Django-admin管理工具

一、admin组件使用

Django 提供了基于 web 的管理工具。

Django 自动管理工具是 django.contrib 的一部分，可以在项目的 settings.py 中的 INSTALLED_APPS 看到它：
INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    "app01"
]
django.contrib是一套庞大的功能集，它是Django基本代码的组成部分。

一般在项目开始会在urls.py中自动设置好：

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

urlpatterns = [
    url(r'^admin/', admin.site.urls),

]

使用管理工具：

　　启动开发服务器，然后在浏览器中访问 http://127.0.0.1:8000/admin/，得到登陆界面，可以通过命令 python manage.py createsuperuser 来创建超级用户。

　　为了让 admin 界面管理某个数据模型，需要先注册该数据模型到admin，即创建表：

from django.db import models

# Create your models here.




class Author(models.Model):

    name=models.CharField( max_length=32)
    age=models.IntegerField()


    def __str__(self):
        return self.name

class Publish(models.Model):

    name=models.CharField( max_length=32)
    email=models.EmailField()

    def __str__(self):
        return self.name


class Book(models.Model):

    title = models.CharField( max_length=32)
    publishDate=models.DateField()
    price=models.DecimalField(max_digits=5,decimal_places=2)

    publisher=models.ForeignKey(to="Publish")
    authors=models.ManyToManyField(to='Author')

    def __str__(self):
        return self.title

admin定制
在admin.py中只需要讲Mode中的某个类注册，即可在Admin中实现增删改查的功能：
如：

　　　 admin.site.register(Book)

　　　admin.site.register(Publish)

　　　admin.site.register(Author)

如果想要进行更多的定制操作，需要利用ModelAdmin进行操作：
方式一：

 class UserAdmin(admin.ModelAdmin):
        list_display = ('user', 'pwd',) 
 admin.site.register(models.UserInfo, UserAdmin) # 第一个参数可以是列表

方式二：

@admin.register(models.UserInfo)                # 第一个参数可以是列表
class UserAdmin(admin.ModelAdmin):
      list_display = ('user', 'pwd',)

ModelAdmin定制功能
（1）list_display，列表，定制显示的列

class BookAdmin(admin.ModelAdmin):
    list_display=("title","price","publish","pub_date"，'xxxxx')
     def xxxxx(self, obj):      #定制扩展内容
        return "xxxxx"

 （2）list_display_links，列表，定制列可以点击跳转。

class BookAdmin(admin.ModelAdmin):
        list_display=("title","price","publish","pub_date")
        list_display_links=("price","title")

 （3）list_filter，列表，定制右侧快速筛选。

class BookAdmin(admin.ModelAdmin):
    list_display=("title","price","publish","pub_date")
    list_filter=("title","price","publish")

 （4）list_select_related，列表，连表查询是否自动select_related

 

 （5）list_editable，列表，可以编辑的列 

 class BookAdmin(admin.ModelAdmin):  
     list_display=("title","price","publish","pub_date")
     list_editable=("price",)

 （6）search_fields，列表，模糊搜索的功能

 class BookAdmin(admin.ModelAdmin):
    list_display=("title","price","publish","pub_date")
    search_fields=("title","price")

 （7）date_hierarchy，列表，对Date和DateTime类型进行搜索

class BookAdmin(admin.ModelAdmin):
    list_display=("title","price","publish","pub_date")
    date_hierarchy="pub_date"

 （8）inlines，详细页面，如果有其他表和当前表做FK，那么详细页面可以进行动态增加和删除

class BookInline(admin.StackedInline):
    extra = 0
    model = Book

class PublishAdmin(admin.ModelAdmin):  
    list_display=("name",)
    inlines =[BookInline,]            #在’一’的那张表

 （9）action，列表，定制action中的操作

class BookAdmin(admin.ModelAdmin):
    list_display=("title","price","publish","pub_date")

# 定制Action行为具体方法
    def func(self, request, queryset):
        print(self, request, queryset)
        print(request.POST.getlist('_selected_action'))
        queryset.update(price=100)

    func.short_description = "中文显示自定义Actions"
    actions = [func, ]
    
    # Action选项都是在页面上方显示
    actions_on_top = True
    # Action选项都是在页面下方显示
    actions_on_bottom = False
 
    # 是否显示选择个数
    actions_selection_counter = True

 （10）定制HTML模板

class BookAdmin(admin.ModelAdmin):
    list_display=("title","price","publish","pub_date")

    add_form_template = None
    change_form_template = None
    change_list_template = None
    delete_confirmation_template = None
    delete_selected_confirmation_template = None
    object_history_template = None

    change_list_template="my_change_list.html"

