Deprecate DjangoFilter backend (#4593)

Deprecate the built-in `rest_framework.filters.DjangoFilterBackend` in favour of the third-party `django_filters.rest_framework.DjangoFilterBackend`.

docs/api-guide/filtering.md

@@ -92,21 +92,21 @@ Generic filters can also present themselves as HTML controls in the browsable AP
 The default filter backends may be set globally, using the `DEFAULT_FILTER_BACKENDS` setting. For example.
 
     REST_FRAMEWORK = {
-        'DEFAULT_FILTER_BACKENDS': ('rest_framework.filters.DjangoFilterBackend',)
+        'DEFAULT_FILTER_BACKENDS': ('django_filters.rest_framework.DjangoFilterBackend',)
     }
 
 You can also set the filter backends on a per-view, or per-viewset basis,
 using the `GenericAPIView` class-based views.
 
+    import django_filters
     from django.contrib.auth.models import User
     from myapp.serializers import UserSerializer
-    from rest_framework import filters
     from rest_framework import generics
 
     class UserListView(generics.ListAPIView):
         queryset = User.objects.all()
         serializer_class = UserSerializer
-        filter_backends = (filters.DjangoFilterBackend,)
+        filter_backends = (django_filters.rest_framework.DjangoFilterBackend,)
 
 ## Filtering and object lookups
 
@@ -139,12 +139,27 @@ Note that you can use both an overridden `.get_queryset()` and generic filtering
 
 ## DjangoFilterBackend
 
-The `DjangoFilterBackend` class supports highly customizable field filtering, using the [django-filter package][django-filter].
+The `django-filter` library includes a `DjangoFilterBackend` class which
+supports highly customizable field filtering for REST framework.
 
-To use REST framework's `DjangoFilterBackend`, first install `django-filter`.
+To use `DjangoFilterBackend`, first install `django-filter`.
 
     pip install django-filter
 
+You should now either add the filter backend to your settings:
+
+    REST_FRAMEWORK = {
+        'DEFAULT_FILTER_BACKENDS': ('django_filters.rest_framework.DjangoFilterBackend',)
+    }
+
+Or add the filter backend to an individual View or ViewSet.
+
+    from django_filters.rest_framework import DjangoFilterBackend
+
+    class UserListView(generics.ListAPIView):
+        ...
+        filter_backends = (DjangoFilterBackend,)
+
 If you are using the browsable API or admin API you may also want to install `django-crispy-forms`, which will enhance the presentation of the filter forms in HTML views, by allowing them to render Bootstrap 3 HTML.
 
     pip install django-crispy-forms
@@ -174,10 +189,9 @@ For more advanced filtering requirements you can specify a `FilterSet` class tha
     import django_filters
     from myapp.models import Product
     from myapp.serializers import ProductSerializer
-    from rest_framework import filters
     from rest_framework import generics
 
-    class ProductFilter(filters.FilterSet):
+    class ProductFilter(django_filters.rest_framework.FilterSet):
         min_price = django_filters.NumberFilter(name="price", lookup_expr='gte')
         max_price = django_filters.NumberFilter(name="price", lookup_expr='lte')
         class Meta:
@@ -187,7 +201,7 @@ For more advanced filtering requirements you can specify a `FilterSet` class tha
     class ProductList(generics.ListAPIView):
         queryset = Product.objects.all()
         serializer_class = ProductSerializer
-        filter_backends = (filters.DjangoFilterBackend,)
+        filter_backends = (django_filters.rest_framework.DjangoFilterBackend,)
         filter_class = ProductFilter
 
 
@@ -199,12 +213,12 @@ You can also span relationships using `django-filter`, let's assume that each
 product has foreign key to `Manufacturer` model, so we create filter that
 filters using `Manufacturer` name. For example:
 
+    import django_filters
     from myapp.models import Product
     from myapp.serializers import ProductSerializer
-    from rest_framework import filters
     from rest_framework import generics
 
-    class ProductFilter(filters.FilterSet):
+    class ProductFilter(django_filters.rest_framework.FilterSet):
         class Meta:
             model = Product
             fields = ['category', 'in_stock', 'manufacturer__name']
@@ -218,10 +232,9 @@ This is nice, but it exposes the Django's double underscore convention as part o
     import django_filters
     from myapp.models import Product
     from myapp.serializers import ProductSerializer
-    from rest_framework import filters
     from rest_framework import generics
 
