Django Rest Framework源码剖析(二)—–权限详解编程语言

class MyPremission(object): 
    message = "您不是会员无权访问" 
    def has_permission(self,request,view): 
        if request.user.user_type == 1: ## user_type 为1代表普通用户，则不能查看 
            return False 
        return True

class OrderView(APIView): 
    '''查看订单''' 
    from utils.permissions import MyPremission 
    authentication_classes = [Authentication,]    #添加认证 
    permission_classes = [MyPremission,]    #添加权限 
    def get(self,request,*args,**kwargs): 
        #request.user 
        #request.auth 
        ret = {'code':1000,'msg':"你的订单已经完成",'data':"买了一个mac"} 
        return JsonResponse(ret,safe=True)

from django.conf.urls import url 
from django.contrib import admin 
from app01 import views 
 
urlpatterns = [ 
 
    url(r'^api/v1/auth', views.AuthView.as_view()), 
    url(r'^api/v1/order', views.OrderView.as_view()), 
]

from django.db import models 
 
class UserInfo(models.Model): 
    user_type_choice = ( 
        (1,"普通用户"), 
        (2,"会员"), 
    ) 
    user_type = models.IntegerField(choices=user_type_choice) 
    username = models.CharField(max_length=32,unique=True) 
    password = models.CharField(max_length=64) 
 
 
class UserToken(models.Model): 
    user = models.OneToOneField(to=UserInfo) 
    token = models.CharField(max_length=64)

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

 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 
        #4.实现认证 
        self.perform_authentication(request) 
        #5.权限判断 
        self.check_permissions(request) 
        self.check_throttles(request)

    def check_permissions(self, request): 
        """ 
        Check if the request should be permitted. 
        Raises an appropriate exception if the request is not permitted. 
        """ 
        for permission in self.get_permissions():   #循环对象get_permissions方法的结果，如果自己没有，则去父类寻找， 
            if not permission.has_permission(request, self): #判断每个对象中的has_permission方法返回值（其实就是权限判断），这就是为什么我们需要对权限类定义has_permission方法 
                self.permission_denied(                        
                    request, message=getattr(permission, 'message', None) #返回无权限信息，也就是我们定义的message共有属性 
                )

 def get_permissions(self): 
        """ 
        Instantiates and returns the list of permissions that this view requires. 
        """ 
        return [permission() for permission in self.permission_classes]  #与权限一样采用列表生成式获取每个认证类对象

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  #权限控制 
    content_negotiation_class = api_settings.DEFAULT_CONTENT_NEGOTIATION_CLASS 
    metadata_class = api_settings.DEFAULT_METADATA_CLASS 
    versioning_class = api_settings.DEFAULT_VERSIONING_CLASS

    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: 
            raise exceptions.NotAuthenticated() 
        raise exceptions.PermissionDenied(detail=message) # 如果定义了message属性，则抛出属性值

#路径：rest_framework.permissions 
##基本权限验证 
class BasePermission(object) 
 
##允许所有 
class AllowAny(BasePermission) 
 
##基于django的认证权限，官方示例 
class IsAuthenticated(BasePermission): 
 
##基于django admin权限控制 
class IsAdminUser(BasePermission) 
 
##也是基于django admin 
class IsAuthenticatedOrReadOnly(BasePermission) 
.....

###全局使用 
REST_FRAMEWORK = { 
   #权限 
    "DEFAULT_PERMISSION_CLASSES":['API.utils.permission.MyPremission'], 
} 
 
##单一视图使用,为空代表不做权限验证 
permission_classes = [MyPremission,]  
 
 
###优先级 
单一视图>全局配置