Django easy_thumbnails和post_delete

Question

我正在从表单中删除一个相关的模型(与django管理方式几乎相同)，我有一个有很多图像的项目，图像属于item (ForeignKey)。在从表单中删除图像/图像时，我实现了一个post_delete信号来删除缩略图和图像，问题是在post_delete缩略图中删除了缩略图，但是db中的图像条目仍然是：

# Auto-delete files from filesystem when they are unneeded:
@receiver(models.signals.post_delete, sender=ImageModel)
def auto_delete_file_on_delete(sender, instance, **kwargs):
    """Deletes file from filesystem
    when corresponding `ImageModel` object is deleted.
    """
    if instance.imagefile:
        thumbmanager = get_thumbnailer(instance.imagefile)
        thumbmanager.delete()

如果最后添加以下内容，则图像实例也将被删除(预期行为)：

# Auto-delete files from filesystem when they are unneeded:
@receiver(models.signals.post_delete, sender=ImageModel)
def auto_delete_file_on_delete(sender, instance, **kwargs):
    """Deletes file from filesystem
    when corresponding `ImageModel` object is deleted.
    """
    if instance.imagefile:
        thumbmanager = get_thumbnailer(instance.imagefile)
        thumbmanager.delete()
        instance.delete()

我是不是遗漏了什么？不应该在删除实例之后发送post_delete信号吗？为什么实例在数据库中持久化？我假定这与Queryset删除行为有关，但我对此表示怀疑，因为如果删除信号，则删除ImageModel实例(尽管缩略图仍保留在数据库中)。请注意，模型使用了ImageField字段中的django构建，并且提供了不容易的缩略图：

class ImageModel(models.Model):
    ...
    imagefile = models.ImageField(upload_to="properties/%m/%Y")
    item = models.ForeignKey('app.ItemModel', related_name='images')
    ...

上面的解决方案(instance.delete())没有问题，只是对行为感到好奇。

Answer 1

好吧，让它加入delete(save=False)：

# These two auto-delete files from filesystem when they are unneeded:
@receiver(models.signals.post_delete, sender=ImageModel)
def auto_delete_file_on_delete(sender, instance, **kwargs):
    """Deletes file from filesystem
    when corresponding `ImageModel` object is deleted.
    """
    if instance.imagefile:
        thumbmanager = get_thumbnailer(instance.imagefile)
        thumbmanager.delete(save=False)

Answer 2

您也可以使用django-清理，当您删除模型时，它会在FileField上自动调用delete方法。

pip install django-cleanup

settings.py

INSTALLED_APPS = (
     ...
    'django_cleanup', # should go after your apps
)