Day62 Django-DRF视图相关

╰半夏微凉° 2023-08-17 15:29 143阅读 0赞

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##### 　　3. 状态码 #####

为了方便设置状态码， REST Framework在rest\_framework.status模块中提供了常用状态码常量。

3.1 信息告知---1XX

HTTP_100_CONTINUE
    HTTP_101_SWITCHING_PROTOCOLS

3.2 成功---2XX

HTTP_200_OK
    HTTP_201_CREATED
    HTTP_202_ACCEPTED
    HTTP_203_NON_AUTHORITATIVE_INFORMATION
    HTTP_204_NO_CONTENT
    HTTP_205_RESET_CONTENT
    HTTP_206_PARTIAL_CONTENT
    HTTP_207_MULTI_STATUS

3.3 重定向---3XX

HTTP_300_MULTIPLE_CHOICES
    HTTP_301_MOVED_PERMANENTLY
    HTTP_302_FOUND
    HTTP_303_SEE_OTHER
    HTTP_304_NOT_MODIFIED
    HTTP_305_USE_PROXY
    HTTP_306_RESERVED
    HTTP_307_TEMPORARY_REDIRECT

3.4 客户端错误---4XX

HTTP_400_BAD_REQUEST
    HTTP_401_UNAUTHORIZED
    HTTP_402_PAYMENT_REQUIRED
    HTTP_403_FORBIDDEN
    HTTP_404_NOT_FOUND
    HTTP_405_METHOD_NOT_ALLOWED
    HTTP_406_NOT_ACCEPTABLE
    HTTP_407_PROXY_AUTHENTICATION_REQUIRED
    HTTP_408_REQUEST_TIMEOUT
    HTTP_409_CONFLICT
    HTTP_410_GONE
    HTTP_411_LENGTH_REQUIRED
    HTTP_412_PRECONDITION_FAILED
    HTTP_413_REQUEST_ENTITY_TOO_LARGE
    HTTP_414_REQUEST_URI_TOO_LONG
    HTTP_415_UNSUPPORTED_MEDIA_TYPE
    HTTP_416_REQUESTED_RANGE_NOT_SATISFIABLE
    HTTP_417_EXPECTATION_FAILED
    HTTP_422_UNPROCESSABLE_ENTITY
    HTTP_423_LOCKED
    HTTP_424_FAILED_DEPENDENCY
    HTTP_428_PRECONDITION_REQUIRED
    HTTP_429_TOO_MANY_REQUESTS
    HTTP_431_REQUEST_HEADER_FIELDS_TOO_LARGE
    HTTP_451_UNAVAILABLE_FOR_LEGAL_REASONS

3.5 服务器错误---5XX

HTTP_500_INTERNAL_SERVER_ERROR
    HTTP_501_NOT_IMPLEMENTED
    HTTP_502_BAD_GATEWAY
    HTTP_503_SERVICE_UNAVAILABLE
    HTTP_504_GATEWAY_TIMEOUT
    HTTP_505_HTTP_VERSION_NOT_SUPPORTED
    HTTP_507_INSUFFICIENT_STORAGE
    HTTP_511_NETWORK_AUTHENTICATION_REQUIRED

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具体代码参考：[https://www.cnblogs.com/Michael--chen/p/11235456.html][https_www.cnblogs.com_Michael--chen_p_11235456.html]

![1673775-20190724192532976-651960448.png][]

用到的序列化器类：

from students.models import Student
    from rest_framework import serializers
    
    
    class StudentModelSerializer(serializers.ModelSerializer):
    
        class Meta:
            model = Student
            fields = ["id", "name", "age", "sex"]
            extra_kwargs = {
                "name": {
        "max_length": 10, "min_length": 4},
                "age": {
        "max_value": 150, "min_value": 0},
            }
    
        def validate_name(self, data):
            if data == "root":
                raise serializers.ValidationError("用户名不能为root！")
            return data
    
        def validate(self, attrs):
            name = attrs.get('name')
            age = attrs.get('age')
    
            if name == "alex" and age == 22:
                raise serializers.ValidationError("alex在22时的故事。。。")
    
            return attrs

对应的urls的文件：

urlpatterns = [
        # View与APIView的区别
        path("student1/", views.Student1View.as_view()),
        path("student2/", views.Student2APIView.as_view()),
    ]

