Files
ormar/orm/models.py
2020-08-03 20:05:57 +02:00

185 lines
6.4 KiB
Python

import json
from typing import Any, Type
from typing import Set, Dict
import pydantic
import sqlalchemy
from pydantic import BaseConfig, create_model
from orm.exceptions import ModelDefinitionError
from orm.fields import BaseField
def parse_pydantic_field_from_model_fields(object_dict: dict):
pydantic_fields = {field_name: (
base_field.__type__,
... if (not base_field.nullable and not base_field.default and not base_field.primary_key) else (
base_field.default() if callable(base_field.default) else base_field.default)
)
for field_name, base_field in object_dict.items()
if isinstance(base_field, BaseField)}
return pydantic_fields
class ModelMetaclass(type):
def __new__(
mcs: type, name: str, bases: Any, attrs: dict
) -> type:
new_model = super().__new__( # type: ignore
mcs, name, bases, attrs
)
if attrs.get("__abstract__"):
return new_model
tablename = attrs["__tablename__"]
metadata = attrs["__metadata__"]
pkname = None
columns = []
model_fields = {}
for field_name, field in attrs.items():
if isinstance(field, BaseField):
model_fields[field_name] = field
if not field.pydantic_only:
if field.primary_key:
pkname = field_name
columns.append(field.get_column(field_name))
# sqlalchemy table creation
attrs['__table__'] = sqlalchemy.Table(tablename, metadata, *columns)
attrs['__columns__'] = columns
attrs['__pkname__'] = pkname
if not pkname:
raise ModelDefinitionError(
'Table has to have a primary key.'
)
# pydantic model creation
pydantic_fields = parse_pydantic_field_from_model_fields(attrs)
config = type('Config', (BaseConfig,), {'orm_mode': True})
pydantic_model = create_model(name, __config__=config, **pydantic_fields)
attrs['__pydantic_fields__'] = pydantic_fields
attrs['__pydantic_model__'] = pydantic_model
attrs['__fields__'] = pydantic_model.__fields__
attrs['__signature__'] = pydantic_model.__signature__
attrs['__annotations__'] = pydantic_model.__annotations__
attrs['__model_fields__'] = model_fields
new_model = super().__new__( # type: ignore
mcs, name, bases, attrs
)
return new_model
class Model(metaclass=ModelMetaclass):
__abstract__ = True
def __init__(self, *args, **kwargs) -> None:
if "pk" in kwargs:
kwargs[self.__pkname__] = kwargs.pop("pk")
self.values = self.__pydantic_model__(**kwargs)
def __setattr__(self, key: str, value: Any) -> None:
if key in self.__fields__:
if self.is_conversion_to_json_needed(key) and not isinstance(value, str):
try:
value = json.dumps(value)
except TypeError: # pragma no cover
pass
setattr(self.values, key, value)
else:
super().__setattr__(key, value)
def __getattribute__(self, key: str) -> Any:
if key != '__fields__' and key in self.__fields__:
item = getattr(self.values, key)
if self.is_conversion_to_json_needed(key) and isinstance(item, str):
try:
item = json.loads(item)
except TypeError: # pragma no cover
pass
return item
return super().__getattribute__(key)
def is_conversion_to_json_needed(self, column_name: str) -> bool:
return self.__model_fields__.get(column_name).__type__ == pydantic.Json
@property
def pk(self):
return getattr(self.values, self.__pkname__)
@pk.setter
def pk(self, value):
setattr(self.values, self.__pkname__, value)
@property
def pk_column(self) -> sqlalchemy.Column:
return self.__table__.primary_key.columns.values()[0]
def dict(self) -> Dict:
return self.values.dict()
def from_dict(self, value_dict: Dict) -> None:
for key, value in value_dict.items():
setattr(self, key, value)
def extract_own_model_fields(self) -> Dict:
related_names = self.extract_related_names()
self_fields = {k: v for k, v in self.dict().items() if k not in related_names}
return self_fields
@classmethod
def extract_related_names(cls) -> Set:
related_names = set()
# for name, field in cls.__fields__.items():
# if inspect.isclass(field.type_) and issubclass(field.type_, pydantic.BaseModel):
# related_names.add(name)
# elif field.sub_fields and any(
# [inspect.isclass(f.type_) and issubclass(f.type_, pydantic.BaseModel) for f in field.sub_fields]):
# related_names.add(name)
return related_names
def extract_model_db_fields(self) -> Dict:
self_fields = self.extract_own_model_fields()
self_fields = {k: v for k, v in self_fields.items() if k in self.__table__.columns}
return self_fields
async def save(self) -> int:
self_fields = self.extract_model_db_fields()
if self.__model_fields__.get(self.__pkname__).autoincrement:
self_fields.pop(self.__pkname__, None)
expr = self.__table__.insert()
expr = expr.values(**self_fields)
item_id = await self.__database__.execute(expr)
setattr(self, 'pk', item_id)
return item_id
async def update(self, **kwargs: Any) -> int:
if kwargs:
new_values = {**self.dict(), **kwargs}
self.from_dict(new_values)
self_fields = self.extract_model_db_fields()
self_fields.pop(self.__pkname__)
expr = self.__table__.update().values(**self_fields).where(
self.pk_column == getattr(self, self.__pkname__))
result = await self.__database__.execute(expr)
return result
async def delete(self) -> int:
expr = self.__table__.delete()
expr = expr.where(self.pk_column == (getattr(self, self.__pkname__)))
result = await self.__database__.execute(expr)
return result
async def load(self) -> 'Model':
expr = self.__table__.select().where(self.pk_column == self.pk)
row = await self.__database__.fetch_one(expr)
self.from_dict(dict(row))
return self