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DRF框架源码分析--认证

January 2, 2019 • python阅读设置

DRF认证源码解析

先来张高清无码大图

请求到 dispatch

dispatch()主要做了两件事

  • 封装request
  • 认证

    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
        #对原始request进行加工,丰富了一些功能
        #Request(
        #     request,
        #     parsers=self.get_parsers(),
        #     authenticators=self.get_authenticators(),
        #     negotiator=self.get_content_negotiator(),
        #     parser_context=parser_context
        # )
        #request(原始request,[BasicAuthentications对象,])
        #获取原生request,request._request
        #获取认证类的对象,request.authticators
        #1.封装request
        request = self.initialize_request(request, *args, **kwargs)
        self.request = request
        self.headers = self.default_response_headers  # deprecate?
    
        try:
            #2.认证
            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
    

源码流程

1.

封装原始request
(1)initialize_request()

可以看到initialize()就是封装原始request

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 )

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]

authentication_classes

APIView里面有个 authentication_classes 字段
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

2.

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

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
        #对原始request进行加工,丰富了一些功能
        #Request(
        #     request,
        #     parsers=self.get_parsers(),
        #     authenticators=self.get_authenticators(),
        #     negotiator=self.get_content_negotiator(),
        #     parser_context=parser_context
        # )
        #request(原始request,[BasicAuthentications对象,])
        #获取原生request,request._request
        #获取认证类的对象,request.authticators
        #1.封装request
        request = self.initialize_request(request, *args, **kwargs)
        self.request = request
        self.headers = self.default_response_headers  # deprecate?

        try:
            #2.认证
            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

initial()

主要看 self.perform_authentication(request),实现认证

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
       #3.实现认证
       self.perform_authentication(request)
       self.check_permissions(request)
       self.check_throttles(request)

perform_authentication()

调用了request.user

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

user

request.user的request的位置

点进去可以看到Request有个user方法,加 @property 表示调用user方法的时候不需要加括号“user()”,可以直接调用:request.user

    @property
    def user(self):
        """
        Returns the user associated with the current request, as authenticated
        by the authentication classes provided to the request.
        """
        if not hasattr(self, '_user'):
            with wrap_attributeerrors():
                #获取认证对象,进行一步步的认证
                self._authenticate()
        return self._user

_authenticate()

循环所有authenticator对象

    def _authenticate(self):
        """
        Attempt to authenticate the request using each authentication instance
        in turn.
        """
        #循环认证类的所有对象
        #执行对象的authenticate方法
        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
                return

        self._not_authenticated()

返回值
return (token_obj.user,token_obj)

当都没有返回值,就执行self._not_authenticated(),相当于匿名用户,没有通过认证

def _not_authenticated(self):
        """
        Set authenticator, user & authtoken representing an unauthenticated request.

        Defaults are None, AnonymousUser & None.
        """
        self._authenticator = None

        if api_settings.UNAUTHENTICATED_USER:
            self.user = api_settings.UNAUTHENTICATED_USER()   #AnonymousUser匿名用户
        else:
            self.user = None

        if api_settings.UNAUTHENTICATED_TOKEN:
            self.auth = api_settings.UNAUTHENTICATED_TOKEN()  #None
        else:
            self.auth = None
最后编辑于: April 2, 2019
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