views.py文件：

from django.views import View
    from django.http import JsonResponse
    
    
    class Student1View(View):
        def get(self, request):
            print(request)  # 这是django提供的HttpRequest类
            print(request.GET)
            """打印效果：
            <WSGIRequest: GET '/req/student1/'>
            """
            data_dict = {
        'name': "alex", "age": 18}
    
            return JsonResponse(data_dict)
    
    
    from rest_framework.views import APIView
    from rest_framework.response import Response
    from rest_framework import status
    
    
    class Student2APIView(APIView):
        def get(self, request):
            print(request)  # rest_framework扩展后的request
            print(request.query_params)
            print(request.data)
            """打印效果
            <rest_framework.request.Request object at 0x00000000054D8898>
            """
            data_dict = {
        'name': "alex", "age": 18}
    
            return Response(data_dict, status=status.HTTP_204_NO_CONTENT, headers={
        "name": "xiaobai"})

小结：
    1.使用Django的View时候，
    导包：
    from django.views import View
    from django.http import JsonResponse
    最初的老办法一步一步开
    2.使用drf的View时候：
    
    from rest_framework.views import APIView
    from rest_framework.response import Response
    from rest_framework import status
    3.返回的方式是drf是根据你的需要就行返回，比较灵活。

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urls.py中的文件：
      path("student4/", views.Student5GenericAPIView.as_view()),
        re_path(r"^student4/(?P<pk>\d+)/$", views.Student6GenericAPIView.as_view()),
    ]

下图中的5改为4.

小结：1.最大改变是

# 当前视图类中操作的公共数据，先从数据库查询出来
        queryset = Student.objects.all()
        # 设置类视图中所有方法共有调用的序列化器类
        serializer_class = StudentModelSerializer

### 2.调用值的方式的改变。从GenericAPIView开始发生变化 ###

#1.self.get_queryset() 获取数据库中的所有对象
    # 类似于之前的在数据库中查询：

student_list = Student.objects.all(）这个也是和APIView的区别。

# 2.# 调用序列化器
     serializer = self.get_serializer(instance=student_list, many=True)

在4的基础上就行再次的封装！

## \# 不带参数的，GenericApIView的 ##

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## \# 带参数的 ##

\# 和不带参数的GenericApIView加上同样的2条之后还有第三条：

#1.  # 获取pk值对应的对象
            instance = self.get_object()
    # 2.生成serializer对象时候，和上面差不多
    serializer = self.get_serializer(instance=instance, data=request.data)
    # 3. pk值是没有管的，直接获取self.get_object()

class Student6GenericAPIView(GenericAPIView):
        # 当前视图类中操作的公共数据，先从数据库查询出来
        queryset = Student.objects.all()
        # 设置类视图中所有方法共有调用的序列化器类
        serializer_class = StudentModelSerializer
    
        def get(self, request, pk):
            """参数pk名，必须要叫pk，否则会报错。"""
            # 获取模型对象
            instance = self.get_object()
            serializer = self.get_serializer(instance=instance)
    
            return Response(serializer.data)
    
        def put(self, request, pk):
            instance = self.get_object()
    
            serializer = self.get_serializer(instance=instance, data=request.data)
    
            serializer.is_valid(raise_exception=True)
    
            serializer.save()
    
            return Response(serializer.data)
    
        def delete(self, request, pk):
            # 获取模型对象
            instance = self.get_object()
            # 删除模型对象
            instance.delete()
    
            return Response(status=status.HTTP_204_NO_CONTENT)

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在上面5的基础上就行进一步的封装.

url中的代码：

path("student5/", views.Student7GenericAPIView.as_view()), 不带参数的是访问模式可以是最开始的Get获取所有数据功能，POST增加单条数据。
     re_path(r"^student5/(?P<pk>\d+)/$", views.Student8GenericAPIView.as_view()),# 带参数的，可以是对应到最开始的PUT/Delete/update对应到这个地方封装的

