DRF视图和路由

from django.conf.urls import url
from SerDemo import views

urlpatterns = [
    # 第一二版本
    # url(r‘^book/$‘, views.BookView.as_view()),
    # url(r‘^book/(?P<edit_id>\d+)‘, views.BookEditView.as_view()),

]

from rest_framework import serializers
from app01 import models


class PublisherSerializer(serializers.Serializer):
    id = serializers.IntegerField()
    title = serializers.CharField(max_length=32)


class AuthorSerializer(serializers.Serializer):
    id = serializers.IntegerField()
    name = serializers.CharField(max_length=32)


# 一个判断某一个字段是否含有敏感信息的函数, 直接调用即可
def my_validate(value):
    if "敏感信息" in value.lower():
        raise serializers.ValidationError("存在敏感词汇!!!")


class BookSerializer(serializers.Serializer):
    id = serializers.IntegerField(required=False)  # required 为False时, 反序列化不做校验
    title = serializers.CharField(max_length=32, validators=[my_validate])
    pub_time = serializers.DateField()
    category = serializers.CharField(source="get_category_display", read_only=True)
    # 自定义一个字段只用来反序列化接收使用
    post_category = serializers.IntegerField(write_only=True)

    publisher = PublisherSerializer(read_only=True)
    publisher_id = serializers.IntegerField(write_only=True)
    # 多对多有many参数
    author = AuthorSerializer(many=True, read_only=True)
    author_list = serializers.ListField(write_only=True)

    # 新增数据要重写的create方法
    def create(self, validated_data):
        # validated_data是验证通过的数据
        # 通过ORM操作给Book表增加数据
        # 添加除多对多字段的所有字段
        book_obj = models.Book.objects.create(
            title=validated_data["title"],
            pub_time=validated_data["pub_time"],
            category=validated_data["post_category"],
            publisher_id=validated_data["publisher_id"],
        )
        # 添加多对多字段
        book_obj.author.add(*validated_data["author_list"])
        return book_obj

    # 更新数据要重写update方法
    def update(self, instance, validated_data):
        # instance 是要更新的对象
        # 对除多对多字段以外的字段进行更新, 并设置当前已存在的数据为默认值
        instance.title = validated_data.get("title", instance.title)
        instance.pub_time = validated_data.get("pub_time", instance.pub_time)
        instance.category = validated_data.get("post_category", instance.category)
        instance.publisher_id = validated_data.get("publisher_id", instance.publisher_id)
        # 判断前端传过来的数据是否含有author_list字段, 如果有则更新, 没有就不变动
        if validated_data.get("author_list"):
            instance.author.set(validated_data["author_list"])
        instance.save()
        return instance


# 对前端传过来的数据进行条件控制
def validate(self, attrs):
    # 相当于钩子函数
    # attrs是一个字典, 含有传过来的所有字段
    if "python" in attrs["title"].lower() and attrs["post_category"] == 1:
        return attrs
    else:
        raise serializers.ValidationError("分类或标题不匹配")

from rest_framework.views import APIView
from app01 import models
from .serializers import BookSerializer
from rest_framework.response import Response

from rest_framework.viewsets import ViewSetMixin



# Create your views here.


# 版本一
class BookView(APIView):
    def get(self, request):
        book_queryset = models.Book.objects.all()
        # 用序列化器进行序列化
        ser_obj = BookSerializer(book_queryset, many=True)

        return Response(ser_obj.data)

    def post(self, request):
        # 接收前端传过来的数据
        book_obj = request.data
        # 对前端传过来的数据使用自定义序列化方法进行校验(是否合法等)
        ser_obj = BookSerializer(data=book_obj)
        # 如果校验通过做些什么
        if ser_obj.is_valid():
            ser_obj.save()
            # validated_data是校验通过之后的数据
            return Response(ser_obj.validated_data)
        # 验证不通过返回错误信息
        return Response(ser_obj.errors)


class BookEditView(APIView):
    def get(self, request, edit_id):
        book_obj = models.Book.objects.filter(id=edit_id).first()
        ser_obj = BookSerializer(book_obj)
        return Response(ser_obj.data)

    def put(self, request, edit_id):
        book_obj = models.Book.objects.filter(id=edit_id).first()
        ser_obj = BookSerializer(instance=book_obj, data=request.data, partial=True)
        if ser_obj.is_valid():
            ser_obj.save()
            return Response(ser_obj.validated_data)
        return Response(ser_obj.errors)

    def delete(self, request, edit_id):
        book_obj = models.Book.objects.filter(id=edit_id).first()
        if not book_obj:
            return Response("删除对象不存在!")
        book_obj.delete()
        return Response("删除成功了呢!")

