serializers

2021-06-15

2021-06-12

本文字数: 1.3k 阅读时长: 6 分钟

阅读次数次

初步使用serializer

使用serializers的好处
- 1.图片路径返回时，普通的view需要手动添加补全路径，drf已封装
- 2.无论是django.core的serializer还是django.forms.models的model_to_dict都已经被serializer封装替代，使用比较方便
- 3.drf的自带文档功能，需要serializer和coreapi的支持
- 4.代替了form验证的功能

serializer

from rest_framework import serializers
from .models import Goods
class GoodsSerializer(serializers.ModelSerializer):
    name = serializers.CharField(required=True, max_length=100)
    click_num = serializers.IntegerField(default=0)

    class Meta:
        model = Goods
        fields = ('name', 'click_num')

views

from .models import Goods
from .serializers import GoodsSerializer
from django.http import Http404
from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework import status

class GoodsListView(APIView):
    """
    List goods
    """
    def get(self, request):
        goods = Goods.objects.all()[:10]
        goods_serializer = GoodsSerializer(goods, many=True)
        return Response(goods_serializer.data)

urls

1 2	# 商品列表页面 path(r'goods/', GoodsListView.as_view(), name="goods-list"),

细枝末节

1.保存数据

# 在serializer中重写create
class GoodsSerializer(serializers.ModelSerializer):
    name = serializers.CharField(required=True, max_length=100)
    click_num = serializers.IntegerField(default=0)

    class Meta:
        model = Goods
        fields = ('name', 'click_num')

    def create(self, validated_data):
        """
        Create and return a new `Snippet` instance, given the validated data.
        """
        return Goods.objects.create(**validated_data)
        
        
class GoodsListView(APIView):
    """
    List goods
    """
    def get(self, request):
        goods = Goods.objects.all()[:10]
        goods_serializer = GoodsSerializer(goods, many=True)
        return Response(goods_serializer.data)

    def post(self, request):
        serializer = GoodsSerializer(data=request.data)
        if serializer.is_valid():
            # save会去调用create
            serializer.save()
            # 保存成功返回201
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

2 fileds = “__all__”即可序列化全部字段

3.外键序列化需要嵌套外键自身的serializer

class CategorySerializer(serializers.ModelSerializer):
    class Meta:
        model = GoodsCategory
        fields = '__all__'

class GoodsSerializer(serializers.ModelSerializer):
    # 嵌套序列化外键
    category = CategorySerializer()
    
    class Meta:
        model = Goods
        fields = '__all__'

Serializer Fields

core
- read_only
  - 不在创建和更新的操作中，在序列化列表时
- write_only
  - 序列化时不使用这个字段，在创建和更新反序列化时使用
- required
  - 反序列化不需要此字段
- default
- allow_null
- source
- error_message
- label
- help_text
- initial
- style
各种字段请查看官方链接

最简单的view-genericapiview/viewSet

Apiview并不是最上流的view，还有更简单的view

from rest_framework import mixins
from rest_framework import generics

class GoodsListView(mixins.ListModelMixin, generics.GenericAPIView):
    queryset = Goods.objects.all()[:10]
    serializer_class = GoodsSerializer

    # list在listModelMixin中，帮助我们分页，调用序列化等
    def get(self, request, *args, **kwargs):
        return self.list(request, *args, **kwargs)

封装好的view

class CreateAPIView(mixins.CreateModelMixin,
                    GenericAPIView):
    """
    Concrete view for creating a model instance.
    """
    def post(self, request, *args, **kwargs):
        return self.create(request, *args, **kwargs)


class ListAPIView(mixins.ListModelMixin,
                  GenericAPIView):
    """
    Concrete view for listing a queryset.
    """
    def get(self, request, *args, **kwargs):
        return self.list(request, *args, **kwargs)


class RetrieveAPIView(mixins.RetrieveModelMixin,
                      GenericAPIView):
    """
    Concrete view for retrieving a model instance.
    """
    def get(self, request, *args, **kwargs):
        return self.retrieve(request, *args, **kwargs)

viewSet

from rest_framework import viewsets


class GoodsListViewSet(mixins.ListModelMixin, viewsets.GenericViewSet):
    queryset = Goods.objects.all()
    serializer_class = GoodsSerializer
    pagination_class = GoodsPagination

