认证组件

rest_framework的认证组件是为了判断用户有没有合法身份，一般认为没有登录或者没有授权即为不合法。

rest_framework在什么时候运行认证组件

说到rest_framework的认证组件，就要说到Django的CBV了。rest_framework模块的APIView类重写了CBV中的dispatch方法。

    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

 其中在运行请求方式对应的视图函数之前，执行了initial方法。APIView类中的initial就是专门执行rest_framework组件的入口。

    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)
        self.check_permissions(request)
        self.check_throttles(request)

其中的perform_authentication就是执行认证组件的方法。 查看perform_authentication方法的代码，发现运行的是request对象的user方法。

    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

再看到request对象是initialize_request方法的返回值，查看initialize_request方法的代码。

    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(),
            negotiator=self.get_content_negotiator(),
            parser_context=parser_context
        )

 initialize_request方法返回的request对象是Request类的实例化对象，所以user方法应该在Request类中。

    @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():
                self._authenticate()
        return self._user

 查看_authenticate方法，才找到了执行认证组件的方法。authenticator.authenticate(self)中的authenticator是组件实例化的对象，authenticate是认证组件的实现认证功能的方法，self是request对象。

    def _authenticate(self):
        """
        Attempt to authenticate the request using each authentication instance
        in turn.
        """
        for authenticator in self.authenticators:
            try:
                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()

 rest_framework自带的认证组件

• BasicAuthentication
  

• SessionAuthentication

• TokenAuthentication

• RemoteUserAuthentication

自定义认证组件

自定义认证组件，需要继承rest_framework.authentication.BaseAuthentication,并重写authenticate方法即可。

注意authenticate的返回值一般是一个有两个元素的元组。下面是继承BaseAuthentication的子类的TokenAuthentication类的自定义组件示例。

from rest_framework.authentication import TokenAuthentication
from rest_framework import exceptions


class UserTokenAuthentication(TokenAuthentication):
    keyword = 'XqCircleToken'

    def get_model(self):
        if self.model is not None:
            return self.model
        return UserToken

    def authenticate(self, request):
        model = self.get_model()
        key = request.META.get('HTTP_AUTHORIZATION', '')
        if not key:
            raise exceptions.AuthenticationFailed(_('Invalid token.'))
        key = key.split()[1]
        try:
            token = model.objects.select_related('user').get(key=key)
        except model.DoesNotExist:
            raise exceptions.AuthenticationFailed(_('Invalid token.'))
        return token.user, token

这里需要注意,有两种方法给函数添加认证功能:
第一种:
在对应函数下添加:
authentication_classes = [LoginAuth, ]
[]内可以添加多个值,如果前面的方法中return了值,后面的方法就不会继续执行,
只有前面的方法中return了None,才会继续执行后面的方法
第二种:
在settings中全局配置:
REST_FRAMEWORK={
'DEFAULT_AUTHENTICATION_CLASSES':['app01.MyAuth.LoginAuth',]
}
配置之后所有的方法都需认证,当想局部禁用认证时,需在对应函数中添加下面这句
authentication_classes = []