Django rest framework源码分析（2）----权限
添加权限
（1）API/utils文件夹下新建premission.py文件，代码如下：
- message是当没有权限时，提示的信息
# utils/permission.py
class SVIPPremission(object):
message = "必须是SVIP才能访问"
def has_permission(self,request,view):
if request.user.user_type != 3:
return False
return True
class MyPremission(object):
def has_permission(self,request,view):
if request.user.user_type == 3:
return False
return True
（2）settings.py全局配置权限
#全局
REST_FRAMEWORK = {
"DEFAULT_AUTHENTICATION_CLASSES":['API.utils.auth.Authentication',],
"DEFAULT_PERMISSION_CLASSES":['API.utils.permission.SVIPPremission'],
}
（3）views.py添加权限
- 默认所有的业务都需要SVIP权限才能访问
- OrderView类里面没写表示使用全局配置的SVIPPremission
- UserInfoView类，因为是普通用户和VIP用户可以访问，不使用全局的，要想局部使用的话，里面就写上自己的权限类
- permission_classes = [MyPremission,] #局部使用权限方法
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 BaseAuthentication
from API.utils.permission import SVIPPremission,MyPremission
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
permission_classes = [] #不里面为空，代表不需要权限
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(只有SVIP用户才能看)
'''
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)
class UserInfoView(APIView):
'''
订单相关业务(普通用户和VIP用户可以看)
'''
permission_classes = [MyPremission,] #不用全局的权限配置的话，这里就要写自己的局部权限
def get(self,request,*args,**kwargs):
print(request.user)
return HttpResponse('用户信息')
# urls.py
from django.contrib import admin
from django.urls import path
from API.views import AuthView,OrderView,UserInfoView
urlpatterns = [
path('admin/', admin.site.urls),
path('api/v1/auth/',AuthView.as_view()),
path('api/v1/order/',OrderView.as_view()),
path('api/v1/info/',UserInfoView.as_view()),
]
# API/utils/auth/py
# 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）测试
普通用户访问OrderView,提示没有权限
普通用户访问UserInfoView，可以返回信息
权限源码流程
（1）dispatch
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
（2）initial
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
#4.实现认证
self.perform_authentication(request)
#5.权限判断
self.check_permissions(request)
self.check_throttles(request)
（3）check_permissions
里面有个has_permission这个就是我们自己写的权限判断
def check_permissions(self, request):
"""
Check if the request should be permitted.
Raises an appropriate exception if the request is not permitted.
"""
#[权限类的对象列表]
for permission in self.get_permissions():
if not permission.has_permission(request, self):
self.permission_denied(
request, message=getattr(permission, 'message', None)
)
（4）get_permissions
def get_permissions(self):
"""
Instantiates and returns the list of permissions that this view requires.
"""
return [permission() for permission in self.permission_classes]
（5）permission_classes
所以settings全局配置就如下
#全局
REST_FRAMEWORK = {
"DEFAULT_PERMISSION_CLASSES":['API.utils.permission.SVIPPremission'],
}
内置权限
django-rest-framework内置权限BasePermission
默认是没有限制权限
class BasePermission(object):
"""
A base class from which all permission classes should inherit.
"""
def has_permission(self, request, view):
"""
Return `True` if permission is granted, `False` otherwise.
"""
return True
def has_object_permission(self, request, view, obj):
"""
Return `True` if permission is granted, `False` otherwise.
"""
return True
我们自己写的权限类，应该去继承BasePermission,修改之前写的permission.py文件
# utils/permission.py
from rest_framework.permissions import BasePermission
class SVIPPremission(BasePermission):
message = "必须是SVIP才能访问"
def has_permission(self,request,view):
if request.user.user_type != 3:
return False
return True
class MyPremission(BasePermission):
def has_permission(self,request,view):
if request.user.user_type == 3:
return False
return True
总结：
（1）使用
- 自己写的权限类：1.必须继承BasePermission类； 2.必须实现：has_permission方法
（2）返回值
- True 有权访问
- False 无权访问
（3）局部
- permission_classes = [MyPremission,]
（4）全局
REST_FRAMEWORK = {
#权限
"DEFAULT_PERMISSION_CLASSES":['API.utils.permission.SVIPPremission'],
}