taiga-back/taiga/base/api/generics.py

494 lines
17 KiB
Python

# Copyright (C) 2014 Andrey Antukh <niwi@niwi.be>
# Copyright (C) 2014 Jesús Espino <jespinog@gmail.com>
# Copyright (C) 2014 David Barragán <bameda@dbarragan.com>
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# This code is partially taken from django-rest-framework:
# Copyright (c) 2011-2014, Tom Christie
import warnings
from django.core.exceptions import ImproperlyConfigured, PermissionDenied
from django.core.paginator import Paginator, InvalidPage
from django.http import Http404
from django.shortcuts import get_object_or_404 as _get_object_or_404
from django.utils.translation import ugettext as _
from rest_framework import exceptions
from rest_framework.request import clone_request
from rest_framework.settings import api_settings
from . import views
from . import mixins
def strict_positive_int(integer_string, cutoff=None):
"""
Cast a string to a strictly positive integer.
"""
ret = int(integer_string)
if ret <= 0:
raise ValueError()
if cutoff:
ret = min(ret, cutoff)
return ret
def get_object_or_404(queryset, *filter_args, **filter_kwargs):
"""
Same as Django's standard shortcut, but make sure to raise 404
if the filter_kwargs don't match the required types.
"""
try:
return _get_object_or_404(queryset, *filter_args, **filter_kwargs)
except (TypeError, ValueError):
raise Http404
class GenericAPIView(views.APIView):
"""
Base class for all other generic views.
"""
# You'll need to either set these attributes,
# or override `get_queryset()`/`get_serializer_class()`.
queryset = None
serializer_class = None
# This shortcut may be used instead of setting either or both
# of the `queryset`/`serializer_class` attributes, although using
# the explicit style is generally preferred.
model = None
# If you want to use object lookups other than pk, set this attribute.
# For more complex lookup requirements override `get_object()`.
lookup_field = 'pk'
lookup_url_kwarg = None
# Pagination settings
paginate_by = api_settings.PAGINATE_BY
paginate_by_param = api_settings.PAGINATE_BY_PARAM
max_paginate_by = api_settings.MAX_PAGINATE_BY
pagination_serializer_class = api_settings.DEFAULT_PAGINATION_SERIALIZER_CLASS
page_kwarg = 'page'
# The filter backend classes to use for queryset filtering
filter_backends = api_settings.DEFAULT_FILTER_BACKENDS
# The following attributes may be subject to change,
# and should be considered private API.
model_serializer_class = api_settings.DEFAULT_MODEL_SERIALIZER_CLASS
paginator_class = Paginator
######################################
# These are pending deprecation...
pk_url_kwarg = 'pk'
slug_url_kwarg = 'slug'
slug_field = 'slug'
allow_empty = True
def get_serializer_context(self):
"""
Extra context provided to the serializer class.
"""
return {
'request': self.request,
'format': self.format_kwarg,
'view': self
}
def get_serializer(self, instance=None, data=None,
files=None, many=False, partial=False):
"""
Return the serializer instance that should be used for validating and
deserializing input, and for serializing output.
"""
serializer_class = self.get_serializer_class()
context = self.get_serializer_context()
return serializer_class(instance, data=data, files=files,
many=many, partial=partial, context=context)
def get_pagination_serializer(self, page):
"""
Return a serializer instance to use with paginated data.
"""
class SerializerClass(self.pagination_serializer_class):
class Meta:
object_serializer_class = self.get_serializer_class()
pagination_serializer_class = SerializerClass
context = self.get_serializer_context()
return pagination_serializer_class(instance=page, context=context)
def paginate_queryset(self, queryset, page_size=None):
"""
Paginate a queryset if required, either returning a page object,
or `None` if pagination is not configured for this view.
"""
deprecated_style = False
if page_size is not None:
warnings.warn('The `page_size` parameter to `paginate_queryset()` '
'is due to be deprecated. '
'Note that the return style of this method is also '
'changed, and will simply return a page object '
'when called without a `page_size` argument.',
PendingDeprecationWarning, stacklevel=2)
deprecated_style = True
else:
# Determine the required page size.
# If pagination is not configured, simply return None.
page_size = self.get_paginate_by()
if not page_size:
return None
if not self.allow_empty:
warnings.warn(
'The `allow_empty` parameter is due to be deprecated. '
'To use `allow_empty=False` style behavior, You should override '
'`get_queryset()` and explicitly raise a 404 on empty querysets.',
PendingDeprecationWarning, stacklevel=2
)
paginator = self.paginator_class(queryset, page_size,
allow_empty_first_page=self.allow_empty)
page_kwarg = self.kwargs.get(self.page_kwarg)
page_query_param = self.request.QUERY_PARAMS.get(self.page_kwarg)
page = page_kwarg or page_query_param or 1
try:
page_number = paginator.validate_number(page)
except InvalidPage:
if page == 'last':
page_number = paginator.num_pages
else:
raise Http404(_("Page is not 'last', nor can it be converted to an int."))
