标签:wrapper action cst efault dispatch 变量 view receive generic
今天一直在整理Django的rest_framework的序列化组件,前面一共写了2篇博客,前面的博客给的方案都是一个中间的状态的博客,其中有很多的冗余的代码,如果有朋友不清楚,可以先看下我前面的博客
第一篇,使用minix类来实现序列化和反序列化
https://www.cnblogs.com/bainianminguo/p/10463741.html
第二篇,使用通用的类的方法实现序列化和反序列化
https://www.cnblogs.com/bainianminguo/p/10463784.html
这篇我给大家介绍一个终极方案,基于ModelViewSet的序列化和反序列化的方案和源码解析
终极方案之需要一个类就可以分别处理model对象的删改查操作,和queryset对象的增和查操作
先把具体的代码贴上来,让大家有一个整体的概念,然后我一一给大家分析
from django.conf.urls import url from django.contrib import admin from django.conf.urls import include from app1 import views app_name = "app1" urlpatterns = [ url(r‘^test/‘, views.test), url(r‘^test_cbv/‘, views.test_cbv.as_view(),name="test1"), url(r‘^test_rest/‘, views.Rest_view.as_view(),name="test2"), url(r‘^book_cbv/‘, views.Book_cbv.as_view(),name="test3"), url(r‘^publish_detail_cbv/(?P<id>\d+)‘, views.Pub_detail_cbv.as_view(),name="publish_url_name"), url(r‘^book_detail_cbv/(?P<id>\d+)‘, views.Book_detail_cbv.as_view(),name="test4"), # url(r‘^autherdetail/(?P<id>\d+)‘, views.Book_detail_cbv.as_view(), name="autherdetail"), # url(r‘^auther/‘, views.Book_cbv.as_view(),name="auther"), url(r‘^autherdetail/(?P<pk>\d+)/‘, views.AutherModelCBV.as_view({"get":"retrieve","delete":"destroy","put":"update"}), name="autherdetail"), url(r‘^auther/‘, views.AutherModelCBV.as_view({"get":"list","post":"create"}),name="auther"), ]
我们用的url是最后两条
我们仔细观察一下,这里的url和之前有3个地方不一样,我一一给大家指出来
a、两个url对应的类是相同的类
b、as_view这个方法有参数,这个参数是一个字典
c、对于model对象的url的url中的变量的名称是pk,之前我们用的id
class authermodelserializer(serializers.ModelSerializer): class Meta: model = models.Auther fields = "__all__"
序列化的类的代码和之前的保持一致,没有任何改变
from rest_framework import viewsets class AutherModelCBV(viewsets.ModelViewSet): queryset = models.Auther.objects.all() serializer_class = authermodelserializer
我们可以看到这个类非常的简单,这个类继承了一个新的类,我们之前没有用过这个类:viewsets.ModelViewSet
as_view的源码
@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 confiugurations. 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) # 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) if hasattr(self, ‘get‘) and not hasattr(self, ‘head‘): self.head = self.get 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)
函数的代码很长,我们只关注需要我们关注的代码
首先,确定as_view的函数中action的值就是我们的urls中as_view方法中的字典
action的值就是as_view方法中的字典,不信你可以实际测试一下
然后我们看下as_view这个方法的返回值
然后我们在看下as_view中的view方法
def view(request, *args, **kwargs): self = cls(**initkwargs) # 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) if hasattr(self, ‘get‘) and not hasattr(self, ‘head‘): self.head = self.get self.request = request self.args = args self.kwargs = kwargs # And continue as usual return self.dispatch(request, *args, **kwargs)
这里很重要,我们要慢慢来分析
然后在看下view这个方法的返回值
self.request = request self.args = args self.kwargs = kwargs # And continue as usual return self.dispatch(request, *args, **kwargs)
我们可以看到这个函数的返回值是self.dispatch
我们注意到self.dispatch这个方法,在as_view和view均找不到,这个self是什么呢?这个self就是视图函数的类,所以我们来我们的视图函数的类中找下
明显我们自定义的AuhterModelCBV这个类没有dispatch这个方法,所以我们要去这个类的父类中查找,也就是viewsets.ModelViewSet类中查找
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
这个类中也没有dispatch方法,但是这个类又继承了6个类,由于继承是从左到右继承,我们从最左边的类开始查找,最终在GeneriViewSet中找到dispatch的方法
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
GeneriViewSet的类中也没有dispatch方法,但是这个类有2个父类,所以我们继续往上找
最终在GenericAPIView类中找到了dispatch方法
这个类中也没有dispatch方法,我们在往他的父类中查找
最后,我们终于在APIView类中找到我们需要的dispatch方法
class APIView(View): def dispatch(self, request, *args, **kwargs): """ `.dispatch()` is pretty much the same as Django‘s regular dispatch, but with extra hooks for startup, finalize, and exception handling. """ self.args = args self.kwargs = kwargs request = self.initialize_request(request, *args, **kwargs) self.request = request self.headers = self.default_response_headers # deprecate? try: self.initial(request, *args, **kwargs) # Get the appropriate handler method if request.method.lower() in self.http_method_names: handler = getattr(self, request.method.lower(), self.http_method_not_allowed) else: handler = self.http_method_not_allowed response = handler(request, *args, **kwargs) except Exception as exc: response = self.handle_exception(exc) self.response = self.finalize_response(request, response, *args, **kwargs) return self.response
下面在看下dispatch方法干了什么
所以执行self.create等方法就会调用我们前面已经对应的self.list。self.update等方法
至此,终极方案我们也完成了!谢谢大家的查阅!
Django的rest_framework的视图之基于ModelViewSet视图源码解析
标签:wrapper action cst efault dispatch 变量 view receive generic
原文地址:https://www.cnblogs.com/bainianminguo/p/10463893.html