（11） fields，详细页面时，显示字段的字段

class BookAdmin(admin.ModelAdmin):
    list_display=("title","price","publish","pub_date")
     fields = ("title","price")]

 （12）exclude，详细页面时，排除的字段

class BookAdmin(admin.ModelAdmin):
    list_display=("title","price","publish","pub_date")
     exclude = ("title","price")]

 （13） fieldsets，详细页面时，使用fieldsets标签对数据进行分割显示

class BookAdmin(admin.ModelAdmin):
    list_display=("title","price","publish","pub_date")

　　 fieldsets = (
        ('基本数据', {
            'fields': ('title',)
        }),
        ('其他', {
            'classes': ("collapse",'wide', 'extrapretty'),  # 'collapse','wide', 'extrapretty'
            'fields': ('price', 'publish'),
        }),
    )

 （14）ordering，列表，数据排序规则

class BookAdmin(admin.ModelAdmin):
    list_display=("title","price","publish","pub_date")

　　 ordering = ('-price',"id")     #降序

 （15） form = ModelForm，用于定制用户请求时候表单验证

class MyForm(ModelForm):

    class Meta:
        model = Book
        fields = "__all__"

class BookAdmin(admin.ModelAdmin):
        list_display=("title","price","publish","pub_date")

        form = MyForm

        def edit(self,obj):
            return mark_safe("<a href='%s/change/'>编辑</a>"%obj.id)    

from django.contrib import admin

# Register your models here.

from .models import *




class BookInline(admin.StackedInline): # TabularInline
    extra = 0
    model = Book

class BookAdmin(admin.ModelAdmin):

    list_display = ("title",'publishDate', 'price',"foo","publisher")
    list_display_links = ('publishDate',"price")
    list_filter = ('price',)
    list_editable=("title","publisher")
    search_fields = ('title',)
    date_hierarchy = 'publishDate'
    preserve_filters=False

    def foo(self,obj):

        return obj.title+str(obj.price)



    # 定制Action行为具体方法
    def func(self, request, queryset):
        print(self, request, queryset)
        print(request.POST.getlist('_selected_action'))

    func.short_description = "中文显示自定义Actions"
    actions = [func, ]
    # Action选项都是在页面上方显示
    actions_on_top = True
    # Action选项都是在页面下方显示
    actions_on_bottom = False

    # 是否显示选择个数
    actions_selection_counter = True



    change_list_template="my_change_list_template.html"



class PublishAdmin(admin.ModelAdmin):
     list_display = ('name', 'email',)
     inlines = [BookInline, ]



admin.site.register(Book, BookAdmin) # 第一个参数可以是列表
admin.site.register(Publish,PublishAdmin)
admin.site.register(Author)

from django.contrib import admin

# Register your models here.
from .models import *

from django.utils.safestring import mark_safe

from django.forms import ModelForm

from django import forms

class MyForm(ModelForm):

    class Meta:
        model = Book
        fields = "__all__"

class BookAdmin(admin.ModelAdmin):
    list_display=("title","price","publish","pub_date")
    #list_display_links=("price","title")
    #list_filter=("title","price","publish")
    list_editable=("price",)
    search_fields=("title","price")
    date_hierarchy="pub_date"

    # 定制Action行为具体方法
    def func(self, request, queryset):
        print(self, request, queryset)
        print(request.POST.getlist('_selected_action'))
        queryset.update(price=100)

    func.short_description = "中文显示自定义Actions"
    actions = [func, ]

    change_list_template="my_change_list.html"


    # fields = ("title","price")]

    fieldsets = (
        ('基本数据', {
            'fields': ('title',)
        }),
        ('其他', {
            'classes': ("collapse",'wide', 'extrapretty'),  # 'collapse','wide', 'extrapretty'
            'fields': ('price', 'publish'),
        }),
    )

    ordering = ('-price',"id")

    form = MyForm

    def edit(self,obj):
        return mark_safe("<a href='%s/change/'>编辑</a>"%obj.id)


class BookInline(admin.StackedInline):
    extra = 0
    model = Book

class PublishAdmin(admin.ModelAdmin):
    list_display=("name",)
    inlines =[BookInline,]


admin.site.register(Book,BookAdmin)

admin.site.register(Publish,PublishAdmin)

admin.site.register(Author)

