子类化 Django ImageFileField

发布于 2024-09-28 08:58:56 字数 718 浏览 3 评论 0原文

我对 django 的 ImageFileField 子类化以允许访问图像 IPTC 元数据感兴趣，例如：

>>> from myapp.models import SomeModel
>>> obj = SomeModel.objects.all()[0] # or what have you
>>> obj.image.iptc['keywords']
('keyword','anotherkeyword','etc')

... 文档对阅读 django 的内部代码，我就是这么做的；我试图生成一个有效的实现，但我不确定我在做什么——我之前定义了自定义字段，但我无法为基于文件的字段提供样板设置。

我知道我需要定义一个 attr_class 和一个 descriptor_class 才能使其工作。有没有人有一个简单的例子或建议，我可以从中开始？

原文

I'm interested in subclassing django's ImageFileField to allow access to the image IPTC metadata, something like:

>>> from myapp.models import SomeModel
>>> obj = SomeModel.objects.all()[0] # or what have you
>>> obj.image.iptc['keywords']
('keyword','anotherkeyword','etc')

... the docs say to read over django's internal code, which I did; I've tried to produce a working implementation and I am not sure what I'm doing -- I've defined custom fields before, but I can't come up with boilerplate setup for a file-based field.

I know I need to define an attr_class and a descriptor_class to make it work. Does anyone have a straightforward example or suggestion, with which I could get started?

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轻拂→两袖风尘 2024-10-05 08:58:56

你的问题并不清楚：你尝试过这样的事情吗？

class ImageMetadataMixin(object):
    """Mixin can be added to any image file"""
    @property
    def iptc(self):
        """Or something like this"""

class ImageWithMetadataFieldFile(ImageMetadataMixin, ImageFieldFile):
    pass

class ImageWithMetadataField(ImageField):
    attr_class = ImageWithMetadataFieldFile

我认为这都是必要的。您认为为什么需要重新定义descriptor_class？

It's not clear from your question: have you tried something like this?

class ImageMetadataMixin(object):
    """Mixin can be added to any image file"""
    @property
    def iptc(self):
        """Or something like this"""

class ImageWithMetadataFieldFile(ImageMetadataMixin, ImageFieldFile):
    pass

class ImageWithMetadataField(ImageField):
    attr_class = ImageWithMetadataFieldFile

I think it's all what necessary. Why do you think you need to redefine descriptor_class?

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