This commit is contained in:
Kevin Turner 2017-09-27 08:52:37 +00:00 committed by GitHub
commit 878ac12d64
2 changed files with 56 additions and 2 deletions

View File

@ -7,6 +7,7 @@ from __future__ import unicode_literals
from base64 import b64decode, b64encode
from collections import OrderedDict, namedtuple
import decimal
from django.core.paginator import Paginator as DjangoPaginator
from django.core.paginator import InvalidPage
@ -497,6 +498,9 @@ class CursorPagination(BasePagination):
# queries, by having a hard cap on the maximum possible size of the offset.
offset_cutoff = 1000
__rounding_down = decimal.Context(prec=14, rounding=decimal.ROUND_FLOOR)
__rounding_up = decimal.Context(prec=14, rounding=decimal.ROUND_CEILING)
def paginate_queryset(self, queryset, request, view=None):
self.page_size = self.get_page_size(request)
if not self.page_size:
@ -775,6 +779,13 @@ class CursorPagination(BasePagination):
attr = instance[field_name]
else:
attr = getattr(instance, field_name)
if isinstance(attr, float):
if ordering[0][0] == '-':
attr = self.__rounding_down.create_decimal_from_float(attr)
else:
attr = self.__rounding_up.create_decimal_from_float(attr)
return six.text_type(attr)
def get_paginated_response(self, data):

View File

@ -7,9 +7,9 @@ from django.db import models
from django.test import TestCase
from rest_framework import (
exceptions, filters, generics, pagination, serializers, status
exceptions, filters, generics, pagination, serializers, status, viewsets
)
from rest_framework.pagination import PAGE_BREAK, PageLink
from rest_framework.pagination import CursorPagination, PAGE_BREAK, PageLink
from rest_framework.request import Request
from rest_framework.test import APIRequestFactory
@ -986,3 +986,46 @@ def test_get_displayed_page_numbers():
assert displayed_page_numbers(7, 9) == [1, None, 6, 7, 8, 9]
assert displayed_page_numbers(8, 9) == [1, None, 7, 8, 9]
assert displayed_page_numbers(9, 9) == [1, None, 7, 8, 9]
class ThreeItemCursorPagination(CursorPagination):
page_size = 3
ordering = 'score'
class FloatyModel(models.Model):
score = models.FloatField()
class PassThroughSerializer(serializers.BaseSerializer):
def to_representation(self, item):
return item
class FloatyViewSet(viewsets.ReadOnlyModelViewSet):
queryset = FloatyModel.objects.all()
pagination_class = ThreeItemCursorPagination
serializer_class = PassThroughSerializer
page_size = 3
class TestCursorPaginationWithFloatingPointPosition(TestCase):
def setUp(self):
self.view = FloatyViewSet.as_view(actions={'get': 'list'})
def test_page_boundary_does_not_repeat_elements(self):
for i in range(12):
FloatyModel.objects.create(score=i/9.0)
request = factory.get('/')
first_response = self.view(request)
first_page_last_item = first_response.data['results'][-1]
second_request = factory.get(first_response.data['next'])
second_response = self.view(second_request)
second_page_first_item = second_response.data['results'][0]
self.assertNotEqual(first_page_last_item.pk, second_page_first_item.pk)
self.assertLess(first_page_last_item.score, second_page_first_item.score)