Django REST framework —— 认证组件源码分析

时间:2024-01-21 09:04:57

我在前面的博客里已经讲过了,我们一般编写API的时候用的方式

class CoursesView(ViewSetMixin,APIView):
        pass

这种方式的有点是,灵活性比较大,可以根据自己的业务逻辑来自定义各种组件逻辑。

这边文章,我将带大家对 认证组件做一个源码分析,写这边文章的原因也是因为自己虽然知道怎么写,但是不知道为什么要这么写,今天看了源码,所以想把自己的一些心得写出来和大家分享。

先看代码

 1 class ShoppingCarView(ViewSetMixin, APIView):
 2     authentication_classes = [LuffyAuthtication,]
 3         def list(self,request, *args, **kwargs):
 4         """
 5         查看购物车信息
 6         :param args:
 7         :param kwargs:
 8         :return:
 9         """
10         try:
11             ret = BaseResponse()
12             pay_course_list = []
13             # key = \'shoppingcar_%s_%s\' % (USERID, \'*\')
14             key = settings.SHOPCAR_FORMAT.format( request.user.id, "*")
15             user_key_list = COON.keys(pattern=key)  # 取到这个用户对应的所有课程字典 对应的键
16             for key in user_key_list:
17                 # 对应的每个键值 去取每个课程对应的信息 和价格列表
18                 temp = {
19                     \'id\': COON.hget(key, \'id\').decode(\'utf8\'),
20                     \'name\': COON.hget(key, \'name\').decode(\'utf8\'),
21                     \'img\': COON.hget(key, \'img\').decode(\'utf8\'),
22                     \'default\': COON.hget(key, \'default\').decode(\'utf8\'),
23                     \'price_dict\': json.loads(COON.hget(key, \'price_dict\').decode(\'utf8\')),
24                 }
25                 pay_course_list.append(temp)
26             ret.data = pay_course_list
27         except Exception as e:
28             ret.data = \'查看失败\'
29             ret.code = 00000
30         return Response(ret.dict)
视图类

 

 

 1 from app01 import models
 2 from rest_framework.authentication import BaseAuthentication
 3 from rest_framework.exceptions import AuthenticationFailed
 4 
 5 
 6 class LuffyAuthtication(BaseAuthentication):
 7 
 8     def authenticate(self, request):
 9         """
10         用于做用户认证
11         :param request:
12         :return:
13         """
14         token = request.query_params.get(\'token\')
15         token_obj = models.UserToken.objects.filter(token=token).first()
16         if not  token_obj:
17             raise AuthenticationFailed({\'code\':10000,\'error\':\'认证失败\'})
18         return token_obj.user,token_obj
认证类

 

 

 

urlpatterns = [
    url(r\'^payment/$\', payment.PaymentView.as_view({\'post\': \'create\',\'put\': \'update\',\'get\':\'list\'})),
]
url

 

以上的就是逻辑代码,就是一个必须要验证为注册用户才能查看购物车的内容。

下面来进行源码分析,来看代码是如何走到我自定义的认证类中的。

1.首先从url中分析

  1.先来到视图类中的as.view()方法

  

  而我们的自定义的方法中没有as.view()方法,那就要去父类ViewSetMixin和APIView中去找,好看源码

2.分析源码

  1.先看ViewSetMixin类中

    

    

class ViewSetMixin(object):
    """
    This is the magic.

    Overrides `.as_view()` so that it takes an `actions` keyword that performs
    the binding of HTTP methods to actions on the Resource.

    For example, to create a concrete view binding the \'GET\' and \'POST\' methods
    to the \'list\' and \'create\' actions...

    view = MyViewSet.as_view({\'get\': \'list\', \'post\': \'create\'})
    """

    @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 suffix initkwarg is reserved for displaying the viewset type.
        # 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))

        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
       # 前面都是在对传参做判断和重新赋值,重要的是下面这一步,最后return 调用了dispatch方法
return self.dispatch(request, *args, **kwargs)

 

   2.找dispatch方法在哪里,答案肯定是在APIView中

  

 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)
     ## request = Request(.....) self.request
= request self.headers = self.default_response_headers 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

 

    所有的关键点都在dispatch方法里面:

    (1)  request = self.initialize_request(request, *args, **kwargs) 

      

def initialize_request(self, request, *args, **kwargs):
        """
        Returns the initial request object.
        """
        parser_context = self.get_parser_context(request)

        return Request(
            request,
            parsers=self.get_parsers(),
            authenticators=self.get_authenticators(),    #[BasicAuthentication(),],把对象封装到request里面了
       negotiator=self.get_content_negotiator(), parser_context=parser_context )

