[Django] 25 - DRF: Pagination and Filtering

实现图片等其他资源的逐步加载。

 

Django Rest Framework for beginners

17 videos

Last updated on Jul 20, 2021

 

Pagination

Ref: Filtering, Searching, and Ordering. Django Rest Framework complete tutorial.#12

Ref: API Pagination. Django Rest Framework complete tutorial.#13

 

 

queryset.filter

• Old

    def get_queryset(self):
        """Retrieve albums for authenticated user."""

        return self.queryset.filter(user=self.request.user).order_by('-id')

• New

    def _params_to_ints(self, qs):
        """Convert a list of strings to integers."""
        return [int(str_id) for str_id in qs.split(',')]

    def get_queryset(self):
        """Retrieve recipes for authenticated user."""
        # -----------------------------------------------------------------
        tags        = self.request.query_params.get('tags')
        ingredients = self.request.query_params.get('ingredients')

        queryset    = self.queryset

        if tags:
            tag_ids        = self._params_to_ints(tags)
            queryset       = queryset.filter(tags__id__in=tag_ids)  # <----

        if ingredients:
            ingredient_ids = self._params_to_ints(ingredients)
            queryset       = queryset.filter(ingredients__id__in=ingredient_ids)  # <----
        # -----------------------------------------------------------------
        return queryset.filter(
            user=self.request.user
        ).order_by('-id').distinct()

 

 

Implement tag and ingredient filtering

• app/dataset/tests/test_photos_api.py 

+    def test_filter_photos_assigned_to_albums(self):
+        """Test listing photos to those assigned to albums."""
+
+        in1 = Photo.objects.create(user=self.user, name='Apples')
+        in2 = Photo.objects.create(user=self.user, name='Turkey')
+        album = Album.objects.create(
+            title='Apple Crumble',
+            time_minutes=5,
+            price=Decimal('4.50'),
+            user=self.user,
+        )
+        album.photos.add(in1)
+
+        res = self.client.get(PHOTOS_URL, {'assigned_only': 1})
+
+        s1 = PhotoSerializer(in1)
+        s2 = PhotoSerializer(in2)
+        self.assertIn(s1.data, res.data)
+        self.assertNotIn(s2.data, res.data)
+
+    def test_filtered_photos_unique(self):
+        """Test filtered photos returns a unique list."""
+
+        ing = Photo.objects.create(user=self.user, name='Eggs')
+        xxx = Photo.objects.create(user=self.user, name='Lentils')
+        album1 = Album.objects.create(
+            title='Eggs Benedict',
+            time_minutes=60,
+            price=Decimal('7.00'),
+            user=self.user,
+        )
+        album2 = Album.objects.create(
+            title='Herb Eggs',
+            time_minutes=20,
+            price=Decimal('4.00'),
+            user=self.user,
+        )
+        album1.photos.add(ing)
+        album2.photos.add(ing)
+
+        res = self.client.get(PHOTOS_URL, {'assigned_only': 1})
+
+        self.assertEqual(len(res.data), 1)

 

• app/dataset/tests/test_tags_api.py 

+    def test_filter_tags_assigned_to_albums(self):
+        """Test listing tags to those assigned to albums."""
+
+        tag1 = Tag.objects.create(user=self.user, name='Breakfast')
+        tag2 = Tag.objects.create(user=self.user, name='Lunch')
+        album = Album.objects.create(
+            title='Green Eggs on Toast',
+            time_minutes=10,
+            price=Decimal('2.50'),
+            user=self.user,
+        )
+        album.tags.add(tag1)
+
+        res = self.client.get(TAGS_URL, {'assigned_only': 1})
+
+        s1 = TagSerializer(tag1)
+        s2 = TagSerializer(tag2)
+        self.assertIn(s1.data, res.data)
+        self.assertNotIn(s2.data, res.data)
+
+    def test_filtered_tags_unique(self):
+        """Test filtered tags returns a unique list."""
+
+        tag = Tag.objects.create(user=self.user, name='Breakfast')
+        xxx = Tag.objects.create(user=self.user, name='Dinner')
+        album1 = Album.objects.create(
+            title='Pancakes',
+            time_minutes=5,
+            price=Decimal('5.00'),
+            user=self.user,
+        )
+        album2 = Album.objects.create(
+            title='Porridge',
+            time_minutes=3,
+            price=Decimal('2.00'),
+            user=self.user,
+        )
+        album1.tags.add(tag)
+        album2.tags.add(tag)
+
+        res = self.client.get(TAGS_URL, {'assigned_only': 1})
+
+        self.assertEqual(len(res.data), 1)

 

• app/dataset/views.py

@extend_schema_view(
    list=extend_schema(
        parameters=[
            OpenApiParameter(
                'assigned_only',
                OpenApiTypes.INT, enum=[0, 1],
                description='Filter by items assigned to albums.',
            ),
        ]
    )
)
class BaseAlbumAttrViewSet(mixins.DestroyModelMixin,
                           mixins.UpdateModelMixin,
                           mixins.ListModelMixin,
                           viewsets.GenericViewSet):
    """Base viewset for album attributes."""
    authentication_classes = [TokenAuthentication]
    permission_classes     = [IsAuthenticated]

    def get_queryset(self):
        """Filter queryset to authenticated user."""

        assigned_only = bool(
            int(self.request.query_params.get('assigned_only', 0))
        )
        queryset = self.queryset
        if assigned_only:
            queryset = queryset.filter(album__isnull=False)

        return queryset.filter(
            user=self.request.user
        ).order_by('-name').distinct()

class TagViewSet(BaseAlbumAttrViewSet):
    """Manage tags in the database."""
    serializer_class = serializers.TagSerializer
    queryset = Tag.objects.all()


class PhotoViewSet(BaseAlbumAttrViewSet):
    """Manage photos in the database."""
    serializer_class = serializers.PhotoSerializer
    queryset = Photo.objects.all()

 

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