一、过滤

restful规范中
-请求地址中带过滤条件
带过滤的接口只有：查询所有

内置过滤类

from rest_framework.filters import SearchFilter
class BookView(GenericViewSet, ListModelMixin):
    queryset = Book.objects.all()
    serializer_class = BookSerialzier
    filter_backends = [SearchFilter]
    # 支持这种搜索
    # # http://127.0.0.1:8000/api/v1/books/?search=红
    # search_fields = ['name']

    #http://127.0.0.1:8000/api/v1/books/?search=11  只要name或price中带11都能搜出来
    search_fields = ['name','price']

第三方过滤类

### 2.1 第三方过滤类
# pip3 install django-filter
from django_filters.rest_framework import DjangoFilterBackend
class BookView(GenericViewSet, ListModelMixin):
    queryset = Book.objects.all()
    serializer_class = BookSerialzier
    filter_backends = [DjangoFilterBackend]
    # http://127.0.0.1:8000/api/v1/books/?name=红楼梦&price=45
    # 按名字和价格精准匹配
    filterset_fields = ['name', 'price']

记得注册

自定义过滤类价格再100----200之间的图书

from .filter import MyFilter
class BookView(GenericViewSet, ListModelMixin):
    queryset = Book.objects.all()
    serializer_class = BookSerialzier
    filter_backends = [MyFilter]
	# 必须配合一个过滤类

新建一个filter文件夹，自己新写一个过滤类

from rest_framework import filters
from django.db.models import Q
class MyFilter(filters.BaseFilterBackend):
    def filter_queryset(self, request, queryset, view):
        # 返回的数据，就是过滤后的数据
        # http://127.0.0.1:8000/api/v1/books/?price=44&name=红楼梦   按名字或价格
        price = request.query_params.get('price')
        name = request.query_params.get('name')
        queryset = queryset.filter(Q(name=name) | Q(price=price))
        return queryset

 # 过滤和排序可以一起使用

二、排序

restful规范中
-请求地址中带过滤条件
排序功能的接口：查询所有

from rest_framework.filters import OrderingFilter

class BookView(GenericViewSet, ListModelMixin):
    queryset = Book.objects.all()
    serializer_class = BookSerialzier
    filter_backends = [OrderingFilter]  # 排序类
    # 配合一个类属性,按哪些字段可以排序
    # http://127.0.0.1:8000/api/v1/books/?ordering=-price,-id
    # 先按价格倒序排，价格一样，再按id倒叙排
    ordering_fields = ['price','id']

三、分页

查询所有接口，过滤和排序了，但是实际上，这个接口，都需要有分页功能
-分页的展现形式
web：下一页点解
app，小程序：下滑下一页
-接口都一样，要支持分页

drf提供给咱们，三种分页方式
基本分页
偏移分页
游标分页

from .page import MyPageNumberPagination,MyLimitOffsetPagination,MyCursorPagination
# 这种方式用的多
class BookView(GenericViewSet, ListModelMixin):
    queryset = Book.objects.all()
    serializer_class = BookSerialzier
    # http://127.0.0.1:8000/api/v1/books/?page=2&page_size=3
    # pagination_class = MyPageNumberPagination  # 只能按一种方式分页，不要放到列表中了

    # http://127.0.0.1:8000/api/v1/books/?limit=4&offset=3  # 从第三条数据开始，取4条
    # pagination_class = MyLimitOffsetPagination  # 只能按一种方式分页，不要放到列表中了


    pagination_class = MyCursorPagination  # 只能按一种方式分页，不要放到列表中了

新建一个page.py文件

from rest_framework.pagination import PageNumberPagination, LimitOffsetPagination, CursorPagination


## 基本分页
class MyPageNumberPagination(PageNumberPagination):
    # 重写几个类属性 ：4个
    page_size = 2  # 每页显示的条数
    page_query_param = 'page'  # page=4 表示第4页
    page_size_query_param = 'page_size'  # page=4&page_size=5 表示查询第4页，每页显示5条
    max_page_size = 5  # 每页最大显示多少条


## 偏移分页
class MyLimitOffsetPagination(LimitOffsetPagination):
    # 重写几个类属性 ：4个
    default_limit = 2  # 每页显示多少条
    limit_query_param = 'limit'  # limit=3  这一页取3条
    offset_query_param = 'offset'  # 偏移量是多少  offset=3&limit=2  从第3条开始，拿2条
    max_limit = 5  # 最多取5条


## 游标分页,只能上一页和下一页，不能直接跳到某一页，但是这个的速度快---》app上用它多
class MyCursorPagination(CursorPagination):
    # 重写几个类属性 ：3个
    cursor_query_param = 'cursor'  # 查询参数，其实用不到
    page_size = 2  # 每页显示多少条
    ordering = 'id'  # 必须是要分页的数据表中的字段，一般按id来

作业

继承APIView，实现上面1，2

过滤和排序

from rest_framework.views import APIView

from .models import Book
from .serializer import BookSerialzer

from rest_framework.response import Response

class BookView(APIView):
    def get(self,request):

        ordering = request.query_params.get('ordering')
        name = request.query_params.get('name')
        book_list = Book.objects.all()
        if ordering:
            book_list = book_list.order_by(ordering)

        if name:
            book_list = book_list.filter(name__contains=name)


        ser = BookSerialzer(instance=book_list,many=True)
        return Response(ser.data)

带分页

# 带分页
from .page import MyPageNumberPagination
from rest_framework.mixins import ListModelMixin
from rest_framework.generics import GenericAPIView

class BookView(APIView):
    def get(self, request):
        ordering = request.query_params.get('ordering')
        name = request.query_params.get('name')
        book_list = Book.objects.all()
        if ordering:
            book_list = book_list.order_by(ordering)
        if name:
            book_list = book_list.filter(name__contains=name)

        # 加入分页
        # page=MyPageNumberPagination().paginate_queryset(book_list, request,self)
        pagination = MyPageNumberPagination()
        page = pagination.paginate_queryset(book_list, request, self)
        ser = BookSerialzier(instance=page, many=True)
        return Response({'code': 100, 'msg': '成功',
                         'count': pagination.page.paginator.count,
                         'next': pagination.get_next_link(),
                         'previous': pagination.get_previous_link(),
                         'results': ser.data})


''' 根据源码写自己的分页
# 配置的分页类的对象调用了paginate_queryset(queryset, self.request, view=self)
page = self.paginate_queryset(queryset) #  是paginate_queryset的GenericAPIView

if page is not None:
    # 把page进行了序列化
   serializer = self.get_serializer(page, many=True)
   return self.get_paginated_response(serializer.data) # GenericAPIView--》self.paginator.get_paginated_response(data)


return Response(OrderedDict([
            ('count', self.page.paginator.count),
            ('next', self.get_next_link()),
            ('previous', self.get_previous_link()),
            ('results', data)
        ]))

'''