10.DRF-認證

時間  2020-12-14
標籤 python git github 數據庫 django api app ide 源碼分析 post 欄目 Python 简体版
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Django rest framework源碼分析（1）----認證

1、基礎

1.1.安裝

兩種方式：python

pip install djangorestframework

1.2.須要先了解的一些知識

理解下面兩個知識點很是重要，django-rest-framework源碼中處處都是基於CBV和麪向對象的封裝git

（1）面向對象封裝的兩大特性github

把同一類方法封裝到類中

將數據封裝到對象中

（2）CBV數據庫

基於反射實現根據請求方式不一樣，執行不一樣的方法django

原理：url-->view方法-->dispatch方法（反射執行其它方法：GET/POST/PUT/DELETE等等）api

2、簡單實例

2.1.settings

先建立一個project和一個app(我這裏命名爲API)app

首先要在settings的app中添加ide

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

一個保存用戶的信息源碼分析

一個保存用戶登陸成功後的tokenpost

from django.db import models

class UserInfo(models.Model):
    USER_TYPE = (
        (1,'普通用戶'),
        (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

用戶登陸（返回token並保存到數據庫）

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，至關於生成一個隨機的字符串
    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'] = '用戶名或密碼錯誤'
            #爲用戶建立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

若是用戶名和密碼正確的話 會生成token值，下次該用戶再登陸時，token的值就會更新

數據庫中能夠看到token的值

當用戶名或密碼錯誤時，拋出異常

3、添加認證

基於上面的例子，添加一個認證的類

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，至關於生成一個隨機的字符串
    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):
    '''用於用戶登陸驗證'''
    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'] = '用戶名或密碼錯誤'
            #爲用戶建立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('用戶認證失敗')
        #在rest framework內部會將這兩個字段賦值給request，以供後續操做使用
        return (token_obj.user,token_obj)

    def authenticate_header(self, request):
        pass

class OrderView(APIView):
    '''訂單相關業務'''

    authentication_classes = [Authentication,]    #添加認證
    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，能夠看到會顯示「用戶認證失敗」

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的源碼。

4、drf的認證源碼分析

源碼流程圖

請求先到dispatch

dispatch()主要作了兩件事

  • 封裝request
  • 認證　　

具體看我寫的代碼裏面的註釋

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對象，])
    #獲取原生request,request._request
    #獲取認證類的對象，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()

能夠看到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(),
        #[BasicAuthentication(),],把對象封裝到request裏面了
        authenticators=self.get_authenticators(),    
        negotiator=self.get_content_negotiator(), parser_context=parser_context )

（2）get_authenticators()

經過列表生成式，返回對象的列表

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裏面有個 authentication_classes 字段

能夠看到默認是去全局的配置文件找（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對象，])
    #獲取原生request,request._request
    #獲取認證類的對象，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()

調用了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

點進去能夠看到Request有個user方法,加 @property 表示調用user方法的時候不須要加括號「user()」，能夠直接調用：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():
            #獲取認證對象，進行一步步的認證
            self._authenticate()
    return self._user

（4）_authenticate()

循環全部authenticator對象

def _authenticate(self):
    """
    Attempt to authenticate the request using each authentication instance
    in turn.
    """
    #循環認證類的全部對象
    #執行對象的authenticate方法
    for authenticator in self.authenticators:
        try:
            #執行認證類的authenticate方法
            #這裏分三種狀況
            #1.若是authenticate方法拋出異常，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內部會將這兩個字段賦值給request，以供後續操做使用
return (token_obj.user,token_obj)     #例子中的return

當都沒有返回值，就執行self._not_authenticated(),至關於匿名用戶，沒有經過認證

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匿名用戶
    else:
        self.user = None

	if api_settings.UNAUTHENTICATED_TOKEN:
        self.auth = api_settings.UNAUTHENTICATED_TOKEN()  #None
	else:
        self.auth = None

