RESTAPI简介与DRF使用

RESTAPI

以资源为url，通过不同的请求方式实现不同的行为。

以资源名作为url

POST:增 …/student/

GET：查所有 …/student/

GET：查单个 …/student/<pk>/ 获取id=pk的学生

DELETE：删 …/student/<pk>/

PUT：改全部 …/student/<pk>/

PATCH：改部分 …/student/<pk>/

视图函数

数据从前端传到服务器时，需要反序列化成能存入数据库的数据，同样，数据从数据库取出，需要序列化成可以传给前端的Json数据，drf里的序列化器可以很好地实现序列化与反序列化两个步骤。

1. 序列化器

1. 自己写的序列化器：

设置字段，然后可以设置POST和UPDATE时数据库的操作

class BookSerializers(serializers.Serializer):title = serializers.CharField(max_length=32)price = serializers.IntegerField()pub_date = serializers.DateField()def create(self, validated_data):# 添加数据逻辑new_book = Book.objects.create(**validated_data)return new_bookdef update(self, instance, validated_data):Book.objects.filter(pk=instance.pk).update(**validated_data)updated_book = Book.objects.get(pk=instance.pk)return updated_book

2. 使用ModelSerializer，里面实现了create和update方法

# ModelSerializer 模型序列化器，只需要配置
class BookSerializers(serializers.ModelSerializer):date = serializers.DateField(source='pub_date')class Meta:model = Book#fields = '__all__'exclude = ["pub_date"]

2. 视图函数

1. 继承APIView，自己写get/post/get/put/delete方法

class BookView(APIView):def get(self, request):# 获取所有书籍book_list = Book.objects.all()# 构建序列化器对象serializer = BookSerializers(instance=book_list, many=True)return Response(serializer.data)def post(self, request):serializer = BookSerializers(data=request.data)if serializer.is_valid():# 通过# new_book = Book.objects.create(**serializer.validated_data)serializer.save()return Response(serializer.data)else:# 校验失败return Response(serializer.errors)return Response()class BookDetailView(APIView):def get(self, request, id):book = Book.objects.get(pk=id)serializer = BookSerializers(instance=book, many=False)return Response(serializer.data)def put(self, request, id):update_book = Book.objects.get(pk=id)serializer = BookSerializers(instance=update_book, data=request.data)if  serializer.is_valid():serializer.save()return Response(serializer.data)else:return Response(serializer.errors)def delete(self, request, id):Book.objects.get(pk=id).delete()return Response()

2. 继承GenericAPIView

好像没有什么区别，就是把请求和序列化器在类里声明了，然后使用self.get_serializer来获得序列化器，用get_objetct来获取查询结果。

class PublishDetailView(GenericAPIView):queryset = Publish.objects.all()serializer_class = PublishSerializersdef get(self, request, pk):serializer = self.get_serializer(instance=self.get_object(), many=False)return Response(serializer.data)def put(self, request, pk):serializer = self.get_serializer(instance=self.get_object(), data=request.data)if serializer.is_valid():serializer.save()return Response(serializer.data)else:return Response(serializer.errors)def delete(self, request, pk):self.get_object().delete()return Response()

3. 继承generic的ListCreateAPIView, RetrieveUpdateDestroyAPIView

查询全体和查询单人需要写两个视图函数

class PublishView(ListCreateAPIView):queryset = Publish.objects.all()serializer_class = PublishSerializersclass PublishDetailView(RetrieveUpdateDestroyAPIView):queryset = Publish.objects.all()serializer_class = PublishSerializers

4. 继承ModelViewSet

一行解决

class AuthorView(ModelViewSet):queryset = Author.objects.all()serializer_class = AuthorSerializers