【一】为什么要使用分页
- 我们数据表中可能会有成千上万条数据
- 当我们访问某张表的所有数据时
- 我们不太可能需要一次把所有的数据都展示出来
- 因为数据量很大
- 对服务端的内存压力比较大还有就是网络传输过程中耗时也会比较大。
- 通常我们会希望一部分一部分去请求数据
【二】DRF使用分页器
【1】分页模式
- rest framework中提供了三种分页模式:
from rest_framework.pagination import PageNumberPagination, LimitOffsetPagination, CursorPagination
【2】全局配置
REST_FRAMEWORK = {
'DEFAULT_PAGINATION_CLASS': 'rest_framework.pagination.LimitOffsetPagination',
'PAGE_SIZE': 100
}
【3】局部配置
class PublisherViewSet(ModelViewSet):
queryset = models.Publisher.objects.all()
serializer_class = PublisherModelSerializer
pagination_class = PageNumberPagination # 注意不是列表(只能有一个分页模式)
【三】DRF内置分页器
(1)分页器
class MyPageNumber(PageNumberPagination):
page_size = 2 # 每页显示多少条
page_size_query_param = 'size' # URL中每页显示条数的参数
page_query_param = 'page' # URL中页码的参数
max_page_size = None # 最大页码数限制
(2)视图
class ArticleList(APIView):
def get(self, request, *args, **kwargs):
res = {"code": 0}
article_list = models.Article.objects.all().order_by("id")
# 分页
page_obj = MyPageNumber()
page_article = page_obj.paginate_queryset(queryset=article_list, request=request, view=self)
ser_obj = ArticleSerializer(page_article, many=True)
res["data"] = ser_obj.data
return Response(res)
(3)返回带页码链接的响应
class ArticleList(APIView):
def get(self, request, *args, **kwargs):
res = {"code": 0}
article_list = models.Article.objects.all().order_by("id")
# 分页
page_obj = MyPageNumber()
page_article = page_obj.paginate_queryset(queryset=article_list, request=request, view=self)
ser_obj = ArticleSerializer(page_article, many=True)
res["data"] = ser_obj.data
return page_obj.get_paginated_response(res)
(1)分页器
# offset分页
class MyLimitOffset(LimitOffsetPagination):
default_limit = 1
limit_query_param = 'limit'
offset_query_param = 'offset'
max_limit = 999
(2)视图
class ArticleList(APIView):
def get(self, request, *args, **kwargs):
res = {"code": 0}
article_list = models.Article.objects.all().order_by("id")
# 分页
page_obj = MyLimitOffset()
page_article = page_obj.paginate_queryset(queryset=article_list, request=request, view=self)
ser_obj = ArticleSerializer(page_article, many=True)
res["data"] = ser_obj.data
return page_obj.get_paginated_response(res)
(1)分页器
# 加密分页
class MyCursorPagination(CursorPagination):
cursor_query_param = 'cursor'
page_size = 1
ordering = '-id' # 重写要排序的字段
(2)视图
class ArticleList(APIView):
def get(self, request, *args, **kwargs):
res = {"code": 0}
article_list = models.Article.objects.all().order_by("id")
# 分页
page_obj = MyCursorPagination()
page_article = page_obj.paginate_queryset(queryset=article_list, request=request, view=self)
ser_obj = ArticleSerializer(page_article, many=True)
res["data"] = ser_obj.data
# return Response(res)
return page_obj.get_paginated_response(res)