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"""
Giving models a custom manager
You can use a custom ``Manager`` in a particular model by extending the base
``Manager`` class and instantiating your custom ``Manager`` in your model.
There are two reasons you might want to customize a ``Manager``: to add extra
``Manager`` methods, and/or to modify the initial ``QuerySet`` the ``Manager``
returns.
"""
from __future__ import unicode_literals
from django.contrib.contenttypes.fields import (
GenericForeignKey, GenericRelation,
)
from django.db import models
from django.utils.encoding import python_2_unicode_compatible
class PersonManager(models.Manager):
def get_fun_people(self):
return self.filter(fun=True)
class PublishedBookManager(models.Manager):
def get_queryset(self):
return super(PublishedBookManager, self).get_queryset().filter(is_published=True)
class CustomQuerySet(models.QuerySet):
def filter(self, *args, **kwargs):
queryset = super(CustomQuerySet, self).filter(fun=True)
queryset._filter_CustomQuerySet = True
return queryset
def public_method(self, *args, **kwargs):
return self.all()
def _private_method(self, *args, **kwargs):
return self.all()
def optout_public_method(self, *args, **kwargs):
return self.all()
optout_public_method.queryset_only = True
def _optin_private_method(self, *args, **kwargs):
return self.all()
_optin_private_method.queryset_only = False
class BaseCustomManager(models.Manager):
def __init__(self, arg):
super(BaseCustomManager, self).__init__()
self.init_arg = arg
def filter(self, *args, **kwargs):
queryset = super(BaseCustomManager, self).filter(fun=True)
queryset._filter_CustomManager = True
return queryset
def manager_only(self):
return self.all()
CustomManager = BaseCustomManager.from_queryset(CustomQuerySet)
class CustomInitQuerySet(models.QuerySet):
# QuerySet with an __init__() method that takes an additional argument.
def __init__(self, custom_optional_arg=None, model=None, query=None, using=None, hints=None):
super(CustomInitQuerySet, self).__init__(model=model, query=query, using=using, hints=hints)
class DeconstructibleCustomManager(BaseCustomManager.from_queryset(CustomQuerySet)):
def __init__(self, a, b, c=1, d=2):
super(DeconstructibleCustomManager, self).__init__(a)
class FunPeopleManager(models.Manager):
def get_queryset(self):
return super(FunPeopleManager, self).get_queryset().filter(fun=True)
class BoringPeopleManager(models.Manager):
def get_queryset(self):
return super(BoringPeopleManager, self).get_queryset().filter(fun=False)
@python_2_unicode_compatible
class Person(models.Model):
first_name = models.CharField(max_length=30)
last_name = models.CharField(max_length=30)
fun = models.BooleanField(default=False)
favorite_book = models.ForeignKey('Book', models.SET_NULL, null=True, related_name='favorite_books')
favorite_thing_type = models.ForeignKey('contenttypes.ContentType', models.SET_NULL, null=True)
favorite_thing_id = models.IntegerField(null=True)
favorite_thing = GenericForeignKey('favorite_thing_type', 'favorite_thing_id')
objects = PersonManager()
fun_people = FunPeopleManager()
boring_people = BoringPeopleManager()
custom_queryset_default_manager = CustomQuerySet.as_manager()
custom_queryset_custom_manager = CustomManager('hello')
custom_init_queryset_manager = CustomInitQuerySet.as_manager()
def __str__(self):
return "%s %s" % (self.first_name, self.last_name)
@python_2_unicode_compatible
class FunPerson(models.Model):
first_name = models.CharField(max_length=30)
last_name = models.CharField(max_length=30)
fun = models.BooleanField(default=True)
favorite_book = models.ForeignKey(
'Book',
models.SET_NULL,
null=True,
related_name='fun_people_favorite_books',
)
favorite_thing_type = models.ForeignKey('contenttypes.ContentType', models.SET_NULL, null=True)
favorite_thing_id = models.IntegerField(null=True)
favorite_thing = GenericForeignKey('favorite_thing_type', 'favorite_thing_id')
objects = FunPeopleManager()
def __str__(self):
return "%s %s" % (self.first_name, self.last_name)
@python_2_unicode_compatible
class Book(models.Model):
title = models.CharField(max_length=50)
author = models.CharField(max_length=30)
is_published = models.BooleanField(default=False)
published_objects = PublishedBookManager()
authors = models.ManyToManyField(Person, related_name='books')
fun_authors = models.ManyToManyField(FunPerson, related_name='books')
favorite_things = GenericRelation(Person,
content_type_field='favorite_thing_type', object_id_field='favorite_thing_id')
fun_people_favorite_things = GenericRelation(FunPerson,
content_type_field='favorite_thing_type', object_id_field='favorite_thing_id')
def __str__(self):
return self.title
class FastCarManager(models.Manager):
def get_queryset(self):
return super(FastCarManager, self).get_queryset().filter(top_speed__gt=150)
@python_2_unicode_compatible
class Car(models.Model):
name = models.CharField(max_length=10)
mileage = models.IntegerField()
top_speed = models.IntegerField(help_text="In miles per hour.")
cars = models.Manager()
fast_cars = FastCarManager()
def __str__(self):
return self.name
class RestrictedManager(models.Manager):
def get_queryset(self):
return super(RestrictedManager, self).get_queryset().filter(is_public=True)
@python_2_unicode_compatible
class RelatedModel(models.Model):
name = models.CharField(max_length=50)
def __str__(self):
return self.name
@python_2_unicode_compatible
class RestrictedModel(models.Model):
name = models.CharField(max_length=50)
is_public = models.BooleanField(default=False)
related = models.ForeignKey(RelatedModel, models.CASCADE)
objects = RestrictedManager()
plain_manager = models.Manager()
def __str__(self):
return self.name
@python_2_unicode_compatible
class OneToOneRestrictedModel(models.Model):
name = models.CharField(max_length=50)
is_public = models.BooleanField(default=False)
related = models.OneToOneField(RelatedModel, models.CASCADE)
objects = RestrictedManager()
plain_manager = models.Manager()
def __str__(self):
return self.name
class AbstractPerson(models.Model):
abstract_persons = models.Manager()
objects = models.CharField(max_length=30)
class Meta:
abstract = True
class PersonFromAbstract(AbstractPerson):
pass
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