Django在更新文件后正确删除图像 [英] Django correctly delete image after updating file

问题描述

有一个类似的问题这里，但那是从2011和Django 1.2。从那以后，很多事情都发生了变化。我正在使用Django 1.9。

There is a similar question here but that is from 2011 and Django 1.2. Many things have changed since then. I'm using Django 1.9.

我想知道如何正确地执行此操作，没有任何可能弄乱文件系统的风险。我在模型中有一个 ImageField ：

I'm wondering how should I do this correctly, without any risks of messing up the filesystem. I have an ImageField in a model:

class CartaMagicPy(models.Model):
    imagen = models.ImageField(null=True, upload_to=ubicar_magicpy)

第一时刻，图像被保存。但是，然后，用户裁剪图像，并获得分配给相同的 ImageField 的新图像。

On a first moment, the image is saved. But then, the user crops the image and I get a new image assigned to the same ImageField.

旧图像不会从文件系统中删除。如何删除它？问题是更新后的 model_object.imagen.path 包含新的图像的路径。如果我在之前删除它，请用新图像进行更新，否则我有可能会失败，然后我完全没有图像。有没有可以使用的后保存信号的组合？任何建议都有帮助。

The old image is not deleted from the filesystem. How can I delete it? The problem is that model_object.imagen.path after being updated contains the path to the new image. And if I delete it before I update it with the new image, I risk that maybe the save could fail and then I end up with no image at all. Is there a combination of post-save signals I could use? Any advice will help.

推荐答案

As 在这个答案中看到，有一个应用程序： django-cleanup 。

As seen in this answer, "there's an app for that": django-cleanup.

如果你喜欢自己实现，在评论中链接的问题@raphv接受的答案给了一些很好的指针。

If you prefer to implement it yourself, the accepted answer to the question @raphv linked in the comment gives some good pointers.

更新更新跟踪的一个很好的解决方案是使用模型信号;我倾向于使用 post_init 和 post_save ，在这种情况下，删除之后的旧图片文件。如下所示：

A good solution for updated change followup is to use model signals; I tend to use post_init and post_save, in this case to delete the old image file after the change has been made. Something like so:

from django.db.models.signals import post_init, post_save
from django.dispatch import receiver

from myapp.models import CartaMagicPy


@receiver(post_init, sender= CartaMagicPy)
def backup_image_path(sender, instance, **kwargs):
    instance._current_imagen_file = instance.imagen


@receiver(post_save, sender= CartaMagicPy)
def delete_old_image(sender, instance, **kwargs):
    if hasattr(instance, '_current_imagen_file'):
        if instance._current_imagen_file != instance.imagen.path:
            instance._current_imagen_file.delete(save=False)

这似乎通常是上面链接的包，加上一些额外的安全检查和清理。

This also seems to be generally what the linked package above does, plus some additional safety checks and cleanup.

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