Django rest framework原始碼分析(1)----認證
目錄
一、基礎
1.1.安裝
兩種方式:
pip install djangorestframework
1.2.需要先了解的一些知識
理解下面兩個知識點非常重要,django-rest-framework原始碼中到處都是基於CBV和麵向物件的封裝
(1)面向物件封裝的兩大特性
把同一類方法封裝到類中
將資料封裝到物件中
(2)CBV
基於反射實現根據請求方式不同,執行不同的方法
原理:url-->view方法-->dispatch方法(反射執行其它方法:GET/POST/PUT/DELETE等等)
二、簡單例項
2.1.settings
先建立一個project和一個app(我這裡命名為API)
首先要在settings的app中新增
INSTALLED_APPS = [ 'rest_framework', ]
2.2.url
from django.contrib import admin from django.urls import path from API.views import AuthView urlpatterns = [ path('admin/', admin.site.urls), path('api/v1/auth/',AuthView.as_view()), ]
2.3.models
一個儲存使用者的資訊
一個儲存使用者登入成功後的token
from django.db import models class UserInfo(models.Model): USER_TYPE = ( (1,'普通使用者'), (2,'VIP'), (3,'SVIP') ) user_type = models.IntegerField(choices=USER_TYPE) username = models.CharField(max_length=32) password= models.CharField(max_length=64) class UserToken(models.Model): user = models.OneToOneField(UserInfo,on_delete=models.CASCADE) token = models.CharField(max_length=64)
2.4.views
使用者登入(返回token並儲存到資料庫)
from django.shortcuts import render from django.http import JsonResponse from rest_framework.views import APIView from API import models def md5(user): import hashlib import time #當前時間,相當於生成一個隨機的字串 ctime = str(time.time()) m = hashlib.md5(bytes(user,encoding='utf-8')) m.update(bytes(ctime,encoding='utf-8')) return m.hexdigest() class AuthView(object): def post(self,request,*args,**kwargs): ret = {'code':1000,'msg':None} try: user = request._request.POST.get('username') pwd = request._request.POST.get('password') obj = models.UserInfo.objects.filter(username=user,password=pwd).first() if not obj: ret['code'] = 1001 ret['msg'] = '使用者名稱或密碼錯誤' #為使用者建立token token = md5(user) #存在就更新,不存在就建立 models.UserToken.objects.update_or_create(user=obj,defaults={'token':token}) ret['token'] = token except Exception as e: ret['code'] = 1002 ret['msg'] = '請求異常' return JsonResponse(ret)
2.5.利用postman發請求
如果使用者名稱和密碼正確的話 會生成token值,下次該使用者再登入時,token的值就會更新
資料庫中可以看到token的值
當用戶名或密碼錯誤時,丟擲異常
三、新增認證
基於上面的例子,新增一個認證的類
3.1.url
path('api/v1/order/',OrderView.as_view()),
3.2.views
from django.shortcuts import render,HttpResponse from django.http import JsonResponse from rest_framework.views import APIView from API import models from rest_framework.request import Request from rest_framework import exceptions from rest_framework.authentication import BasicAuthentication ORDER_DICT = { 1:{ 'name':'apple', 'price':15 }, 2:{ 'name':'dog', 'price':100 } } def md5(user): import hashlib import time #當前時間,相當於生成一個隨機的字串 ctime = str(time.time()) m = hashlib.md5(bytes(user,encoding='utf-8')) m.update(bytes(ctime,encoding='utf-8')) return m.hexdigest() class AuthView(object): '''用於使用者登入驗證''' def post(self,request,*args,**kwargs): ret = {'code':1000,'msg':None} try: user = request._request.POST.get('username') pwd = request._request.POST.get('password') obj = models.UserInfo.objects.filter(username=user,password=pwd).first() if not obj: ret['code'] = 1001 ret['msg'] = '使用者名稱或密碼錯誤' #為使用者建立token token = md5(user) #存在就更新,不存在就建立 models.UserToken.objects.update_or_create(user=obj,defaults={'token':token}) ret['token'] = token except Exception as e: ret['code'] = 1002 ret['msg'] = '請求異常' return JsonResponse(ret) class Authentication(APIView): '''認證''' def authenticate(self,request): token = request._request.GET.get('token') token_obj = models.UserToken.objects.filter(token=token).first() if not token_obj: raise exceptions.AuthenticationFailed('使用者認證失敗') #在rest framework內部會將這兩個欄位賦值給request,以供後續操作使用 return (token_obj.user,token_obj) def authenticate_header(self, request): pass class OrderView(APIView): '''訂單相關業務''' authentication_classes = [Authentication,] #新增認證 def get(self,request,*args,**kwargs): #request.user #request.auth ret = {'code':1000,'msg':None,'data':None} try: ret['data'] = ORDER_DICT except Exception as e: pass return JsonResponse(ret)
3.3用postman發get請求
請求的時候沒有帶token,可以看到會顯示“使用者認證失敗”
這樣就達到了認證的效果,django-rest-framework的認證是怎麼實現的呢,下面基於這個例子來剖析drf的原始碼。
四、drf的認證原始碼分析
原始碼流程圖
請求先到dispatch
dispatch()主要做了兩件事
- 封裝request
- 認證
具體看我寫的程式碼裡面的註釋
