pythonnative/src/pythonnative/native_modules/biometrics.py at main · andevsr/pythonnative · GitHub

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"""Biometric authentication (Face ID / Touch ID / fingerprint).

[`Biometrics`][pythonnative.Biometrics] gates an action behind the

device's biometric hardware via ``LAContext`` (iOS) and

``BiometricPrompt`` (Android).

``is_available`` is synchronous; ``authenticate`` is a coroutine that

presents the system prompt and resolves to ``True`` on success or

``False`` on failure / cancellation.

Example:

```python

import pythonnative as pn

async def unlock():

if await pn.Biometrics.authenticate("Unlock your vault"):

show_secrets()

```

"""

from __future__ import annotations

import asyncio

from typing import Any, Callable, Dict

from .. import diagnostics

from ..runtime import resolve_future

from ..utils import IS_ANDROID, IS_IOS

_pending: Dict[int, Any] = {}

class Biometrics:

"""Biometric authentication interface."""

@staticmethod

def is_available() -> bool:

"""Return ``True`` when biometric auth can be attempted."""

if IS_IOS:

return _ios_available()

if IS_ANDROID:

return _android_available()

return False

@staticmethod

async def authenticate(reason: str = "Authenticate") -> bool:

"""Present the biometric prompt; resolve ``True`` on success."""

loop = asyncio.get_running_loop()

future: asyncio.Future[bool] = loop.create_future()

def _done(ok: bool) -> None:

resolve_future(future, ok)

if IS_IOS:

_ios_authenticate(reason, _done)

elif IS_ANDROID:

_android_authenticate(reason, _done)

else:

_done(False)

return await future

# ======================================================================

# iOS: LAContext

# ======================================================================

def _ios_context() -> Any:

from rubicon.objc import ObjCClass

return ObjCClass("LAContext").alloc().init()

def _ios_available() -> bool:

try:

# LAPolicyDeviceOwnerAuthenticationWithBiometrics == 1

return bool(_ios_context().canEvaluatePolicy_error_(1, None))

except Exception:

return False

def _ios_authenticate(reason: str, on_done: Callable[[bool], None]) -> None:

try:

from rubicon.objc import Block, ObjCClass

context = _ios_context()

token = id(context)

_pending[token] = context

def _reply(success: bool, error: Any) -> None:

del error

_pending.pop(token, None)

try:

on_done(bool(success))

except Exception:

diagnostics.swallowed("biometrics._ios_authenticate._reply")

context.evaluatePolicy_localizedReason_reply_(1, reason, Block(_reply, None, bool, ObjCClass("NSError")))

except Exception:

on_done(False)

# ======================================================================

# Android: BiometricPrompt

# ======================================================================

def _android_available() -> bool:

try:

from java import jclass

from ..utils import get_android_context

BiometricManager = jclass("androidx.biometric.BiometricManager")

manager = BiometricManager.from_(get_android_context())

Authenticators = jclass("androidx.biometric.BiometricManager$Authenticators")

result = manager.canAuthenticate(Authenticators.BIOMETRIC_WEAK)

return result == BiometricManager.BIOMETRIC_SUCCESS

except Exception:

return False

def _android_authenticate(reason: str, on_done: Callable[[bool], None]) -> None:

try:

from java import dynamic_proxy, jclass

from ..utils import get_android_context

ctx = get_android_context()

FragmentActivity = jclass("androidx.fragment.app.FragmentActivity")

if not FragmentActivity.isInstance(ctx):

on_done(False)

return

BiometricPrompt = jclass("androidx.biometric.BiometricPrompt")

ContextCompat = jclass("androidx.core.content.ContextCompat")

executor = ContextCompat.getMainExecutor(ctx)

class _Callback(dynamic_proxy(BiometricPrompt.AuthenticationCallback)): # type: ignore[misc]

def onAuthenticationSucceeded(self, result: Any) -> None: # noqa: N802, ARG002

on_done(True)

def onAuthenticationError(self, code: int, message: Any) -> None: # noqa: N802, ARG002

on_done(False)

def onAuthenticationFailed(self) -> None: # noqa: N802

# Fired on a non-matching attempt; the prompt stays up,

# so don't resolve yet.

pass

prompt = BiometricPrompt(ctx, executor, _Callback())

Builder = jclass("androidx.biometric.BiometricPrompt$PromptInfo$Builder")

info = Builder().setTitle(reason).setNegativeButtonText("Cancel").build()

prompt.authenticate(info)

except Exception:

on_done(False)

pythonnative/src/pythonnative/native_modules/biometrics.py at main · andevsr/pythonnative · GitHub

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