如何在Rails应用程序中使用mini_magick获取EXIF关键字？ [英] How to get EXIF keywords using mini_magick in a Rails app?

问题描述

我正在尝试为具有EXIF关键字属性值的图像提取EXIF信息。我已经使用mini_magick成功读取了EXIF信息，只需打开图像并使用：

I am attempting to pull the EXIF information for images that have values for the EXIF "keywords" attribute. I have successfully read EXIF information using mini_magick by simply opening an image and using:

image["EXIF:Model"]

出于某种原因，以下所有内容都不会返回我知道的图像的关键字：

For some reason, none of the following will return keywords for an image that I know has them:

image["EXIF:Keywords"]
image["EXIF:XPKeywords"]
image["EXIF:Subject"]

我已使用此实用程序确认相关图像确实包含此信息： http://regex.info/exif.cgi

I have confirmed that the image in question does have this information using this utility: http://regex.info/exif.cgi

mini_magick只能访问某些EXIF值吗？看起来很奇怪，我可以访问某些EXIF信息但不能访问其他信息。

Does mini_magick only have access to certain EXIF values? It seems so odd that I can access certain EXIF information but not others.

推荐答案

EXIF元数据由相机创建，因此它仅包含技术相关内容。您真正想要访问的是 IPTC 和 XMP 。

EXIF metadata is created by camera, therefore it contains only technical related stuff. What you actually want to access is IPTC and XMP.

Imagemagick，它位于mini_magick之后，允许阅读IPTC ，例如图片[％[IPTC：2：25]] 关键字（更新：了解性能问题，请参阅评论）。

Imagemagick, which is behind mini_magick, allows to read IPTC, e.g. image["%[IPTC:2:25]"] for keywords (update: be aware of perfomance issues, see comments).

至于XMP，我不知道一个简单的方法。您可以尝试运行

As for XMP, I don't know an easy way to do this. You can try to run

`identify -verbose #{your_filename}`

然后grub包含 xmp 的行。

and then grub lines that include xmp.

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