Source code for permission.backends

# coding=utf-8
"""
Logical permission backends module
"""
from permission.conf import settings
from permission.utils.handlers import registry
from permission.utils.permissions import perm_to_permission

__all__ = ("PermissionBackend",)


[docs]class PermissionBackend(object): """ A handler based permission backend """ supports_object_permissions = True supports_anonymous_user = True supports_inactive_user = True # pylint:disable=unused-argument
[docs] def authenticate(self, username, password): """ Always return ``None`` to prevent authentication within this backend. """ return None
[docs] def has_perm(self, user_obj, perm, obj=None): """ Check if user have permission (of object) based on registered handlers. It will raise ``ObjectDoesNotExist`` exception when the specified string permission does not exist and ``PERMISSION_CHECK_PERMISSION_PRESENCE`` is ``True`` in ``settings`` module. Parameters ---------- user_obj : django user model instance A django user model instance which be checked perm : string `app_label.codename` formatted permission string obj : None or django model instance None or django model instance for object permission Returns ------- boolean Whether the specified user have specified permission (of specified object). Raises ------ django.core.exceptions.ObjectDoesNotExist If the specified string permission does not exist and ``PERMISSION_CHECK_PERMISSION_PRESENCE`` is ``True`` in ``settings`` module. """ if settings.PERMISSION_CHECK_PERMISSION_PRESENCE: # get permission instance from string permission (perm) # it raise ObjectDoesNotExists when the permission is not exists try: perm_to_permission(perm) except AttributeError: # Django 1.2 internally use wrong permission string thus ignore pass # get permission handlers fot this perm cache_name = "_%s_cache" % perm if hasattr(self, cache_name): handlers = getattr(self, cache_name) else: handlers = [ h for h in registry.get_handlers() if perm in h.get_supported_permissions() ] setattr(self, cache_name, handlers) for handler in handlers: if handler.has_perm(user_obj, perm, obj=obj): return True return False
[docs] def has_module_perms(self, user_obj, app_label): """ Check if user have permission of specified app based on registered handlers. It will raise ``ObjectDoesNotExist`` exception when the specified string permission does not exist and ``PERMISSION_CHECK_PERMISSION_PRESENCE`` is ``True`` in ``settings`` module. Parameters ---------- user_obj : django user model instance A django user model instance which is checked app_label : string `app_label.codename` formatted permission string Returns ------- boolean Whether the specified user have specified permission. Raises ------ django.core.exceptions.ObjectDoesNotExist If the specified string permission does not exist and ``PERMISSION_CHECK_PERMISSION_PRESENCE`` is ``True`` in ``settings`` module. """ # get permission handlers fot this perm cache_name = "_%s_cache" % app_label if hasattr(self, cache_name): handlers = getattr(self, cache_name) else: handlers = [ h for h in registry.get_handlers() if app_label in h.get_supported_app_labels() ] setattr(self, cache_name, handlers) for handler in handlers: if handler.has_module_perms(user_obj, app_label): return True return False