import warnings
from datetime import datetime
from datetime import timedelta
from flask import _request_ctx_stack
from flask import abort
from flask import current_app
from flask import flash
from flask import has_app_context
from flask import redirect
from flask import request
from flask import session
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_header
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 decode_cookie
from .utils import encode_cookie
from .utils import expand_login_view
from .utils import login_url as make_login_url
from .utils import make_next_param
[docs]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)
[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)
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["_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)
[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 ``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
[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.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."""
ctx = _request_ctx_stack.top
ctx.user = self.anonymous_user() if user is None else 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 "
"http://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")
if user_id is not None and self._user_callback is not None:
user = self._user_callback(user_id)
# 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)
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):
user_id = decode_cookie(cookie)
if user_id is not None:
session["_user_id"] = user_id
session["_fresh"] = False
user = None
if self._user_callback:
user = self._user_callback(user_id)
if user is not None:
app = current_app._get_current_object()
user_loaded_from_cookie.send(app, user=user)
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()
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
data = encode_cookie(str(session["_user_id"]))
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."""
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."""
current_app.config["LOGIN_DISABLED"] = newvalue
