【Django】REST_Framework框架——Mixin类和GenericAPIView中的视图子类源码解析

ゞ浴缸里的玫瑰 2024-04-07 10:10 59阅读 0赞

![在这里插入图片描述][615cfc20a084444bbb5599e58877fce2.png_pic_center]

## 一、Mixin类 ##

**提供了几种后端视图（对数据资源进行增删改查）处理流程的实现，如果需要编写的视图属于这五种，则视图可以通过继承相应的扩展类来复用代码，减少自己编写的代码量。**

**这五个扩展类需要搭配GenericAPIView通用视图基类来开发业务接口**

### 1、ListModelMixin ###

> 列表视图扩展类，提供 list(request, \*args, \*\*kwargs)方法快速实现列表视图，返回200状态码。  
> 该Mixin的list方法会对数据进行过滤和分页，如果不重写过滤和分页的方法是不会进行过滤和分页的。

#### 源码简化 ####

class ListModelMixin:
    	def list(self,request,*args,**kwargs):
    	      queryset=self.get_queryset()
    	      serializer=self.get_serializer(instance=queryset,many=True)
    	      return Response(serializer.data)

#### 源码 ####

class ListModelMixin:
        """
        List a queryset.
        """
        def list(self, request, *args, **kwargs):
            queryset = self.filter_queryset(self.get_queryset())
    
            page = self.paginate_queryset(queryset)
            if page is not None:
                serializer = self.get_serializer(page, many=True)
                return self.get_paginated_response(serializer.data)
    
            serializer = self.get_serializer(queryset, many=True)
            return Response(serializer.data)

### 2、CreateModelMixin ###

> 创建视图扩展类，提供 create(request, \*args, \*\*kwargs)方法快速实现创建资源的视图，成功返回201状态码。  
> 如果序列化器对前端发送的数据验证失败，返回400错误；所以要对反序列化输入字段要进行验证，校验不通过提供指定的报错。

#### 源码简化 ####

class CreateModelMixin:
    	def create(self,request,*args,**kwargs):
    	      serializer=self.get_serializer(data=request.data)
    	      serializer.is_valid(raise_exception=True)
    	      serializer.save()
    	      return Response(serializer.data)

#### 源码 ####

class CreateModelMixin:
        """
        Create a model instance.
        """
        def create(self, request, *args, **kwargs):
            serializer = self.get_serializer(data=request.data)
            serializer.is_valid(raise_exception=True)
            self.perform_create(serializer)
            headers = self.get_success_headers(serializer.data)
            return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)
    
        def perform_create(self, serializer):
            serializer.save()
    
        def get_success_headers(self, data):
            try:
                return {
        'Location': str(data[api_settings.URL_FIELD_NAME])}
            except (TypeError, KeyError):
                return {
        }

### 3、RetrieveModelMixin ###

> 详情视图扩展类，提供 retrieve(request, \*args, \*\*kwargs)方法，可以快速实现返回一个存在的数据对象。  
> 如果存在，返回200， 否则返回404。

#### 源码 ####

class RetrieveModelMixin:
    	def retrieve(self,request,*args,**kwargs):
    	      instance=self.get_object()
    	      serializer=ProjectsSerializer(instance=instance)
    	      return Response(serializer.data)

### 4、UpdateModelMixin ###

> 更新视图扩展类，提供 update(request, \*args, \*\*kwargs)方法，可以快速实现更新一个存在的数据对象。  
> 同时也提供 partial\_update(request, \*args, \*\*kwargs)方法，可以实现局部更新。  
> 成功返回200，序列化器校验数据失败时，返回400错误。

#### 源码简化 ####

class UpdateModelMixin:
    	def update(self,request,*args,**kwargs):
    	     obj=self.get_object()
    	     serializer=ProjectsSerializer(instance=obj,data=request.data)
    	     serializer.is_valid(raise_exception=True)
    	     serializer.save()
    	     return Response(serializer.data)

#### 源码 ####

class UpdateModelMixin:
        """
        Update a model instance.
        """
        def update(self, request, *args, **kwargs):
            partial = kwargs.pop('partial', False)
            instance = self.get_object()
            serializer = self.get_serializer(instance, data=request.data, partial=partial)
            serializer.is_valid(raise_exception=True)
            self.perform_update(serializer)
    
            if getattr(instance, '_prefetched_objects_cache', None):
                # If 'prefetch_related' has been applied to a queryset, we need to
                # forcibly invalidate the prefetch cache on the instance.
                instance._prefetched_objects_cache = {
        }
    
            return Response(serializer.data)
    
        def perform_update(self, serializer):
            serializer.save()
    
        def partial_update(self, request, *args, **kwargs):
            kwargs['partial'] = True
            return self.update(request, *args, **kwargs)

### 5、DestroyModelMixin ###

> 删除视图扩展类，提供 destroy(request, \*args, \*\*kwargs)方法，可以快速实现删除一个存在的数据对象。  
> 成功返回204，不存在返回404。

#### 源码简化 ####

class DestroyModelMixin
    	def destroy(self,request,*args,**kwargs):
    	     obj=self.get_object()
    	     obj.delete()
    	     return Response({
        'msg':'删除数据成功'},status=204)

