
