133 lines
4.7 KiB
Python
133 lines
4.7 KiB
Python
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"""Support for alias configurations."""
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from __future__ import annotations
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import dataclasses
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from typing import Any, Callable, Literal
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from pydantic_core import PydanticUndefined
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from ._internal import _internal_dataclass
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__all__ = ('AliasGenerator', 'AliasPath', 'AliasChoices')
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@dataclasses.dataclass(**_internal_dataclass.slots_true)
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class AliasPath:
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"""Usage docs: https://docs.pydantic.dev/2.8/concepts/alias#aliaspath-and-aliaschoices
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A data class used by `validation_alias` as a convenience to create aliases.
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Attributes:
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path: A list of string or integer aliases.
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"""
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path: list[int | str]
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def __init__(self, first_arg: str, *args: str | int) -> None:
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self.path = [first_arg] + list(args)
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def convert_to_aliases(self) -> list[str | int]:
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"""Converts arguments to a list of string or integer aliases.
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Returns:
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The list of aliases.
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"""
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return self.path
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def search_dict_for_path(self, d: dict) -> Any:
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"""Searches a dictionary for the path specified by the alias.
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Returns:
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The value at the specified path, or `PydanticUndefined` if the path is not found.
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"""
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v = d
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for k in self.path:
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if isinstance(v, str):
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# disallow indexing into a str, like for AliasPath('x', 0) and x='abc'
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return PydanticUndefined
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try:
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v = v[k]
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except (KeyError, IndexError, TypeError):
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return PydanticUndefined
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return v
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@dataclasses.dataclass(**_internal_dataclass.slots_true)
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class AliasChoices:
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"""Usage docs: https://docs.pydantic.dev/2.8/concepts/alias#aliaspath-and-aliaschoices
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A data class used by `validation_alias` as a convenience to create aliases.
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Attributes:
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choices: A list containing a string or `AliasPath`.
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"""
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choices: list[str | AliasPath]
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def __init__(self, first_choice: str | AliasPath, *choices: str | AliasPath) -> None:
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self.choices = [first_choice] + list(choices)
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def convert_to_aliases(self) -> list[list[str | int]]:
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"""Converts arguments to a list of lists containing string or integer aliases.
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Returns:
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The list of aliases.
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"""
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aliases: list[list[str | int]] = []
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for c in self.choices:
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if isinstance(c, AliasPath):
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aliases.append(c.convert_to_aliases())
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else:
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aliases.append([c])
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return aliases
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@dataclasses.dataclass(**_internal_dataclass.slots_true)
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class AliasGenerator:
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"""Usage docs: https://docs.pydantic.dev/2.8/concepts/alias#using-an-aliasgenerator
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A data class used by `alias_generator` as a convenience to create various aliases.
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Attributes:
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alias: A callable that takes a field name and returns an alias for it.
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validation_alias: A callable that takes a field name and returns a validation alias for it.
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serialization_alias: A callable that takes a field name and returns a serialization alias for it.
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"""
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alias: Callable[[str], str] | None = None
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validation_alias: Callable[[str], str | AliasPath | AliasChoices] | None = None
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serialization_alias: Callable[[str], str] | None = None
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def _generate_alias(
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self,
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alias_kind: Literal['alias', 'validation_alias', 'serialization_alias'],
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allowed_types: tuple[type[str] | type[AliasPath] | type[AliasChoices], ...],
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field_name: str,
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) -> str | AliasPath | AliasChoices | None:
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"""Generate an alias of the specified kind. Returns None if the alias generator is None.
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Raises:
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TypeError: If the alias generator produces an invalid type.
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"""
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alias = None
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if alias_generator := getattr(self, alias_kind):
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alias = alias_generator(field_name)
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if alias and not isinstance(alias, allowed_types):
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raise TypeError(
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f'Invalid `{alias_kind}` type. `{alias_kind}` generator must produce one of `{allowed_types}`'
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)
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return alias
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def generate_aliases(self, field_name: str) -> tuple[str | None, str | AliasPath | AliasChoices | None, str | None]:
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"""Generate `alias`, `validation_alias`, and `serialization_alias` for a field.
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Returns:
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A tuple of three aliases - validation, alias, and serialization.
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"""
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alias = self._generate_alias('alias', (str,), field_name)
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validation_alias = self._generate_alias('validation_alias', (str, AliasChoices, AliasPath), field_name)
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serialization_alias = self._generate_alias('serialization_alias', (str,), field_name)
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return alias, validation_alias, serialization_alias # type: ignore
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