源码剖析Django REST framework的认证方式及自定义认证

源码剖析Django REST framework的认证方式

由Django的CBV模式流程,可以知道在url匹配完成后,会执行自定义的类中的as_view方法

如果自定义的类中没有定义as_view方法,根据面向对象中类的继承可以知道,则会执行其父类View中的as_view方法

在Django的View的as_view方法中,又会调用dispatch方法

现在来看看Django restframework的认证流程

Django restframework是基于Django的框架,所以基于CBV的模式也会执行自定义的类中的as_view方法

先新建一个项目,配置url

from django.conf.urls import url
from django.contrib import admin

from app01 import views

urlpatterns = [
    url(r'^user/', views.UserView.as_view()),
]

views.py文件内容

from django.shortcuts import render,HttpResponse
from rest_framework.views import APIView

class UserView(APIView):

    def get(self,request,*args,**kwargs):
        print(request.__dict__)
        print(request.user)
        return HttpResponse("UserView GET")

    def post(self,request,*args,**kwargs):
        return HttpResponse("UserView POST")

启动项目,用浏览器向http://127.0.0.1:8000/user/发送get请求

可以知道请求发送成功。现在来看看源码流程,由于UserView继承APIView,查看APIView中的as_view方法

class APIView(View):
	...
    @classmethod
    def as_view(cls, **initkwargs):
        if isinstance(getattr(cls, 'queryset', None), models.query.QuerySet):
            def force_evaluation():
                raise RuntimeError(
                    'Do not evaluate the `.queryset` attribute directly, '
                    'as the result will be cached and reused between requests. '
                    'Use `.all()` or call `.get_queryset()` instead.'
                )
            cls.queryset._fetch_all = force_evaluation

        view = super(APIView, cls).as_view(**initkwargs)
        view.cls = cls
        view.initkwargs = initkwargs
        return csrf_exempt(view)

通过super来执行APIView的父类Django的View中的as_view方法。上一篇文章源码解析Django CBV的本质中已经知道,View类的as_view方法会调用dispatch方法。

View类的as_view方法源码如下所示

class View(object):
	...
    @classonlymethod
    def as_view(cls, **initkwargs):
		...
        def view(request, *args, **kwargs):
            self = cls(**initkwargs)
            if hasattr(self, 'get') and not hasattr(self, 'head'):
                self.head = self.get
            self.request = request
            self.args = args
            self.kwargs = kwargs
            return self.dispatch(request, *args, **kwargs)
		...

as_view方法中的self实际上指的是自定义的UserView这个类,上面的代码会执行UserView类中dispatch方法。

由于UserView类中并没有定义dispatch方法,而UserView类继承自Django restframework的APIView类,所以会执行APIView类中的dispatch方法

def dispatch(self, request, *args, **kwargs):
    self.args = args
    self.kwargs = kwargs
    request = self.initialize_request(request, *args, **kwargs)
    self.request = request
    self.headers = self.default_response_headers  # deprecate?

    try:
        self.initial(request, *args, **kwargs)
        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

可以看到,先执行initialize_request方法处理浏览器发送的request请求

来看看initialize_request方法的源码

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(),
        negotiator=self.get_content_negotiator(),
        parser_context=parser_context
    )

在initialize_request方法里,把浏览器发送的request和restframework的处理器,认证,选择器等对象列表作为参数实例化Request类中得到新的request对象并返回,其中跟认证相关的对象就是authenticators。

def get_authenticators(self):
    """
    Instantiates and returns the list of authenticators that this view can use.
    """
    return [auth() for auth in self.authentication_classes]

get_authenticators方法通过列表生成式得到一个列表,列表中包含认证类实例化后的对象

在这里,authentication_classes来自于api_settings的配置

authentication_classes = api_settings.DEFAULT_AUTHENTICATION_CLASSES

通过查看api_settings的源码可以知道,可以在项目的settings.py文件中进行认证相关的配置

api_settings = APISettings(None, DEFAULTS, IMPORT_STRINGS)

def reload_api_settings(*args, **kwargs):
    setting = kwargs['setting']
    if setting == 'REST_FRAMEWORK':
        api_settings.reload()

Django restframework通过initialize_request方法对原始的request进行一些封装后实例化得到新的request对象

然后执行initial方法来处理新得到的request对象,再来看看initial方法中又执行了哪些操作

def initial(self, request, *args, **kwargs):
    self.format_kwarg = self.get_format_suffix(**kwargs)
    neg = self.perform_content_negotiation(request)
    request.accepted_renderer, request.accepted_media_type = neg

    version, scheme = self.determine_version(request, *args, **kwargs)
    request.version, request.versioning_scheme = version, scheme

    self.perform_authentication(request)
    self.check_permissions(request)
    self.check_throttles(request)

