First attempt at adding filter support.

The filter support uses django-filter to work its magic.

requirements.txt

 Django>=1.3
+-e git+https://github.com/alex/django-filter.git#egg=django-filter

rest_framework/generics.py

 """
-Generic views that provide commmonly needed behaviour.
+Generic views that provide commonly needed behaviour.
 """
 
 from rest_framework import views, mixins
 from rest_framework.settings import api_settings
 from django.views.generic.detail import SingleObjectMixin
 from django.views.generic.list import MultipleObjectMixin
-
+import django_filters
 
 ### Base classes for the generic views ###
 
@@ -58,6 +58,37 @@ class MultipleObjectBaseView(MultipleObjectMixin, BaseView):
 
     pagination_serializer_class = api_settings.PAGINATION_SERIALIZER
     paginate_by = api_settings.PAGINATE_BY
+    filter_class = None
+    filter_fields = None
+
+    def get_filter_class(self):
+        """
+        Return the django-filters `FilterSet` used to filter the queryset.
+        """
+        if self.filter_class:
+            return self.filter_class
+
+        if self.filter_fields:
+            class AutoFilterSet(django_filters.FilterSet):
+                class Meta:
+                    model = self.model
+                fields = self.filter_fields
+            return AutoFilterSet
+
+        return None
+
+    def filter_queryset(self, queryset):
+        filter_class = self.get_filter_class()
+
+        if filter_class:
+            assert issubclass(filter_class.Meta.model, self.model), \
+                "%s is not a subclass of %s" % (filter_class.Meta.model, self.model)
+            return filter_class(self.request.GET, queryset=queryset)
+
+        return queryset
+
+    def get_filtered_queryset(self):
+        return self.filter_queryset(self.get_queryset())
 
     def get_pagination_serializer_class(self):
         """

rest_framework/mixins.py

@@ -33,7 +33,7 @@ class ListModelMixin(object):
     empty_error = u"Empty list and '%(class_name)s.allow_empty' is False."
 
     def list(self, request, *args, **kwargs):
-        self.object_list = self.get_queryset()
+        self.object_list = self.get_filtered_queryset()
 
         # Default is to allow empty querysets.  This can be altered by setting
         # `.allow_empty = False`, to raise 404 errors on empty querysets.

