Django 프레임워크의 백엔드 관리 시스템 기술(2부)

class Product(models.Model):
    name = models.CharField(max_length=100)
    category = models.ForeignKey(ProductCategory, default=get_default_category)

   def get_default_category():
        """
        返回默认的ProductCategory实例或者创建一个新的实例
        """
        category, _ = ProductCategory.objects.get_or_create(name='Default Category')
        return category

from singleton_models.models import SingletonModel

class GlobalSettings(SingletonModel):
    site_name = models.CharField(max_length=100, default='')
    site_url = models.URLField(default='')
    # 其他全局设置字段

MIDDLEWARE = [
    # 默认的中间件
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    # 自定义中间件
    'myapp.middleware.ConfirmPasswordMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

CONFIRMED_ACTIONS = (
    'myapp.views.EditProductView',
    'myapp.views.DeleteProductView',
)

class ConfirmPasswordMiddleware:
    def __init__(self, get_response):
        self.get_response = get_response

    def __call__(self, request):
        # 根据请求的URL判断是哪个视图函数，如果是CONFIRMED_ACTIONS中的视图函数，需要做二次确认
        view_func = resolve(request.path_info).func
        if view_func and view_func.__module__ + "." + view_func.__name__ in CONFIRMED_ACTIONS:
            if not request.session.get('password_confirmed', False):
                # 没有输入二次确认密码，跳转到输入页面
                return redirect(reverse('confirm-password'))

        response = self.get_response(request)

        return response

from django.contrib import admin
from django.core.serializers import serialize
from django.http import HttpResponse

class ProductAdmin(admin.ModelAdmin):
    # 列表视图显示的字段列表
    list_display = ('name', 'price', 'category')

    # 自定义action函数
    def export_as_json(self, request, queryset):
        response = HttpResponse(content_type="application/json")
        serializers.serialize("json", queryset, stream=response)
        return response
    export_as_json.short_description = "导出为JSON"

    # 自定义函数按钮
    change_list_template = 'admin/myapp/product/list.html'

    def get_urls(self):
        urls = super().get_urls()
        my_urls = [
            path('my_view/', self.my_view),
        ]
        return my_urls + urls

    def my_view(self, request):
        data = serialize('json', Product.objects.all())
        return JsonResponse(data, safe=False)

admin.site.register(Product, ProductAdmin)