Question

我正在从表单中删除相关模型（与django admin几乎相同），我有一个项目有很多图像，图像属于Item（ForeignKey）。我已经实现了post_delete信号来删除缩略图和从图像中删除图像/图像时的图像，问题是post_delete缩略图被删除但数据库中的图像条目仍然存在：

# 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()

如果我最后添加以下内容，也会删除图像实例（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()

我错过了什么吗？删除实例后，是否应该发送post_delete信号？为什么实例在db中持久存在？我假设这与Queryset删除行为有关，但我对此持怀疑态度，因为如果删除信号，则删除ImageModel的实例（尽管缩略图仍保留在数据库中）。请注意，模型在ImageField字段中使用django构建，而不是简单的缩略图提供字段：

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（））没有任何问题，只是对行为感到好奇。

Answer 1

您也可以使用django-cleanup，当您删除模型时，它会自动在FileField上调用delete方法。

pip install django-cleanup

settings.py

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

Answer 2

好的，它可以添加删除（保存=错误）：

# 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)

Django easy_thumbnails和post_delete

2 个答案: