Can't create multiple versions of image

[hakunin]

I am trying to create two new versions of the uploaded image, one large and one small.

What I found is, the large is always the same size as thumb.

require "image_processing/mini_magick"

class AttachmentUploader < Shrine
  include ImageProcessing::MiniMagick

  plugin :activerecord
  plugin :logging, logger: Rails.logger

  plugin :determine_mime_type
  plugin :store_dimensions
  plugin :direct_upload, max_size: 20*1024*1024, presign: -> (r) do
    r.params["fields"] || {}
  end
  plugin :remove_attachment
  plugin :versions, names: [:original, :large, :thumb]

  def process(io, context)
    if context[:phase] == :store
      file = io.download
      large = resize_to_limit!(file, 1200, 1200)
      thumb = resize_to_limit!(file, 300, 300)

      {
        original: io, 
        large: large,
        thumb: thumb,
      }
    end
  end
end

The data behind this:

pp JSON.parse(Upload.last.attachment_data)
  Upload Load (0.5ms)  SELECT  "uploads".* FROM "uploads"  ORDER BY "uploads"."id" DESC LIMIT 1
{"original"=>
  {"id"=>"3a0768ce990db7637c54126d634a3e2ebee35ee6d3546bf3fba599f46939.jpg",
   "storage"=>"store",
   "metadata"=>
    {"filename"=>"Interstellar UHD 2.jpg",
     "size"=>1691252,
     "mime_type"=>"image/jpeg",
     "width"=>3840,
     "height"=>2160}},
 "large"=>
  {"id"=>"21c487c57e193eae3650025b453b0669ee083603621af0879823f454025c.jpg",
   "storage"=>"store",
   "metadata"=>
    {"filename"=>"Interstellar UHD 2.jpg",
     "size"=>14306,
     "mime_type"=>"image/jpeg",
     "width"=>300,
     "height"=>169}},
 "thumb"=>
  {"id"=>"7bd60d5ac34e0cc8164067571c36914588135bc87673f9f9b68660277ee7.jpg",
   "storage"=>"store",
   "metadata"=>
    {"filename"=>"Interstellar UHD 2.jpg",
     "size"=>14306,
     "mime_type"=>"image/jpeg",
     "width"=>300,
     "height"=>169}}}

[janko]

This is actually expected behaviour. If you use resize_to_limit! (with a bang), that modifies the file in-place. So in your example, large will have the same path as file, and thumb as well. So when you resize_to_limit! the file again and assign it to thumb, it will modify large as well. This is generally how references work.

What is not expected was that I was recommending it in the README. In processing versions you should generally always use the non-bang methods (resize_to_limit instead of resize_to_limit!). I updated the documentation with this recommendation.

[hakunin]

👍 Awesome, thanks :)