由上面的源码可以知道,在initial方法中,执行perform_authentication来对request对象进行认证操作

def perform_authentication(self, request):
    request.user

perform_authentication方法中调用执行request中的user方法这里的request是封装了原始request,认证对象列表,处理器列表等之后的request对象

class Request(object):
	...
    @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

从request中获取_user的值,如果获取到则执行_authenticate方法,否则返回_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

在这里self.authenticators实际上是get_authenticators方法执行完成后返回的对象列表

class Request(object):

    def __init__(self, request, parsers=None, authenticators=None,
                 negotiator=None, parser_context=None):
        assert isinstance(request, HttpRequest), (
            'The `request` argument must be an instance of '
            '`django.http.HttpRequest`, not `{}.{}`.'
            .format(request.__class__.__module__, request.__class__.__name__)
        )

        self._request = request
        self.parsers = parsers or ()
        self.authenticators = authenticators or ()
		...

循环认证的对象列表,执行每一个认证方法的类中的authenticate方法,得到通过认证的用户及用户的口令的元组,并返回元组完成认证的流程

_authenticate方法中使用了try/except方法来捕获authenticate方法可能出现的异常

如果出现异常,就调用_not_authenticated方法来设置返回元组中的用户及口令并终止程序继续运行

总结,Django restframework的认证流程如下图

Django restframework内置的认证类

在上面的项目例子中,在UsersView的get方法中,打印authentication_classesrequest._user的值

class UserView(APIView):
    # authentication_classes = [MyAuthentication,]

    def get(self,request,*args,**kwargs):
        print('authentication_classes:', self.authentication_classes)
        print(request._user)
        return HttpResponse("UserView GET")

打印结果为

authentication_classes: [<class 'rest_framework.authentication.SessionAuthentication'>, <class 'rest_framework.authentication.BasicAuthentication'>]
AnonymousUser

由此可以知道,authentication_classes默认是Django restframework内置的认证类,而request._user为AnonymousUser,因为发送GET请求,用户没有进行登录认证,所以为匿名用户

在视图函数中导入这两个类,再查看这两个类的源码,可以知道

class BasicAuthentication(BaseAuthentication):

	www_authenticate_realm = 'api' 

	def authenticate(self, request):

		...

	def authenticate_credentials(self, userid, password):

		...

class SessionAuthentication(BaseAuthentication):

	def authenticate(self, request):

		...

	def enforce_csrf(self, request):

		...
		
class TokenAuthentication(BaseAuthentication):
	...

从上面的源码可以发现,这个文件中不仅定义了SessionAuthenticationBasicAuthentication这两个类,

相关的类还有TokenAuthentication,而且这三个认证相关的类都是继承自BaseAuthentication

从上面的源码可以大概知道,这三个继承自BaseAuthentication的类是Django restframework内置的认证方式.

自定义认证功能

在上面我们知道,Request会调用认证相关的类及方法,APIView会设置认证相关的类及方法

所以如果想自定义认证功能,只需要重写authenticate方法及authentication_classes的对象列表即可

修改上面的例子的views.py文件

from django.shortcuts import render, HttpResponse
from rest_framework.views import APIView
from rest_framework.authentication import BaseAuthentication
from rest_framework import exceptions

TOKEN_LIST = [  # 定义token_list
    'aabbcc',
    'ddeeff',
]

class UserAuthView(BaseAuthentication):
    def authenticate(self, request):
        tk = request._request.GET.get("tk")  # request._request为原生的request

        if tk in TOKEN_LIST:
            return (tk, None)  # 返回一个元组
        raise exceptions.AuthenticationFailed("用户认证失败")

    def authenticate_header(self, request):
        # 如果不定义authenticate_header方法会抛出异常
        pass

class UserView(APIView):
    authentication_classes = [UserAuthView, ]

    def get(self, request, *args, **kwargs):
        print(request.user)

        return HttpResponse("UserView GET")

启动项目,在浏览器中输入http://127.0.0.1:8000/users/?tk=aabbcc,然后回车,在服务端后台会打印

aabbcc

把浏览器中的url换为http://127.0.0.1:8000/users/?tk=ddeeff,后台打印信息则变为

ddeeff

这样就实现REST framework的自定义认证功能

Django restframework认证的扩展

基于Token进行用户认证

修改上面的项目,在urls.py文件中添加一条路由记录

from django.conf.urls import url
from django.contrib import admin
from app01 import views

urlpatterns = [
	url(r'^admin/', admin.site.urls),
	url(r'^users/',views.UsersView.as_view()),
	url(r'^auth/',views.AuthView.as_view()),
]

