覆盖同名的图像 - Django

Question

通过我的项目，我有用户上传个人资料图片。我将个人资料图片保存为userID.jpg。如果他们上传了新的个人资料图片，我想覆盖旧的个人资料图片，所以我不会浪费存储空间。通过浏览stackoverflow上的先前问题，我重新定义了OverwriteStorage：

class OverwriteStorage(FileSystemStorage):
    def get_available_name(self, name, max_length=None):
        if self.exists(name):
             os.remove(os.path.join(settings.MEDIA_ROOT, name))
        return name

当我上传个人资料图片时，我可以在计算机上的目录中看到图片已被成功覆盖。图像以“media / profile / userID.jpg”路径保存。但是，当我在我的网站上显示图像时，它仍然是旧图片。通过Django站点，当我打开路径时，我看到旧图片，当我尝试通过管理员更改它时，我收到以下错误：

[WinError 32] The process cannot access the file because it is being used by another process: '\media\\profile\\userID.jpg'

我想我错误地覆盖了文件而另一个实例仍然是打开的，要解决它，我需要在覆盖前正确关闭图像。我试过这样做，但没有成功。

Answer 1

我做了类似的事情，但我使用信号来更新和删除图像。

Firstable，我在helpers.py中定义了图像的名称

from django.conf import settings
from datetime import datetime

def upload_to_image_post(self, filename):
    """
    Stores the image in a specific path regards to date 
    and changes the name of the image with for the name of the post
    """    
    ext = filename.split('.')[-1]
    current_date = datetime.now()

    return '%s/posts/main/{year}/{month}/{day}/%s'.format(
        year=current_date.strftime('%Y'), month=current_date.strftime('%m'), 
        day=current_date.strftime('%d')) % (settings.MEDIA_ROOT, filename)

所以，我在我的模型中调用了def，特别是在图像的字段中

from django.db import models
from django.utils.text import slugify
from .helpers import upload_to_image_post

class Post(models.Model):
    """
    Store a simple Post entry. 
    """
    title = models.CharField('Title', max_length=200, help_text='Title of the post')
    body = models.TextField('Body', help_text='Enter the description of the post')   
    slug = models.SlugField('Slug', max_length=200, db_index=True, unique=True, help_text='Title in format of URL')        
    image_post = models.ImageField('Image', max_length=80, blank=True, upload_to=upload_to_image_post, help_text='Main image of the post')

    class Meta:
        verbose_name = 'Post'
        verbose_name_plural = 'Posts'

最后，我定义了信号，以便在模型中发生操作（更新或删除）之前更新或删除图像。

import os
from django.db import models
from django.dispatch import receiver
from django.db.models.signals import pre_delete, pre_save
from .models import Post

@receiver(pre_delete, sender=Post)
def post_delete(sender, instance, **kwargs):
    """
    Deleting the specific image of a Post after delete it
    """
    if instance.image_post:
        if os.path.isfile(instance.image_post.path):
            os.remove(instance.image_post.path)

@receiver(pre_save, sender=Post)
def post_update(sender, instance, **kwargs):
    """
    Replacing the specific image of a Post after update
    """
    if not instance.pk:
        return False

    if sender.objects.get(pk=instance.pk).image_post:
        old_image = sender.objects.get(pk=instance.pk).image_post
        new_image = instance.image_post
        if not old_image == new_image:
            if os.path.isfile(old_image.path):
                os.remove(old_image.path)
    else:
        return False

我希望，这对你有帮助。

Answer 2

让它将旧的重命名为userID-old.jpg，然后保存userID.jpg。很快就没有人会注意到它的发生。