-    class ProductFilter(filters.FilterSet):
+    class ProductFilter(django_filters.rest_framework.FilterSet):
         manufacturer = django_filters.CharFilter(name="manufacturer__name")
 
         class Meta:
@@ -454,4 +467,3 @@ The [djangorestframework-word-filter][django-rest-framework-word-search-filter]
 [django-rest-framework-word-search-filter]: https://github.com/trollknurr/django-rest-framework-word-search-filter
 [django-url-filter]: https://github.com/miki725/django-url-filter
 [drf-url-filter]: https://github.com/manjitkumar/drf-url-filters
-

requirements/requirements-optionals.txt

@@ -1,5 +1,5 @@
 # Optional packages which may be used with REST framework.
 markdown==2.6.4
 django-guardian==1.4.6
-django-filter==0.14.0
+django-filter==0.15.3
 coreapi==2.0.8

rest_framework/filters.py

@@ -5,9 +5,9 @@ returned by list views.
 from __future__ import unicode_literals
 
 import operator
+import warnings
 from functools import reduce
 
-from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
 from django.db import models
 from django.db.models.constants import LOOKUP_SEP
@@ -16,50 +16,10 @@ from django.utils import six
 from django.utils.translation import ugettext_lazy as _
 
 from rest_framework.compat import (
-    coreapi, crispy_forms, distinct, django_filters, guardian, template_render
+    coreapi, distinct, django_filters, guardian, template_render
 )
 from rest_framework.settings import api_settings
 
-if 'crispy_forms' in settings.INSTALLED_APPS and crispy_forms and django_filters:
-    # If django-crispy-forms is installed, use it to get a bootstrap3 rendering
-    # of the DjangoFilterBackend controls when displayed as HTML.
-    from crispy_forms.helper import FormHelper
-    from crispy_forms.layout import Layout, Submit
-
-    class FilterSet(django_filters.FilterSet):
-        def __init__(self, *args, **kwargs):
-            super(FilterSet, self).__init__(*args, **kwargs)
-            for field in self.form.fields.values():
-                field.help_text = None
-
-            layout_components = list(self.form.fields.keys()) + [
-                Submit('', _('Submit'), css_class='btn-default'),
-            ]
-
-            helper = FormHelper()
-            helper.form_method = 'GET'
-            helper.template_pack = 'bootstrap3'
-            helper.layout = Layout(*layout_components)
-
-            self.form.helper = helper
-
-    filter_template = 'rest_framework/filters/django_filter_crispyforms.html'
-
-elif django_filters:
-    # If django-crispy-forms is not installed, use the standard
-    # 'form.as_p' rendering when DjangoFilterBackend is displayed as HTML.
-    class FilterSet(django_filters.FilterSet):
-        def __init__(self, *args, **kwargs):
-            super(FilterSet, self).__init__(*args, **kwargs)
-            for field in self.form.fields.values():
-                field.help_text = None
-
-    filter_template = 'rest_framework/filters/django_filter.html'
-
-else:
-    FilterSet = None
-    filter_template = None
-
 
 class BaseFilterBackend(object):
     """
@@ -77,78 +37,34 @@ class BaseFilterBackend(object):
         return []
 
 
+class FilterSet(object):
+    def __new__(cls, *args, **kwargs):
+        warnings.warn(
+            "The built in 'rest_framework.filters.FilterSet' is pending deprecation. "
+            "You should use 'django_filters.rest_framework.FilterSet' instead.",
+            PendingDeprecationWarning
+        )
+        from django_filters.rest_framework import FilterSet
+        return FilterSet(*args, **kwargs)
+
+
 class DjangoFilterBackend(BaseFilterBackend):
     """
     A filter backend that uses django-filter.
     """
-    default_filter_set = FilterSet
+    def __new__(cls, *args, **kwargs):
-    template = filter_template
-
-    def __init__(self):
         assert django_filters, 'Using DjangoFilterBackend, but django-filter is not installed'
+        assert django_filters.VERSION >= (0, 15, 3), 'django-filter 0.15.3 and above is required'
 
