Django rest framework源码分析（1）----认证
一、基础
1.1.安装
两种方式：
- github
- pip直接安装
pip install djangorestframework
1.2.需要先了解的一些知识
理解下面两个知识点非常重要，django-rest-framework源码中到处都是基于CBV和面向对象的封装
（1）面向对象封装的两大特性
把同一类方法封装到类中
将数据封装到对象中
（2）CBV
基于反射实现根据请求方式不同，执行不同的方法
原理：url-->view方法-->dispatch方法（反射执行其它方法：GET/POST/PUT/DELETE等等）
二、简单实例
2.1.settings
先创建一个project和一个app(我这里命名为API)
首先要在settings的app中添加
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
一个保存用户的信息
一个保存用户登录成功后的token
from django.db import models
class UserInfo(models.Model):
USER_TYPE = (
(1,'普通用户'),
(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
用户登录（返回token并保存到数据库）
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
#当前时间，相当于生成一个随机的字符串
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'] = '用户名或密码错误'
#为用户创建token
token = md5(user)
#存在就更新，不存在就创建
models.UserToken.objects.update_or_create(user=obj,defaults={'token':token})
ret['token'] = token
except Exception as e:
ret['code'] = 1002
ret['msg'] = '请求异常'
return JsonResponse(ret)
2.5.利用postman发请求
如果用户名和密码正确的话 会生成token值，下次该用户再登录时，token的值就会更新
数据库中可以看到token的值
当用户名或密码错误时，抛出异常
三、添加认证
基于上面的例子，添加一个认证的类
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
#当前时间，相当于生成一个随机的字符串
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):
'''用于用户登录验证'''
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'] = '用户名或密码错误'
#为用户创建token
token = md5(user)
#存在就更新，不存在就创建
models.UserToken.objects.update_or_create(user=obj,defaults={'token':token})
ret['token'] = token
except Exception as e:
ret['code'] = 1002
ret['msg'] = '请求异常'
return JsonResponse(ret)
class Authentication(APIView):
'''认证'''
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('用户认证失败')
#在rest framework内部会将这两个字段赋值给request，以供后续操作使用
return (token_obj.user,token_obj)
def authenticate_header(self, request):
pass
class OrderView(APIView):
'''订单相关业务'''
authentication_classes = [Authentication,] #添加认证
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发get请求
请求的时候没有带token，可以看到会显示“用户认证失败”
这样就达到了认证的效果，django-rest-framework的认证是怎么实现的呢，下面基于这个例子来剖析drf的源码。
四、drf的认证源码分析
源码流程图
请求先到dispatch
dispatch()主要做了两件事
- 封装request
- 认证
具体看我写的代码里面的注释
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
4.1.reuqest
（1）initialize_request()
可以看到initialize()就是封装原始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(),],把对象封装到request里面了
authenticators=self.get_authenticators(),
negotiator=self.get_content_negotiator(), parser_context=parser_context )
（2）get_authenticators()
通过列表生成式，返回对象的列表
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里面有个 authentication_classes 字段
可以看到默认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.认证
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
#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
（1）initial()
主要看 self.perform_authentication(request),实现认证
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.实现认证
self.perform_authentication(request)
self.check_permissions(request)
self.check_throttles(request)
（2）perform_authentication()
调用了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
点进去可以看到Request有个user方法,加 @property 表示调用user方法的时候不需要加括号“user()”，可以直接调用：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():
#获取认证对象，进行一步步的认证
self._authenticate()
return self._user
（4）_authenticate()
循环所有authenticator对象
def _authenticate(self):
"""
Attempt to authenticate the request using each authentication instance
in turn.
