drf(请求封装/认证/权限/节流)

1.请求的封装

class HttpRequest(object):
    def __init__(self):
        pass

    @propery
    def GET(self):
        pass

    @propery
    def POST(self):
        pass

    @propery
    def body(self):
        pass
​
class Request(object):
    def __init__(self,request):
        self._request = request

    def data(self):
        if content-type == "application/json"
            reutrn json.loads(self._request.body.decode('urf-8'))
        elif content-type == "x-www-...":
            return self._request.POST

    def query_params(self):
        return self._reqeust.GET
​
req = HttpRequest()
request = Request(req)
​
request.data
request.query_prams
request._request.GET
request._request.POST
request._request.body

drf入口请求流程：

• 路由

  urlpatterns = [
      url(r'^order/$', views.OrderView.as_view()),
  ]

• 视图关系

  class View(object):
      @classonlymethod
      def as_view(cls, **initkwargs):
          def view(request, *args, **kwargs):
              return self.dispatch(request, *args, **kwargs)
          return view
  
  class APIView(View):
  
      @classmethod
      def as_view(cls, **initkwargs):
          view = super().as_view(**initkwargs)
          return csrf_exempt(view)
      def dispatch(self, request, *args, **kwargs):
          # 新request内部包含老request(_reuqest=老request)
          request = self.initialize_request(request, *args, **kwargs)
          self.request = request
          
          self.initial(request, *args, **kwargs)
          
          # 通过反射执行“get”方法，并传入新的request
          handler = getattr(self, request.method.lower())
          response = handler(request, *args, **kwargs) # get(requst)
          return self.response
      
  class OrderView(APIView):
  
      def get(self,request,*args,**kwargs):
          return Response('海狗')
  
  ​

2.版本

from django.conf.urls import url,include
from django.contrib import admin
from . import views
urlpatterns = [
    url(r'^order/$', views.OrderView.as_view()),
]

from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework.request import Request
​
class OrderView(APIView):
    def get(self,request,*args,**kwargs):
        print(request.version)
        print(request.versioning_scheme)
        return Response('...')
​
    def post(self,request,*args,**kwargs):
        return Response('post')

源码流程：

​
​
class APIView(View):
    versioning_class = api_settings.DEFAULT_VERSIONING_CLASS
    
    def dispatch(self, request, *args, **kwargs):
       
        # ###################### 第一步 ###########################
        """
        request,是django的request，它的内部有：request.GET/request.POST/request.method
        args,kwargs是在路由中匹配到的参数，如：
            url(r'^order/(\d+)/(?P<version>\w+)/$', views.OrderView.as_view()),
            http://www.xxx.com/order/1/v2/
        """
        self.args = args
        self.kwargs = kwargs
​
        """
        request = 生成了一个新的request对象，此对象的内部封装了一些值。
        request = Request(request)
            - 内部封装了 _request = 老的request
        """
        request = self.initialize_request(request, *args, **kwargs)
        self.request = request
​
        self.headers = self.default_response_headers  # deprecate?
​
        try:
            # ###################### 第二步 ###########################
            self.initial(request, *args, **kwargs)
​
            执行视图函数。。

    def initial(self, request, *args, **kwargs):
       
        # ############### 2.1 处理drf的版本 ##############
        version, scheme = self.determine_version(request, *args, **kwargs)
        request.version, request.versioning_scheme = version, scheme
        ...
        
    def determine_version(self, request, *args, **kwargs):
        if self.versioning_class is None:
            return (None, None)
        scheme = self.versioning_class() # obj = XXXXXXXXXXXX()
        return (scheme.determine_version(request, *args, **kwargs), scheme)
        
class OrderView(APIView):
    versioning_class = URLPathVersioning
    def get(self,request,*args,**kwargs):
        print(request.version)
        print(request.versioning_scheme)
        return Response('...')
​
    def post(self,request,*args,**kwargs):
        return Response('post')

class URLPathVersioning(BaseVersioning):
    """
    urlpatterns = [
        url(r'^(?P<version>[v1|v2]+)/users/$', users_list, name='users-list'),
       
    ]
    """
    invalid_version_message = _('Invalid version in URL path.')
​
    def determine_version(self, request, *args, **kwargs):
        version = kwargs.get(self.version_param, self.default_version)
        if version is None:
            version = self.default_version
​
        if not self.is_allowed_version(version):
            raise exceptions.NotFound(self.invalid_version_message)
        return version
​

