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55 lines
2.4 KiB
Python
55 lines
2.4 KiB
Python
from django.db.models.fields.related import (
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create_many_to_many_intermediary_model,
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ManyToManyField, ManyToManyRel, RelatedField,
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RECURSIVE_RELATIONSHIP_CONSTANT, ReverseManyRelatedObjectsDescriptor,
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)
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from django.utils.functional import curry
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class CustomManyToManyField(RelatedField):
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"""
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Ticket #24104 - Need to have a custom ManyToManyField,
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which is not an inheritor of ManyToManyField.
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"""
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many_to_many = True
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def __init__(self, to, db_constraint=True, swappable=True, **kwargs):
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try:
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to._meta
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except AttributeError:
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to = str(to)
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kwargs['rel'] = ManyToManyRel(
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self, to,
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related_name=kwargs.pop('related_name', None),
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related_query_name=kwargs.pop('related_query_name', None),
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limit_choices_to=kwargs.pop('limit_choices_to', None),
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symmetrical=kwargs.pop('symmetrical', to == RECURSIVE_RELATIONSHIP_CONSTANT),
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through=kwargs.pop('through', None),
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through_fields=kwargs.pop('through_fields', None),
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db_constraint=db_constraint,
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)
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self.swappable = swappable
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self.db_table = kwargs.pop('db_table', None)
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if kwargs['rel'].through is not None:
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assert self.db_table is None, "Cannot specify a db_table if an intermediary model is used."
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super(CustomManyToManyField, self).__init__(**kwargs)
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def contribute_to_class(self, cls, name, **kwargs):
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if self.rel.symmetrical and (self.rel.to == "self" or self.rel.to == cls._meta.object_name):
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self.rel.related_name = "%s_rel_+" % name
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super(CustomManyToManyField, self).contribute_to_class(cls, name, **kwargs)
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if not self.rel.through and not cls._meta.abstract and not cls._meta.swapped:
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self.rel.through = create_many_to_many_intermediary_model(self, cls)
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setattr(cls, self.name, ReverseManyRelatedObjectsDescriptor(self))
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self.m2m_db_table = curry(self._get_m2m_db_table, cls._meta)
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def get_internal_type(self):
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return 'ManyToManyField'
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# Copy those methods from ManyToManyField because they don't call super() internally
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contribute_to_related_class = ManyToManyField.__dict__['contribute_to_related_class']
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_get_m2m_attr = ManyToManyField.__dict__['_get_m2m_attr']
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_get_m2m_reverse_attr = ManyToManyField.__dict__['_get_m2m_reverse_attr']
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_get_m2m_db_table = ManyToManyField.__dict__['_get_m2m_db_table']
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