• Language: en

Source code for django.contrib.auth

import inspect
import re
import warnings

from django.apps import apps as django_apps
from django.conf import settings
from django.core.exceptions import ImproperlyConfigured, PermissionDenied
from django.middleware.csrf import rotate_token
from django.utils.crypto import constant_time_compare
from django.utils.deprecation import RemovedInDjango21Warning
from django.utils.module_loading import import_string
from django.utils.translation import LANGUAGE_SESSION_KEY

from .signals import user_logged_in, user_logged_out, user_login_failed

SESSION_KEY = '_auth_user_id'
BACKEND_SESSION_KEY = '_auth_user_backend'
HASH_SESSION_KEY = '_auth_user_hash'
REDIRECT_FIELD_NAME = 'next'


def load_backend(path):
    return import_string(path)()


def _get_backends(return_tuples=False):
    backends = []
    for backend_path in settings.AUTHENTICATION_BACKENDS:
        backend = load_backend(backend_path)
        backends.append((backend, backend_path) if return_tuples else backend)
    if not backends:
        raise ImproperlyConfigured(
            'No authentication backends have been defined. Does '
            'AUTHENTICATION_BACKENDS contain anything?'
        )
    return backends


def get_backends():
    return _get_backends(return_tuples=False)


def _clean_credentials(credentials):
    """
    Clean a dictionary of credentials of potentially sensitive info before
    sending to less secure functions.

    Not comprehensive - intended for user_login_failed signal
    """
    SENSITIVE_CREDENTIALS = re.compile('api|token|key|secret|password|signature', re.I)
    CLEANSED_SUBSTITUTE = '********************'
    for key in credentials:
        if SENSITIVE_CREDENTIALS.search(key):
            credentials[key] = CLEANSED_SUBSTITUTE
    return credentials


def _get_user_session_key(request):
    # This value in the session is always serialized to a string, so we need
    # to convert it back to Python whenever we access it.
    return get_user_model()._meta.pk.to_python(request.session[SESSION_KEY])


[docs]def authenticate(request=None, **credentials): """ If the given credentials are valid, return a User object. """ for backend, backend_path in _get_backends(return_tuples=True): try: user = _authenticate_with_backend(backend, backend_path, request, credentials) except PermissionDenied: # This backend says to stop in our tracks - this user should not be allowed in at all. break if user is None: continue # Annotate the user object with the path of the backend. user.backend = backend_path return user # The credentials supplied are invalid to all backends, fire signal user_login_failed.send(sender=__name__, credentials=_clean_credentials(credentials), request=request)
def _authenticate_with_backend(backend, backend_path, request, credentials): args = (request,) # Does the backend accept a request argument? try: inspect.getcallargs(backend.authenticate, request, **credentials) except TypeError: args = () credentials.pop('request', None) # Does the backend accept a request keyword argument? try: inspect.getcallargs(backend.authenticate, request=request, **credentials) except TypeError: # Does the backend accept credentials without request? try: inspect.getcallargs(backend.authenticate, **credentials) except TypeError: # This backend doesn't accept these credentials as arguments. Try the next one. return None else: warnings.warn( "Update %s.authenticate() to accept a positional " "`request` argument." % backend_path, RemovedInDjango21Warning ) else: credentials['request'] = request warnings.warn( "In %s.authenticate(), move the `request` keyword argument " "to the first positional argument." % backend_path, RemovedInDjango21Warning ) return backend.authenticate(*args, **credentials)
[docs]def login(request, user, backend=None): """ Persist a user id and a backend in the request. This way a user doesn't have to reauthenticate on every request. Note that data set during the anonymous session is retained when the user logs in. """ session_auth_hash = '' if user is None: user = request.user if hasattr(user, 'get_session_auth_hash'): session_auth_hash = user.get_session_auth_hash() if SESSION_KEY in request.session: if _get_user_session_key(request) != user.pk or ( session_auth_hash and not constant_time_compare(request.session.get(HASH_SESSION_KEY, ''), session_auth_hash)): # To avoid reusing another user's session, create a new, empty # session if the existing session corresponds to a different # authenticated user. request.session.flush() else: request.session.cycle_key() try: backend = backend or user.backend except AttributeError: backends = _get_backends(return_tuples=True) if len(backends) == 1: _, backend = backends[0] else: raise ValueError( 'You have multiple authentication backends configured and ' 'therefore must provide the `backend` argument or set the ' '`backend` attribute on the user.' ) request.session[SESSION_KEY] = user._meta.pk.value_to_string(user) request.session[BACKEND_SESSION_KEY] = backend request.session[HASH_SESSION_KEY] = session_auth_hash if hasattr(request, 'user'): request.user = user rotate_token(request) user_logged_in.send(sender=user.__class__, request=request, user=user)
[docs]def logout(request): """ Remove the authenticated user's ID from the request and flush their session data. """ # Dispatch the signal before the user is logged out so the receivers have a # chance to find out *who* logged out. user = getattr(request, 'user', None) if hasattr(user, 'is_authenticated') and not user.is_authenticated: user = None user_logged_out.send(sender=user.__class__, request=request, user=user) # remember language choice saved to session language = request.session.get(LANGUAGE_SESSION_KEY) request.session.flush() if language is not None: request.session[LANGUAGE_SESSION_KEY] = language if hasattr(request, 'user'): from django.contrib.auth.models import AnonymousUser request.user = AnonymousUser()
[docs]def get_user_model(): """ Return the User model that is active in this project. """ try: return django_apps.get_model(settings.AUTH_USER_MODEL, require_ready=False) except ValueError: raise ImproperlyConfigured("AUTH_USER_MODEL must be of the form 'app_label.model_name'") except LookupError: raise ImproperlyConfigured( "AUTH_USER_MODEL refers to model '%s' that has not been installed" % settings.AUTH_USER_MODEL )
[docs]def get_user(request): """ Return the user model instance associated with the given request session. If no user is retrieved, return an instance of `AnonymousUser`. """ from .models import AnonymousUser user = None try: user_id = _get_user_session_key(request) backend_path = request.session[BACKEND_SESSION_KEY] except KeyError: pass else: if backend_path in settings.AUTHENTICATION_BACKENDS: backend = load_backend(backend_path) user = backend.get_user(user_id) # Verify the session if hasattr(user, 'get_session_auth_hash'): session_hash = request.session.get(HASH_SESSION_KEY) session_hash_verified = session_hash and constant_time_compare( session_hash, user.get_session_auth_hash() ) if not session_hash_verified: request.session.flush() user = None return user or AnonymousUser()
def get_permission_codename(action, opts): """ Return the codename of the permission for the specified action. """ return '%s_%s' % (action, opts.model_name)
[docs]def update_session_auth_hash(request, user): """ Updating a user's password logs out all sessions for the user. Take the current request and the updated user object from which the new session hash will be derived and update the session hash appropriately to prevent a password change from logging out the session from which the password was changed. """ request.session.cycle_key() if hasattr(user, 'get_session_auth_hash') and request.user == user: request.session[HASH_SESSION_KEY] = user.get_session_auth_hash()
default_app_config = 'django.contrib.auth.apps.AuthConfig'
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