#加载每个app下面的admin.py文件
def autodiscover():autodiscover_modules('admin', register_to=site)

#admin.site : 单例对象
class AdminSite():def __init__(self, name='admin'):self._registry = {}def register(self, model, admin_class=None, **options):if not admin_class:admin_class = ModelAdminself._registry[model] = admin_class(model, self)# site._registry:{模型类:该模型类的配置类对象,........}site = AdminSite() 

from django.contrib import adminadmin.site.register(Book)    #  site._registry:{Book:ModelAdmin(Book)}
admin.site.register(Publish) #  site._registry:{Book:ModelAdmin(Book),Publish:ModelAdmin(Publish)} 

django-admin的源码流程
我们自己生成的动态的访问url
====================================初级版=========================
from django.shortcuts import HttpResponse
from django.conf.urls import url
from django.contrib import admin
from app01 import views
def login(request):return HttpResponse("ok")url_list = []for model_class,v in admin.site._registry.items():print(model_class)  #打印的是每一个类<class 'app01.models.UserInfo'>cls_name = model_class._meta.model_name #当前类名称的小写app_name = model_class._meta.app_label  #当前app的名称val = url(r'^{0}/{1}/$'.format(app_name,cls_name), login, name="login")url_list.append(val)urlpatterns = [url(r'^admin/', admin.site.urls),# admin.site这个对象里面有一个属性_registry = {}#点击urls查看源码返回的是一个元组，元组的第一个元素是一个列表url(r'^index/', ([url(r'^app01/userinfo/$', login,name="login"),url(r'^app01/roles/$', login,name="login"),],None,None)),url(r'^index2/', (url_list,None,None,)),  #吧上面定义的列表拿下来，这是后就动态生成了
]

================================升级============================
路径http://127.0.0.1:8001/index/app01/roles/后面还有增删改查的路径
http://127.0.0.1:8001/index/app01/roles/add/
http://127.0.0.1:8001/index/app01/roles/1/change/
http://127.0.0.1:8001/index/app01/roles/1/del/实现流程
from django.shortcuts import HttpResponse
from django.conf.urls import url
from django.contrib import admin
from app01 import views
def login(request):return HttpResponse("ok")def change_list(request):return HttpResponse("列表页面")def add_view(request):return HttpResponse("添加页面")def change_view(request,nid):return HttpResponse("修改页面")def delete_view(request,nid):return HttpResponse("删除页面")url_list = []for model_class,v in admin.site._registry.items():print(model_class)  #打印的是每一个类<class 'app01.models.UserInfo'>cls_name = model_class._meta.model_name #当前类名称的小写app_name = model_class._meta.app_label  #当前app的名称urls_list = url(r'^{0}/{1}/$'.format(app_name,cls_name), change_list, name="login")url_list.append(urls_list)add_url = url(r'^{0}/{1}/add/$'.format(app_name, cls_name), add_view, name="login")url_list.append(add_url)change_url = url(r'^{0}/{1}/(\d+)/change/$'.format(app_name, cls_name), change_view, name="login")url_list.append(change_url)del_url = url(r'^{0}/{1}/(\d+)/del/$'.format(app_name, cls_name), delete_view, name="login")url_list.append(del_url)urlpatterns = [url(r'^admin/', admin.site.urls),# admin.site这个对象里面有一个属性_registry = {}#点击urls查看源码返回的是一个元组，元组的第一个元素是一个列表url(r'^index/', ([url(r'^app01/userinfo/$', login,name="login"),url(r'^app01/roles/$', login,name="login"),],None,None)),url(r'^index2/', (url_list,None,None,)),  #吧上面定义的列表拿下来，这是后就动态生成了
]说明了：url的本质：它读取_registry所有字典里面的数据，为字典里面的每一个类生成了4个url

