from datetime import datetime from datetime import timedelta import hashlib from flask import abort from flask import current_app from flask import flash from flask import g from flask import has_app_context from flask import redirect from flask import request from flask import session from itsdangerous import URLSafeSerializer from flask.json.tag import TaggedJSONSerializer from .config import AUTH_HEADER_NAME from .config import COOKIE_DURATION from .config import COOKIE_HTTPONLY from .config import COOKIE_NAME from .config import COOKIE_SAMESITE from .config import COOKIE_SECURE from .config import ID_ATTRIBUTE from .config import LOGIN_MESSAGE from .config import LOGIN_MESSAGE_CATEGORY from .config import REFRESH_MESSAGE from .config import REFRESH_MESSAGE_CATEGORY from .config import SESSION_KEYS from .config import USE_SESSION_FOR_NEXT from .mixins import AnonymousUserMixin from .signals import session_protected from .signals import user_accessed from .signals import user_loaded_from_cookie from .signals import user_loaded_from_request from .signals import user_needs_refresh from .signals import user_unauthorized from .utils import _create_identifier from .utils import _user_context_processor from .utils import confirm_login from .utils import expand_login_view from .utils import login_url as make_login_url from .utils import make_next_param class LoginManager: """This object is used to hold the settings used for logging in. Instances of :class:`LoginManager` are *not* bound to specific apps, so you can create one in the main body of your code and then bind it to your app in a factory function. """ def __init__(self, app=None, add_context_processor=True): #: A class or factory function that produces an anonymous user, which #: is used when no one is logged in. self.anonymous_user = AnonymousUserMixin #: The name of the view to redirect to when the user needs to log in. #: (This can be an absolute URL as well, if your authentication #: machinery is external to your application.) self.login_view = None #: Names of views to redirect to when the user needs to log in, #: per blueprint. If the key value is set to None the value of #: :attr:`login_view` will be used instead. self.blueprint_login_views = {} #: The message to flash when a user is redirected to the login page. self.login_message = LOGIN_MESSAGE #: The message category to flash when a user is redirected to the login #: page. self.login_message_category = LOGIN_MESSAGE_CATEGORY #: The name of the view to redirect to when the user needs to #: reauthenticate. self.refresh_view = None #: The message to flash when a user is redirected to the 'needs #: refresh' page. self.needs_refresh_message = REFRESH_MESSAGE #: The message category to flash when a user is redirected to the #: 'needs refresh' page. self.needs_refresh_message_category = REFRESH_MESSAGE_CATEGORY #: The mode to use session protection in. This can be either #: ``'basic'`` (the default) or ``'strong'``, or ``None`` to disable #: it. self.session_protection = "basic" #: If present, used to translate flash messages ``self.login_message`` #: and ``self.needs_refresh_message`` self.localize_callback = None self.unauthorized_callback = None self.needs_refresh_callback = None self.id_attribute = ID_ATTRIBUTE self._user_callback = None self._header_callback = None self._request_callback = None self._session_identifier_generator = _create_identifier if app is not None: self.init_app(app, add_context_processor) def setup_app(self, app, add_context_processor=True): # pragma: no cover """ This method has been deprecated. Please use :meth:`LoginManager.init_app` instead. """ import warnings warnings.warn( "'setup_app' is deprecated and will be removed in" " Flask-Login 0.7. Use 'init_app' instead.", DeprecationWarning, stacklevel=2, ) self.init_app(app, add_context_processor) def init_app(self, app, add_context_processor=True): """ Configures an application. This registers an `after_request` call, and attaches this `LoginManager` to it as `app.login_manager`. :param app: The :class:`flask.Flask` object to configure. :type app: :class:`flask.Flask` :param add_context_processor: Whether to add a context processor to the app that adds a `current_user` variable to the template. Defaults to ``True``. :type add_context_processor: bool """ app.login_manager = self app.after_request(self._update_remember_cookie) if add_context_processor: app.context_processor(_user_context_processor) def unauthorized(self): """ This is called when the user is required to log in. If you register a callback with :meth:`LoginManager.unauthorized_handler`, then it will be called. Otherwise, it will take the following actions: - Flash :attr:`LoginManager.login_message` to the user. - If the app is using blueprints find the login view for the current blueprint using `blueprint_login_views`. If the app is not using blueprints or the login view for the current blueprint is not specified use the value of `login_view`. - Redirect the user to the login view. (The page they were attempting to access will be passed in the ``next`` query string variable, so you can redirect there if present instead of the homepage. Alternatively, it will be added to the session as ``next`` if USE_SESSION_FOR_NEXT is set.) If :attr:`LoginManager.login_view` is not defined, then it will simply raise a HTTP 401 (Unauthorized) error instead. This should be returned from a view or before/after_request function, otherwise the redirect will have no