Django 缓存 - 显示从缓存中检索的图像时出现问题

Question

我正在使用django 1.4，python 2.7，Memcache，python-memcached和easy-thumbnails。

当我尝试使用缓存数据访问项目页面时，出现以下模板错误：

Couldn't get the thumbnail uploads/items/item_images/logo.jpeg: 'ImageFieldFile' object has no attribute 'instance'

当我从 shell 中的数据库访问有问题的数据时，我得到：

>>> log = item.get_logo()
>>> logo
<ImageFieldFile: uploads/items/item_images/logo.png>
>>> logo.instance
<Media: uploads/items/item_images/logo.png>

当我尝试从缓存中访问相同的数据时，我得到：

>>> cache.set('logo',item.get_logo())
>>> logo = cache.get('logo')
>>> logo
<ImageFieldFile: uploads/items/item_images/logo.png>
>>> logo.instance
Traceback (most recent call last):
  File "<console>", line 1, in <module>
AttributeError: 'ImageFieldFile' object has no attribute 'instance'

我的问题是你如何缓存ImageFieldFile以便它可以在原始状态下检索？我需要将该对象传递给我的模板以与简易缩略图一起使用。

Answer 1

因此，

我没有尝试缓存ImageFieldFile而是缓存了ImageFieldFile所在的对象（Media），现在一切正常。

数据库：

>>> logo = item.get_logo()
>>> logo
<Media: uploads/items/item_images/logo.png>
>>> logo.image #this is what I was trying to cache before
<ImageFieldFile: uploads/items/item_images/logo.png>
>>> logo.image.instance
<Media: uploads/items/item_images/logo.png>

缓存：

>>> cache.set('logo',logo)
>>> cachedLogo = cache.get('logo')
>>> logo
<Media: uploads/items/item_images/logo.png>
>>> logo.image
<ImageFieldFile: uploads/items/item_images/logo.png>
>>> logo.image.instance
<Media: uploads/items/item_images/logo.png>