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