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100 lines
3.4 KiB
100 lines
3.4 KiB
"""Handle Model Serialization."""
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import logging
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from typing import Dict, Callable, Any, List, Optional, Type
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from atheneum import errors
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from atheneum.db import db
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LOGGER = logging.getLogger(__name__)
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class BaseTransformer:
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"""Base Model serializer."""
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type: Type[db.Model]
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def __init__(self, model: Type[db.Model]) -> None:
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"""Initialize the base serializer."""
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self._fields: Dict[str, Callable[[db.Model], Any]] = {}
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self.model = model
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def serialize(self, options: Optional[List[str]]) -> Any:
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"""Convert Model field and factories to dicts."""
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field_factories = self._serializers()
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if not options:
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options = list(field_factories.keys())
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ret = {}
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for key in options:
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if key not in field_factories:
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raise errors.ValidationError(
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'Invalid key: %r. Valid keys: %r.' % (
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key, list(sorted(field_factories.keys()))))
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factory = field_factories[key]
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val = factory()
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if val is not None:
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ret[key] = val
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return ret
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def deserialize(self,
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json_model: dict,
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options: Optional[List[str]]) -> Any:
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"""Convert dict to Model."""
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field_factories = self._deserializers()
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if not options:
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options = list(field_factories.keys())
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for key in options:
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if key not in field_factories:
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raise errors.ValidationError(
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'Invalid key: %r. Valid keys: %r.' % (
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key, list(sorted(field_factories.keys()))))
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factory = field_factories[key]
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try:
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value = json_model[key]
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if value is not None:
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factory(self.model, value)
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except KeyError as key_error:
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LOGGER.error('Unable to transform field: %s %s', key, key_error)
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return self.model
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def _serializers(self) -> Dict[str, Callable[[], Any]]:
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"""Field definitions."""
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raise NotImplementedError()
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def _deserializers(
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self) -> Dict[str, Callable[[db.Model, Any], None]]:
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"""Field definitions."""
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raise NotImplementedError()
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_model_transformers: Dict[str, Type[BaseTransformer]] = {}
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def register_transformer(
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model_name: str, model_serializer: Type[BaseTransformer]) -> None:
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"""Add a model to the serializer mapping."""
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_model_transformers[model_name] = model_serializer
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def serialize_model(model_obj: db.Model,
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options: Optional[List[str]] = None) -> Any:
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"""Lookup a Model and hand off to the serializer."""
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try:
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return _model_transformers[
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type(model_obj).__name__](model_obj).serialize(options)
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except KeyError:
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raise NotImplementedError(
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'{} has no registered serializers'.format(model_obj.__name__))
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def deserialize_model(
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model_type: str,
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json_model_object: dict,
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options: Optional[List[str]] = None) -> Type[db.Model]:
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"""Lookup a Model and hand it off to the deserializer."""
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try:
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transformer = _model_transformers[model_type]
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return transformer(
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transformer.type()).deserialize(json_model_object, options)
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except KeyError:
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raise NotImplementedError(
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'{} has no registered serializers'.format(model_type))
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