"""Passlib Hashing Backend."""
from typing import TYPE_CHECKING, Any, Union
from advanced_alchemy.exceptions import MissingDependencyError
from advanced_alchemy.types.password_hash.base import HashingBackend
from advanced_alchemy.typing import PASSLIB_INSTALLED
if TYPE_CHECKING:
from passlib.context import CryptContext
from sqlalchemy import BinaryExpression, ColumnElement
__all__ = ("PasslibHasher",)
[docs]
class PasslibHasher(HashingBackend):
"""Hashing backend using Passlib.
Relies on the `passlib` package being installed.
Install with `pip install passlib` or `uv pip install passlib`.
"""
[docs]
def __init__(self, context: "CryptContext") -> None:
"""Initialize PasslibBackend.
Args:
context: The Passlib CryptContext to use for hashing and verification.
Raises:
MissingDependencyError: If the ``passlib`` package is not installed.
"""
if not PASSLIB_INSTALLED:
raise MissingDependencyError(package="passlib")
self.context = context
[docs]
def hash(self, value: "Union[str, bytes]") -> str:
"""Hash the given value using the Passlib context.
Args:
value: The plain text value to hash. Will be converted to string.
Returns:
The hashed string.
"""
return self.context.hash(self._ensure_bytes(value))
[docs]
def verify(self, plain: "Union[str, bytes]", hashed: str) -> bool:
"""Verify a plain text value against a hash using the Passlib context.
Args:
plain: The plain text value to verify. Will be converted to string.
hashed: The hash to verify against.
Returns:
True if the plain text matches the hash, False otherwise.
"""
try:
return self.context.verify(self._ensure_bytes(plain), hashed)
except Exception: # noqa: BLE001
# Passlib can raise various errors for invalid hashes
return False
[docs]
def needs_rehash(self, hashed: str) -> bool:
"""Return True if the stored hash uses an outdated scheme or cost.
Args:
hashed: The stored hash string.
Returns:
True if the hash should be regenerated; False for an unparsable or foreign hash.
"""
try:
return self.context.needs_update(hashed)
except Exception: # noqa: BLE001
return False
[docs]
def compare_expression(self, column: "ColumnElement[str]", plain: Any) -> "BinaryExpression[bool]":
"""Direct SQL comparison is not supported for Passlib.
Raises:
NotImplementedError: Always raised.
"""
msg = "PasslibHasher does not support direct SQL comparison."
raise NotImplementedError(msg)