effect. """ user_unauthorized.send(current_app._get_current_object()) if self.unauthorized_callback: return self.unauthorized_callback() if request.blueprint in self.blueprint_login_views: login_view = self.blueprint_login_views[request.blueprint] else: login_view = self.login_view if not login_view: abort(401) if self.login_message: if self.localize_callback is not None: flash( self.localize_callback(self.login_message), category=self.login_message_category, ) else: flash(self.login_message, category=self.login_message_category) config = current_app.config if config.get("USE_SESSION_FOR_NEXT", USE_SESSION_FOR_NEXT): login_url = expand_login_view(login_view) session["_id"] = self._session_identifier_generator() session["next"] = make_next_param(login_url, request.url) redirect_url = make_login_url(login_view) else: redirect_url = make_login_url(login_view, next_url=request.url) return redirect(redirect_url) def user_loader(self, callback): """ This sets the callback for reloading a user from the session. The function you set should take a user ID (a ``str``) and return a user object, or ``None`` if the user does not exist. :param callback: The callback for retrieving a user object. :type callback: callable """ self._user_callback = callback return self.user_callback @property def user_callback(self): """Gets the user_loader callback set by user_loader decorator.""" return self._user_callback def request_loader(self, callback): """ This sets the callback for loading a user from a Flask request. The function you set should take Flask request object and return a user object, or `None` if the user does not exist. :param callback: The callback for retrieving a user object. :type callback: callable """ self._request_callback = callback return self.request_callback @property def request_callback(self): """Gets the request_loader callback set by request_loader decorator.""" return self._request_callback def unauthorized_handler(self, callback): """ This will set the callback for the `unauthorized` method, which among other things is used by `login_required`. It takes no arguments, and should return a response to be sent to the user instead of their normal view. :param callback: The callback for unauthorized users. :type callback: callable """ self.unauthorized_callback = callback return callback def needs_refresh_handler(self, callback): """ This will set the callback for the `needs_refresh` method, which among other things is used by `fresh_login_required`. It takes no arguments, and should return a response to be sent to the user instead of their normal view. :param callback: The callback for unauthorized users. :type callback: callable """ self.needs_refresh_callback = callback return callback def needs_refresh(self): """ This is called when the user is logged in, but they need to be reauthenticated because their session is stale. If you register a callback with `needs_refresh_handler`, then it will be called. Otherwise, it will take the following actions: - Flash :attr:`LoginManager.needs_refresh_message` to the user. - Redirect the user to :attr:`LoginManager.refresh_view`. (The page they were attempting to access will be passed in the ``next`` query string variable, so you can redirect there if present instead of the homepage.) If :attr:`LoginManager.refresh_view` is not defined, then it will simply raise a HTTP 401 (Unauthorized) error instead. This should be returned from a view or before/after_request function, otherwise the redirect will have no effect. """ user_needs_refresh.send(current_app._get_current_object()) if self.needs_refresh_callback: return self.needs_refresh_callback() if not self.refresh_view: abort(401) if self.needs_refresh_message: if self.localize_callback is not None: flash( self.localize_callback(self.needs_refresh_message), category=self.needs_refresh_message_category, ) else: flash( self.needs_refresh_message, category=self.needs_refresh_message_category, ) config = current_app.config if config.get("USE_SESSION_FOR_NEXT", USE_SESSION_FOR_NEXT): login_url = expand_login_view(self.refresh_view) session["_id"] = self._session_identifier_generator() session["next"] = make_next_param(login_url, request.url) redirect_url = make_login_url(self.refresh_view) else: login_url = self.refresh_view redirect_url = make_login_url(login_url, next_url=request.url) return redirect(redirect_url) def _update_request_context_with_user(self, user=None): """Store the given user as ctx.user.""" if user is None: user = self.anonymous_user() g._login_user = user def _load_user(self): """Loads user from session or remember_me cookie as applicable""" if self._user_callback is None and self._request_callback is None: raise Exception( "Missing user_loader or request_loader. Refer to " "https://flask-login.readthedocs.io/#how-it-works " "for more info." ) user_accessed.send(current_app._get_current_object()) # Check SESSION_PROTECTION if self._session_protection_failed(): return self._update_request_context_with_user() user = None # Load user from Flask Session user_id = session.get("_user_id") user_random = session.get("_random") user_session_key = session.get("_id") if (user_id is not None and user_random is not None and user_session_key is not None and self._user_callback is not None): user = self._user_callback(user_id, user_random, user_session_key) # Load user from Remember Me Cookie or Request Loader if user is None: config = current_app.config cookie_name = config.get("REMEMBER_COOKIE_NAME", COOKIE_NAME) header_name = config.get("AUTH_HEADER_NAME", AUTH_HEADER_NAME) has_cookie = ( cookie_name in request.cookies and session.get("_remember") != "clear" ) if has_cookie: cookie = request.cookies[cookie_name] user = self._load_user_from_remember_cookie(cookie) elif self._request_callback: user = self._load_user_from_request(request) elif header_name in request.headers: header = request.headers[header_name] user = self._load_user_from_header(header) if not user: self._update_request_context_with_user() return self._update_request_context_with_user(user) def _session_protection_failed(self): sess = session._get_current_object() ident = self._session_identifier_generator() app = current_app._get_current_object() mode = app.config.get("SESSION_PROTECTION", self.session_protection) if not mode or mode not in ["basic", "strong"]: return False # if the sess is empty, it's an anonymous user or just logged out # so we can skip this if sess and ident != sess.get("_id", None): if mode == "basic" or sess.permanent: if sess.get("_fresh") is not False: sess["_fresh"] = False session_protected.send(app) return False elif mode == "strong": for k in SESSION_KEYS: sess.pop(k, None) sess["_remember"] = "clear" session_protected.send(app) return True return False def _load_user_from_remember_cookie(self, cookie): signer_kwargs = dict( key_derivation="hmac", digest_method=staticmethod(hashlib.sha1) ) try: remember_dict = URLSafeSerializer( current_app.secret_key, salt="remember", serializer=TaggedJSONSerializer(), signer_kwargs=signer_kwargs, ).loads(cookie) except Exception: return None if remember_dict['user'] is not None: session["_user_id"] = remember_dict['user'] if "_random" not in session: session["_random"] = remember_dict['random'] session["_fresh"] = False user = None if self._user_callback: user = self._user_callback(remember_dict['user'], session["_random"], None) if user is not None: app = current_app._get_current_object() user_loaded_from_cookie.send(app, user=user) # if session was restored from remember me cookie make login valid confirm_login() return user return None def _load_user_from_header(self, header): if self._header_callback: user = self._header_callback(header) if user is not None: app = current_app._get_current_object() from .signals import _user_loaded_from_header _user_loaded_from_header.send(app, user=user) return user return None def _load_user_from_request(self, request): if self._request_callback: user = self._request_callback(request) if user is not None: app = current_app._get_current_object() user_loaded_from_request.send(app, user=user) return user return None def _update_remember_cookie(self, response): # Don't modify the session unless there's something to do. if "_remember" not in session and current_app.config.get( "REMEMBER_COOKIE_REFRESH_EACH_REQUEST" ): session["_remember"] = "set" if "_remember" in session: operation = session.pop("_remember", None) if operation == "set" and "_user_id" in session: self._set_cookie(response) elif operation == "clear": self._clear_cookie(response) return response def _set_cookie(self, response): # cookie settings config = current_app.config cookie_name = config.get("REMEMBER_COOKIE_NAME", COOKIE_NAME) domain = config.get("REMEMBER_COOKIE_DOMAIN") path = config.get("REMEMBER_COOKIE_PATH", "/") secure = config.get("REMEMBER_COOKIE_SECURE", COOKIE_SECURE) httponly = config.get("REMEMBER_COOKIE_HTTPONLY", COOKIE_HTTPONLY) samesite = config.get("REMEMBER_COOKIE_SAMESITE", COOKIE_SAMESITE) if "_remember_seconds" in session: duration = timedelta(seconds=session["_remember_seconds"]) else: duration = config.get("REMEMBER_COOKIE_DURATION", COOKIE_DURATION) # prepare data max_age = int(current_app.permanent_session_lifetime.total_seconds()) signer_kwargs = dict( key_derivation="hmac", digest_method=staticmethod(hashlib.sha1) ) # save data = URLSafeSerializer( current_app.secret_key, salt="remember", serializer=TaggedJSONSerializer(), signer_kwargs=signer_kwargs, ).dumps({"user":session["_user_id"], "random":session["_random"]}) if isinstance(duration, int): duration = timedelta(seconds=duration) try: expires = datetime.utcnow() + duration except TypeError as e: raise Exception( "REMEMBER_COOKIE_DURATION must be a datetime.timedelta," f" instead got: {duration}" ) from e # actually set it response.set_cookie( cookie_name, value=data, expires=expires, domain=domain, path=path, secure=secure, httponly=httponly, samesite=samesite, ) def _clear_cookie(self, response): config = current_app.config cookie_name = config.get("REMEMBER_COOKIE_NAME", COOKIE_NAME) domain = config.get("REMEMBER_COOKIE_DOMAIN") path = config.get("REMEMBER_COOKIE_PATH", "/") response.delete_cookie(cookie_name, domain=domain, path=path) @property def _login_disabled(self): """Legacy property, use app.config['LOGIN_DISABLED'] instead.""" import warnings warnings.warn( "'_login_disabled' is deprecated and will be removed in" " Flask-Login 0.7. Use 'LOGIN_DISABLED' in 'app.config'" " instead.", DeprecationWarning, stacklevel=2, ) if has_app_context(): return current_app.config.get("LOGIN_DISABLED", False) return False @_login_disabled.setter def _login_disabled(self, newvalue): """Legacy property setter, use app.config['LOGIN_DISABLED'] instead.""" import warnings warnings.warn( "'_login_disabled' is deprecated and will be removed in" " Flask-Login 0.7. Use 'LOGIN_DISABLED' in 'app.config'" " instead.", DeprecationWarning, stacklevel=2, ) current_app.config["LOGIN_DISABLED"] = newvalue