def create_view(self, callback, method, request=None):
"""
customized create_view which is called when all routes are traversed. part of this
is instantiating views with default params. in case of custom routes (@action) the
custom AutoSchema is injected properly through 'initkwargs' on view. However, when
decorating plain views like retrieve, this initialization logic is not running.
Therefore forcefully set the schema if @extend_schema decorator was used.
"""
override_view = OpenApiViewExtension.get_match(callback.cls)
if override_view:
callback.cls = override_view.view_replacement()
view = super().create_view(callback, method, request)
if isinstance(view, viewsets.GenericViewSet) or isinstance(
view, viewsets.ViewSet):
action = getattr(view, view.action)
elif isinstance(view, views.APIView):
action = getattr(view, method.lower())
else:
error(
'Using not supported View class. Class must be derived from APIView '
'or any of its subclasses like GenericApiView, GenericViewSet.'
)
return view
# in case of @extend_schema, manually init custom schema class here due to
# weakref reverse schema.view bug for multi annotations.
schema = getattr(action, 'kwargs', {}).get('schema', None)
if schema and inspect.isclass(schema):
view.schema = schema()
return view
def _map_model_field(self, model_field, direction):
assert isinstance(model_field, models.Field)
# to get a fully initialized serializer field we use DRF's own init logic
try:
field_cls, field_kwargs = serializers.ModelSerializer().build_field(
field_name=model_field.name,
info=get_field_info(model_field.model),
model_class=model_field.model,
nested_depth=0,
)
field = field_cls(**field_kwargs)
except: # noqa
field = None
# For some cases, the DRF init logic either breaks (custom field with internal type) or
# the resulting field is underspecified with regards to the schema (ReadOnlyField).
if field and not anyisinstance(field, [serializers.ReadOnlyField, serializers.ModelField]):
return self._map_serializer_field(field, direction)
elif isinstance(model_field, models.ForeignKey):
return self._map_model_field(model_field.target_field, direction)
elif hasattr(models, model_field.get_internal_type()):
# be graceful when the model field is not explicitly mapped to a serializer
internal_type = getattr(models, model_field.get_internal_type())
field_cls = serializers.ModelSerializer.serializer_field_mapping[internal_type]
return self._map_serializer_field(field_cls(), direction)
else:
error(
f'could not resolve model field "{model_field}". failed to resolve through '
f'serializer_field_mapping, get_internal_type(), or any override mechanism. '
f'defaulting to "string"'
)
return build_basic_type(OpenApiTypes.STR)
def create_view(self, callback, method, request=None):
"""
customized create_view which is called when all routes are traversed. part of this
is instantiating views with default params. in case of custom routes (@action) the
custom AutoSchema is injected properly through 'initkwargs' on view. However, when
decorating plain views like retrieve, this initialization logic is not running.
Therefore forcefully set the schema if @extend_schema decorator was used.
"""
override_view = OpenApiViewExtension.get_match(callback.cls)
if override_view:
original_cls = callback.cls
callback.cls = override_view.view_replacement()
view = super().create_view(callback, method, request)
# callback.cls is hosted in urlpatterns and is therefore not an ephemeral modification.
# restore after view creation so potential revisits have a clean state as basis.
if override_view:
callback.cls = original_cls
if isinstance(view, viewsets.ViewSetMixin):
action = getattr(view, view.action)
elif isinstance(view, views.APIView):
action = getattr(view, method.lower())
else:
error(
'Using not supported View class. Class must be derived from APIView '
'or any of its subclasses like GenericApiView, GenericViewSet.'
)
return view
action_schema = getattr(action, 'kwargs', {}).get('schema', None)
if not action_schema:
# there is no method/action customized schema so we are done here.
return view
# action_schema is either a class or instance. when @extend_schema is used, it
# is always a class to prevent the weakref reverse "schema.view" bug for multi
# annotations. The bug is prevented by delaying the instantiation of the schema
# class until create_view (here) and not doing it immediately in @extend_schema.
action_schema_class = get_class(action_schema)
view_schema_class = get_class(callback.cls.schema)
if not issubclass(action_schema_class, view_schema_class):