try:
page = paginator.page(page_number)
except InvalidPage as e:
raise Http404(_('Invalid page (%(page_number)s): %(message)s') % {
'page_number': page_number,
'message': str(e)
})
if deprecated_style:
return (paginator, page, page.object_list, page.has_other_pages())
return page
def filter_queryset(self, queryset):
"""
Given a queryset, filter it with whichever filter backend is in use.
You are unlikely to want to override this method, although you may need
to call it either from a list view, or from a custom `get_object`
method if you want to apply the configured filtering backend to the
default queryset.
"""
for backend in self.get_filter_backends():
queryset = backend().filter_queryset(self.request, queryset, self)
return queryset
def get_filter_backends(self):
"""
Returns the list of filter backends that this view requires.
"""
filter_backends = self.filter_backends or []
if not filter_backends and hasattr(self, 'filter_backend'):
raise RuntimeException('The `filter_backend` attribute and `FILTER_BACKEND` setting '
'are due to be deprecated in favor of a `filter_backends` '
'attribute and `DEFAULT_FILTER_BACKENDS` setting, that take '
'a *list* of filter backend classes.')
return filter_backends
########################
### The following methods provide default implementations
### that you may want to override for more complex cases.
def get_paginate_by(self, queryset=None):
"""
Return the size of pages to use with pagination.
If `PAGINATE_BY_PARAM` is set it will attempt to get the page size
from a named query parameter in the url, eg. ?page_size=100
Otherwise defaults to using `self.paginate_by`.
"""
if queryset is not None:
raise RuntimeException('The `queryset` parameter to `get_paginate_by()` '
'is due to be deprecated.')
if self.paginate_by_param:
try:
return strict_positive_int(
self.request.QUERY_PARAMS[self.paginate_by_param],
cutoff=self.max_paginate_by
)
except (KeyError, ValueError):
pass
return self.paginate_by
def get_serializer_class(self):
if self.action == "list" and hasattr(self, "list_serializer_class"):
return self.list_serializer_class
serializer_class = self.serializer_class
if serializer_class is not None:
return serializer_class
assert self.model is not None, \
"'%s' should either include a 'serializer_class' attribute, " \
"or use the 'model' attribute as a shortcut for " \
"automatically generating a serializer class." \
% self.__class__.__name__
class DefaultSerializer(self.model_serializer_class):
class Meta:
model = self.model
return DefaultSerializer
def get_queryset(self):
"""
Get the list of items for this view.
This must be an iterable, and may be a queryset.
Defaults to using `self.queryset`.
You may want to override this if you need to provide different
querysets depending on the incoming request.
(Eg. return a list of items that is specific to the user)
"""
if self.queryset is not None:
return self.queryset._clone()
if self.model is not None:
return self.model._default_manager.all()
raise ImproperlyConfigured("'%s' must define 'queryset' or 'model'"
% self.__class__.__name__)
def get_object(self, queryset=None):
"""
Returns the object the view is displaying.
You may want to override this if you need to provide non-standard
queryset lookups. Eg if objects are referenced using multiple
keyword arguments in the url conf.
"""
# Determine the base queryset to use.
if queryset is None:
queryset = self.filter_queryset(self.get_queryset())
else:
# NOTE: explicit exception for avoid and fix
# usage of deprecated way of get_object
raise RuntimeException("DEPRECATED")
# Perform the lookup filtering.
# Note that `pk` and `slug` are deprecated styles of lookup filtering.
lookup_url_kwarg = self.lookup_url_kwarg or self.lookup_field
lookup = self.kwargs.get(lookup_url_kwarg, None)
pk = self.kwargs.get(self.pk_url_kwarg, None)
slug = self.kwargs.get(self.slug_url_kwarg, None)
if lookup is not None:
filter_kwargs = {self.lookup_field: lookup}
elif pk is not None and self.lookup_field == 'pk':
raise RuntimeException('The `pk_url_kwarg` attribute is due to be deprecated. '
'Use the `lookup_field` attribute instead')
elif slug is not None and self.lookup_field == 'pk':
raise RuntimeException('The `slug_url_kwarg` attribute is due to be deprecated. '
'Use the `lookup_field` attribute instead')
else:
raise ImproperlyConfigured(
'Expected view %s to be called with a URL keyword argument '
'named "%s". Fix your URL conf, or set the `.lookup_field` '
'attribute on the view correctly.' %
(self.__class__.__name__, self.lookup_field)
)
obj = get_object_or_404(queryset, **filter_kwargs)
return obj
def get_object_or_none(self):
try:
return self.get_object()
except Http404:
return None
########################
### The following are placeholder methods,
### and are intended to be overridden.
###
### The are not called by GenericAPIView directly,
### but are used by the mixin methods.
def pre_conditions_on_save(self, obj):
"""
Placeholder method called by mixins before save for check
some conditions before save.
"""
pass
def pre_conditions_on_delete(self, obj):
"""
Placeholder method called by mixins before delete for check
some conditions before delete.
"""
pass
def pre_save(self, obj):
"""
Placeholder method for calling before saving an object.
May be used to set attributes on the object that are implicit
in either the request, or the url.
"""
pass
def post_save(self, obj, created=False):
"""
Placeholder method for calling after saving an object.
"""
pass
def pre_delete(self, obj):
"""
Placeholder method for calling before deleting an object.
"""
pass
def post_delete(self, obj):
"""
Placeholder method for calling after deleting an object.
"""
pass
##########################################################
### Concrete view classes that provide method handlers ###
### by composing the mixin classes with the base view. ###
### NOTE: not used by taiga. ###
##########################################################
class CreateAPIView(mixins.CreateModelMixin,
GenericAPIView):
"""
Concrete view for creating a model instance.
"""
def post(self, request, *args, **kwargs):
return self.create(request, *args, **kwargs)
class ListAPIView(mixins.ListModelMixin,
GenericAPIView):
"""
Concrete view for listing a queryset.
"""
def get(self, request, *args, **kwargs):
return self.list(request, *args, **kwargs)
class RetrieveAPIView(mixins.RetrieveModelMixin,
GenericAPIView):
"""
Concrete view for retrieving a model instance.
"""
def get(self, request, *args, **kwargs):
return self.retrieve(request, *args, **kwargs)
class DestroyAPIView(mixins.DestroyModelMixin,
GenericAPIView):
"""
Concrete view for deleting a model instance.
"""
def delete(self, request, *args, **kwargs):
return self.destroy(request, *args, **kwargs)
class UpdateAPIView(mixins.UpdateModelMixin,
GenericAPIView):
"""
Concrete view for updating a model instance.
"""
def put(self, request, *args, **kwargs):
return self.update(request, *args, **kwargs)
def patch(self, request, *args, **kwargs):
return self.partial_update(request, *args, **kwargs)
class ListCreateAPIView(mixins.ListModelMixin,
mixins.CreateModelMixin,
GenericAPIView):
"""
Concrete view for listing a queryset or creating a model instance.
"""
def get(self, request, *args, **kwargs):
return self.list(request, *args, **kwargs)
def post(self, request, *args, **kwargs):
return self.create(request, *args, **kwargs)
class RetrieveUpdateAPIView(mixins.RetrieveModelMixin,
mixins.UpdateModelMixin,
GenericAPIView):
"""
Concrete view for retrieving, updating a model instance.
"""
def get(self, request, *args, **kwargs):
return self.retrieve(request, *args, **kwargs)
def put(self, request, *args, **kwargs):
return self.update(request, *args, **kwargs)
def patch(self, request, *args, **kwargs):
return self.partial_update(request, *args, **kwargs)
class RetrieveDestroyAPIView(mixins.RetrieveModelMixin,
mixins.DestroyModelMixin,
GenericAPIView):
"""
Concrete view for retrieving or deleting a model instance.
"""
def get(self, request, *args, **kwargs):
return self.retrieve(request, *args, **kwargs)
def delete(self, request, *args, **kwargs):
return self.destroy(request, *args, **kwargs)
class RetrieveUpdateDestroyAPIView(mixins.RetrieveModelMixin,
mixins.UpdateModelMixin,
mixins.DestroyModelMixin,
GenericAPIView):
"""
Concrete view for retrieving, updating or deleting a model instance.
"""
def get(self, request, *args, **kwargs):
return self.retrieve(request, *args, **kwargs)
def put(self, request, *args, **kwargs):
return self.update(request, *args, **kwargs)
def patch(self, request, *args, **kwargs):
return self.partial_update(request, *args, **kwargs)
def delete(self, request, *args, **kwargs):
return self.destroy(request, *args, **kwargs)