修改视图函数

from django.shortcuts import render,HttpResponse
from rest_framework.views import APIView
from rest_framework.authentication import BaseAuthentication
from rest_framework import exceptions
from django.http import JsonResponse

def gen_token(username):
	"""
	利用时间和用户名生成用户token
	:param username: 
	:return: 
	"""
	import time
	import hashlib
	ctime=str(time.time())
	hash=hashlib.md5(username.encode("utf-8"))
	hash.update(ctime.encode("utf-8"))
	return hash.hexdigest()

class AuthView(APIView):
	def post(self, request, *args, **kwargs):
		"""
		获取用户提交的用户名和密码,如果用户名和密码正确,则生成token,并返回给用户
		:param request:
		:param args:
		:param kwargs:
		:return:
		"""
		res = {'code': 1000, 'msg': None}
		user = request.data.get("user")
		pwd = request.data.get("pwd")

		from app01 import models
		user_obj = models.UserInfo.objects.filter(user=user, pwd=pwd).first()

		if user_obj:
			token = gen_token(user) # 生成用户口令

			# 如果数据库中存在口令则更新,如果数据库中不存在口令则创建用户口令
			models.Token.objects.update_or_create(user=user_obj, defaults={'token': token})
			print("user_token:", token)
			res['code'] = 1001
			res['token'] = token
		else:
			res['msg'] = "用户名或密码错误"

		return JsonResponse(res)
	
class UserAuthView(BaseAuthentication):
	def authenticate(self,request):
		tk=request.query_params.GET.get("tk")   # 获取请求头中的用户token

		from app01 import models

		token_obj=models.Token.objects.filter(token=tk).first()

		if token_obj:   # 用户数据库中已经存在用户口令返回认证元组
			return (token_obj.user,token_obj)

		raise exceptions.AuthenticationFailed("认证失败")

	def authenticate_header(self,request):
		pass

class UsersView(APIView):
	authentication_classes = [UserAuthView,]

	def get(self,request,*args,**kwargs):

		return HttpResponse(".....")

创建用户数据库的类

from django.db import models

class UserInfo(models.Model):
	user=models.CharField(max_length=32)
	pwd=models.CharField(max_length=64)
	email=models.CharField(max_length=64)

class Token(models.Model):
	user=models.OneToOneField(UserInfo)
	token=models.CharField(max_length=64)

创建数据库,并添加两条用户记录

再创建一个test_client.py文件,来发送post请求

import requests

response=requests.post(
	url="http://127.0.0.1:8000/auth/",
	data={'user':'user1','pwd':'user123'},
)

print("response_text:",response.text)

启动Django项目,运行test_client.py文件,则项目的响应信息为

response_text: {"code": 1001, "msg": null, "token": "eccd2d256f44cb25b58ba602fe7eb42d"}

由此,就完成了自定义的基于token的用户认证

如果想在项目中使用自定义的认证方式时,可以在authentication_classes继承刚才的认证的类即可

authentication_classes = [UserAuthView,]

全局自定义认证

在正常的项目中,一个用户登录成功之后,进入自己的主页,可以看到很多内容,比如用户的订单,用户的收藏,用户的主页等

此时,难倒要在每个视图类中都定义authentication_classes,然后在authentication_classes中追加自定义的认证类吗?

通过对Django restframework认证的源码分析知道,可以直接在项目的settings.py配置文件中引入自定义的认证类,即可以对所有的url进行用户认证流程

在应用app01目录下创建utils包,在utils包下创建auth.py文件,内容为自定义的认证类

from rest_framework import exceptions
from api import models

class Authtication(object):
    def authenticate(self,request):
        token = request._request.GET.get("token")		# 获取浏览器传递的token
        token_obj = models.UserToken.objects.filter(token=token).first()	# 到数据库中进行token查询,判断用户是否通过认证
        if not token_obj:
            raise exceptions.AuthenticationFailed("用户认证失败")

        # restframework会将元组赋值给request,以供后面使用
        return (token_obj.user,token_obj)
    
    # 必须创建authenticate_header方法,否则会抛出异常
    def authenticate_header(self,request):
        pass

在settings.py文件中添加内容

REST_FRAMEWORK = {
    'DEFAULT_AUTHENTICATION_CLASSES':['app01.utils.auth.Authtication',]
}

