feat: add light pagination

drf_kit/pagination/__init__.py

@@ -1 +1,2 @@
 from drf_kit.pagination.custom_pagination import CustomPagePagination
+from drf_kit.pagination.light_pagination import LightPagePagination

drf_kit/pagination/light_pagination.py

@@ -0,0 +1,81 @@
+# ruff: noqa: ERA001
+# We are keeping the comments here to show what is removed from parent implementation
+
+from django.core.paginator import InvalidPage
+from django.core.paginator import Page as DefaultPage
+from django.core.paginator import Paginator as DefaultPaginator
+from rest_framework.exceptions import NotFound
+from rest_framework.response import Response
+
+from drf_kit.pagination.custom_pagination import CustomPagePagination
+
+
+class LightPage(DefaultPage):
+    def has_next(self):
+        return len(self.object_list) >= self.paginator.per_page
+
+
+class LightPaginator(DefaultPaginator):
+    def validate_number(self, number):
+        try:
+            value = int(number)
+        except ValueError:
+            value = 0
+        return max(value, 0)
+
+    def page(self, number):
+        """Return a Page object for the given 1-based page number."""
+        number = self.validate_number(number)
+        bottom: int = (number - 1) * self.per_page
+        top: int = bottom + self.per_page
+        # if top + self.orphans >= self.count:
+        #     top = self.count
+        return LightPage(self.object_list[bottom:top], number, self)
+
+    @property
+    def count(self):
+        raise NotImplementedError()
+
+
+class LightPagePagination(CustomPagePagination):
+    django_paginator_class = LightPaginator
+
+    def get_paginated_response(self, data):
+        return Response(
+            {
+                # 'count': self.page.paginator.count,
+                "next": self.get_next_link(),
+                "previous": self.get_previous_link(),
+                "results": data,
+            }
+        )
+
+    def paginate_queryset(self, queryset, request, view=None):
+        """
+        Paginate a queryset if required, either returning a
+        page object, or `None` if pagination is not configured for this view.
+        """
+        page_size = self.get_page_size(request)
+        if not page_size:
+            return None
+
+        paginator = self.django_paginator_class(queryset, page_size)
+        page_number = request.query_params.get(self.page_query_param, self.page_start)
+        if page_number in self.last_page_strings:
+            page_number = paginator.num_pages
+
+        try:
+            self.page = paginator.page(int(page_number) + self._shift)
+        except InvalidPage as exc:
+            msg = self.invalid_page_message.format(
+                page_number=page_number,
+                message=str(exc),
+            )
+            raise NotFound(msg) from exc
+
+        if self.template is not None:
+            # The browsable API should display pagination controls.
+            self.display_page_controls = True
+
+        self.request = request
+        return list(self.page)

test_app/tests/tests_views/tests_paginated_views.py

@@ -64,3 +64,66 @@ def test_invalid_page(self):
 
         response = self.client.get(url, {"page_size": 12, "page": 15000})
         self.assertResponseNotFound(response=response, expected_item={"detail": "Invalid page."})
+
+
+class TestLightPaginatedView(TestPaginatedView):
+    url = "/spells-light"
+
+    def test_first_page(self):
+        url = self.url
+
+        response = self.client.get(url, {"page_size": 12})
+
+        self.assertEqual(list(range(1, 13)), [spell["id"] for spell in response.json()["results"]])
+        self.assertRegex(response.json()["next"], r"page=2")
+        self.assertEqual(None, response.json()["previous"])
+        self.assertNotIn("count", response.json())
+
+    def test_second_page(self):
+        url = self.url
+
+        response = self.client.get(url, {"page_size": 12, "page": 2})
+
+        self.assertEqual(list(range(13, 25)), [spell["id"] for spell in response.json()["results"]])
+        self.assertRegex(response.json()["next"], r"page=3")
+        self.assertNotRegex(response.json()["previous"], r"page=\d+")
+        self.assertNotIn("count", response.json())
+
+    def test_third_page(self):
+        url = self.url
+
+        response = self.client.get(url, {"page_size": 12, "page": 3})
+
+        self.assertEqual(list(range(25, 37)), [spell["id"] for spell in response.json()["results"]])
+        self.assertRegex(response.json()["next"], r"page=4")
+        self.assertRegex(response.json()["previous"], r"page=2")
+        self.assertNotIn("count", response.json())
+
+    def test_fourth_page(self):
+        url = self.url
+
+        response = self.client.get(url, {"page_size": 12, "page": 4})
+
+        self.assertEqual(list(range(37, 49)), [spell["id"] for spell in response.json()["results"]])
+        self.assertRegex(response.json()["next"], r"page=5")
+        self.assertRegex(response.json()["previous"], r"page=3")
+        self.assertNotIn("count", response.json())
+
+    def test_last_page(self):
+        url = self.url
+
+        response = self.client.get(url, {"page_size": 12, "page": 5})
+
+        self.assertEqual(list(range(49, 50)), [spell["id"] for spell in response.json()["results"]])
+        self.assertEqual(None, response.json().get("next"))
+        self.assertRegex(response.json()["previous"], r"page=4")
+        self.assertNotIn("count", response.json())
+
+    def test_invalid_page(self):
+        url = self.url
+
+        response = self.client.get(url, {"page_size": 12, "page": 15000})
+        self.assertEqual([], response.json()["results"])
+        self.assertEqual(None, response.json().get("next"))
+        self.assertRegex(response.json()["previous"], r"page=14999")
+        self.assertNotIn("count", response.json())

test_app/urls.py

@@ -28,6 +28,12 @@
     "spell",
 )
 
+router.register(
+    r"spells-light",
+    views.SpellLightViewSet,
+    "spell-light",
+)
+
 router.register(
     r"wizards/(?P<wizard_id>[^/.]+)/patronus",
     views.WizardPatronusViewSet,

test_app/views.py

@@ -2,6 +2,7 @@
 from rest_framework import status
 from rest_framework.response import Response
 
+from drf_kit import pagination
 from drf_kit.views import (
     BulkMixin,
     ModelViewSet,
@@ -85,6 +86,10 @@ class SpellViewSet(ReadOnlyModelViewSet):
     serializer_detail_class = serializers.SpellSerializer
 
 
+class SpellLightViewSet(SpellViewSet):
+    pagination_class = pagination.LightPagePagination
+
+
 class SpellCastViewSet(ModelViewSet):
     queryset = models.SpellCast.objects.all()
     serializer_class = serializers.SpellCastSerializer