"""
#循环认证类的所有对象
#执行对象的authenticate方法
for authenticator in self.authenticators:
try:
#执行认证类的authenticate方法
#这里分三种情况
#1.如果authenticate方法抛出异常，self._not_authenticated()执行
#2.有返回值，必须是元组：（request.user,request.auth）
#3.返回None，表示当前认证不处理，等下一个认证来处理
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内部会将这两个字段赋值给request，以供后续操作使用
return (token_obj.user,token_obj) #例子中的return
当都没有返回值，就执行self._not_authenticated(),相当于匿名用户，没有通过认证
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匿名用户
else:
self.user = None
if api_settings.UNAUTHENTICATED_TOKEN:
self.auth = api_settings.UNAUTHENTICATED_TOKEN() #None
else:
self.auth = None
面向对象知识：
子类继承 父类，调用方法的时候：
- 优先去自己里面找有没有这个方法，有就执行自己的
- 只有当自己里面没有这个方法的时候才会去父类找
因为authenticate方法我们自己写，所以当执行authenticate()的时候就是执行我们自己写的认证
父类中的authenticate方法
def authenticate(self, request):
return (self.force_user, self.force_token)
我们自己写的
class Authentication(APIView):
'''用于用户登录验证'''
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('用户认证失败')
#在rest framework内部会将这两个字段赋值给request，以供后续操作使用
return (token_obj.user,token_obj)
认证的流程就是上面写的，弄懂了原理，再写代码就更容易理解为什么了。
4.3.配置文件
继续解读源码
默认是去全局配置文件中找，所以我们应该在settings.py中配置好路径
api_settings源码
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文件夹下面新建文件夹utils,再新建auth.py文件，里面写上认证的类
settings.py
#设置全局认证
REST_FRAMEWORK = {
"DEFAULT_AUTHENTICATION_CLASSES":['API.utils.auth.Authentication',] #里面写你的认证的类的路径
}
auth.py
# API/utils/auth.py
from rest_framework import exceptions
from API import models
class Authentication(object):
'''用于用户登录验证'''
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('用户认证失败')
#在rest framework内部会将这两个字段赋值给request，以供后续操作使用
return (token_obj.user,token_obj)
def authenticate_header(self, request):
pass
在settings里面设置的全局认证，所有业务都需要经过认证，如果想让某个不需要认证，只需要在其中添加下面的代码：
authentication_classes = [] #里面为空，代表不需要认证
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
#当前时间，相当于生成一个随机的字符串
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):
'''用于用户登录验证'''
authentication_classes = [] #里面为空，代表不需要认证
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'] = '用户名或密码错误'
#为用户创建token
token = md5(user)
#存在就更新，不存在就创建
models.UserToken.objects.update_or_create(user=obj,defaults={'token':token})
ret['token'] = token
except Exception as e:
ret['code'] = 1002
ret['msg'] = '请求异常'
return JsonResponse(ret)
class OrderView(APIView):
'''订单相关业务'''
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代码
再测试一下我们的代码
不带token发请求
带token发请求
五、drf的内置认证
rest_framework里面内置了一些认证，我们自己写的认证类都要继承内置认证类 "BaseAuthentication"
4.1.BaseAuthentication源码：
class BaseAuthentication(object):
"""
All authentication classes should extend BaseAuthentication.
"""
def authenticate(self, request):
"""
Authenticate the request and return a two-tuple of (user, token).
"""
#内置的认证类，authenticate方法，如果不自己写，默认则抛出异常
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，作用是当认证失败的时候，返回的响应头
pass
4.2.修改自己写的认证类
自己写的Authentication必须继承内置认证类BaseAuthentication
# API/utils/auth/py
from rest_framework import exceptions
from API import models
from rest_framework.authentication import BaseAuthentication
class Authentication(BaseAuthentication):
'''用于用户登录验证'''
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('用户认证失败')
#在rest framework内部会将这两个字段赋值给request，以供后续操作使用
return (token_obj.user,token_obj)
def authenticate_header(self, request):
pass
4.3.其它内置认证类
rest_framework里面还内置了其它认证类，我们主要用到的就是BaseAuthentication，剩下的很少用到
六、总结
自己写认证类方法梳理
（1）创建认证类
- 继承BaseAuthentication --->>1.重写authenticate方法；2.authenticate_header方法直接写pass就可以（这个方法必须写）
（2）authenticate()返回值（三种）
- None ----->>>当前认证不管，等下一个认证来执行
- raise exceptions.AuthenticationFailed('用户认证失败') # from rest_framework import exceptions
- 有返回值元祖形式：（元素1，元素2） #元素1复制给request.user; 元素2复制给request.auth
（3）局部使用
- authentication_classes = [BaseAuthentication,]
（4）全局使用
#设置全局认证
REST_FRAMEWORK = {
"DEFAULT_AUTHENTICATION_CLASSES":['API.utils.auth.Authentication',]
}
源码流程
--->>dispatch
--封装request
---获取定义的认证类（全局/局部），通过列表生成式创建对象
---initial
----peform_authentication
-----request.user （每部循环创建的对象）