-    def get_filter_class(self, view, queryset=None):
+        warnings.warn(
-        """
+            "The built in 'rest_framework.filters.DjangoFilterBackend' is pending deprecation. "
-        Return the django-filters `FilterSet` used to filter the queryset.
+            "You should use 'django_filters.rest_framework.DjangoFilterBackend' instead.",
-        """
+            PendingDeprecationWarning
-        filter_class = getattr(view, 'filter_class', None)
+        )
-        filter_fields = getattr(view, 'filter_fields', None)
 
-        if filter_class:
+        from django_filters.rest_framework import DjangoFilterBackend
-            filter_model = filter_class.Meta.model
 
-            assert issubclass(queryset.model, filter_model), \
+        return DjangoFilterBackend(*args, **kwargs)
-                'FilterSet model %s does not match queryset model %s' % \
-                (filter_model, queryset.model)
-
-            return filter_class
-
-        if filter_fields:
-            class AutoFilterSet(self.default_filter_set):
-                class Meta:
-                    model = queryset.model
-                    fields = filter_fields
-
-            return AutoFilterSet
-
-        return None
-
-    def filter_queryset(self, request, queryset, view):
-        filter_class = self.get_filter_class(view, queryset)
-
-        if filter_class:
-            return filter_class(request.query_params, queryset=queryset).qs
-
-        return queryset
-
-    def to_html(self, request, queryset, view):
-        filter_class = self.get_filter_class(view, queryset)
-        if not filter_class:
-            return None
-        filter_instance = filter_class(request.query_params, queryset=queryset)
-        context = {
-            'filter': filter_instance
-        }
-        template = loader.get_template(self.template)
-        return template_render(template, context)
-
-    def get_schema_fields(self, view):
-        assert coreapi is not None, 'coreapi must be installed to use `get_schema_fields()`'
-        filter_class = getattr(view, 'filter_class', None)
-        if filter_class:
-            return [
-                coreapi.Field(name=field_name, required=False, location='query')
-                for field_name in filter_class().filters.keys()
-            ]
-
-        filter_fields = getattr(view, 'filter_fields', None)
-        if filter_fields:
-            return [
-                coreapi.Field(name=field_name, required=False, location='query')
-                for field_name in filter_fields
-            ]
-
-        return []
 
 
 class SearchFilter(BaseFilterBackend):

tests/test_filters.py

@@ -2,6 +2,7 @@ from __future__ import unicode_literals
 
 import datetime
 import unittest
+import warnings
 from decimal import Decimal
 
 from django.conf.urls import url
@@ -134,6 +135,39 @@ class IntegrationTestFiltering(CommonFilteringTestCase):
     Integration tests for filtered list views.
     """
 
+    @unittest.skipUnless(django_filters, 'django-filter not installed')
+    def test_backend_deprecation(self):
+        with warnings.catch_warnings(record=True) as w:
+            warnings.simplefilter("always")
+
+            view = FilterFieldsRootView.as_view()
+            request = factory.get('/')
+            response = view(request).render()
+
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertEqual(response.data, self.data)
+
+        self.assertTrue(issubclass(w[-1].category, PendingDeprecationWarning))
+        self.assertIn("'rest_framework.filters.DjangoFilterBackend' is pending deprecation.", str(w[-1].message))
+
+    @unittest.skipUnless(django_filters, 'django-filter not installed')
+    def test_no_df_deprecation(self):
+        with warnings.catch_warnings(record=True) as w:
+            warnings.simplefilter("always")
+
+            import django_filters.rest_framework
+
+            class DFFilterFieldsRootView(FilterFieldsRootView):
+                filter_backends = (django_filters.rest_framework.DjangoFilterBackend,)
+
+            view = DFFilterFieldsRootView.as_view()
+            request = factory.get('/')
+            response = view(request).render()
+
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        self.assertEqual(response.data, self.data)
+        self.assertEqual(len(w), 0)
+
     @unittest.skipUnless(django_filters, 'django-filter not installed')
     def test_get_filtered_fields_root_view(self):
         """