from __future__ import annotations
from re import Pattern # noqa: TC003
from typing import (
TYPE_CHECKING,
Any,
ClassVar,
)
from pydantic import validate_call
from pydantic_core.core_schema import (
chain_schema,
custom_error_schema,
str_schema,
)
if TYPE_CHECKING:
from pydantic import GetCoreSchemaHandler
from pydantic_core.core_schema import CoreSchema
[docs]
class RegexValidator:
"""Base class for creating reusable Pydantic regex validators."""
__slots__ = ()
pattern: ClassVar[Pattern[str]]
error_message: ClassVar[str]
[docs]
@classmethod
@validate_call
def __init_subclass__(cls, pattern: Pattern[str], error_message: str) -> None:
"""Configure the validator subclass with a specific regex pattern.
Args:
pattern (Pattern[str]): The compiled regular expression to validate against.
error_message (str): The custom message returned when validation fails.
"""
cls.pattern = pattern
cls.error_message = error_message
[docs]
@classmethod
def __get_pydantic_core_schema__(cls, source: type[Any], handler: GetCoreSchemaHandler) -> CoreSchema:
"""Generate the Pydantic Core Schema for the validator.
Integrates the custom regex check into the standard validation chain.
"""
return chain_schema(
steps=[
handler(source),
custom_error_schema(
schema=str_schema(pattern=cls.pattern),
custom_error_type="value_error",
custom_error_context={"error": cls.error_message},
),
]
)
