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