DRF的权限组件(源码分析)

1. 创建用户表

from django.db import models


# Create your models here.
class UserInfo(models.Model):
    role_choice = ((1, 'CEO'), (2, 'CTO'), (3, 'CFO'))
    role = models.SmallIntegerField(verbose_name='类型', choices=role_choice, default=1)
    username = models.CharField(verbose_name='用户名', max_length=32)
    password = models.CharField(verbose_name='密码', max_length=32)
    token = models.CharField(verbose_name='TOKEN', max_length=64, null=True, blank=True)

2. 自定义权限类

from rest_framework.permissions import BasePermission


class PermissionA(BasePermission):
    message = {'code': 1003, 'data': '无权访问'}

    def has_permission(self, request, view):
        if request.user.role == 2:
            return True
        return False

    def has_object_permission(self, request, view, obj):
        return True

3. 视图函数中添加认证

局部配置(views.py)

class UserView(APIView):
    permission_classes = [PermissionA, ]  # role权限
    
    def get(self, request):
        ...

全局配置(settings.py)

REST_FRAMEWORK = {
    # 权限
    "DEFAULT_PERMISSION_CLASSES": ["app01.permission.PermissionA", ]
}

4. 多个权限类

当开发过程中需要用户同时具备多个权限（缺一不可）时，可以用多个权限类来实现。

权限组件内部处理机制：按照列表的顺序逐一执行 has_permission 方法，如果返回True，则继续执行后续的权限类；如果返回None或False，则抛出权限异常并停止后续权限类的执行。

# models.py

from django.db import models


class Role(models.Model):
    """ 角色表 """
    title = models.CharField(verbose_name="名称", max_length=32)


class UserInfo(models.Model):
    """ 用户表 """
    username = models.CharField(verbose_name="用户名", max_length=32)
    password = models.CharField(verbose_name="密码", max_length=64)
    token = models.CharField(verbose_name="TOKEN", max_length=64, null=True, blank=True)

    roles = models.ManyToManyField(verbose_name="角色", to="Role")

# urls.py

from django.urls import path, re_path, include
from app01 import views

urlpatterns = [
    path('api/auth/', views.AuthView.as_view()),
    path('api/order/', views.OrderView.as_view()),
]

# views.py

import uuid
from rest_framework.views import APIView
from rest_framework.request import Request
from rest_framework.response import Response
from rest_framework.authentication import BaseAuthentication
from rest_framework.permissions import BasePermission
from rest_framework.exceptions import AuthenticationFailed

from app01 import models


class AuthView(APIView):
    """ 用户登录认证 """

    def post(self, request, *args, **kwargs):
        print(request.data)  # {"username": "wupeiqi", "password": "123"}
        username = request.data.get('username')
        password = request.data.get('password')

        user_object = models.UserInfo.objects.filter(username=username, password=password).first()
        if not user_object:
            return Response({"code": 1000, "data": "用户名或密码错误"})

        token = str(uuid.uuid4())

        user_object.token = token
        user_object.save()

        return Response({"code": 0, "data": {"token": token, "name": username}})


class TokenAuthentication(BaseAuthentication):
    def authenticate(self, request):
        token = request.query_params.get("token")
        if not token:
            raise AuthenticationFailed({"code": 1002, "data": "认证失败"})
        user_object = models.UserInfo.objects.filter(token=token).first()
        if not user_object:
            raise AuthenticationFailed({"code": 1002, "data": "认证失败"})
        return user_object, token

    def authenticate_header(self, request):
        return 'Bearer realm="API"'


class PermissionA(BasePermission):
    message = {"code": 1003, 'data': "无权访问"}

    def has_permission(self, request, view):
        exists = request.user.roles.filter(title="员工").exists()
        if exists:
            return True
        return False

    def has_object_permission(self, request, view, obj):
        return True


class PermissionB(BasePermission):
    message = {"code": 1003, 'data': "无权访问"}

    def has_permission(self, request, view):
        exists = request.user.roles.filter(title="主管").exists()
        if exists:
            return True
        return False

    def has_object_permission(self, request, view, obj):
        return True

class OrderView(APIView):
    authentication_classes = [TokenAuthentication, ]
    permission_classes = [PermissionA, PermissionA]

    def get(self, request, *args, **kwargs):
        return Response({"code": 0, "data": {"user": None, 'list': [1, 2, 3]}})


class PayView(APIView):
    authentication_classes = [TokenAuthentication, ]
    permission_classes = [PermissionA, ]

    def get(self, request, *args, **kwargs):
        return Response({"code": 0, "data": "数据..."})