 

 

     (2)authenticators=self.get_authenticators(),

       通过列表生成式,返回对象的列表  

 def get_authenticators(self):
        """
        Instantiates and returns the list of authenticators that this view can use.
        """
        return [auth() for auth in self.authentication_classes]

    (3)authentication_classes

     APIView里面有个  authentication_classes   字段  ,这里如果写了静态变量就直接在类的静态变量中找,否则就到全局配置文文件中去找 

    可以看到默认是去全局的配置文件找(api_settings)

  

class APIView(View):

    # The following policies may be set at either globally, or per-view.
    renderer_classes = api_settings.DEFAULT_RENDERER_CLASSES
    parser_classes = api_settings.DEFAULT_PARSER_CLASSES
    authentication_classes = api_settings.DEFAULT_AUTHENTICATION_CLASSES
    throttle_classes = api_settings.DEFAULT_THROTTLE_CLASSES
    permission_classes = api_settings.DEFAULT_PERMISSION_CLASSES
    content_negotiation_class = api_settings.DEFAULT_CONTENT_NEGOTIATION_CLASS
    metadata_class = api_settings.DEFAULT_METADATA_CLASS
    versioning_class = api_settings.DEFAULT_VERSIONING_CLASS

 

     (4)开始验证 

    (5)self.initial(request,*args,**kwargs)

    def initial(self, request, *args, **kwargs):
        """
        Runs anything that needs to occur prior to calling the method handler.
        """
        self.format_kwarg = self.get_format_suffix(**kwargs)

        # Perform content negotiation and store the accepted info on the request
        neg = self.perform_content_negotiation(request)
        request.accepted_renderer, request.accepted_media_type = neg

        # Determine the API version, if versioning is in use.
        version, scheme = self.determine_version(request, *args, **kwargs)
        request.version, request.versioning_scheme = version, scheme

        # Ensure that the incoming request is permitted
        self.perform_authentication(request)    认证
        self.check_permissions(request)      权限
        self.check_throttles(request)        频率

 

    (6)self.perform_authentication(request)

    

    def perform_authentication(self, request):
        """
        Perform authentication on the incoming request.

        Note that if you override this and simply \'pass\', then authentication
        will instead be performed lazily, the first time either
        `request.user` or `request.auth` is accessed.
        """
        request.user

  这里没有返回值,直接调用了request.user,那这个user方法是谁的呢????

 

   

              还记得这个Request吧,对没错就是他的,我们点进去看看

    (7)request.user

    

    (8)self._authenticate() 方法

 

def _authenticate(self):
        """
        Attempt to authenticate the request using each authentication instance
        in turn.
        """
        #循环认证类的所有对象
        for authenticator in self.authenticators:
            try:
                #执行认证类的authenticate方法
                #这里分三种情况
                #1.如果authenticate方法抛出异常,self._not_authenticated()执行
                #2.有返回值,必须是元组:(request.user,request.auth)
                #3.返回None,表示当前认证不处理,等下一个认证来处理
                user_auth_tuple = authenticator.authenticate(self)
            except exceptions.APIException:
                self._not_authenticated()
                raise

            if user_auth_tuple is not None:
                self._authenticator = authenticator
                self.user, self.auth = user_auth_tuple    元祖
                return

        self._not_authenticated()

 

 

   返回的元组就是上面自定义认证类代码中的

   token_obj.user,  可以再后续的request.user中取到

           token_obj        ,可以再后续的request.auth中取到

 到这里整个认证组件的源码就分析完了

 

自己写认证类方法梳理

 (1)创建认证类

  • 继承BaseAuthentication    --->>1.重写authenticate方法;2.authenticate_header方法直接写pass就可以(这个方法必须写)

(2)authenticate()返回值(三种)

  • None ----->>>当前认证不管,等下一个认证来执行,可用于对请求的过滤上
  • raise exceptions.AuthenticationFailed(\'用户认证失败\')       # from rest_framework import exceptions
  •  有返回值元祖形式:(元素1,元素2)      #元素1复制给request.user;  元素2复制给request.auth

 (3)局部使用

  • authentication_classes = [BaseAuthentication,]

(4)全局使用

#设置全局认证
REST_FRAMEWORK = {
    "DEFAULT_AUTHENTICATION_CLASSES":[\'API.utils.auth.Authentication\',]
}

 

源码流程

--->>dispatch

    --封装request

       ---获取定义的认证类(全局/局部),通过列表生成式创建对象 

     ---initial

       ----peform_authentication

         -----request.user   (每部循环创建的对象)