114 lines
3.8 KiB
Python
114 lines
3.8 KiB
Python
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from django.contrib.contenttypes.fields import GenericRelation
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from django.db import models
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from modelcluster.fields import ParentalKey, ParentalManyToManyField
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from modelcluster.models import ClusterableModel
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def _extract_field_data(source, exclude_fields=None):
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"""
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Get dictionaries representing the model's field data.
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This excludes many to many fields (which are handled by _copy_m2m_relations)'
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"""
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exclude_fields = exclude_fields or []
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data_dict = {}
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for field in source._meta.get_fields():
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# Ignore explicitly excluded fields
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if field.name in exclude_fields:
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continue
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# Ignore reverse relations
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if field.auto_created:
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continue
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# Ignore reverse generic relations
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if isinstance(field, GenericRelation):
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continue
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# Copy parental m2m relations
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if field.many_to_many:
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if isinstance(field, ParentalManyToManyField):
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parental_field = getattr(source, field.name)
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if hasattr(parental_field, "all"):
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values = parental_field.all()
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if values:
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data_dict[field.name] = values
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continue
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# Ignore parent links (page_ptr)
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if isinstance(field, models.OneToOneField) and field.remote_field.parent_link:
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continue
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if isinstance(field, models.ForeignKey):
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# Use attname to copy the ID instead of retrieving the instance
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# Note: We first need to set the field to None to unset any object
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# that's there already just setting _id on its own won't change the
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# field until its saved.
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data_dict[field.name] = None
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data_dict[field.attname] = getattr(source, field.attname)
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else:
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data_dict[field.name] = getattr(source, field.name)
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return data_dict
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def _copy_m2m_relations(source, target, exclude_fields=None, update_attrs=None):
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"""
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Copies non-ParentalManyToMany m2m relations
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"""
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update_attrs = update_attrs or {}
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exclude_fields = exclude_fields or []
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for field in source._meta.get_fields():
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# Copy m2m relations. Ignore explicitly excluded fields, reverse relations, and Parental m2m fields.
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if (
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field.many_to_many
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and field.name not in exclude_fields
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and not field.auto_created
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and not isinstance(field, ParentalManyToManyField)
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):
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try:
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# Do not copy m2m links with a through model that has a ParentalKey to the model being copied - these will be copied as child objects
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through_model_parental_links = [
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field
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for field in field.through._meta.get_fields()
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if isinstance(field, ParentalKey)
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and issubclass(source.__class__, field.related_model)
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]
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if through_model_parental_links:
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continue
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except AttributeError:
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pass
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if field.name in update_attrs:
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value = update_attrs[field.name]
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else:
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value = getattr(source, field.name).all()
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getattr(target, field.name).set(value)
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def _copy(source, exclude_fields=None, update_attrs=None):
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data_dict = _extract_field_data(source, exclude_fields=exclude_fields)
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target = source.__class__(**data_dict)
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if update_attrs:
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for field, value in update_attrs.items():
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if field not in data_dict:
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continue
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setattr(target, field, value)
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if isinstance(source, ClusterableModel):
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child_object_map = source.copy_all_child_relations(
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target, exclude=exclude_fields
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)
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else:
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child_object_map = {}
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return target, child_object_map
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