修改views.py文件

from django.shortcuts import render, HttpResponse
from rest_framework.views import APIView
from rest_framework.authentication import BaseAuthentication
from rest_framework import exceptions
from django.http import JsonResponse

def gen_token(username):
    """
    利用时间和用户名生成用户token
    :param username:
    :return:
    """
    import time
    import hashlib
    ctime = str(time.time())
    hash = hashlib.md5(username.encode("utf-8"))
    hash.update(ctime.encode("utf-8"))
    return hash.hexdigest()

class AuthView(APIView):
    authentication_classes = []		# 在这里定义authentication_classes后,用户访问auth页面不需要进行认证
    def post(self, request, *args, **kwargs):
        """
        获取用户提交的用户名和密码,如果用户名和密码正确,则生成token,并返回给用户
        :param request:
        :param args:
        :param kwargs:
        :return:
        """
        res = {'code': 1000, 'msg': None}
        user = request.data.get("user")
        pwd = request.data.get("pwd")

        from app01 import models
        user_obj = models.UserInfo.objects.filter(user=user, pwd=pwd).first()

        if user_obj:
            token = gen_token(user)  # 生成用户口令

            # 如果数据库中存在口令则更新,如果数据库中不存在口令则创建用户口令
            models.Token.objects.update_or_create(user=user_obj, defaults={'token': token})
            print("user_token:", token)
            res['code'] = 1001
            res['token'] = token
        else:
            res['msg'] = "用户名或密码错误"

        return JsonResponse(res)

class UserView(APIView):
    def get(self, request, *args, **kwargs):
        return HttpResponse("UserView GET")

class OrderView(APIView):
    def get(self,request,*args,**kwargs):
        return HttpResponse("OrderView GET")

启动项目,使用POSTMAN向http://127.0.0.1:8000/order/?token=eccd2d256f44cb25b58ba602fe7eb42dhttp://127.0.0.1:8000/user/?token=eccd2d256f44cb25b58ba602fe7eb42d发送GET请求,响应结果如下

在url中不带token,使用POSTMAN向http://127.0.0.1:8000/order/http://127.0.0.1:8000/user/发送GET请求,则会出现"认证失败"的提示

由此可以知道,在settings.py配置文件中配置自定义的认证类也可以实现用户认证功能

配置匿名用户

修改settings.py文件

REST_FRAMEWORK = {
    'DEFAULT_AUTHENTICATION_CLASSES': ['app01.utils.auth.Authtication', ],
    'UNAUTHENTICATED_USER': lambda :"匿名用户",		# 用户未登录时显示的名称
    'UNAUTHENTICATED_TOKEN': lambda :"无效token",	# 用户未登录时打印的token名
}

修改views.py文件中的OrderView类

class OrderView(APIView):
    authentication_classes = []			# authentication_classes为空列表表示视图类不进行认证
    def get(self,request,*args,**kwargs):
        print(request.user)
        print(request.auth)
        return HttpResponse("OrderView GET")

使用浏览器向http://127.0.0.1:8000/order/发送GET请求,后台打印

这说明在settings.py文件中配置的匿名用户和匿名用户的token起到作用

建议把匿名用户及匿名用户的token都设置为:None

Django restframework内置的认证类

从rest_framework中导入authentication

from rest_framework import authentication

可以看到Django restframework内置的认证类

class BaseAuthentication(object):
    def authenticate(self, request):
        ...

    def authenticate_header(self, request):
        pass


class BasicAuthentication(BaseAuthentication):
    def authenticate(self, request):
        ...

    def authenticate_credentials(self, userid, password, request=None):
        ...

    def authenticate_header(self, request):
        ...


class SessionAuthentication(BaseAuthentication):

    def authenticate(self, request):
        ...

    def enforce_csrf(self, request):
        ...


class TokenAuthentication(BaseAuthentication):
    def authenticate(self, request):
        ...

    def authenticate_credentials(self, key):
        ...

    def authenticate_header(self, request):
        ...


class RemoteUserAuthentication(BaseAuthentication):
    def authenticate(self, request):
        ...

可以看到,Django restframework内置的认证包含下面的四种:

BasicAuthentication
SessionAuthentication
TokenAuthentication
RemoteUserAuthentication

而这四种认证类都继承自BaseAuthentication在BaseAuthentication中定义了两个方法:authenticate和authenticate_header

总结:

为了让认证更规范,自定义的认证类要继承 BaseAuthentication类
自定义认证类必须要实现authenticate和authenticate_header方法
authenticate_header方法的作用:在认证失败的时候,给浏览器返回的响应头,可以直接pass,不实现authenticate_header程序会抛出异常
posted @ 2018-08-25 18:42  renpingsheng  阅读(1026)  评论(1编辑  收藏