from django.apps import apps from django.conf import settings from django.contrib.auth import REDIRECT_FIELD_NAME from django.db.models import Model from django.db.models.base import ModelBase from django.db.models.query import QuerySet from django.shortcuts import get_object_or_404 from django.utils.functional import wraps from guardian.exceptions import GuardianError from guardian.utils import get_40x_or_None def permission_required(perm, lookup_variables=None, **kwargs): """ Decorator for views that checks whether a user has a particular permission enabled. Optionally, instances for which check should be made may be passed as an second argument or as a tuple parameters same as those passed to ``get_object_or_404`` but must be provided as pairs of strings. This way decorator can fetch i.e. ``User`` instance based on performed request and check permissions on it (without this, one would need to fetch user instance at view's logic and check permission inside a view). :param login_url: if denied, user would be redirected to location set by this parameter. Defaults to ``django.conf.settings.LOGIN_URL``. :param redirect_field_name: name of the parameter passed if redirected. Defaults to ``django.contrib.auth.REDIRECT_FIELD_NAME``. :param return_403: if set to ``True`` then instead of redirecting to the login page, response with status code 403 is returned ( ``django.http.HttpResponseForbidden`` instance or rendered template - see :setting:`GUARDIAN_RENDER_403`). Defaults to ``False``. :param return_404: if set to ``True`` then instead of redirecting to the login page, response with status code 404 is returned ( ``django.http.HttpResponseNotFound`` instance or rendered template - see :setting:`GUARDIAN_RENDER_404`). Defaults to ``False``. :param accept_global_perms: if set to ``True``, then *object level permission* would be required **only if user does NOT have global permission** for target *model*. If turned on, makes this decorator like an extension over standard ``django.contrib.admin.decorators.permission_required`` as it would check for global permissions first. Defaults to ``False``. Examples:: @permission_required('auth.change_user', return_403=True) def my_view(request): return HttpResponse('Hello') @permission_required('auth.change_user', (User, 'username', 'username')) def my_view(request, username): ''' auth.change_user permission would be checked based on given 'username'. If view's parameter would be named ``name``, we would rather use following decorator:: @permission_required('auth.change_user', (User, 'username', 'name')) ''' user = get_object_or_404(User, username=username) return user.get_absolute_url() @permission_required('auth.change_user', (User, 'username', 'username', 'groups__name', 'group_name')) def my_view(request, username, group_name): ''' Similar to the above example, here however we also make sure that one of user's group is named same as request's ``group_name`` param. ''' user = get_object_or_404(User, username=username, group__name=group_name) return user.get_absolute_url() """ login_url = kwargs.pop('login_url', settings.LOGIN_URL) redirect_field_name = kwargs.pop( 'redirect_field_name', REDIRECT_FIELD_NAME) return_403 = kwargs.pop('return_403', False) return_404 = kwargs.pop('return_404', False) accept_global_perms = kwargs.pop('accept_global_perms', False) # Check if perm is given as string in order not to decorate # view function itself which makes debugging harder if not isinstance(perm, str): raise GuardianError("First argument must be in format: " "'app_label.codename or a callable which return similar string'") def decorator(view_func): def _wrapped_view(request, *args, **kwargs): # if more than one parameter is passed to the decorator we try to # fetch object for which check would be made obj = None if lookup_variables: model, lookups = lookup_variables[0], lookup_variables[1:] # Parse model if isinstance(model, str): splitted = model.split('.') if len(splitted) != 2: raise GuardianError("If model should be looked up from " "string it needs format: 'app_label.ModelClass'") model = apps.get_model(*splitted) elif issubclass(model.__class__, (Model, ModelBase, QuerySet)): pass else: raise GuardianError("First lookup argument must always be " "a model, string pointing at app/model or queryset. " "Given: %s (type: %s)" % (model, type(model))) # Parse lookups if len(lookups) % 2 != 0: raise GuardianError("Lookup variables must be provided " "as pairs of lookup_string and view_arg") lookup_dict = {} for lookup, view_arg in zip(lookups[::2], lookups[1::2]): if view_arg not in kwargs: raise GuardianError("Argument %s was not passed " "into view function" % view_arg) lookup_dict[lookup] = kwargs[view_arg] obj = get_object_or_404(model, **lookup_dict) response = get_40x_or_None(request, perms=[perm], obj=obj, login_url=login_url, redirect_field_name=redirect_field_name, return_403=return_403, return_404=return_404, accept_global_perms=accept_global_perms) if response: return response return view_func(request, *args, **kwargs) return wraps(view_func)(_wrapped_view) return decorator def permission_required_or_403(perm, *args, **kwargs): """ Simple wrapper for permission_required decorator. Standard Django's permission_required decorator redirects user to login page in case permission check failed. This decorator may be used to return HttpResponseForbidden (status 403) instead of redirection. The only difference between ``permission_required`` decorator is that this one always set ``return_403`` parameter to ``True``. """ kwargs['return_403'] = True return permission_required(perm, *args, **kwargs) def permission_required_or_404(perm, *args, **kwargs): """ Simple wrapper for permission_required decorator. Standard Django's permission_required decorator redirects user to login page in case permission check failed. This decorator may be used to return HttpResponseNotFound (status 404) instead of redirection. The only difference between ``permission_required`` decorator is that this one always set ``return_404`` parameter to ``True``. """ kwargs['return_404'] = True return permission_required(perm, *args, **kwargs)