from django.conf.urls import url
from SerDemo import views

urlpatterns = [
    # 第一二版本
    # url(r‘^book/$‘, views.BookView.as_view()),
    # url(r‘^book/(?P<edit_id>\d+)‘, views.BookEditView.as_view()),


]

class GenericAPIView(APIView):
    """
    定义一个公共的类, 用来获取需要的资源
    """
    # 设置默认操作的数据为空
    queryset = None
    # 设置需要使用的序列化器为空
    serializer_class = None

    def get_queryset(self):
        """
        定义一个获取需要操作的数据的函数
        子类函数直接调用即可
        子类中调用此方法, 返回值中的self指的是调用此方法的子类的实力化对象
        queryset属性在本类中是None, 每一个继承此类的子类中都会重写queryset和serializer_class方法
        然后子类中执行此类中的方法是去执行子类对应的属性.
        :return:
        """
        return self.queryset.all()

    def get_serializer_class(self, *args, **kwargs):
        return self.serializer_class(*args, **kwargs)


class ListModelMixin:
    """
    定义一个展示类,将展示方法统一写成一个方法
    """

    def list(self, request):
        queryset = self.get_queryset()
        ser_obj = self.get_serializer_class(queryset, many=True)
        return Response(ser_obj.data)


class CreateModeMixin:
    """
    新增的视图类
    """

    def create(self, request):
        ser_obj = self.get_serializer_class(data=request.data)
        if ser_obj.is_valid():
            ser_obj.save()
            return Response(ser_obj.validated_data)
        return Response(ser_obj.errors)


class EditModeMixin:
    """
    编辑的视图类
    """

    def retrieve(self, request, id):
        obj = self.get_queryset().filter(id=id).first()
        ser_obj = self.get_serializer_class(obj)
        return Response(ser_obj.data)


class UpdateModeMixin:
    """
    更新的视图类
    """

    def update(self, request, id):
        obj = self.get_queryset().filter(id=id).first()
        ser_obj = self.get_serializer_class(instance=obj, data=request.data, partial=True)
        if ser_obj.is_valid():
            ser_obj.save()
            return Response(ser_obj.validated_data)
        return Response(ser_obj.errors)


class DeleteModeMixin:
    """
    删除的视图类
    """

    def destroy(self, request, id):
        obj = self.get_queryset().filter(id=id).first()
        if not obj:
            return Response("删除的对象不存在!")
        obj.delete()
        return Response("删除了呢")


class ListCreateAPIview(GenericAPIView, ListModelMixin, CreateModeMixin):
    pass


class OperationAPIview(GenericAPIView, EditModeMixin, UpdateModeMixin, DeleteModeMixin):
    pass


class BookView(ListCreateAPIview):
    # 定义queryset属性时, DRF方法内部和关键字重名, 内部会识别并将此属性做缓存
    # 换个名字DRF不识别属性, 不做缓存, 也就不需要.all()
    queryset = models.Book.objects.all()
    serializer_class = BookSerializer

    def get(self, request):
        return self.list(request)

    def post(self, request):
        return self.create(request)


class BookEditView(OperationAPIview):
    queryset = models.Book.objects.all()
    serializer_class = BookSerializer

    def get(self, request, edit_id):
        return self.retrieve(request, edit_id)

    def put(self, request, edit_id):
        return self.update(request, edit_id)

    def delete(self, request, edit_id):
        return self.destroy(request, edit_id)

from SerDemo import views

urlpatterns = [

    # 第三版
    # url(r‘^book/$‘, views.BookModelView.as_view({"get": "list", "post": "create"})),
    # url(r‘^book/(?P<pk>\d+)‘, views.BookModelView.as_view({"get": "retrieve", "put": "update", "delete": "destroy"})),
]

from rest_framework.viewsets import ViewSetMixin


# 重写了源码中的as_view()方法, 是as_view方法可以传参数
# 在执行dispatch()方法之前
class ModelViewSet(ViewSetMixin, ListCreateAPIview, OperationAPIview):
    pass


class BookModelView(viewsets.ModelViewSet):
    queryset = models.Book.objects.all()
    serializer_class = BookSerializer