 二、admin流程

单例模式

单例模式（Singleton Pattern）是一种常用的软件设计模式，该模式的主要目的是确保某一个类只有一个实例存在。
当你希望在整个系统中，某个类只能出现一个实例时，单例对象就能派上用场。

在 Python 中，我们可以用多种方法来实现单例模式：

• 使用模块
• 使用 __new__
• 使用装饰器（decorator）
• 使用元类（metaclass）

单例模式（__new__）：实例始终只有一个，它的属性可以随着你的改变而改变

class A:
    def __init__(self):
        self.x = 1
        print('in init function')

    def __new__(cls, *args, **kwargs):
        print('in new function')
        return object.__new__(A, *args, **kwargs)

a = A()

1

class Singleton(object):
    _instance = None
    def __new__(cls, *args, **kw):
        if not cls._instance:
            cls._instance = super(Singleton, cls).__new__(cls, *args, **kw)  
        return cls._instance  

class MyClass(Singleton):  
    a = 1

在上面的代码中，我们将类的实例和一个类变量 _instance 关联起来，如果 cls._instance 为 None 则创建实例，否则直接返回 cls._instance。

使用模块：Python的模块就是天然的单例模式，因为模块在第一次导入时，会生成 .pyc 文件，当第二次导入时，就会直接加载 .pyc 文件，而不会再次执行模块代码。因此，我们只需把相关的函数和数据定义在一个模块中，就可以获得一个单例对象了。如果我们真的想要一个单例类，可以考虑这样做：

# mysingleton.py
class My_Singleton(object):
    def foo(self):
        pass
 
my_singleton = My_Singleton()



#将上面的代码保存在文件 mysingleton.py 中，然后这样使用：

from mysingleton import my_singleton
 
my_singleton.foo()

admin流程
（1）循环加载执行所有已经注册的app中的admin.py文件

from django.utils.module_loading import autodiscover_modules

def autodiscover():
    autodiscover_modules('admin', register_to=site)

 （2） 执行代码

from django.contrib import admin
from .models import *
# Register your models here.

class AutorityAdmin(admin.ModelAdmin):
    list_display = ("title",'url', 'codes')

admin.site.register(Autority，AutorityAdmin)

（3）admin.site会调用AdminSite这个类，应用了单例模式

class AdminSite(object):
    """
    An AdminSite object encapsulates an instance of the Django admin application, ready
    to be hooked in to your URLconf. Models are registered with the AdminSite using the
    register() method, and the get_urls() method can then be used to access Django view
    functions that present a full admin interface for the collection of registered
    models.
    """

    # Text to put at the end of each page's <title>.
    site_title = ugettext_lazy('Django site admin')

    # Text to put in each page's <h1>.
    site_header = ugettext_lazy('Django administration')

    # Text to put at the top of the admin index page.
    index_title = ugettext_lazy('Site administration')

    # URL for the "View site" link at the top of each admin page.
    site_url = '/'

    _empty_value_display = '-'

    login_form = None
    index_template = None
    app_index_template = None
    login_template = None
    logout_template = None
    password_change_template = None
    password_change_done_template = None

    def __init__(self, name='admin'):
        self._registry = {}  # model_class class -> admin_class instance
        self.name = name
        self._actions = {'delete_selected': actions.delete_selected}
        self._global_actions = self._actions.copy()
        all_sites.add(self)

    def check(self, app_configs):
        """
        Run the system checks on all ModelAdmins, except if they aren't
        customized at all.
        """
        if app_configs is None:
            app_configs = apps.get_app_configs()
        app_configs = set(app_configs)  # Speed up lookups below

        errors = []
        modeladmins = (o for o in self._registry.values() if o.__class__ is not ModelAdmin)
        for modeladmin in modeladmins:
            if modeladmin.model._meta.app_config in app_configs:
                errors.extend(modeladmin.check())
        return errors

    def register(self, model_or_iterable, admin_class=None, **options):
        """
        Registers the given model(s) with the given admin class.

        The model(s) should be Model classes, not instances.

        If an admin class isn't given, it will use ModelAdmin (the default
        admin options). If keyword arguments are given -- e.g., list_display --
        they'll be applied as options to the admin class.

        If a model is already registered, this will raise AlreadyRegistered.