面向對象知識：

子類繼承 父類，調用方法的時候：

  • 優先去本身裏面找有沒有這個方法，有就執行本身的
  • 只有當本身裏面沒有這個方法的時候纔會去父類找

由於authenticate方法咱們本身寫，因此當執行authenticate()的時候就是執行咱們本身寫的認證

父類中的authenticate方法

def authenticate(self, request):
    return (self.force_user, self.force_token)

咱們本身寫的

class Authentication(APIView):
    '''用於用戶登陸驗證'''
    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('用戶認證失敗')
        #在rest framework內部會將這兩個字段賦值給request，以供後續操做使用
        return (token_obj.user,token_obj)

認證的流程就是上面寫的，弄懂了原理，再寫代碼就更容易理解爲何了。

4.3.配置文件

繼續解讀源碼

默認是去全局配置文件中找，因此咱們應該在settings.py中配置好路徑

api_settings源碼

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

全局配置方法：

API文件夾下面新建文件夾utils,再新建auth.py文件，裏面寫上認證的類

settings.py

#設置全局認證
REST_FRAMEWORK = {
    "DEFAULT_AUTHENTICATION_CLASSES":['API.utils.auth.Authentication',]   #裏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):
    '''用於用戶登陸驗證'''
    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('用戶認證失敗')
        #在rest framework內部會將這兩個字段賦值給request，以供後續操做使用
        return (token_obj.user,token_obj)

    def authenticate_header(self, request):
        pass

在settings裏面設置的全局認證，全部業務都須要通過認證，若是想讓某個不須要認證，只須要在其中添加下面的代碼：

authentication_classes = []    #裏面爲空，表明不須要認證
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，至關於生成一個隨機的字符串
    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):
    '''用於用戶登陸驗證'''

    authentication_classes = []    #裏面爲空，表明不須要認證

    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'] = '用戶名或密碼錯誤'
            #爲用戶建立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代碼

再測試一下咱們的代碼

不帶token發請求

帶token發請求

5、drf的內置認證

rest_framework裏面內置了一些認證，咱們本身寫的認證類都要繼承內置認證類 "BaseAuthentication"

4.1.BaseAuthentication源碼：

class BaseAuthentication(object):
    """
    All authentication classes should extend BaseAuthentication.
    """

    def authenticate(self, request):
        """
        Authenticate the request and return a two-tuple of (user, token).
        """
        #內置的認證類，authenticate方法，若是不本身寫，默認則拋出異常
        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，做用是當認證失敗的時候，返回的響應頭
        pass

4.2.修改本身寫的認證類

本身寫的Authentication必須繼承內置認證類BaseAuthentication

# API/utils/auth/py

from rest_framework import exceptions
from API import models
from rest_framework.authentication import BaseAuthentication


class Authentication(BaseAuthentication):
    '''用於用戶登陸驗證'''
    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('用戶認證失敗')
        #在rest framework內部會將這兩個字段賦值給request，以供後續操做使用
        return (token_obj.user,token_obj)

    def authenticate_header(self, request):
        pass

4.3.其它內置認證類

rest_framework裏面還內置了其它認證類，咱們主要用到的就是BaseAuthentication，剩下的不多用到

6、總結

本身寫認證類方法梳理

（1）建立認證類

  • 繼承BaseAuthentication --->>1.重寫authenticate方法；2.authenticate_header方法直接寫pass就能夠（這個方法必須寫）

（2）authenticate()返回值（三種）

  • None ----->>>當前認證無論，等下一個認證來執行
  • raise exceptions.AuthenticationFailed('用戶認證失敗') # 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）局部使用

  • authentication_classes = [BaseAuthentication,]

（4）全局使用

#設置全局認證
REST_FRAMEWORK = {
    "DEFAULT_AUTHENTICATION_CLASSES":['API.utils.auth.Authentication',]
}

源碼流程

--->>dispatch

　　　　--封裝request

　　　　　　　---獲取定義的認證類（全局/局部），經過列表生成式建立對象　

　　　　 ---initial

　　　　　　　----peform_authentication

　　　　　　　　　-----request.user （每部循環建立的對象）

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