使用（局部）

• url中写version

  url(r'^(?P<version>[v1|v2]+)/users/$', users_list, name='users-list'),

• 在视图中应用

  from rest_framework.views import APIView
  from rest_framework.response import Response
  from rest_framework.request import Request
  from rest_framework.versioning import URLPathVersioning
  ​
  ​
  class OrderView(APIView):
  ​
      versioning_class = URLPathVersioning
      def get(self,request,*args,**kwargs):
          print(request.version)
          print(request.versioning_scheme)
          return Response('...')
  ​
      def post(self,request,*args,**kwargs):
          return Response('post')

• 在settings中配置

  REST_FRAMEWORK = {
      "PAGE_SIZE":2,
      "DEFAULT_PAGINATION_CLASS":"rest_framework.pagination.PageNumberPagination",
      "ALLOWED_VERSIONS":['v1','v2'],
      'VERSION_PARAM':'version'
  }

使用（全局）推荐

• url中写version

  url(r'^(?P<version>[v1|v2]+)/users/$', users_list, name='users-list'),
  ​
  url(r'^(?P<version>\w+)/users/$', users_list, name='users-list'),

• 在视图中应用

  from rest_framework.views import APIView
  from rest_framework.response import Response
  from rest_framework.request import Request
  from rest_framework.versioning import URLPathVersioning
  ​
  ​
  class OrderView(APIView):
      def get(self,request,*args,**kwargs):
          print(request.version)
          print(request.versioning_scheme)
          return Response('...')
  ​
      def post(self,request,*args,**kwargs):
          return Response('post')

• 在settings中配置

  REST_FRAMEWORK = {
      "PAGE_SIZE":2,
      "DEFAULT_PAGINATION_CLASS":"rest_framework.pagination.PageNumberPagination",
      "DEFAULT_VERSIONING_CLASS":"rest_framework.versioning.URLPathVersioning",
      "ALLOWED_VERSIONS":['v1','v2'],
      'VERSION_PARAM':'version'
  }

####

3.认证（面试）

from django.conf.urls import url,include
from django.contrib import admin
from . import views
urlpatterns = [
    url(r'^login/$', views.LoginView.as_view()),
    url(r'^order/$', views.OrderView.as_view()),
    url(r'^user/$', views.UserView.as_view()),
]
​

import uuid
from django.shortcuts import render
from django.views import View
from django.views.decorators.csrf import csrf_exempt
from django.utils.decorators import method_decorator
from rest_framework.versioning import URLPathVersioning
from rest_framework.views import APIView
from rest_framework.response import Response
​
from . import models
​
class LoginView(APIView):
​
    def post(self,request,*args,**kwargs):
        user_object = models.UserInfo.objects.filter(**request.data).first()
        if not user_object:
            return Response('登录失败')
        random_string = str(uuid.uuid4())
        user_object.token = random_string
        user_object.save()
        return Response(random_string)
​
class MyAuthentication:
    def authenticate(self, request):
        """
        Authenticate the request and return a two-tuple of (user, token).
        """
        token = request.query_params.get('token')
        user_object = models.UserInfo.objects.filter(token=token).first()
        if user_object:
            return (user_object,token)
        return (None,None)
​
class OrderView(APIView):
    authentication_classes = [MyAuthentication, ]
    def get(self,request,*args,**kwargs):
        print(request.user)
        print(request.auth)
        return Response('order')
​
class UserView(APIView):
    authentication_classes = [MyAuthentication,]
    def get(self,request,*args,**kwargs):
        print(request.user)
        print(request.auth)
        return Response('user')

源码分析

class Request:
​
    def __init__(self, request,authenticators=None):
        self._request = request
        self.authenticators = authenticators or ()
        
    @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
    
    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()
        
    @user.setter
    def user(self, value):
        """
        Sets the user on the current request. This is necessary to maintain
        compatibility with django.contrib.auth where the user property is
        set in the login and logout functions.
​
        Note that we also set the user on Django's underlying `HttpRequest`
        instance, ensuring that it is available to any middleware in the stack.
        """
        self._user = value
        self._request.user = value

​
class APIView(View):
    authentication_classes = api_settings.DEFAULT_AUTHENTICATION_CLASSES
    