==================================修改上面的版本=============================
定义了一个
def get_urls():temp = [url(r'^$'.format(app_name, cls_name), change_list),url(r'^add/$'.format(app_name, cls_name), add_view),url(r'^del/$'.format(app_name, cls_name), delete_view),url(r'^change/$'.format(app_name, cls_name), change_view)]return tempurl_list = []
for model_class,v in admin.site._registry.items():print('-------',model_class)  #打印的是每一个类<class 'app01.models.UserInfo'>cls_name = model_class._meta.model_name #当前类名称的小写app_name = model_class._meta.app_label  #当前app的名称
    方式一：# all_urls = url(r'^{0}/{1}/'.format(app_name,cls_name), (get_urls(),None,None,))
    方式二：all_urls = url(r'^{0}/{1}/'.format(app_name,cls_name), include(get_urls()) )   url_list.append(all_urls)urlpatterns = [url(r'^admin/', admin.site.urls),# admin.site这个对象里面有一个属性_registry = {}#点击urls查看源码返回的是一个元组，元组的第一个元素是一个列表url(r'^index/', ([url(r'^app01/userinfo/', ([url(r'^$', change_list, name="login"),url(r'^add/$', add_view, name="login"),url(r'^(\d+)/del/$', delete_view, name="login"),url(r'^(\d+)/change/$', change_view, name="login"),],None,None),name="login"),url(r'^app01/usertype/', ([url(r'^$', change_list, name="login"),url(r'^add/$', add_view, name="login"),url(r'^(\d+)/del/$', delete_view, name="login"),url(r'^(\d+)/change/$', change_view, name="login"),], None, None), name="login"),],None,None)),url(r'^app02/article/', ([url(r'^$', change_list, name="login"),url(r'^add/$', add_view, name="login"),url(r'^(\d+)/del/$', delete_view, name="login"),url(r'^(\d+)/change/$', change_view, name="login"),],None,None),name="login"),# index和index2的两个是一样的，我们可以用index2的方式替代indexurl(r'^index2/', (url_list,None,None,)),  #吧上面定义的列表拿下来，这是后就动态生成了
]include的本质就是：返回了一个元组，元组的第一个是这个模块
include里面既可以写一个列表include([])，利用include做分发也可以返回一个字符串：帮我们去找到这个模块，找到所有的映射关系include(model_admin.urls)
model_admin是什么？ModelAdmin对象的urls

- admin源码流程a. 运行程序，找到每一个app中的 admin.py 文件，并加载- app01.admin.py - 创建admin.site中的对象- 执行对象的 register方法，目的：将注册类添加到 _registry中 _registry = {  key是传进来的model   value:是ModelAdmin的对象，传了两个参数models.Role: ModelAdmin(models.Role,admin.site),models.UserInfo: ModelAdmin(models.UserInfo,admin.site)models.UserType: ModelAdmin(models.UserType,admin.site)}- app02.admin.py- 用app01.admin中创建那个admin.site对象- 执行对象的 register方法，目的：讲注册类添加到 _registry中 _registry = {models.Role: ModelAdmin(models.Role,admin.site),models.UserInfo: ModelAdmin(models.UserInfo,admin.site)models.UserType: ModelAdmin(models.UserType,admin.site)models.Article: ModelAdmin(models.Article,admin.site)}admin.site是一个对象（单例模式创建），其中封装了： _registry = {models.Role: ModelAdmin(models.Role,admin.site),models.UserInfo: ModelAdmin(models.UserInfo,admin.site)models.UserType: ModelAdmin(models.UserType,admin.site)models.Article: ModelAdmin(models.Article,admin.site)}b. urls.py 再次调用 admin.site 对象的 urls属性：urlpatterns = [url(r'^admin/', admin.site.urls),]class ModelAdmin(object):def __init__(self,model_class,site):self.model_class = model_classself.site = site def changelist_view(self,request):data_list = self.model_class.objects.all()   #是动态的return HttpResponse('列表页面')def add_view(self,request):return HttpResponse('添加页面')def delete_view(self,request,nid):return HttpResponse('删除页面')def change_view(self,request,nid):return HttpResponse('修改页面')def get_urls(self):urlpatterns = [url(r'^$', self.changelist_view),url(r'^add/$', self.add_view),url(r'^(.+)/delete/$', self.delete_view),url(r'^(.+)/change/$', self.change_view),]return urlpatterns@property def urls(self):return self.get_urls()class AdminSite(object):def __init__(self):self._registry = {}def register(self,model_class,model_admin):self._registry[model_class] = model_admin(model_class,self)def get_urls(self):"""models.Role: ModelAdmin(models.Role,admin.site),models.UserInfo: ModelAdmin(models.UserInfo,admin.site)models.UserType: ModelAdmin(models.UserType,admin.site)models.Article: ModelAdmin(models.Article,admin.site)"""url_list = []for model_class,model_admin in self._registry.items():model_class是一个类app_name = model_class._meta.app_labelmodel_name = model_class._meta.model_name url_list += [url('%s/%s' %(app_name,model_name,), include(model_admin.urls))]return url_list@propertydef urls(self):return (self.get_urls(), None,None )