        If a model is abstract, this will raise ImproperlyConfigured.
        """
        if not admin_class:
            admin_class = ModelAdmin

        if isinstance(model_or_iterable, ModelBase):
            model_or_iterable = [model_or_iterable]
        for model in model_or_iterable:
            if model._meta.abstract:
                raise ImproperlyConfigured(
                    'The model %s is abstract, so it cannot be registered with admin.' % model.__name__
                )

            if model in self._registry:
                raise AlreadyRegistered('The model %s is already registered' % model.__name__)

            # Ignore the registration if the model has been
            # swapped out.
            if not model._meta.swapped:
                # If we got **options then dynamically construct a subclass of
                # admin_class with those **options.
                if options:
                    # For reasons I don't quite understand, without a __module__
                    # the created class appears to "live" in the wrong place,
                    # which causes issues later on.
                    options['__module__'] = __name__
                    admin_class = type("%sAdmin" % model.__name__, (admin_class,), options)

                # Instantiate the admin class to save in the registry
                self._registry[model] = admin_class(model, self)

    def unregister(self, model_or_iterable):
        """
        Unregisters the given model(s).

        If a model isn't already registered, this will raise NotRegistered.
        """
        if isinstance(model_or_iterable, ModelBase):
            model_or_iterable = [model_or_iterable]
        for model in model_or_iterable:
            if model not in self._registry:
                raise NotRegistered('The model %s is not registered' % model.__name__)
            del self._registry[model]

    def is_registered(self, model):
        """
        Check if a model class is registered with this `AdminSite`.
        """
        return model in self._registry

    def add_action(self, action, name=None):
        """
        Register an action to be available globally.
        """
        name = name or action.__name__
        self._actions[name] = action
        self._global_actions[name] = action

    def disable_action(self, name):
        """
        Disable a globally-registered action. Raises KeyError for invalid names.
        """
        del self._actions[name]

    def get_action(self, name):
        """
        Explicitly get a registered global action whether it's enabled or
        not. Raises KeyError for invalid names.
        """
        return self._global_actions[name]

    @property
    def actions(self):
        """
        Get all the enabled actions as an iterable of (name, func).
        """
        return six.iteritems(self._actions)

    @property
    def empty_value_display(self):
        return self._empty_value_display

    @empty_value_display.setter
    def empty_value_display(self, empty_value_display):
        self._empty_value_display = empty_value_display

    def has_permission(self, request):
        """
        Returns True if the given HttpRequest has permission to view
        *at least one* page in the admin site.
        """
        return request.user.is_active and request.user.is_staff

    def admin_view(self, view, cacheable=False):
        """
        Decorator to create an admin view attached to this ``AdminSite``. This
        wraps the view and provides permission checking by calling
        ``self.has_permission``.

        You'll want to use this from within ``AdminSite.get_urls()``:

            class MyAdminSite(AdminSite):

                def get_urls(self):
                    from django.conf.urls import url

                    urls = super(MyAdminSite, self).get_urls()
                    urls += [
                        url(r'^my_view/$', self.admin_view(some_view))
                    ]
                    return urls

        By default, admin_views are marked non-cacheable using the
        ``never_cache`` decorator. If the view can be safely cached, set
        cacheable=True.
        """
        def inner(request, *args, **kwargs):
            if not self.has_permission(request):
                if request.path == reverse('admin:logout', current_app=self.name):
                    index_path = reverse('admin:index', current_app=self.name)
                    return HttpResponseRedirect(index_path)
                # Inner import to prevent django.contrib.admin (app) from
                # importing django.contrib.auth.models.User (unrelated model).
                from django.contrib.auth.views import redirect_to_login
                return redirect_to_login(
                    request.get_full_path(),
                    reverse('admin:login', current_app=self.name)
                )
            return view(request, *args, **kwargs)
        if not cacheable:
            inner = never_cache(inner)
        # We add csrf_protect here so this function can be used as a utility
        # function for any view, without having to repeat 'csrf_protect'.
        if not getattr(view, 'csrf_exempt', False):
            inner = csrf_protect(inner)
        return update_wrapper(inner, view)

    def get_urls(self):
        from django.conf.urls import url, include
        # Since this module gets imported in the application's root package,
        # it cannot import models from other applications at the module level,
        # and django.contrib.contenttypes.views imports ContentType.
        from django.contrib.contenttypes import views as contenttype_views

        def wrap(view, cacheable=False):
            def wrapper(*args, **kwargs):
                return self.admin_view(view, cacheable)(*args, **kwargs)
            wrapper.admin_site = self
            return update_wrapper(wrapper, view)