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 #對原始request進行加工,豐富了一些功能 #Request( # request, # parsers=self.get_parsers(), # authenticators=self.get_authenticators(), # negotiator=self.get_content_negotiator(), # parser_context=parser_context # ) #request(原始request,[BasicAuthentications物件,]) #獲取原生request,request._request #獲取認證類的物件,request.authticators #1.封裝request request = self.initialize_request(request, *args, **kwargs) self.request = request self.headers = self.default_response_headers # deprecate? try: #2.認證 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
4.1.reuqest
(1)initialize_request()
可以看到initialize()就是封裝原始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(),],把物件封裝到request裡面了
negotiator=self.get_content_negotiator(), parser_context=parser_context )
(2)get_authenticators()
通過列表生成式,返回物件的列表
def get_authenticators(self): """ Instantiates and returns the list of authenticators that this view can use. """ return [auth() for auth in self.authentication_classes]
(3)authentication_classes
APIView裡面有個 authentication_classes 欄位
可以看到預設是去全域性的配置檔案找(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
4.2.認證
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 #對原始request進行加工,豐富了一些功能 #Request( # request, # parsers=self.get_parsers(), # authenticators=self.get_authenticators(), # negotiator=self.get_content_negotiator(), # parser_context=parser_context # ) #request(原始request,[BasicAuthentications物件,]) #獲取原生request,request._request #獲取認證類的物件,request.authticators #1.封裝request request = self.initialize_request(request, *args, **kwargs) self.request = request self.headers = self.default_response_headers # deprecate? try: #2.認證 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
(1)initial()
主要看 self.perform_authentication(request),實現認證
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.實現認證 self.perform_authentication(request) self.check_permissions(request) self.check_throttles(request)
(2)perform_authentication()
呼叫了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
(3)user
request.user的request的位置
點進去可以看到Request有個user方法,加 @property 表示呼叫user方法的時候不需要加括號“user()”,可以直接呼叫: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(): #獲取認證物件,進行一步步的認證 self._authenticate() return self._user
(4)_authenticate()
迴圈所有authenticator物件
def _authenticate(self): """ Attempt to authenticate the request using each authentication instance in turn. """ #迴圈認證類的所有物件 #執行物件的authenticate方法 for authenticator in self.authenticators: try: #執行認證類的authenticate方法 #這裡分三種情況 #1.如果authenticate方法丟擲異常,self._not_authenticated()執行 #2.有返回值,必須是元組:(request.user,request.auth) #3.返回None,表示當前認證不處理,等下一個認證來處理 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()
返回值就是例子中的:
token_obj.user-->>request.user
token_obj-->>request.auth
#在rest framework內部會將這兩個欄位賦值給request,以供後續操作使用 return (token_obj.user,token_obj) #例子中的return
當都沒有返回值,就執行self._not_authenticated(),相當於匿名使用者,沒有通過認證
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匿名使用者 else: self.user = None if api_settings.UNAUTHENTICATED_TOKEN: self.auth = api_settings.UNAUTHENTICATED_TOKEN() #None else: self.auth = None
面向物件知識:
子類繼承 父類,呼叫方法的時候:
- 優先去自己裡面找有沒有這個方法,有就執行自己的
- 只有當自己裡面沒有這個方法的時候才會去父類找
因為authenticate方法我們自己寫,所以當執行authenticate()的時候就是執行我們自己寫的認證
父類中的authenticate方法
def authenticate(self, request): return (self.force_user, self.force_token)
我們自己寫的
class Authentication(APIView): '''用於使用者登入驗證''' def authenticate(self,request): token = request._request.GET.get('token') token_obj = models.UserToken.objects.filter(token=token).first() if not token_obj: raise exceptions.AuthenticationFailed('使用者認證失敗') #在rest framework內部會將這兩個欄位賦值給request,以供後續操作使用 return (token_obj.user,token_obj)
認證的流程就是上面寫的,弄懂了原理,再寫程式碼就更容易理解為什麼了。
4.3.配置檔案
繼續解讀原始碼
預設是去全域性配置檔案中找,所以我們應該在settings.py中配置好路徑
api_settings原始碼
api_settings = APISettings(None, DEFAULTS, IMPORT_STRINGS) def reload_api_settings(*args, **kwargs): setting = kwargs['setting'] if setting == 'REST_FRAMEWORK': api_settings.reload()
setting中‘REST_FRAMEWORK’中找
全域性配置方法:
API資料夾下面新建資料夾utils,再新建auth.py檔案,裡面寫上認證的類
settings.py
