【Django】REST_Framework框架——视图集ViewSet和ModelViewSet源码解析

秒速五厘米 2024-04-07 10:16 54阅读 0赞

![在这里插入图片描述][370bd5ef0f954a6b9528050dafc073cb.webp_pic_center]

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## 一、ViewSet ##

继承APIView和ViewSetMixin；  
作用也与APIView基本类似，提供了身份认证、权限校验、流量管理等。  
ViewSet在开发接口中不经常用

### 1、ViewSet源码 ###

> **在ViewSet中，没有提供任何动作action方法，需要我们自己实现action方法。**

class ViewSet(ViewSetMixin, views.APIView):
        """
        The base ViewSet class does not provide any actions by default.
        """
        pass

> **ViewSet视图集类不再限制视图方法名只允许get()、post()等这种情况了，而是实现允许开发者根据自己的需要定义自定义方法名，例如 list() 、create() 等，然后经过路由中使用http和这些视图方法名进行绑定调用**  
>

### 2、ViewSetMixin源码 ###

> **ViewSet主要通过继承ViewSetMixin来实现在调用as\_view()时传入字典\{“http请求”：“视图方法”\}的映射处理工作，如  
> \{‘get’:’list’，  
> ‘post’:‘create’,  
> ‘put’:‘update’,  
> ‘delete’:‘destory’\}，**  
> ![在这里插入图片描述][a016f5de542d44309d607e13751214f9.png]

@classonlymethod
        def as_view(cls, actions=None, **initkwargs):
            """
            Because of the way class based views create a closure around the
            instantiated view, we need to totally reimplement `.as_view`,
            and slightly modify the view function that is created and returned.
            """
            # The name and description initkwargs may be explicitly overridden for
            # certain route configurations. eg, names of extra actions.
            cls.name = None
            cls.description = None
    
            # The suffix initkwarg is reserved for displaying the viewset type.
            # This initkwarg should have no effect if the name is provided.
            # eg. 'List' or 'Instance'.
            cls.suffix = None
    
            # The detail initkwarg is reserved for introspecting the viewset type.
            cls.detail = None
    
            # Setting a basename allows a view to reverse its action urls. This
            # value is provided by the router through the initkwargs.
            cls.basename = None
    
            # actions must not be empty
            if not actions:
                raise TypeError("The `actions` argument must be provided when "
                                "calling `.as_view()` on a ViewSet. For example "
                                "`.as_view({'get': 'list'})`")
    
            # sanitize keyword arguments
            for key in initkwargs:
                if key in cls.http_method_names:
                    raise TypeError("You tried to pass in the %s method name as a "
                                    "keyword argument to %s(). Don't do that."
                                    % (key, cls.__name__))
                if not hasattr(cls, key):
                    raise TypeError("%s() received an invalid keyword %r" % (
                        cls.__name__, key))
    
            # name and suffix are mutually exclusive
            if 'name' in initkwargs and 'suffix' in initkwargs:
                raise TypeError("%s() received both `name` and `suffix`, which are "
                                "mutually exclusive arguments." % (cls.__name__))
    
            def view(request, *args, **kwargs):
                self = cls(**initkwargs)
    
                if 'get' in actions and 'head' not in actions:
                    actions['head'] = actions['get']
    
                # We also store the mapping of request methods to actions,
                # so that we can later set the action attribute.
                # eg. `self.action = 'list'` on an incoming GET request.
                self.action_map = actions
    
                # Bind methods to actions
                # This is the bit that's different to a standard view
                for method, action in actions.items():
                    handler = getattr(self, action)
                    setattr(self, method, handler)
    
                self.request = request
                self.args = args
                self.kwargs = kwargs
    
                # And continue as usual
                return self.dispatch(request, *args, **kwargs)
    
            # take name and docstring from class
            update_wrapper(view, cls, updated=())
    
            # and possible attributes set by decorators
            # like csrf_exempt from dispatch
            update_wrapper(view, cls.dispatch, assigned=())
    
            # We need to set these on the view function, so that breadcrumb
            # generation can pick out these bits of information from a
            # resolved URL.
            view.cls = cls
            view.initkwargs = initkwargs
            view.actions = actions
            return csrf_exempt(view)

## 二、ModelViewSet ##

**使用ViewSet通常并不方便，因为list、retrieve、create、update、destory等action  
方法都需要自己编写，而这些方法与前面讲过的Mixin扩展类提供的方法同名，所以我们可以通过继承Mixin扩展类来复用这些方法而无需自己编写。**

**ModelViewSet继承自 GenericViewSet，同时包括了ListModelMixin、RetrieveModelMixin、CreateModelMixin、UpdateModelMixin、DestoryModelMixin。**

### 1、ModelViewSet源码 ###

class ModelViewSet(mixins.CreateModelMixin,
                       mixins.RetrieveModelMixin,
                       mixins.UpdateModelMixin,
                       mixins.DestroyModelMixin,
                       mixins.ListModelMixin,
                       GenericViewSet):
        """
        A viewset that provides default `create()`, `retrieve()`, `update()`,
        `partial_update()`, `destroy()` and `list()` actions.
        """
        pass

## 三、ReadOnlyModelViewSet ##

**ReadOnlyModelViewSet承自 GenericViewSet，同时包括了ListModelMixin、RetrieveModelMixin。**

### 1、ReadOnlyModelViewSet源码 ###

class ReadOnlyModelViewSet(mixins.RetrieveModelMixin,
                               mixins.ListModelMixin,
                               GenericViewSet):
        """
        A viewset that provides default `list()` and `retrieve()` actions.
        """
        pass

## 四、GenericViewSet ##

**GenericViewSet继承ViewSetMixin、GenericAPIView  
继承ViewSetMixin：实现了在调用as\_view()时传入字典\{“http请求”：“视图方法”\}的映射处理工作，如  
\{‘get’:’list’，  
‘post’:‘create’,  
‘put’:‘update’,  
‘delete’:‘destory’\}，  
继承了GenericAPIView：实现了分页、限流、过滤功能**

class GenericViewSet(ViewSetMixin, generics.GenericAPIView):
        """
        The GenericViewSet class does not provide any actions by default,
        but does include the base set of generic view behavior, such as
        the `get_object` and `get_queryset` methods.
        """
        pass

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![在这里插入图片描述][1d3ab8f2618e4a5da6a2bb855ff15dc6.png_pic_center]

[370bd5ef0f954a6b9528050dafc073cb.webp_pic_center]: https://img-blog.csdnimg.cn/370bd5ef0f954a6b9528050dafc073cb.webp#pic_center
[a016f5de542d44309d607e13751214f9.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/07/c92a895fe3554b3bb011f78dbcc2e682.png
[1d3ab8f2618e4a5da6a2bb855ff15dc6.png_pic_center]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/07/27c38d5413104e23bf7b884dead50d72.png