如何实现注册model？

在app_plug中创建service文件夹，创建v1.py用于接收，封装，和处理model，此处我们首先需要实现的是接收，封装，具体做法如下：

class BasePlugModel:    def __init__(self, model_class, site):        self.model_class = model_class        self.site = siteclass AppPlugSite(object):    def __init__(self):        self._registry = {}        self.app_name = "app_plug"        self.namespace = "app_plug"    def register(self, model_class, app_plug_model_class=BasePlugModel):        self._registry[model_class] = app_plug_model_class(model_class, self)

在别的app中注册model时只需要：

v1.site.register(models.UserInfo)

自动生成URL

对于此类问题肯定要首先解决路由分发的问题，以前运用include函数可以将URL分层管理，进入include源码可以发现，源码如下：

def include(arg, namespace=None):    app_name = None    if isinstance(arg, tuple):        # Callable returning a namespace hint.        try:            urlconf_module, app_name = arg        except ValueError:            if namespace:                raise ImproperlyConfigured(                    'Cannot override the namespace for a dynamic module that '                    'provides a namespace.'                )            raise ImproperlyConfigured(                'Passing a %d-tuple to include() is not supported. Pass a '                '2-tuple containing the list of patterns and app_name, and '                'provide the namespace argument to include() instead.' % len(arg)            )    else:        # No namespace hint - use manually provided namespace.        urlconf_module = arg    if isinstance(urlconf_module, str):        urlconf_module = import_module(urlconf_module)    patterns = getattr(urlconf_module, 'urlpatterns', urlconf_module)    app_name = getattr(urlconf_module, 'app_name', app_name)    if namespace and not app_name:        raise ImproperlyConfigured(            'Specifying a namespace in include() without providing an app_name '            'is not supported. Set the app_name attribute in the included '            'module, or pass a 2-tuple containing the list of patterns and '            'app_name instead.',        )    namespace = namespace or app_name    # Make sure the patterns can be iterated through (without this, some    # testcases will break).    if isinstance(patterns, (list, tuple)):        for url_pattern in patterns:            pattern = getattr(url_pattern, 'pattern', None)            if isinstance(pattern, LocalePrefixPattern):                raise ImproperlyConfigured(                    'Using i18n_patterns in an included URLconf is not allowed.'                )    return (urlconf_module, app_name, namespace)

大部分地方可以不用管，我们需要了解的是他的返回值，返回值的属性分别为：url关系列表或模块（模块内部必须有urlpatterns属性）；app_name；namespace

了解了返回值之后我们可以自己写一个函数来模仿include函数所做的事，其实这个函数的返回值和include函数的返回值要求相同即可，在AppPlugSite类中创建：

def urls(self):        """        创建URL对应关系        :return: 元组类型：url关系列表或模块（模块内部必须有urlpatterns属性）；app_name；namespace        """        return self.get_urls(), self.app_name, self.namespace

然后要处理的就是get_urls函数该怎么写，首先要明确的时这个函数的返回值一定是个列表类型，简单的写：

def get_urls(self):        """        封装url至列表        :return: 装有url的列表        """        from django.conf.urls import include        from django.urls import re_path        # urlpatterns变量名不能更改，因为include内部实现寻找url时就是查找urlpatterns变量获取        urlpatterns = [            # url(r'^$', self.index, name='index'),            re_path(r'^login/$', self.login, name='login'),            re_path(r'^logout/$', self.logout, name='logout'),        ]        return urlpatterns

然后在urls.py中添加：

re_path(r'^plug/', v1.site.urls),

这样就添加了一些二级的URL，但是我们所要做的是要对任何数据列表进行增删改查的操作，URL格式应该为:http://127.0.0.1:8000/plug/app01/userinfo/1/delete/ 这样的，这个URL所含的信息有包名，models的类名，还有操作方式和操作对象id

获取包名和类名的方法为: 类._meta.app_label,类._meta.model_name，这样在BasePlugModel类中再创建：

def another_urls(self):        """        钩子函数，用于自定义额外的URL        :return:        """        return []    def get_urls(self):        """        配置最后一段URL用于增删改查等操作        :return:        """        from django.urls import re_path        # 获取包名和类名,方便日后反向生成URL        info = self.model_class._meta.app_label, self.model_class._meta.model_name        urlpatterns = [            re_path(r'^$', self.list_view, name='%s_%s_list' % info),            re_path(r'^add/$', self.add_view, name='%s_%s_add' % info),            re_path(r'^(.+)/delete/$', self.delete_view, name='%s_%s_delete' % info),            re_path(r'^(.+)/change/$', self.change_view, name='%s_%s_change' % info),            # re_path(r'^(.+)/detail/$', self.detail_view, name='%s_%s_detail' % info),        ]        urlpatterns += self.another_urls()        return urlpatterns    @property    def urls(self):        return self.get_urls()

这样，就可以对任何数据列表进行增删改查的操作。

在AppPlugSite中的完整的get_urls函数为：

def get_urls(self):        """        封装url至列表        :return: 装有url的列表        """        from django.conf.urls import include        from django.urls import re_path        # urlpatterns变量名不能更改，因为include内部实现寻找url时就是查找urlpatterns变量获取        urlpatterns = [            # url(r'^$', self.index, name='index'),            re_path(r'^login/$', self.login, name='login'),            re_path(r'^logout/$', self.logout, name='logout'),        ]        # 根据model动态生成URL        for model_class, plug_model_obj in self._registry.items():            # 获取包名和类名            app_label = model_class._meta.app_label            model_name = model_class._meta.model_name            # 拼接URL            urlpatterns += [re_path(r'^%s/%s/' % (app_label, model_name), include(plug_model_obj.urls)), ]        return urlpatterns