rest_framework/tests/filterset.py

+import datetime
+from django.test import TestCase
+from django.test.client import RequestFactory
+from rest_framework import generics, status
+from rest_framework.tests.models import FilterableItem, BasicModel
+import django_filters
+
+factory = RequestFactory()
+
+# Basic filter on a list view.
+class FilterFieldsRootView(generics.ListCreateAPIView):
+    model = FilterableItem
+    filter_fields = ['decimal', 'date']
+
+
+# These class are used to test a filter class.
+class SeveralFieldsFilter(django_filters.FilterSet):
+    text = django_filters.CharFilter(lookup_type='icontains')
+    decimal = django_filters.NumberFilter(lookup_type='lt')
+    date = django_filters.DateFilter(lookup_type='gt')
+    class Meta:
+        model = FilterableItem
+        fields = ['text', 'decimal', 'date']
+
+
+class FilterClassRootView(generics.ListCreateAPIView):
+    model = FilterableItem
+    filter_class = SeveralFieldsFilter
+
+
+# These classes are used to test a misconfigured filter class.
+class MisconfiguredFilter(django_filters.FilterSet):
+    text = django_filters.CharFilter(lookup_type='icontains')
+    class Meta:
+        model = BasicModel
+        fields = ['text']
+
+
+class IncorrectlyConfiguredRootView(generics.ListCreateAPIView):
+    model = FilterableItem
+    filter_class = MisconfiguredFilter
+
+
+class IntegrationTestFiltering(TestCase):
+    """
+    Integration tests for filtered list views.
+    """
+
+    def setUp(self):
+        """
+        Create 10 FilterableItem instances.
+        """
+        base_data = ('a', 0.25, datetime.date(2012, 10, 8))
+        for i in range(10):
+            text = chr(i + ord(base_data[0])) * 3  # Produces string 'aaa', 'bbb', etc.
+            decimal = base_data[1] + i
+            date = base_data[2] - datetime.timedelta(days=i * 2)
+            FilterableItem(text=text, decimal=decimal, date=date).save()
+
+        self.objects = FilterableItem.objects
+        self.data = [
+        {'id': obj.id, 'text': obj.text, 'decimal': obj.decimal, 'date': obj.date}
+        for obj in self.objects.all()
+        ]
+
+    def test_get_filtered_fields_root_view(self):
+        """
+        GET requests to paginated ListCreateAPIView should return paginated results.
+        """
+        view = FilterFieldsRootView.as_view()
+
+        # Basic test with no filter.
+        request = factory.get('/')
+        response = view(request).render()
+        self.assertEquals(response.status_code, status.HTTP_200_OK)
+        self.assertEquals(response.data, self.data)
+
+        # Tests that the decimal filter works.
+        search_decimal = 2.25
+        request = factory.get('/?decimal=%s' % search_decimal)
+        response = view(request).render()
+        self.assertEquals(response.status_code, status.HTTP_200_OK)
+        expected_data = [ f for f in self.data if f['decimal'] == search_decimal ]
+        self.assertEquals(response.data, expected_data)
+
+        # Tests that the date filter works.
+        search_date = datetime.date(2012, 9, 22)
+        request = factory.get('/?date=%s' % search_date)  # search_date str: '2012-09-22'
+        response = view(request).render()
+        self.assertEquals(response.status_code, status.HTTP_200_OK)
+        expected_data = [ f for f in self.data if f['date'] == search_date ]
+        self.assertEquals(response.data, expected_data)
+
+    def test_get_filtered_class_root_view(self):
+        """
+        GET requests to filtered ListCreateAPIView that have a filter_class set
+        should return filtered results.
+        """
+        view = FilterClassRootView.as_view()
+
+        # Basic test with no filter.
+        request = factory.get('/')
+        response = view(request).render()
+        self.assertEquals(response.status_code, status.HTTP_200_OK)
+        self.assertEquals(response.data, self.data)
+
+        # Tests that the decimal filter set with 'lt' in the filter class works.
+        search_decimal = 4.25
+        request = factory.get('/?decimal=%s' % search_decimal)
+        response = view(request).render()
+        self.assertEquals(response.status_code, status.HTTP_200_OK)
+        expected_data = [ f for f in self.data if f['decimal'] < search_decimal ]
+        self.assertEquals(response.data, expected_data)
+
+        # Tests that the date filter set with 'gt' in the filter class works.
+        search_date = datetime.date(2012, 10, 2)
+        request = factory.get('/?date=%s' % search_date)  # search_date str: '2012-10-02'
+        response = view(request).render()
+        self.assertEquals(response.status_code, status.HTTP_200_OK)
+        expected_data = [ f for f in self.data if f['date'] > search_date ]
+        self.assertEquals(response.data, expected_data)
+
+        # Tests that the text filter set with 'icontains' in the filter class works.
+        search_text = 'ff'
+        request = factory.get('/?text=%s' % search_text)
+        response = view(request).render()
+        self.assertEquals(response.status_code, status.HTTP_200_OK)
+        expected_data = [ f for f in self.data if search_text in f['text'].lower() ]
+        self.assertEquals(response.data, expected_data)
+
+        # Tests that multiple filters works.
+        search_decimal = 5.25
+        search_date = datetime.date(2012, 10, 2)
+        request = factory.get('/?decimal=%s&date=%s' % (search_decimal, search_date))
+        response = view(request).render()
+        self.assertEquals(response.status_code, status.HTTP_200_OK)
+        expected_data = [ f for f in self.data if f['date'] > search_date and
+                                                  f['decimal'] < search_decimal ]
+        self.assertEquals(response.data, expected_data)
+
+    def test_incorrectly_configured_filter(self):
+        """
+        An error should be displayed when the filter class is misconfigured.
+        """
+        view = IncorrectlyConfiguredRootView.as_view()
+
+        request = factory.get('/')
+        self.assertRaises(AssertionError, view, request)
+
+    # TODO Return 400 filter paramater requested that hasn't been configured.
+    def test_bad_request(self):
+        """
+        GET requests with filters that aren't configured should return 400.
+        """
+        view = FilterFieldsRootView.as_view()
+
+        search_integer = 10
+        request = factory.get('/?integer=%s' % search_integer)
+        response = view(request).render()
+        self.assertEquals(response.status_code, status.HTTP_400_BAD_REQUEST)
\ No newline at end of file

rest_framework/tests/models.py

@@ -85,6 +85,13 @@ class Bookmark(RESTFrameworkModel):
     tags = GenericRelation(TaggedItem)
 
