allow setting a custom Django Paginator in pagination.PageNumberPagination

docs/api-guide/pagination.md

@@ -95,6 +95,7 @@ The `PageNumberPagination` class includes a number of attributes that may be ove
 
 To set these attributes you should override the `PageNumberPagination` class, and then enable your custom pagination class as above.
 
+* `django_paginator_class` - The Django Paginator class to use. Default is `django.core.paginator.Paginator`, which should be fine for most usecases.
 * `page_size` - A numeric value indicating the page size. If set, this overrides the `PAGE_SIZE` setting. Defaults to the same value as the `PAGE_SIZE` settings key.
 * `page_query_param` - A string value indicating the name of the query parameter to use for the pagination control.
 * `page_size_query_param` - If set, this is a string value indicating the name of a query parameter that allows the client to set the page size on a per-request basis. Defaults to `None`, indicating that the client may not control the requested page size.

rest_framework/pagination.py

@@ -168,6 +168,8 @@ class PageNumberPagination(BasePagination):
     # Defaults to `None`, meaning pagination is disabled.
     page_size = api_settings.PAGE_SIZE
 
+    django_paginator_class = DjangoPaginator
+
     # Client can control the page using this query parameter.
     page_query_param = 'page'
 
@@ -194,7 +196,7 @@ class PageNumberPagination(BasePagination):
         if not page_size:
             return None
 
-        paginator = DjangoPaginator(queryset, page_size)
+        paginator = self.django_paginator_class(queryset, page_size)
         page_number = request.query_params.get(self.page_query_param, 1)
         if page_number in self.last_page_strings:
             page_number = paginator.num_pages

tests/test_pagination.py

@@ -2,6 +2,7 @@
 from __future__ import unicode_literals
 
 import pytest
+from django.core.paginator import Paginator as DjangoPaginator
 
 from rest_framework import (
     exceptions, filters, generics, pagination, serializers, status
@@ -249,6 +250,64 @@ class TestPageNumberPagination:
             self.paginate_queryset(request)
 
 
+class TestPageNumberPaginationOverride:
+    """
+    Unit tests for `pagination.PageNumberPagination`.
+
+    the Django Paginator Class is overridden.
+    """
+
+    def setup(self):
+        class OverriddenDjangoPaginator(DjangoPaginator):
+            # override the count in our overriden Django Paginator
+            # we will only return one page, with one item
+            count = 1
+
+        class ExamplePagination(pagination.PageNumberPagination):
+            django_paginator_class = OverriddenDjangoPaginator
+            page_size = 5
+
+        self.pagination = ExamplePagination()
+        self.queryset = range(1, 101)
+
+    def paginate_queryset(self, request):
+        return list(self.pagination.paginate_queryset(self.queryset, request))
+
+    def get_paginated_content(self, queryset):
+        response = self.pagination.get_paginated_response(queryset)
+        return response.data
+
+    def get_html_context(self):
+        return self.pagination.get_html_context()
+
+    def test_no_page_number(self):
+        request = Request(factory.get('/'))
+        queryset = self.paginate_queryset(request)
+        content = self.get_paginated_content(queryset)
+        context = self.get_html_context()
+        assert queryset == [1]
+        assert content == {
+            'results': [1, ],
+            'previous': None,
+            'next': None,
+            'count': 1
+        }
+        assert context == {
+            'previous_url': None,
+            'next_url': None,
+            'page_links': [
+                PageLink('http://testserver/', 1, True, False),
+            ]
+        }
+        assert not self.pagination.display_page_controls
+        assert isinstance(self.pagination.to_html(), type(''))
+
+    def test_invalid_page(self):
+        request = Request(factory.get('/', {'page': 'invalid'}))
+        with pytest.raises(exceptions.NotFound):
+            self.paginate_queryset(request)
+
+
 class TestLimitOffset:
     """
     Unit tests for `pagination.LimitOffsetPagination`.