使用 API-View 在 Django-Rest-Framework 中分页

Question

我目前有一个 API 视图设置如下：

class CartView(APIView):
    authentication_classes = [SessionAuthentication, TokenAuthentication]
    permission_classes = [IsAuthenticated, ]
    api_view = ['GET', 'POST']

    def get(self, request, format=None):
        try:
            cart = request.user.cart
        except Cart.DoesNotExist:
            cart = Cart.objects.create(user=request.user)
        cart_details = cart.cart_details.all()
        serializer = CartDetailSerializer(cart_details, many=True, fields=['id', 'item', 'quantity', 'product_type'])
        return Response(serializer.data)

这里CartDetailSerializer是一个普通的ModelSerializer。

我想对此进行分页 API。然而，在 DRF 的文档中，我发现了这个：

If you're using a regular APIView, you'll need to call into the pagination API yourself to ensure you return a paginated response.

没有提供关于如何对常规 APIView API 进行分页的示例。

任何人都可以 post 我可以在上面的场景中使用的示例。

谢谢。

Answer 1

使用常规APIView时，需要使用Django自带的Paginatorclass。

Django Pagination in Views

在您的情况下，您可以在将查询集发送到序列化程序之前对其进行分页。

像这样：

def get(self, request, format=None):
    try:
        cart = request.user.cart
    except Cart.DoesNotExist:
        cart = Cart.objects.create(user=request.user)
    cart_details = cart.cart_details.all()

    paginator = Paginator(cart_details, 10)
    page = request.GET.get('page')

    try:
        cart_details = paginator.page(page)
    except PageNotAnInteger:
        # If page is not an integer, deliver first page.
        cart_details = paginator.page(1)
    except EmptyPage:
        # If page is out of range (e.g. 9999), deliver last page of results.
        cart_details = paginator.page(paginator.num_pages)
    serializer = CartDetailSerializer(cart_details, many=True, fields=['id', 'item', 'quantity', 'product_type'])
    return Response(serializer.data)

希望对您有所帮助。

Answer 2

虽然 rayy 提到的方式是可能的，但 django-rest-framework 可以通过一些额外的功能在内部处理这个问题，使您的 API 工作变得更加容易。（*注意 django-rest-framework 的分页是从 django.core.paginator 的 Django paginator 构建的）

紧接着你引用的是解决这个问题的关键信息：

Pagination is only performed automatically if you're using the generic views or viewsets. If you're using a regular APIView, you'll need to call into the pagination API yourself to ensure you return a paginated response. See the source code for the mixins.ListMixin and generics.GenericAPIView classes for an example.

对此处陈述的内容稍作更正：查看 ListModelMixin。

如果您转到这两个链接，您可以看到上述文件的源代码： generics.py mixins.py

你需要做的是包含类似下面的东西，让分页在 APIView 中工作（**注意：这段代码未经测试，但想法是正确的。还有一个更好的方法写这篇文章而不是必须在每个视图中都包含代码，但我会把它留给你让我的回答简短易懂）：

from __future__ import absolute_import
# if this is where you store your django-rest-framework settings
from django.conf import settings
from rest_framework.views import APIView
from rest_framework.response import Response

from .models import Cart 

class CartView(APIView):
    pagination_class = settings.DEFAULT_PAGINATION_CLASS

    def get(self, request, format=None):
        #assuming every other field in the model has a default value    
        cart = Cart.objects.get_or_create(user=request.user)

        #for a clear example
        cart_details = Cart.objects.all()

        page = self.paginate_queryset(cart_details)
        if page is not None:
            serializer = CartDetailSerializer(page, many=True)
            return self.get_paginated_response(serializer.data)

        serializer = CartDetailSerializer(cart_details, many=True)
        return Response(serializer.data)

    @property
    def paginator(self):
        """
        The paginator instance associated with the view, or `None`.
        """
        if not hasattr(self, '_paginator'):
            if self.pagination_class is None:
                self._paginator = None
            else:
                self._paginator = self.pagination_class()
        return self._paginator

    def paginate_queryset(self, queryset):
        """
        Return a single page of results, or `None` if pagination is disabled.
        """
        if self.paginator is None:
            return None
        return self.paginator.paginate_queryset(queryset, self.request, view=self)

    def get_paginated_response(self, data):
        """
        Return a paginated style `Response` object for the given output data.
        """
        assert self.paginator is not None
        return self.paginator.get_paginated_response(data)

我希望这对您和遇到此问题的其他人有更多帮助post。

Answer 3

我正在使用 DRF 3.6.2 版。你不需要写那么多代码。只需使用这个简单的步骤。

 class ProductPagination(PageNumberPagination):
        page_size = 5

    class product_api(generics.ListCreateAPIView):    
            queryset = Products.objects.all()
            serializer_class = product_serilizer
            pagination_class = ProductPagination

如果你想通过get方法实现搜索功能，你可以写下面的代码

class ProductPagination(PageNumberPagination):
        page_size = 5

class product_api(generics.ListCreateAPIView):
    queryset = Products.objects.all()
    serializer_class = product_serilizer
    pagination_class = SearchProductPagination    

    def get_queryset(self):
        qs = super(product_search_api,self).get_queryset()
        searched_product = self.request.query_params.get('searched_product',None)
        if search:
            qs = Products.objects.filter(Q(product_name__icontains= searched_product))
        return qs

Answer 4

我更喜欢扩展 Paginator class，这是它的样子：

from rest_framework import status
from rest_framework.exceptions import NotFound as NotFoundError
from rest_framework.pagination import PageNumberPagination # Any other type works as well
from rest_framework.response import Response
from rest_framework.views import APIView

class CustomPaginator(PageNumberPagination):
    page_size = 10 # Number of objects to return in one page

    def generate_response(self, query_set, serializer_obj, request):
        try:
            page_data = self.paginate_queryset(query_set, request)
        except NotFoundError:
            return Response({"error": "No results found for the requested page"}, status=status.HTTP_400_BAD_REQUEST)

        serialized_page = serializer_obj(page_data, many=True)
        return self.get_paginated_response(serialized_page.data)

class CartView(APIView):

    def get(self, request, format=None):
        cart_details = Cart.objects.filter(user=request.user) # or any other query
        paginator = CustomPaginator()
        response = paginator.generate_response(cart_details, CartDetailSerializer, request)
        return response

使用 API-View 在 Django-Rest-Framework 中分页

Pagination in Django-Rest-Framework using API-View

django

django-pagination

django-rest-framework