Rails 5.2 Activestorage Save and Then Read Exif Data

Rails 5.2 ActiveStorage save and then read Exif data

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)

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'
})

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.

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

• ActiveStorage::Variant
• ActiveStorage::Variation

Reading from Active Storage Attachment Before Save

Rails 6 changed the moment of uploading the file to storage to during the actual save of the record.

This means that a before_save or validation cannot access the file the regular way.

If you need to access the newly uploaded file you can get a file reference like this:

record.attachment_changes['<attributename>'].attachable

This will be a tempfile of the to-be-attached file.

NOTE: The above is an undocumented internal api and subject to change (https://github.com/rails/rails/pull/37005)

How to retrieve EXIF information of an ActiveStorage image in Rails

If you have a user with avatar maybe ou have a class like that

class User < ApplicationRecord
  has_one_attached :avatar
end

To get a exif info you can run this:

user = User.find 1
MiniMagick::Image.open(user.avatar).exif 

A gem that you need:

gem "mini_magick"

More about MiniMagick

Rails Api Save MiniMagick Image to Active Storage

Yes, you can. Currently you are trying to save an instance of MiniMagick::Image to ActiveStorage, and that's why you receive that error. Instead you should attach the :io directly to ActiveStorage.

Using your example, if you wanted to attach mini_img to a hypothetical User, that's how you would do it:

User.first.attach io: StringIO.open(mini_img.to_blob), filename: "filename.extension"

In this example I am calling to_blob on mini_img, which is an instance of MiniMagick::Image, and passing it as argument to StringIO#open. Make sure to include the :filename option when attaching to ActiveStorage this way.

EXTRA

Since you already have the content_type when using MiniMagick you might want to provide it to ActiveStorage directly.

metadata = mini_img.data
User.first.attach io: StringIO.open(mini_img.to_blob), filename: metadata["baseName"], content_type: metadata["mimeType"], identify: false

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