#### 源码 ####

class DestroyModelMixin:
        """
        Destroy a model instance.
        """
        def destroy(self, request, *args, **kwargs):
            instance = self.get_object()
            self.perform_destroy(instance)
            return Response(status=status.HTTP_204_NO_CONTENT)
    
        def perform_destroy(self, instance):
            instance.delete()

## 二、GenericAPIView的视图子类 ##

### 1、CreateAPIView ###

> 提供post方法  
> 继承关系：CreateModelMixin、GenericAPIView  
> 使用：基本属性定义：queryset、serializer\_class

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

### 2、ListAPIView ###

> 提供get方法  
> 继承关系：ListModelMixin、GenericAPIView  
> 使用：基本属性定义：queryset、serializer\_class

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

### 3、RetrieveAPIView ###

> 提供get方法  
> 继承关系：RetrieveModelMixin、GenericAPIView  
> 使用：基本属性定义：queryset、serializer\_class

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

### 4、UpdateAPIView ###

> 提供put、patch方法  
> 继承关系：UpdateModelMixin、GenericAPIView  
> 使用：基本属性定义：queryset、serializer\_class

class UpdateAPIView(mixins.UpdateModelMixin,
                        GenericAPIView):
        """
        Concrete view for updating a model instance.
        """
        def put(self, request, *args, **kwargs):
            return self.update(request, *args, **kwargs)
    
        def patch(self, request, *args, **kwargs):
            return self.partial_update(request, *args, **kwargs)

### 5、DestoryAPIView ###

> 提供delete方法  
> 继承关系：DestoryModelMixin、GenericAPIView  
> 使用：基本属性定义：queryset、serializer\_class

class DestroyAPIView(mixins.DestroyModelMixin,
                         GenericAPIView):
        """
        Concrete view for deleting a model instance.
        """
        def delete(self, request, *args, **kwargs):
            return self.destroy(request, *args, **kwargs)

### 6、ListCreateAPIView ###

> 提供get、post方法  
> 继承关系：ListModelMixin、CreateModelMixin、GenericAPIView  
> 使用：基本属性定义：queryset、serializer\_class

class ListCreateAPIView(mixins.ListModelMixin,
                            mixins.CreateModelMixin,
                            GenericAPIView):
        """
        Concrete view for listing a queryset or creating a model instance.
        """
        def get(self, request, *args, **kwargs):
            return self.list(request, *args, **kwargs)
    
        def post(self, request, *args, **kwargs):
            return self.create(request, *args, **kwargs)

### 7、RetrieveUpdateAPIView ###

> 提供get、put、patch方法  
> 继承关系：RetrieveModelMixin、UpdateModelMixin、GenericAPIView  
> 使用：基本属性定义：queryset、serializer\_class

class RetrieveUpdateAPIView(mixins.RetrieveModelMixin,
                                mixins.UpdateModelMixin,
                                GenericAPIView):
        """
        Concrete view for retrieving, updating a model instance.
        """
        def get(self, request, *args, **kwargs):
            return self.retrieve(request, *args, **kwargs)
    
        def put(self, request, *args, **kwargs):
            return self.update(request, *args, **kwargs)
    
        def patch(self, request, *args, **kwargs):
            return self.partial_update(request, *args`

### 8、RetrieveDestoryAPIView ###

> 提供get、delete方法  
> 继承关系：RetrieveModelMixin、DestoryModelMixin、GenericAPIView  
> 使用：基本属性定义：queryset、serializer\_class

class RetrieveDestroyAPIView(mixins.RetrieveModelMixin,
                                 mixins.DestroyModelMixin,
                                 GenericAPIView):
        """
        Concrete view for retrieving or deleting a model instance.
        """
        def get(self, request, *args, **kwargs):
            return self.retrieve(request, *args, **kwargs)
    
        def delete(self, request, *args, **kwargs):
            return self.destroy(request, *args, **kwargs)

### 9、RetrieveUpdateDestoryAPIView ###

> 提供get、put、patch、delete方法  
> 继承关系：RetrieveModelMixin、UpdateModelMixin、DestoryModelMixin、GenericAPIView  
> 使用：基本属性定义：queryset、serializer\_class

class RetrieveUpdateDestroyAPIView(mixins.RetrieveModelMixin,
                                       mixins.UpdateModelMixin,
                                       mixins.DestroyModelMixin,
                                       GenericAPIView):
        """
        Concrete view for retrieving, updating or deleting a model instance.
        """
        def get(self, request, *args, **kwargs):
            return self.retrieve(request, *args, **kwargs)
    
        def put(self, request, *args, **kwargs):
            return self.update(request, *args, **kwargs)
    
        def patch(self, request, *args, **kwargs):
            return self.partial_update(request, *args, **kwargs)
    
        def delete(self, request, *args, **kwargs):
            return self.destroy(request, *args, **kwargs)

![在这里插入图片描述][b588fc2618c74bb88aae537d37d6f639.webp_pic_center]

[615cfc20a084444bbb5599e58877fce2.png_pic_center]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/07/a6a258f393c548ff94311cdf091f9d6d.png
[b588fc2618c74bb88aae537d37d6f639.webp_pic_center]: https://img-blog.csdnimg.cn/b588fc2618c74bb88aae537d37d6f639.webp#pic_center