This getter is usable for checking permissions of "create" methods, especially in combination with rest_framework_nested.
Real world example
------------------
In the example below, EducationAreaViewSet is nested inside the StudyProgrammeViewSet (study programme has many education areas). The url of the EducationAreaViewSet is:
/programmes/<programme_pk>/education-areas/...
We want all operations on EducationArea to be checked against the containing StudyProgramme.
To differentiate the actions (such as update) on EducationArea and on StudyProgramme in permission handlers defined on StudyProgramme we map all operations on EducationArea to a virtual 'edit_education_area' action and send this to StudyProgramme permissions instead. The mapping parameter can be a dict if one needs to differentiate the actions.
python
from rest_delegated_permissions import DelegatedPermission, kwargs_delegated_object_getter
from rest_framework_nested import routers
from angular_dynamic_forms import AngularFormMixin, autocomplete, AutoCompleteMixin
perms.apply(permissions=[
DelegatedPermission(perms, 'programmes', mapping='edit_education_area',
delegated_objects_getter=kwargs_delegated_object_getter(
{'programmes': 'programme_pk'}
)),
])
class EducationAreaViewSet(AutoCompleteMixin, AngularFormMixin, viewsets.ModelViewSet):
its 'programmes' m2m point to StudyProgramme model
model = EducationArea
serializer_class = EducationAreaSerializer
...
perms.apply(permissions=[
OpenIDPermission('http://vscht.cz/openidpermission-studyprogrammes-edit',
perms={..., 'edit_education_area', ...}),
OwnerPermission(owner_username_path='studyprogrammepersonrole__person__user__username',
extra_filter=Q(studyprogrammepersonrole__role__in=(
StudyProgrammePersonRole.GUARANTEE,
StudyProgrammePersonRole.COOPERATING
)),
perms={... 'edit_education_area' ...})
AuthenticatedReadPermission()
])
class StudyProgrammeViewSet(...)
...
programmes_router = DefaultRouter()
programmes_router.register(r'programmes', StudyProgrammeViewSet)
education_area_router = routers.NestedSimpleRouter(programmes_router,
r'accreditations/study_programme/programmes', lookup='programme')
education_area_router.register(r'education-areas', EducationAreaViewSet,
base_name='study-programmes-education-areas')