remote_user_api_auth_backend.py

#
# Licensed to the Apache Software Foundation (ASF) under one
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# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
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#
#   http://www.apache.org/licenses/LICENSE-2.0
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"""Default authentication backend - everything is allowed"""
import logging
from functools import wraps
from typing import Callable, Optional, Tuple, TypeVar, Union, cast

from flask import Response, current_app, request
from flask_login import login_user
from requests.auth import AuthBase

log = logging.getLogger(__name__)

CLIENT_AUTH: Optional[Union[Tuple[str, str], AuthBase]] = None


def init_app(_):
    """Initializes authentication backend"""


T = TypeVar("T", bound=Callable)  # pylint: disable=invalid-name


def _lookup_user(user_email_or_username: str):
    security_manager = current_app.appbuilder.sm
    user = (
        security_manager.find_user(email=user_email_or_username)
        or security_manager.find_user(username=user_email_or_username)
    )
    if not user:
        return None

    if not user.is_active:
        return None

    return user


def requires_authentication(function: T):
    """Decorator for functions that require authentication"""
    @wraps(function)
    def decorated(*args, **kwargs):
        user_id = request.remote_user
        if not user_id:
            log.debug("Missing REMOTE_USER.")
            return Response("Forbidden", 403)

        log.debug("Looking for user: %s", user_id)

        user = _lookup_user(user_id)
        if not user:
            return Response("Forbidden", 403)

        log.debug("Found user: %s", user)

        login_user(user, remember=False)
        return function(*args, **kwargs)

    return cast(T, decorated)