Rails 5.2 ActiveStorage保存然后读取Exif数据

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问题描述

在Rails 5.2上，我试图通过ActiveStorage保存一个化身，但似乎未在活动存储Blob中保存图像整理数据.

On Rails 5.2 I am trying to save an avatar via ActiveStorage but it seems as though not image oriantation data is being saved in the active storage blob.

我正在通过创建动作我的file_field保存化身

I am saving the avatar via a file_field on a create action my

#user model

has_one_attached :avatar

private

def avatar_validation
  if avatar.attached?
    if avatar.blob.byte_size > 1000000
      avatar.purge
      errors.add(:avatar, 'file is too large')
    elsif !avatar.blob.content_type.in?(%w[image/png image/jpg
          image/jpeg])
      avatar.purge
      errors.add(:avatar, 'file type needs to be JPEG, JPG, or PNG')
    end
  end
end

我一直在阅读minimagick的一些文档 https://github.com/minimagick/minimagick 但还没有弄清楚我该如何关联

I have been reading some documentation for minimagick https://github.com/minimagick/minimagick but have not figured out how I can associate

user.avatar.blob

与

image = MiniMagick::Image.open("input.jpg")

我尝试过

image = MiniMagick::Image.open("user.avatar.blob")

但是没有运气

我需要尝试解决这个问题，因为一些存储在活动存储中的化身会旋转90度显示.

I need to try and figure this out because some avatars stored in active storage are being displayed rotated 90 degrees.

https://edgeguides.rubyonrails.org/active_storage_overview.html 关于图像处理的话题，但我对Gems Rails的建议也没有好运

https://edgeguides.rubyonrails.org/active_storage_overview.htmltalks of image processing but I have also had no luck with the gem rails recommends

推荐答案

我认为您要在显示图像时使用一种变体，而不是尝试编辑存储的图像.要确定方向，您可以说:

I think you want to use a variant when displaying the image rather than trying to edit the stored image. To fix the orientation, you could say:

user.avatar.variant(auto_orient: true)

如果您想一次执行多个操作(而不是在管道中)，请使用combine_options:

And if you want to do several operations at once (rather than in a pipeline), use combine_options:

user.avatar.variant(combine_options: {
  auto_orient: true,
  gravity:     'center',
  resize:      '23x42',    # Using real dimensions of course.
  crop:        '23x42+0+0'
})

已编辑的图像将被缓存，因此您仅在首次访问时执行转换工作.您可能希望将variant放到视图助手中(或者根据您的需要甚至考虑模型问题)，以便可以隔离噪音.

The edited image will be cached so you only do the transformation work on first access. You might want to put your variants into view helpers (or maybe even a model concern depending on your needs) so that you can isolate the noise.

您可能希望参考API文档以及指南:

You might want to refer to the API docs as well as the guide:

ActiveStorage :: Variant
ActiveStorage :: Variation

ActiveStorage::Variant
ActiveStorage::Variation

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