user_auth.py

# Licensed to the Apache Software Foundation (ASF) under one
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# distributed with this work for additional information
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# to you under the Apache License, Version 2.0 (the
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#
#   http://www.apache.org/licenses/LICENSE-2.0
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"""
   User authentication backend
   Referencies
     - https://flask-appbuilder.readthedocs.io/en/latest/_modules/flask_appbuilder/security/manager.html
     - https://github.com/apache/airflow/blob/main/airflow/api/auth/backend/basic_auth.py
"""
import logging
import jwt
from functools import wraps
from typing import Any, Callable, Optional, Tuple, TypeVar, Union, cast
from flask import Response, current_app, request
from flask_appbuilder.const import AUTH_OAUTH, AUTH_LDAP, AUTH_DB
from flask_appbuilder.security.sqla.models import User
from flask_login import login_user

CLIENT_AUTH: Optional[Union[Tuple[str, str], Any]] = None
log = logging.getLogger(__name__)
def init_app(_):
    """Initializes authentication backend"""

T = TypeVar("T", bound=Callable)
def auth_current_user() -> Optional[User]:
    """Authenticate and set current user if Authorization header exists"""

    ab_security_manager = current_app.appbuilder.sm
    user = None
    
    if ab_security_manager.auth_type == AUTH_OAUTH:
        token = request.headers['Authorization']
        if token is None:
            return None
        tokeninfo = token.split()
        if tokeninfo is None or len(tokeninfo) < 2:
            return None
        me = jwt.decode(tokeninfo[1], algorithms="RS256", verify=False)
        groups = me["resource_access"]["airflow"]["roles"] # unsafe
        if len(groups) < 1:
            groups = ["airflow_public"]
        else:
            groups = [str for str in groups if "airflow" in str]
            userinfo = {
                "username": me.get("preferred_username"),
                "email": me.get("email"),
                "first_name": me.get("given_name"),
                "last_name": me.get("family_name"),
                "role_keys": groups,
            }
        user = ab_security_manager.auth_user_oauth(userinfo)
    else:
        auth = request.authorization
        if auth is None or not auth.username or not auth.password:
            return None
        if ab_security_manager.auth_type == AUTH_LDAP:
            user = ab_security_manager.auth_user_ldap(auth.username, auth.password)
        if ab_security_manager.auth_type == AUTH_DB:
            user = ab_security_manager.auth_user_db(auth.username, auth.password)
    if user is not None:
        log.info("user: {0}".format(user))
        login_user(user, remember=False)
    return user

def requires_authentication(function: T):
    """Decorator for functions that require authentication"""
    
    @wraps(function)
    def decorated(*args, **kwargs):
        if auth_current_user() is not None:
            return function(*args, **kwargs)
        else:
            return Response("Unauthorized", 401, {"WWW-Authenticate": "Basic"})
    return cast(T, decorated)