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5ed20b3aa3
Allows model fields to override the descriptor class used on the model instance attribute.
27 lines
832 B
Python
27 lines
832 B
Python
from django.db import models
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from django.db.models.query_utils import DeferredAttribute
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class CustomTypedField(models.TextField):
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def db_type(self, connection):
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return 'custom_field'
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class CustomDeferredAttribute(DeferredAttribute):
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def __get__(self, instance, cls=None):
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self._count_call(instance, 'get')
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return super().__get__(instance, cls)
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def __set__(self, instance, value):
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self._count_call(instance, 'set')
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instance.__dict__[self.field.attname] = value
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def _count_call(self, instance, get_or_set):
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count_attr = '_%s_%s_count' % (self.field.attname, get_or_set)
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count = getattr(instance, count_attr, 0)
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setattr(instance, count_attr, count + 1)
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class CustomDescriptorField(models.CharField):
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descriptor_class = CustomDeferredAttribute
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