英文:
Django signals post_save method
问题
以下是翻译好的部分：
我正在使用django-rest-framework创建在线商店的API，但由于某种原因无法使我的post_save信号工作。我的想法是：我有一个模型Product和Category。Product模型有一个名为in_stock的字段，默认为True。至于Category模型，它也有一个in_stock字段，但这里是False。当创建产品实例时，我希望使用信号将Category字段的in_stock分配为True值。以下是模型的代码：
class Category(models.Model):category_name = models.CharField(max_length=255, verbose_name='Категория')description = models.TextField(verbose_name='Описание')in_stock = models.BooleanField(default=False, verbose_name='В наличии')slug = models.SlugField()image_url = models.ImageField(upload_to='categories/uploads/%Y/%m/%d/', null=True, blank=True,default='media/images.png', verbose_name='Изображение')parent = models.ForeignKey('self', on_delete=models.PROTECT, related_name='children', null=True, blank=True,verbose_name='Родительская категория')def __str__(self):return f'{self.parent}, {self.category_name}'class Product(models.Model):product_name = models.CharField(max_length=255, verbose_name='Товар')description = models.TextField(verbose_name='Описание')price = models.IntegerField(verbose_name='Цена')discount_percent = models.IntegerField(default=0, verbose_name='Процент скидки')in_stock = models.BooleanField(default=True, verbose_name='В наличии')amount = models.IntegerField(verbose_name='Количество')vendor = models.ForeignKey(Vendor, on_delete=models.CASCADE, verbose_name='Поставщик')category = models.ForeignKey(Category, on_delete=models.CASCADE, verbose_name='Категория')brand = models.ForeignKey(Brand, on_delete=models.CASCADE, verbose_name='Бренд')image = models.ForeignKey(ProductImage, on_delete=models.SET_DEFAULT, default=1,verbose_name='Изображение')
以下是信号：
@receiver(post_save, sender=Product)def update_category_is_active(sender, instance, created, **kwargs):print(instance)if created and instance.in_stock:instance.category.in_stock = Trueinstance.category.save()
英文:
I am creating API for online-store with django-rest-framework and can't get my post_save signal working for some reason. The idea is: I have a model Product and Category. Product model has a field named in_stock, which is True by default. As for model Category, it also has field in_stock, but here it is False. When the product instance created, I want assign Category field in_stock to True value using singals. Here is the code of models:
class Category(models.Model):category_name = models.CharField(max_length=255, verbose_name='Категория')description = models.TextField(verbose_name='Описание')in_stock = models.BooleanField(default=False, verbose_name='В наличии')slug = models.SlugField()image_url = models.ImageField(upload_to='categories/uploads/%Y/%m/%d/', null=True, blank=True,default='media/images.png', verbose_name='Изображение')parent = models.ForeignKey('self', on_delete=models.PROTECT, related_name='children', null=True, blank=True,verbose_name='Родительская категория')def __str__(self):return f'{self.parent}, {self.category_name}'class Product(models.Model):product_name = models.CharField(max_length=255, verbose_name='Товар')description = models.TextField(verbose_name='Описание')price = models.IntegerField(verbose_name='Цена')discount_percent = models.IntegerField(default=0, verbose_name='Процент скидки')in_stock = models.BooleanField(default=True, verbose_name='В наличии')amount = models.IntegerField(verbose_name='Количество')vendor = models.ForeignKey(Vendor, on_delete=models.CASCADE, verbose_name='Поставщик')category = models.ForeignKey(Category, on_delete=models.CASCADE, verbose_name='Категория')brand = models.ForeignKey(Brand, on_delete=models.CASCADE, verbose_name='Бренд')image = models.ForeignKey(ProductImage, on_delete=models.SET_DEFAULT, default=1,verbose_name='Изображение')
Here is signals:
@receiver(post_save, sender=Product)def update_category_is_active(sender, instance, created, **kwargs):print(instance)if created and instance.in_stock:instance.category.in_stock = Trueinstance.category.save()
答案1
得分: 1
你可以通过重写save()方法来在没有信号的情况下获取它。
英文:
You can get it without signals by overriding save() method
class Product(models.Model):...def save(self, *args, **kwargs):if self.pk is None:if self.in_stock:self.category.in_stock = Trueself.category.save()super().save(*args, **kwargs)
答案2
得分: 0
你是否在 apps.py 文件中添加了一个 ready 函数？这是必需的，因为 Django 需要知道哪些文件具有额外的代码（如 pre_save / post_save 等），在服务器运行时应该执行。它会类似于这样：
from django.apps import AppConfigclass AppNameConfig(AppConfig):name = 'appname'def ready(self):import appname.signals
英文:
Did you add a ready function in the apps.py file? This is required as Django should know which files have additional code(like pre_save/ post_save) which should be executed when the server is running.
It will look like something like this:
from django.apps import AppConfigclass AppNameConfig(AppConfig):name = 'appname'def ready(self):import appname.signals
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