    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.
        """
        # ###################### 第一步 ###########################
        """
        request,是django的request，它的内部有：request.GET/request.POST/request.method
        args,kwargs是在路由中匹配到的参数，如：
            url(r'^order/(\d+)/(?P<version>\w+)/$', views.OrderView.as_view()),
            http://www.xxx.com/order/1/v2/
        """
        self.args = args
        self.kwargs = kwargs
​
​
        """
        request = 生成了一个新的request对象，此对象的内部封装了一些值。
        request = Request(request)
            - 内部封装了 _request = 老的request
            - 内部封装了 authenticators = [MyAuthentication(), ]
        """
        request = self.initialize_request(request, *args, **kwargs)
        self.request = 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(), # [MyAuthentication(),]
            negotiator=self.get_content_negotiator(),
            parser_context=parser_context
        )
​
    def get_authenticators(self):
        """
        Instantiates and returns the list of authenticators that this view can use.
        """
        return [ auth() for auth in self.authentication_classes ]
    
class LoginView(APIView):
    authentication_classes = []
    def post(self,request,*args,**kwargs):
        user_object = models.UserInfo.objects.filter(**request.data).first()
        if not user_object:
            return Response('登录失败')
        random_string = str(uuid.uuid4())
        user_object.token = random_string
        user_object.save()
        return Response(random_string)
​
class OrderView(APIView):
    # authentication_classes = [TokenAuthentication, ]
    def get(self,request,*args,**kwargs):
        print(request.user)
        print(request.auth)
        if request.user:
            return Response('order')
        return Response('滚')
​
class UserView(APIView):
    同上

总结

当用户发来请求时，找到认证的所有类并实例化成为对象列表，然后将对象列表封装到新的request对象中。
​
以后在视同中调用request.user
​
在内部会循环认证的对象列表，并执行每个对象的authenticate方法，该方法用于认证，他会返回两个值分别会赋值给
request.user/request.auth 

作业：将认证的功能添加到呼啦圈中。

• 登录表

• 登录视图

• 写认证类

• 应用认证类：全局应用

• Login视图不应用认证

4.权限

from rest_framework.permissions import BasePermission
from rest_framework import exceptions
​
class MyPermission(BasePermission):
    message = {'code': 10001, 'error': '你没权限'}
    def has_permission(self, request, view):
        """
        Return `True` if permission is granted, `False` otherwise.
        """
        if request.user:
            return True
​
        # raise exceptions.PermissionDenied({'code': 10001, 'error': '你没权限'})
        return False
​
    def has_object_permission(self, request, view, obj):
        """
        Return `True` if permission is granted, `False` otherwise.
        """
        return False

class OrderView(APIView):
    permission_classes = [MyPermission,]
    def get(self,request,*args,**kwargs):
        return Response('order')
​
​
class UserView(APIView):
    permission_classes = [MyPermission, ]
    def get(self,request,*args,**kwargs):
        return Response('user')
​

REST_FRAMEWORK = {
    "PAGE_SIZE":2,
    "DEFAULT_PAGINATION_CLASS":"rest_framework.pagination.PageNumberPagination",
    "DEFAULT_VERSIONING_CLASS":"rest_framework.versioning.URLPathVersioning",
    "ALLOWED_VERSIONS":['v1','v2'],
    'VERSION_PARAM':'version',
    "DEFAULT_AUTHENTICATION_CLASSES":["kka.auth.TokenAuthentication",]
}

源码分析

class APIView(View):
    permission_classes = api_settings.DEFAULT_PERMISSION_CLASSES
    
    def dispatch(self, request, *args, **kwargs):
        封装request对象
        self.initial(request, *args, **kwargs)
        通过反射执行视图中的方法
​
    def initial(self, request, *args, **kwargs):
        版本的处理
        # 认证
        self.perform_authentication(request)

        # 权限判断
        self.check_permissions(request)
        
        
        self.check_throttles(request)
        
    def perform_authentication(self, request):
        request.user

    def check_permissions(self, request):
        # [对象,对象，]
        for permission in self.get_permissions():
            if not permission.has_permission(request, self):
                self.permission_denied(request, message=getattr(permission, 'message', None))
    def permission_denied(self, request, message=None):
        if request.authenticators and not request.successful_authenticator:
            raise exceptions.NotAuthenticated()
        raise exceptions.PermissionDenied(detail=message)
        
    def get_permissions(self):
        return [permission() for permission in self.permission_classes]
    
class UserView(APIView):
    permission_classes = [MyPermission, ]
    
    def get(self,request,*args,**kwargs):
        return Response('user')

实现呼啦圈

• 视图：ListAPIView

• 序列化：多个序列化

• 分页：给列表页面做分页

• 版本：版本设置

• 认证：认证流程 request.user赋值

• 权限：能否访问