 
+# Model to test filtering.
+class FilterableItem(RESTFrameworkModel):
+    text = models.CharField(max_length=100)
+    decimal = models.DecimalField(max_digits=4, decimal_places=2)
+    date = models.DateField()
+
+
 # Model for regression test for #285
 
 class Comment(RESTFrameworkModel):

rest_framework/tests/pagination.py

+import datetime
 from django.core.paginator import Paginator
 from django.test import TestCase
 from django.test.client import RequestFactory
 from rest_framework import generics, status, pagination
-from rest_framework.tests.models import BasicModel
+from rest_framework.tests.models import BasicModel, FilterableItem
+import django_filters
 
 factory = RequestFactory()
 
@@ -15,6 +17,19 @@ class RootView(generics.ListCreateAPIView):
     paginate_by = 10
 
 
+class DecimalFilter(django_filters.FilterSet):
+    decimal = django_filters.NumberFilter(lookup_type='lt')
+    class Meta:
+        model = FilterableItem
+        fields = ['text', 'decimal', 'date']
+
+
+class FilterFieldsRootView(generics.ListCreateAPIView):
+    model = FilterableItem
+    paginate_by = 10
+    filter_class = DecimalFilter
+
+
 class IntegrationTestPagination(TestCase):
     """
     Integration tests for paginated list views.
@@ -22,7 +37,7 @@ class IntegrationTestPagination(TestCase):
 
     def setUp(self):
         """
-        Create 26 BasicModel intances.
+        Create 26 BasicModel instances.
         """
         for char in 'abcdefghijklmnopqrstuvwxyz':
             BasicModel(text=char * 3).save()
@@ -61,6 +76,56 @@ class IntegrationTestPagination(TestCase):
         self.assertEquals(response.data['next'], None)
         self.assertNotEquals(response.data['previous'], None)
 
+class IntegrationTestPaginationAndFiltering(TestCase):
+
+    def setUp(self):
+        """
+        Create 50 FilterableItem instances.
+        """
+        base_data = ('a', 0.25, datetime.date(2012, 10, 8))
+        for i in range(26):
+            text = chr(i + ord(base_data[0])) * 3  # Produces string 'aaa', 'bbb', etc.
+            decimal = base_data[1] + i
+            date = base_data[2] - datetime.timedelta(days=i * 2)
+            FilterableItem(text=text, decimal=decimal, date=date).save()
+
+        self.objects = FilterableItem.objects
+        self.data = [
+        {'id': obj.id, 'text': obj.text, 'decimal': obj.decimal, 'date': obj.date}
+        for obj in self.objects.all()
+        ]
+        self.view = FilterFieldsRootView.as_view()
+
+    def test_get_paginated_filtered_root_view(self):
+        """
+        GET requests to paginated filtered ListCreateAPIView should return
+        paginated results. The next and previous links should preserve the
+        filtered parameters.
+        """
+        request = factory.get('/?decimal=15.20')
+        response = self.view(request).render()
+        self.assertEquals(response.status_code, status.HTTP_200_OK)
+        self.assertEquals(response.data['count'], 15)
+        self.assertEquals(response.data['results'], self.data[:10])
+        self.assertNotEquals(response.data['next'], None)
+        self.assertEquals(response.data['previous'], None)
+
+        request = factory.get(response.data['next'])
+        response = self.view(request).render()
+        self.assertEquals(response.status_code, status.HTTP_200_OK)
+        self.assertEquals(response.data['count'], 15)
+        self.assertEquals(response.data['results'], self.data[10:15])
+        self.assertEquals(response.data['next'], None)
+        self.assertNotEquals(response.data['previous'], None)
+
+        request = factory.get(response.data['previous'])
+        response = self.view(request).render()
+        self.assertEquals(response.status_code, status.HTTP_200_OK)
+        self.assertEquals(response.data['count'], 15)
+        self.assertEquals(response.data['results'], self.data[:10])
+        self.assertNotEquals(response.data['next'], None)
+        self.assertEquals(response.data['previous'], None)
+
 
 class UnitTestPagination(TestCase):
     """