django-rest-framework/rest_framework/mixins.py

169 lines
5.7 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.http import Http404
from rest_framework import status
from rest_framework.response import Response
from rest_framework.request import clone_request
def _get_validation_exclusions(obj, pk=None, slug_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.
"""
include = []
if pk:
pk_field = obj._meta.pk
while pk_field.rel:
pk_field = pk_field.rel.to._meta.pk
include.append(pk_field.name)
if slug_field:
include.append(slug_field)
return [field.name for field in obj._meta.fields if field.name not in include]
class CreateModelMixin(object):
"""
Create a model instance.
Should be mixed in with any `GenericAPIView`.
"""
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['url']}
except (TypeError, KeyError):
return {}
class ListModelMixin(object):
"""
List a queryset.
Should be mixed in with `MultipleObjectAPIView`.
"""
empty_error = "Empty list and '%(class_name)s.allow_empty' is False."
def list(self, request, *args, **kwargs):
queryset = self.get_queryset()
self.object_list = self.filter_queryset(queryset)
# Default is to allow empty querysets. This can be altered by setting
# `.allow_empty = False`, to raise 404 errors on empty querysets.
allow_empty = self.get_allow_empty()
if not allow_empty and not self.object_list:
class_name = self.__class__.__name__
error_msg = self.empty_error % {'class_name': class_name}
raise Http404(error_msg)
# Pagination size is set by the `.paginate_by` attribute,
# which may be `None` to disable pagination.
page_size = self.get_paginate_by(self.object_list)
if page_size:
packed = self.paginate_queryset(self.object_list, page_size)
paginator, page, queryset, is_paginated = packed
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.
Should be mixed in with `SingleObjectAPIView`.
"""
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.
Should be mixed in with `SingleObjectAPIView`.
"""
def update(self, request, *args, **kwargs):
partial = kwargs.pop('partial', False)
self.object = None
try:
self.object = self.get_object()
except Http404:
# If this is a PUT-as-create operation, we need to ensure that
# we have relevant permissions, as if this was a POST request.
self.check_permissions(clone_request(request, 'POST'))
created = True
save_kwargs = {'force_insert': True}
success_status_code = status.HTTP_201_CREATED
else:
created = False
save_kwargs = {'force_update': True}
success_status_code = status.HTTP_200_OK
serializer = self.get_serializer(self.object, data=request.DATA,
files=request.FILES, partial=partial)
if serializer.is_valid():
self.pre_save(serializer.object)
self.object = serializer.save(**save_kwargs)
self.post_save(self.object, created=created)
return Response(serializer.data, status=success_status_code)
return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
def pre_save(self, obj):
"""
Set any attributes on the object that are implicit in the request.
"""
# pk and/or slug attributes are implicit in the URL.
pk = self.kwargs.get(self.pk_url_kwarg, None)
slug = self.kwargs.get(self.slug_url_kwarg, None)
slug_field = slug and self.get_slug_field() or None
if pk:
setattr(obj, 'pk', pk)
if slug:
setattr(obj, slug_field, slug)
# 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, pk, slug_field)
obj.full_clean(exclude)
class DestroyModelMixin(object):
"""
Destroy a model instance.
Should be mixed in with `SingleObjectAPIView`.
"""
def destroy(self, request, *args, **kwargs):
obj = self.get_object()
obj.delete()
return Response(status=status.HTTP_204_NO_CONTENT)