django-rest-framework/rest_framework/mixins.py
2014-08-29 11:29:26 +01:00

160 lines
5.5 KiB
Python

"""
Basic building blocks for generic class based views.
We don't bind behaviour to http method handlers yet,
which allows mixin classes to be composed in interesting ways.
"""
from __future__ import unicode_literals
from django.core.exceptions import ValidationError
from django.http import Http404
from rest_framework import status
from rest_framework.response import Response
from rest_framework.request import clone_request
from rest_framework.settings import api_settings
def _get_validation_exclusions(obj, lookup_field=None):
"""
Given a model instance, and an optional pk and slug field,
return the full list of all other field names on that model.
For use when performing full_clean on a model instance,
so we only clean the required fields.
"""
if lookup_field == 'pk':
pk_field = obj._meta.pk
while pk_field.rel:
pk_field = pk_field.rel.to._meta.pk
lookup_field = pk_field.name
return [field.name for field in obj._meta.fields if field.name != lookup_field]
class CreateModelMixin(object):
"""
Create a model instance.
"""
def create(self, request, *args, **kwargs):
serializer = self.get_serializer(data=request.DATA, files=request.FILES)
if serializer.is_valid():
self.pre_save(serializer.object)
self.object = serializer.save(force_insert=True)
self.post_save(self.object, created=True)
headers = self.get_success_headers(serializer.data)
return Response(serializer.data, status=status.HTTP_201_CREATED,
headers=headers)
return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
def get_success_headers(self, data):
try:
return {'Location': data[api_settings.URL_FIELD_NAME]}
except (TypeError, KeyError):
return {}
class ListModelMixin(object):
"""
List a queryset.
"""
def list(self, request, *args, **kwargs):
self.object_list = self.filter_queryset(self.get_queryset())
# Switch between paginated or standard style responses
page = self.paginate_queryset(self.object_list)
if page is not None:
serializer = self.get_pagination_serializer(page)
else:
serializer = self.get_serializer(self.object_list, many=True)
return Response(serializer.data)
class RetrieveModelMixin(object):
"""
Retrieve a model instance.
"""
def retrieve(self, request, *args, **kwargs):
self.object = self.get_object()
serializer = self.get_serializer(self.object)
return Response(serializer.data)
class UpdateModelMixin(object):
"""
Update a model instance.
"""
def update(self, request, *args, **kwargs):
partial = kwargs.pop('partial', False)
self.object = self.get_object_or_none()
serializer = self.get_serializer(self.object, data=request.DATA,
files=request.FILES, partial=partial)
if not serializer.is_valid():
return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
try:
self.pre_save(serializer.object)
except ValidationError as err:
# full_clean on model instance may be called in pre_save,
# so we have to handle eventual errors.
return Response(err.message_dict, status=status.HTTP_400_BAD_REQUEST)
if self.object is None:
self.object = serializer.save(force_insert=True)
self.post_save(self.object, created=True)
return Response(serializer.data, status=status.HTTP_201_CREATED)
self.object = serializer.save(force_update=True)
self.post_save(self.object, created=False)
return Response(serializer.data, status=status.HTTP_200_OK)
def partial_update(self, request, *args, **kwargs):
kwargs['partial'] = True
return self.update(request, *args, **kwargs)
def get_object_or_none(self):
try:
return self.get_object()
except Http404:
if self.request.method == 'PUT':
# For PUT-as-create operation, we need to ensure that we have
# relevant permissions, as if this was a POST request. This
# will either raise a PermissionDenied exception, or simply
# return None.
self.check_permissions(clone_request(self.request, 'POST'))
else:
# PATCH requests where the object does not exist should still
# return a 404 response.
raise
def pre_save(self, obj):
"""
Set any attributes on the object that are implicit in the request.
"""
lookup_url_kwarg = self.lookup_url_kwarg or self.lookup_field
lookup_value = self.kwargs[lookup_url_kwarg]
setattr(obj, self.lookup_field, lookup_value)
# Ensure we clean the attributes so that we don't eg return integer
# pk using a string representation, as provided by the url conf kwarg.
if hasattr(obj, 'full_clean'):
exclude = _get_validation_exclusions(obj, self.lookup_field)
obj.full_clean(exclude)
class DestroyModelMixin(object):
"""
Destroy a model instance.
"""
def destroy(self, request, *args, **kwargs):
obj = self.get_object()
self.pre_delete(obj)
obj.delete()
self.post_delete(obj)
return Response(status=status.HTTP_204_NO_CONTENT)