        # Admin-site-wide views.
        urlpatterns = [
            url(r'^$', wrap(self.index), name='index'),
            url(r'^login/$', self.login, name='login'),
            url(r'^logout/$', wrap(self.logout), name='logout'),
            url(r'^password_change/$', wrap(self.password_change, cacheable=True), name='password_change'),
            url(r'^password_change/done/$', wrap(self.password_change_done, cacheable=True),
                name='password_change_done'),
            url(r'^jsi18n/$', wrap(self.i18n_javascript, cacheable=True), name='jsi18n'),
            url(r'^r/(?P<content_type_id>\d+)/(?P<object_id>.+)/$', wrap(contenttype_views.shortcut),
                name='view_on_site'),
        ]

        # Add in each model's views, and create a list of valid URLS for the
        # app_index
        valid_app_labels = []
        for model, model_admin in self._registry.items():
            urlpatterns += [
                url(r'^%s/%s/' % (model._meta.app_label, model._meta.model_name), include(model_admin.urls)),
            ]
            if model._meta.app_label not in valid_app_labels:
                valid_app_labels.append(model._meta.app_label)

        # If there were ModelAdmins registered, we should have a list of app
        # labels for which we need to allow access to the app_index view,
        if valid_app_labels:
            regex = r'^(?P<app_label>' + '|'.join(valid_app_labels) + ')/$'
            urlpatterns += [
                url(regex, wrap(self.app_index), name='app_list'),
            ]
        return urlpatterns

    @property
    def urls(self):
        return self.get_urls(), 'admin', self.name

    def each_context(self, request):
        """
        Returns a dictionary of variables to put in the template context for
        *every* page in the admin site.

        For sites running on a subpath, use the SCRIPT_NAME value if site_url
        hasn't been customized.
        """
        script_name = request.META['SCRIPT_NAME']
        site_url = script_name if self.site_url == '/' and script_name else self.site_url
        return {
            'site_title': self.site_title,
            'site_header': self.site_header,
            'site_url': site_url,
            'has_permission': self.has_permission(request),
            'available_apps': self.get_app_list(request),
        }

    def password_change(self, request, extra_context=None):
        """
        Handles the "change password" task -- both form display and validation.
        """
        from django.contrib.admin.forms import AdminPasswordChangeForm
        from django.contrib.auth.views import PasswordChangeView
        url = reverse('admin:password_change_done', current_app=self.name)
        defaults = {
            'form_class': AdminPasswordChangeForm,
            'success_url': url,
            'extra_context': dict(self.each_context(request), **(extra_context or {})),
        }
        if self.password_change_template is not None:
            defaults['template_name'] = self.password_change_template
        request.current_app = self.name
        return PasswordChangeView.as_view(**defaults)(request)

    def password_change_done(self, request, extra_context=None):
        """
        Displays the "success" page after a password change.
        """
        from django.contrib.auth.views import PasswordChangeDoneView
        defaults = {
            'extra_context': dict(self.each_context(request), **(extra_context or {})),
        }
        if self.password_change_done_template is not None:
            defaults['template_name'] = self.password_change_done_template
        request.current_app = self.name
        return PasswordChangeDoneView.as_view(**defaults)(request)

    def i18n_javascript(self, request, extra_context=None):
        """
        Displays the i18n JavaScript that the Django admin requires.

        `extra_context` is unused but present for consistency with the other
        admin views.
        """
        return JavaScriptCatalog.as_view(packages=['django.contrib.admin'])(request)

    @never_cache
    def logout(self, request, extra_context=None):
        """
        Logs out the user for the given HttpRequest.

        This should *not* assume the user is already logged in.
        """
        from django.contrib.auth.views import LogoutView
        defaults = {
            'extra_context': dict(
                self.each_context(request),
                # Since the user isn't logged out at this point, the value of
                # has_permission must be overridden.
                has_permission=False,
                **(extra_context or {})
            ),
        }
        if self.logout_template is not None:
            defaults['template_name'] = self.logout_template
        request.current_app = self.name
        return LogoutView.as_view(**defaults)(request)

