Files
ormar/ormar/models/mixins/save_mixin.py
2021-01-03 17:54:09 +01:00

112 lines
4.5 KiB
Python

from typing import Dict
import ormar
from ormar.exceptions import ModelPersistenceError
from ormar.models.mixins import AliasMixin
from ormar.models.mixins.relation_mixin import RelationMixin
class SavePrepareMixin(RelationMixin, AliasMixin):
"""
Used to prepare models to be saved in database
"""
@classmethod
def _prepare_model_to_save(cls, new_kwargs: dict) -> dict:
"""
Combines all preparation methods before saving.
Removes primary key for if it's nullable or autoincrement pk field,
and it's set to None.
Substitute related models with their primary key values as fk column.
Populates the default values for field with default set and no value.
Translate columns into aliases (db names).
:param new_kwargs: dictionary of model that is about to be saved
:type new_kwargs: Dict[str, str]
:return: dictionary of model that is about to be saved
:rtype: Dict[str, str]
"""
new_kwargs = cls._remove_pk_from_kwargs(new_kwargs)
new_kwargs = cls.substitute_models_with_pks(new_kwargs)
new_kwargs = cls.populate_default_values(new_kwargs)
new_kwargs = cls.translate_columns_to_aliases(new_kwargs)
return new_kwargs
@classmethod
def _remove_pk_from_kwargs(cls, new_kwargs: dict) -> dict:
"""
Removes primary key for if it's nullable or autoincrement pk field,
and it's set to None.
:param new_kwargs: dictionary of model that is about to be saved
:type new_kwargs: Dict[str, str]
:return: dictionary of model that is about to be saved
:rtype: Dict[str, str]
"""
pkname = cls.Meta.pkname
pk = cls.Meta.model_fields[pkname]
if new_kwargs.get(pkname, ormar.Undefined) is None and (
pk.nullable or pk.autoincrement
):
del new_kwargs[pkname]
return new_kwargs
@classmethod
def substitute_models_with_pks(cls, model_dict: Dict) -> Dict: # noqa CCR001
"""
Receives dictionary of model that is about to be saved and changes all related
models that are stored as foreign keys to their fk value.
:param model_dict: dictionary of model that is about to be saved
:type model_dict: Dict
:return: dictionary of model that is about to be saved
:rtype: Dict
"""
for field in cls.extract_related_names():
field_value = model_dict.get(field, None)
if field_value is not None:
target_field = cls.Meta.model_fields[field]
target_pkname = target_field.to.Meta.pkname
if isinstance(field_value, ormar.Model):
pk_value = getattr(field_value, target_pkname)
if not pk_value:
raise ModelPersistenceError(
f"You cannot save {field_value.get_name()} "
f"model without pk set!"
)
model_dict[field] = pk_value
elif field_value: # nested dict
if isinstance(field_value, list):
model_dict[field] = [
target.get(target_pkname) for target in field_value
]
else:
model_dict[field] = field_value.get(target_pkname)
else:
model_dict.pop(field, None)
return model_dict
@classmethod
def populate_default_values(cls, new_kwargs: Dict) -> Dict:
"""
Receives dictionary of model that is about to be saved and populates the default
value on the fields that have the default value set, but no actual value was
passed by the user.
:param new_kwargs: dictionary of model that is about to be saved
:type new_kwargs: Dict
:return: dictionary of model that is about to be saved
:rtype: Dict
"""
for field_name, field in cls.Meta.model_fields.items():
if (
field_name not in new_kwargs
and field.has_default(use_server=False)
and not field.pydantic_only
):
new_kwargs[field_name] = field.get_default()
# clear fields with server_default set as None
if field.server_default is not None and not new_kwargs.get(field_name):
new_kwargs.pop(field_name, None)
return new_kwargs