#設定全域性認證 REST_FRAMEWORK = { "DEFAULT_AUTHENTICATION_CLASSES":['API.utils.auth.Authentication',] #裡面寫你的認證的類的路徑 }
auth.py
# API/utils/auth.py from rest_framework import exceptions from API import models class Authentication(object): '''用於使用者登入驗證''' def authenticate(self,request): token = request._request.GET.get('token') token_obj = models.UserToken.objects.filter(token=token).first() if not token_obj: raise exceptions.AuthenticationFailed('使用者認證失敗') #在rest framework內部會將這兩個欄位賦值給request,以供後續操作使用 return (token_obj.user,token_obj) def authenticate_header(self, request): pass
在settings裡面設定的全域性認證,所有業務都需要經過認證,如果想讓某個不需要認證,只需要在其中新增下面的程式碼:
authentication_classes = [] #裡面為空,代表不需要認證
from django.shortcuts import render,HttpResponse from django.http import JsonResponse from rest_framework.views import APIView from API import models from rest_framework.request import Request from rest_framework import exceptions from rest_framework.authentication import BasicAuthentication ORDER_DICT = { 1:{ 'name':'apple', 'price':15 }, 2:{ 'name':'dog', 'price':100 } } def md5(user): import hashlib import time #當前時間,相當於生成一個隨機的字串 ctime = str(time.time()) m = hashlib.md5(bytes(user,encoding='utf-8')) m.update(bytes(ctime,encoding='utf-8')) return m.hexdigest() class AuthView(APIView): '''用於使用者登入驗證''' authentication_classes = [] #裡面為空,代表不需要認證 def post(self,request,*args,**kwargs): ret = {'code':1000,'msg':None} try: user = request._request.POST.get('username') pwd = request._request.POST.get('password') obj = models.UserInfo.objects.filter(username=user,password=pwd).first() if not obj: ret['code'] = 1001 ret['msg'] = '使用者名稱或密碼錯誤' #為使用者建立token token = md5(user) #存在就更新,不存在就建立 models.UserToken.objects.update_or_create(user=obj,defaults={'token':token}) ret['token'] = token except Exception as e: ret['code'] = 1002 ret['msg'] = '請求異常' return JsonResponse(ret) class OrderView(APIView): '''訂單相關業務''' def get(self,request,*args,**kwargs): # self.dispatch #request.user #request.auth ret = {'code':1000,'msg':None,'data':None} try: ret['data'] = ORDER_DICT except Exception as e: pass return JsonResponse(ret)API/view.py程式碼
再測試一下我們的程式碼
不帶token發請求
帶token發請求
五、drf的內建認證
rest_framework裡面內建了一些認證,我們自己寫的認證類都要繼承內建認證類 "BaseAuthentication"
4.1.BaseAuthentication原始碼:
class BaseAuthentication(object): """ All authentication classes should extend BaseAuthentication. """ def authenticate(self, request): """ Authenticate the request and return a two-tuple of (user, token). """ #內建的認證類,authenticate方法,如果不自己寫,預設則丟擲異常 raise NotImplementedError(".authenticate() must be overridden.") def authenticate_header(self, request): """ Return a string to be used as the value of the `WWW-Authenticate` header in a `401 Unauthenticated` response, or `None` if the authentication scheme should return `403 Permission Denied` responses. """ #authenticate_header方法,作用是當認證失敗的時候,返回的響應頭 pass
4.2.修改自己寫的認證類
自己寫的Authentication必須繼承內建認證類BaseAuthentication
# API/utils/auth/py from rest_framework import exceptions from API import models from rest_framework.authentication import BaseAuthentication class Authentication(BaseAuthentication): '''用於使用者登入驗證''' def authenticate(self,request): token = request._request.GET.get('token') token_obj = models.UserToken.objects.filter(token=token).first() if not token_obj: raise exceptions.AuthenticationFailed('使用者認證失敗') #在rest framework內部會將這兩個欄位賦值給request,以供後續操作使用 return (token_obj.user,token_obj) def authenticate_header(self, request): pass
4.3.其它內建認證類
rest_framework裡面還內建了其它認證類,我們主要用到的就是BaseAuthentication,剩下的很少用到
六、總結
自己寫認證類方法梳理
(1)建立認證類
- 繼承BaseAuthentication --->>1.重寫authenticate方法;2.authenticate_header方法直接寫pass就可以(這個方法必須寫)
(2)authenticate()返回值(三種)
- None ----->>>當前認證不管,等下一個認證來執行
- raise exceptions.AuthenticationFailed('使用者認證失敗') # from rest_framework import exceptions
- 有返回值元祖形式:(元素1,元素2) #元素1複製給request.user; 元素2複製給request.auth
(3)區域性使用
- authentication_classes = [BaseAuthentication,]
(4)全域性使用
#設定全域性認證 REST_FRAMEWORK = { "DEFAULT_AUTHENTICATION_CLASSES":['API.utils.auth.Authentication',] }
原始碼流程
--->>dispatch
--封裝request
---獲取定義的認證類(全域性/區域性),通過列表生成式建立物件
---initial
----peform_authentication
-----request.user (每部迴圈建立的物件)