# this handles the case of having a manually set custom AutoSchema on the
# view together with extend_schema. In most cases, the decorator mechanics
# prevent extend_schema from having access to the view's schema class. So
# extend_schema is forced to use DEFAULT_SCHEMA_CLASS as fallback base class
# instead of the correct base class set in view. We remedy this chicken-egg
# problem here by rearranging the class hierarchy.
mro = tuple(
cls for cls in action_schema_class.__mro__
if cls not in api_settings.DEFAULT_SCHEMA_CLASS.__mro__
) + view_schema_class.__mro__
action_schema_class = type('ExtendedRearrangedSchema', mro, {})
view.schema = action_schema_class()
return view
def _map_model_field(self, model_field, direction):
assert isinstance(model_field, models.Field)
# to get a fully initialized serializer field we use DRF's own init logic
try:
field_cls, field_kwargs = serializers.ModelSerializer(
).build_field(
field_name=model_field.name,
info=get_field_info(model_field.model),
model_class=model_field.model,
nested_depth=0,
)
field = field_cls(**field_kwargs)
except: # noqa
field = None
# For some cases, the DRF init logic either breaks (custom field with internal type) or
# the resulting field is underspecified with regards to the schema (ReadOnlyField).
if field and isinstance(field, serializers.PrimaryKeyRelatedField):
# special case handling only for _resolve_path_parameters() where neither queryset nor
# parent is set by build_field. patch in queryset as _map_serializer_field requires it
if not field.queryset:
field.queryset = model_field.related_model.objects.none()
return self._map_serializer_field(field, direction)
elif field and not anyisinstance(
field, [serializers.ReadOnlyField, serializers.ModelField]):
return self._map_serializer_field(field, direction)
elif isinstance(model_field, models.ForeignKey):
return self._map_model_field(model_field.target_field, direction)
elif hasattr(models, 'JSONField') and isinstance(
model_field, models.JSONField):
# fix for DRF==3.11 with django>=3.1 as it is not yet represented in the field_mapping
return build_basic_type(OpenApiTypes.OBJECT)
elif hasattr(models, model_field.get_internal_type()):
# be graceful when the model field is not explicitly mapped to a serializer
internal_type = getattr(models, model_field.get_internal_type())
field_cls = serializers.ModelSerializer.serializer_field_mapping.get(
internal_type)
if not field_cls:
warn(
f'model field "{model_field.get_internal_type()}" has no mapping in '
f'ModelSerializer. it may be a deprecated field. defaulting to "string"'
)
return build_basic_type(OpenApiTypes.STR)
return self._map_serializer_field(field_cls(), direction)
else:
error(
f'could not resolve model field "{model_field}". failed to resolve through '
f'serializer_field_mapping, get_internal_type(), or any override mechanism. '
f'defaulting to "string"')
return build_basic_type(OpenApiTypes.STR)
def _map_model_field(self, field):
assert isinstance(field, models.Field)
drf_mapping = serializers.ModelSerializer.serializer_field_mapping
if field.__class__ in drf_mapping:
# use DRF native field resolution - taken from ModelSerializer.get_fields()
return self._map_serializer_field(drf_mapping[field.__class__]())
elif isinstance(field, models.ForeignKey):
return self._map_model_field(field.target_field)
else:
error(
f'could not resolve model field "{field}" due to missing mapping.'
'either your field is custom and not based on a known subclasses '
'or we missed something. let us know.'
)
return build_basic_type(OpenApiTypes.STR)
def _get_serializer(self):
view = self.view
try:
if isinstance(view, GenericAPIView):
# try to circumvent queryset issues with calling get_serializer. if view has NOT
# overridden get_serializer, its safe to use get_serializer_class.
if view.__class__.get_serializer == GenericAPIView.get_serializer:
return view.get_serializer_class()()
return view.get_serializer()
elif isinstance(view, APIView):
# APIView does not implement the required interface, but be lenient and make
# good guesses before giving up and emitting a warning.
if callable(getattr(view, 'get_serializer', None)):
return view.get_serializer()
elif callable(getattr(view, 'get_serializer_class', None)):
return view.get_serializer_class()()
elif hasattr(view, 'serializer_class'):
return view.serializer_class
else:
error(
f'Unable to guess serializer for {view.__class__.__name__}. This is graceful '
f'fallback handling for APIViews. Consider using GenericAPIView as view base '
f'class, if view is under your control. ignoring view for now. '
)
else:
error(
'Encountered unknown view base class. please report this issue. ignoring for now'
)
except Exception as exc:
error(
f'Exception raised while getting serializer from {view.__class__.__name__}. Hint: '
f'Is get_serializer_class() returning None or is get_queryset() not working without '
f'a request? Ignoring the view for now. (Exception: {exc})')