Source code for flask_login.login_manager

# -*- coding: utf-8 -*-
'''
    flask_login.login_manager
    -------------------------
    The LoginManager class.
'''


import warnings
from datetime import datetime

from flask import (_request_ctx_stack, abort, current_app, flash, redirect,
                   request, session)

from ._compat import text_type
from .config import (COOKIE_NAME, COOKIE_DURATION, COOKIE_SECURE,
                     COOKIE_HTTPONLY, LOGIN_MESSAGE, LOGIN_MESSAGE_CATEGORY,
                     REFRESH_MESSAGE, REFRESH_MESSAGE_CATEGORY, ID_ATTRIBUTE,
                     AUTH_HEADER_NAME, SESSION_KEYS, USE_SESSION_FOR_NEXT)
from .mixins import AnonymousUserMixin
from .signals import (user_loaded_from_cookie, user_loaded_from_header,
                      user_loaded_from_request, user_unauthorized,
                      user_needs_refresh, user_accessed, session_protected)
from .utils import (_get_user, login_url as make_login_url, _create_identifier,
                    _user_context_processor, encode_cookie, decode_cookie,
                    make_next_param, expand_login_view)


[docs]class LoginManager(object): '''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.user_callback = None self.unauthorized_callback = None self.needs_refresh_callback = None self.id_attribute = ID_ATTRIBUTE 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)
[docs] def setup_app(self, app, add_context_processor=True): # pragma: no cover ''' This method has been deprecated. Please use :meth:`LoginManager.init_app` instead. ''' warnings.warn('Warning setup_app is deprecated. Please use init_app.', DeprecationWarning) 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) self._login_disabled = app.config.get('LOGIN_DISABLED', False) if add_context_processor: app.context_processor(_user_context_processor)
[docs] 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['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)
[docs] 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 ``unicode``) 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 callback
[docs] def header_loader(self, callback): ''' This function has been deprecated. Please use :meth:`LoginManager.request_loader` instead. This sets the callback for loading a user from a header value. The function you set should take an authentication token 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.header_callback = callback return 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 callback
[docs] 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
[docs] 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
[docs] 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.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['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 reload_user(self, user=None): ctx = _request_ctx_stack.top if user is None: user_id = session.get('user_id') if user_id is None: ctx.user = self.anonymous_user() else: if self.user_callback is None: raise Exception( "No user_loader has been installed for this " "LoginManager. Add one with the " "'LoginManager.user_loader' decorator.") user = self.user_callback(user_id) if user is None: ctx.user = self.anonymous_user() else: ctx.user = user else: ctx.user = user def _load_user(self): '''Loads user from session or remember_me cookie as applicable''' user_accessed.send(current_app._get_current_object()) # first check SESSION_PROTECTION config = current_app.config if config.get('SESSION_PROTECTION', self.session_protection): deleted = self._session_protection() if deleted: return self.reload_user() # If a remember cookie is set, and the session is not, move the # cookie user ID to the session. # # However, the session may have been set if the user has been # logged out on this request, 'remember' would be set to clear, # so we should check for that and not restore the session. is_missing_user_id = 'user_id' not in session if is_missing_user_id: 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: return self._load_from_cookie(request.cookies[cookie_name]) elif self.request_callback: return self._load_from_request(request) elif header_name in request.headers: return self._load_from_header(request.headers[header_name]) return self.reload_user() def _session_protection(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 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: 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_from_cookie(self, cookie): user_id = decode_cookie(cookie) if user_id is not None: session['user_id'] = user_id session['_fresh'] = False self.reload_user() if _request_ctx_stack.top.user is not None: app = current_app._get_current_object() user_loaded_from_cookie.send(app, user=_get_user()) def _load_from_header(self, header): user = None if self.header_callback: user = self.header_callback(header) if user is not None: self.reload_user(user=user) app = current_app._get_current_object() user_loaded_from_header.send(app, user=_get_user()) else: self.reload_user() def _load_from_request(self, request): user = None if self.request_callback: user = self.request_callback(request) if user is not None: self.reload_user(user=user) app = current_app._get_current_object() user_loaded_from_request.send(app, user=_get_user()) else: self.reload_user() def _update_remember_cookie(self, response): # Don't modify the session unless there's something to do. 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) duration = config.get('REMEMBER_COOKIE_DURATION', COOKIE_DURATION) 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) # prepare data data = encode_cookie(text_type(session['user_id'])) try: expires = datetime.utcnow() + duration except TypeError: raise Exception('REMEMBER_COOKIE_DURATION must be a ' + 'datetime.timedelta, instead got: {0}'.format( duration)) # actually set it response.set_cookie(cookie_name, value=data, expires=expires, domain=domain, path=path, secure=secure, httponly=httponly) 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)