ListModelMixin      实现查询所有数据功能 get
    CreateModelMixin    实现添加数据的功能 post
    RetrieveModelMixin  实现查询一条数据功能get
    UpdateModelMixin    更新一条数据的功能 update
    DestroyModelMixin   删除一条数据的功能 destroy

from rest_framework.mixins import ListModelMixin, CreateModelMixin
    
    
    class Student7GenericAPIView(GenericAPIView, ListModelMixin, CreateModelMixin):
        queryset = Student.objects.all()
        serializer_class = StudentModelSerializer
    
        def get(self, request):
            return self.list(request)
    
        def post(self, request):
            return self.create(request)
    
    
    from rest_framework.mixins import RetrieveModelMixin, UpdateModelMixin, DestroyModelMixin
    
    
    class Student8GenericAPIView(GenericAPIView, RetrieveModelMixin, UpdateModelMixin, DestroyModelMixin):
        queryset = Student.objects.all()
        serializer_class = StudentModelSerializer
    
        def get(self, request, pk):
            return self.retrieve(request)
    
        def put(self, request, pk):
            return self.update(request)
    
        def delete(self, request, pk):
            return self.destroy(request)

小结：中间代码的环节不用写了，在内部封装好了！

比如上面的get方法中的

def get(self, request, pk):
            """参数pk名，必须要叫pk，否则会报错。"""
            # 获取模型对象
            instance = self.get_object()
            serializer = self.get_serializer(instance=instance)
    
            return Response(serializer.data)

只需要写出函数名和返回值即可。

![1673775-20190724192629996-369241082.png][]

urls.py中的代码：

# 使用内置的扩展子类，生成API接口
        path("student6/", views.Student9GenericAPIView.as_view()),
        re_path(r"^student6/(?P<pk>\d+)/$", views.Student10GenericAPIView.as_view()),

在6的基础上就行封装！

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"""
    DRF里面，内置了一些同时继承了GenericAPIView和Mixins扩展类的视图子类，
    我们可以直接继承这些子类就可以生成对应的API接口
    """
    
    """
    ListAPIView      获取所有数据
    CreateAPIView    添加数据
    """
    from rest_framework.generics import ListAPIView, CreateAPIView
    
    
    class Student9GenericAPIView(ListAPIView, CreateAPIView):
        queryset = Student.objects.all()
        serializer_class = StudentModelSerializer
    
    
    """
    RetrieveAPIView                 获取一条数据
    UpdateAPIView                   更新一条数据
    DestorAPIView                   删除一条数据
    RetrieveUpdateDestoryAPIView    上面三个的缩写
    """
    from rest_framework.generics import RetrieveUpdateDestroyAPIView
    
    
    class Student10GenericAPIView(RetrieveUpdateDestroyAPIView):
        queryset = Student.objects.all()
        serializer_class = StudentModelSerializer
    复制代码

![1673775-20190724192646085-2141289713.png][]

视图集
    上面５个接口使用了８行代码生成，但是我们可以发现有一半的代码重复了
    所以，我们要把这些重复的代码进行整合，但是依靠原来的类视图，其实有２方面产生冲突的
    1. 查询所有数据、添加数据是不需要声明pk的，而其他的接口需要    [路由冲突了]
    2. 查询所有数据和查询一条数据，都是属于get请求                 [请求方法冲突了]
    为了解决上面的２个问题，所以DRF提供了视图集来解决这个问题

urls.py中的代码：

path("student7/", views.Student11GenericAPIView.as_view({
        "get": "list", "post": "create"})),
        re_path(r"^student7/(?P<pk>\d+)/$", views.Student11GenericAPIView.as_view({
        "get": "retrieve", "put": "update", "delete": "destroy"})),

掌握最后一个就可以了！，直接在视图的位置就行指定，就可以达到对应的访问。无敌！

from rest_framework.viewsets import GenericViewSet, ModelViewSet
    from rest_framework.mixins import ListModelMixin, CreateModelMixin, DestroyModelMixin, UpdateModelMixin, RetrieveModelMixin
    
    
    # 这两个是等价的
    # class Student11GenericAPIView(GenericViewSet, ListModelMixin, CreateModelMixin, DestroyModelMixin, UpdateModelMixin, RetrieveModelMixin):
    class Student11GenericAPIView(ModelViewSet):
        queryset = Student.objects.all()
        serializer_class = StudentModelSerializer

转载于:https://www.cnblogs.com/longerandergou/p/11240651.html

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[1673775-20190724192402082-2085838061.png]: /images/20230810/b70792edd12b4fb1bf0acb2900601abd.png
[https_www.cnblogs.com_Michael--chen_p_11235456.html]: https://www.cnblogs.com/Michael--chen/p/11235456.html
[1673775-20190724192532976-651960448.png]: /images/20230810/f805218feeea490e9c809efcfc9a257a.png
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[1673775-20190724192629996-369241082.png]: /images/20230810/d1cf4390a66e44d992d8789226d5906f.png
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