rest_framework 权限流程

权限流程

权限流程与认证流程非常相似，只是后续操作稍有不同

当用户访问是首先执行dispatch函数，当执行当第二部时：

   #2.处理版本信息 处理认证信息 处理权限信息 对用户的访问频率进行限制
            self.initial(request, *args, **kwargs)

进入到initial方法：

 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.
        #2.1处理版本信息
        version, scheme = self.determine_version(request, *args, **kwargs)
        request.version, request.versioning_scheme = version, scheme

        # Ensure that the incoming request is permitted
        #2.2处理认证信息
        self.perform_authentication(request)
        #2.3处理权限信息
        self.check_permissions(request)
        #2.4对用户的访问频率进行限制
        self.check_throttles(request

 #处理权限信息
        self.check_permissions(request)

下面开始权限的具体分析：

进入到check_permissions函数中

 #检查权限
    def check_permissions(self, request):
        """
        Check if the request should be permitted.
        Raises an appropriate exception if the request is not permitted.
        """
        #elf.get_permissions()得到的是一个权限对象列表
        for permission in self.get_permissions():
            #在自定义的Permission中has_permission方法是必须要有的
            #判断当前has_permission返回的是True，False，还是抛出异常
            #如果是True则表示权限通过,False执行下面代码
            if not permission.has_permission(request, self):
                #为False的话则抛出异常，当然这个异常返回的提示信息是英文的,如果我们想让他显示我们自定义的提示信息
                #我们重写permission_denied方法即可
                self.permission_denied(
                    #从自定义的Permission类中获取message(权限错误提示信息),一般自定义的话都建议写上,如果没有则为默认的(英文提示)
                    request, message=getattr(permission, 'message', None)
                )

查看permission_denied方法(如果has_permission返回True则不执行该方法)

 def permission_denied(self, request, message=None):
        """
        If request is not permitted, determine what kind of exception to raise.
        """
        if request.authenticators and not request.successful_authenticator:
            #没有登录提示的错误信息
            raise exceptions.NotAuthenticated()
        #一般是登陆了但是没有权限提示
        raise exceptions.PermissionDenied(detail=message)

局部权限

permissions.py

# 局部权限
from rest_framework.permissions import BasePermission
class SVIPPermissions(BasePermission):
    # 提示信息
    message = "滚！您没有权限"
    def has_permission(self,request,view):

        # 获取到认证的返回值
        user_obj=request.user.user
        if user_obj.user_type==3:
            return True
        else:
            return False

view.py

class BookViewsSet(viewsets.ModelViewSet): 

   # 权限
    permission_classes=[SVIPPermissions]

    queryset = Book.objects.all()
    serializer_class = BookModelSerializer

全局权限

permissions.py

# 局部权限
from rest_framework.permissions import BasePermission
class SVIPPermissions(BasePermission):
    # 提示信息
    message = "滚！您没有权限"
    def has_permission(self,request,view):

        # 获取到认证的返回值
        user_obj=request.user.user
        if user_obj.user_type==3:
            return True
        else:
            return False

settings.py

REST_FRAMEWORK={
     "DEFAULT_PERMISSION_CLASSES":["api.servise.permission.SVIPPermissions"],
}

待续