两种路由注册方式：

1.正常注册

from goods.views import GoodsListViewSet
goods_list = GoodsListViewSet.as_view({
        'get': 'list',
        'post': 'create'
})
- path(r'goods/', goods_list, name="goods-list"),

2.使用router

from rest_framework.routers import DefaultRouter

router = DefaultRouter()
# 配置goods的url(把注册的东西转换为url的配置）
router.register(r'goods', GoodsListViewSet)
path(r'', include(router.urls))
# 它会自动把get转到list，post转到create等

分页

在setting里配置REST_FRAMEWORK

REST_FRAMEWORK = {
        'DEFAULT_PAGINATION_CLASS': 'rest_framework.pagination.PageNumberPagination',
        # Pagination
        'PAGE_SIZE': 10,
}

这里可以看出可以简单自定义继承PageNumberPagination的分页

class ArticlePagination(PageNumberPagination):
    page_size = 4 # 表示每页的默认显示数量
    page_size_query_param = 'page_size' # 表示url中每页数量参数
    page_query_param = 'p' # 表示url中的页码参数
    max_page_size = 100  # 表示每页最大显示数量，做限制使用，避免突然大量的查询数据，数据库崩溃

在view中指定pagination_class即可

过滤

1.通过sql进行简单过滤

class GoodsListViewSet(mixins.ListModelMixin, viewsets.GenericViewSet):

    serializer_class = GoodsSerializer
    pagination_class = GoodsPagination

    def get_queryset(self):
        self.queryset = Goods.objects.all()  # 这里只是帮我们拼凑了sql脚本，并没有执行，只有在for循环的时候执行
        price_min = self.request.query_params.get("price_min", 0)
        if price_min:
            self.queryset = self.queryset.filter(shop_price__gt=int(price_min))
        return self.queryset

2.通过django-filter

from django_filters.rest_framework import DjangoFilterBackend

class GoodsListViewSet(mixins.ListModelMixin, viewsets.GenericViewSet):
    queryset = Goods.objects.all()  # 这里只是帮我们拼凑了sql脚本，并没有执行，只有在for循环的时候执行
    serializer_class = GoodsSerializer
    pagination_class = GoodsPagination
    filter_backends = (DjangoFilterBackend, )
    filter_fields = ('name', 'shop_price')

通过rest_framework的seachfilter进行过滤

from .filters import GoodsFilter
from rest_framework import filters


class GoodsListViewSet(mixins.ListModelMixin, viewsets.GenericViewSet):
    queryset = Goods.objects.all()  # 这里只是帮我们拼凑了sql脚本，并没有执行，只有在for循环的时候执行
    serializer_class = GoodsSerializer
    pagination_class = GoodsPagination
    filter_backends = (DjangoFilterBackend, filters.SearchFilter)

排序过滤

1	filter_backends = (DjangoFilterBackend, filters.SearchFilter, filters.OrderingFilter)

通过django_filter.rest_framework.FielterSet自定义(新建filter文件夹)

from .models import Goods
import django_filters

class GoodsFilter(django_filters.rest_framework.FilterSet):
    """商品的过滤类"""
    price_min = django_filters.NumberFilter(field_name="shop_price", lookup_expr='gte')  # greater than or equal to
    price_max = django_filters.NumberFilter(field_name="shop_price", lookup_expr='lte')  # less than or equal to
    name = django_filters.CharFilter(field_name='name', lookup_expr='icontains')
    
    class Meta:
        model = Goods
        fields = ["name", "price_min", "price_max"]
        
class GoodsListViewSet(mixins.ListModelMixin, viewsets.GenericViewSet):
    queryset = Goods.objects.all()  # 这里只是帮我们拼凑了sql脚本，并没有执行，只有在for循环的时候执行
    serializer_class = GoodsSerializer
    pagination_class = GoodsPagination
    filter_backends = (DjangoFilterBackend, filters.SearchFilter)
    filter_class = GoodsFilter
    # 不限于某个字段，只要配置进了search_fields就可以模糊搜索
    search_fields = ('name', 'goods_brief', 'goods_desc')

webframedjango

serializers

初步使用serializer

细枝末节

Serializer Fields

最简单的view-genericapiview/viewSet

分页

过滤

跨域问题