    @never_cache
    def login(self, request, extra_context=None):
        """
        Displays the login form for the given HttpRequest.
        """
        if request.method == 'GET' and self.has_permission(request):
            # Already logged-in, redirect to admin index
            index_path = reverse('admin:index', current_app=self.name)
            return HttpResponseRedirect(index_path)

        from django.contrib.auth.views import LoginView
        # Since this module gets imported in the application's root package,
        # it cannot import models from other applications at the module level,
        # and django.contrib.admin.forms eventually imports User.
        from django.contrib.admin.forms import AdminAuthenticationForm
        context = dict(
            self.each_context(request),
            title=_('Log in'),
            app_path=request.get_full_path(),
            username=request.user.get_username(),
        )
        if (REDIRECT_FIELD_NAME not in request.GET and
                REDIRECT_FIELD_NAME not in request.POST):
            context[REDIRECT_FIELD_NAME] = reverse('admin:index', current_app=self.name)
        context.update(extra_context or {})

        defaults = {
            'extra_context': context,
            'authentication_form': self.login_form or AdminAuthenticationForm,
            'template_name': self.login_template or 'admin/login.html',
        }
        request.current_app = self.name
        return LoginView.as_view(**defaults)(request)

    def _build_app_dict(self, request, label=None):
        """
        Builds the app dictionary. Takes an optional label parameters to filter
        models of a specific app.
        """
        app_dict = {}

        if label:
            models = {
                m: m_a for m, m_a in self._registry.items()
                if m._meta.app_label == label
            }
        else:
            models = self._registry

        for model, model_admin in models.items():
            app_label = model._meta.app_label

            has_module_perms = model_admin.has_module_permission(request)
            if not has_module_perms:
                continue

            perms = model_admin.get_model_perms(request)

            # Check whether user has any perm for this module.
            # If so, add the module to the model_list.
            if True not in perms.values():
                continue

            info = (app_label, model._meta.model_name)
            model_dict = {
                'name': capfirst(model._meta.verbose_name_plural),
                'object_name': model._meta.object_name,
                'perms': perms,
            }
            if perms.get('change'):
                try:
                    model_dict['admin_url'] = reverse('admin:%s_%s_changelist' % info, current_app=self.name)
                except NoReverseMatch:
                    pass
            if perms.get('add'):
                try:
                    model_dict['add_url'] = reverse('admin:%s_%s_add' % info, current_app=self.name)
                except NoReverseMatch:
                    pass

            if app_label in app_dict:
                app_dict[app_label]['models'].append(model_dict)
            else:
                app_dict[app_label] = {
                    'name': apps.get_app_config(app_label).verbose_name,
                    'app_label': app_label,
                    'app_url': reverse(
                        'admin:app_list',
                        kwargs={'app_label': app_label},
                        current_app=self.name,
                    ),
                    'has_module_perms': has_module_perms,
                    'models': [model_dict],
                }

        if label:
            return app_dict.get(label)
        return app_dict

    def get_app_list(self, request):
        """
        Returns a sorted list of all the installed apps that have been
        registered in this site.
        """
        app_dict = self._build_app_dict(request)

        # Sort the apps alphabetically.
        app_list = sorted(app_dict.values(), key=lambda x: x['name'].lower())

        # Sort the models alphabetically within each app.
        for app in app_list:
            app['models'].sort(key=lambda x: x['name'])

        return app_list

    @never_cache
    def index(self, request, extra_context=None):
        """
        Displays the main admin index page, which lists all of the installed
        apps that have been registered in this site.
        """
        app_list = self.get_app_list(request)

        context = dict(
            self.each_context(request),
            title=self.index_title,
            app_list=app_list,
        )
        context.update(extra_context or {})

        request.current_app = self.name

        return TemplateResponse(request, self.index_template or 'admin/index.html', context)

    def app_index(self, request, app_label, extra_context=None):
        app_dict = self._build_app_dict(request, app_label)
        if not app_dict:
            raise Http404('The requested admin page does not exist.')
        # Sort the models alphabetically within each app.
        app_dict['models'].sort(key=lambda x: x['name'])
        app_name = apps.get_app_config(app_label).verbose_name
        context = dict(
            self.each_context(request),
            title=_('%(app)s administration') % {'app': app_name},
            app_list=[app_dict],
            app_label=app_label,
        )
        context.update(extra_context or {})

        request.current_app = self.name

        return TemplateResponse(request, self.app_index_template or [
            'admin/%s/app_index.html' % app_label,
            'admin/app_index.html'
        ], context)


# This global object represents the default admin site, for the common case.
# You can instantiate AdminSite in your own code to create a custom admin site.
site = AdminSite()

　　执行的每一个app中的每一个admin.site都是一个对象

（4）执行register方法

 

admin.site.register(Autority，AutorityAdmin)

class ModelAdmin(BaseModelAdmin):pass

def register(self, model_or_iterable, admin_class=None, **options):
    if not admin_class:
            admin_class = ModelAdmin
    # Instantiate the admin class to save in the registry
    self._registry[model] = admin_class(model, self)


admin注册结束