mirror of
https://github.com/Hopiu/django-model-utils.git
synced 2026-04-25 05:14:43 +00:00
122 lines
3.7 KiB
Python
122 lines
3.7 KiB
Python
from datetime import datetime
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from django.db import models
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from django.db.models.base import ModelBase
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from django.contrib.contenttypes.models import ContentType
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from django.utils.translation import ugettext_lazy as _
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from django.db.models.fields import FieldDoesNotExist
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from model_utils.managers import QueryManager
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from model_utils.fields import AutoCreatedField, AutoLastModifiedField, \
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ConditionField, ConditionModifedField
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class InheritanceCastModel(models.Model):
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"""
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An abstract base class that provides a ``real_type`` FK to ContentType.
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For use in trees of inherited models, to be able to downcast
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parent instances to their child types.
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"""
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real_type = models.ForeignKey(ContentType, editable=False, null=True)
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def save(self, *args, **kwargs):
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if not self.id:
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self.real_type = self._get_real_type()
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super(InheritanceCastModel, self).save(*args, **kwargs)
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def _get_real_type(self):
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return ContentType.objects.get_for_model(type(self))
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def cast(self):
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return self.real_type.get_object_for_this_type(pk=self.pk)
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class Meta:
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abstract = True
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class TimeStampedModel(models.Model):
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"""
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An abstract base class model that provides self-updating
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``created`` and ``modified`` fields.
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"""
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created = AutoCreatedField(_('created'))
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modified = AutoLastModifiedField(_('modified'))
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class Meta:
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abstract = True
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class TimeFramedBaseModel(ModelBase):
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"""
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A model base class for the ``TimeFramedModel`` that adds
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a special model manager ``timeframed`` for time frames.
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"""
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def _prepare(cls):
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super(TimeFramedBaseModel, cls)._prepare()
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try:
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cls._meta.get_field('timeframed')
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raise ValueError("Model %s has a field named 'timeframed' and "
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"conflicts with a manager." % cls.__name__)
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except FieldDoesNotExist:
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pass
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cls.add_to_class('timeframed', QueryManager(
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(models.Q(starts__lte=datetime.now()) | models.Q(starts__isnull=True)) &
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(models.Q(ends__gte=datetime.now()) | models.Q(ends__isnull=True))
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))
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class TimeFramedModel(models.Model):
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"""
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An abstract base class model that provides ``starts``
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and ``ends`` fields to record a timeframe.
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"""
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__metaclass__ = TimeFramedBaseModel
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starts = models.DateTimeField(_('starts'), null=True, blank=True)
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ends = models.DateTimeField(_('ends'), null=True, blank=True)
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class Meta:
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abstract = True
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class ConditionalBaseModel(ModelBase):
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"""
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A model base class for the ``ConditionalModel`` to add
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a series of model managers for each given condition.
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"""
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def _prepare(cls):
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super(ConditionalBaseModel, cls)._prepare()
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conditions = getattr(cls, 'CONDITIONS', None)
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if conditions is None:
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return
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for value, name in conditions._choices:
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try:
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cls._meta.get_field(name)
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raise ValueError("Model %s has a field named '%s' and "
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"conflicts with a condition."
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% (cls.__name__, name))
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except FieldDoesNotExist:
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pass
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cls.add_to_class(name, QueryManager(**{'condition': value}))
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class ConditionalModel(models.Model):
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"""
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An abstract base class model that provides self-updating
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condition fields like ``deleted`` and ``restored``.
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"""
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__metaclass__ = ConditionalBaseModel
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condition = ConditionField(_('condition'))
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condition_date = ConditionModifedField(_('condition date'))
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def __unicode__(self):
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return self.get_condition_display()
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class Meta:
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abstract = True
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