Migrate refile files to active storage

migrate_refile_to_active_storage.rb

require 'mini_magick' # included by the image_processing gem
require 'aws-sdk-s3' # included by the aws-sdk-s3 gem

class MigrateRefileToActiveStorage
  attr_accessor :model, :attribute
  def initialize(model, attribute)
    @model = model
    @attribute = attribute
  end

  def run
    puts "Migrating #{@mode} #{@attribute} file from Refile to ActiveStorage"
    @model.constantize.where.not(:"#{@attribute}_id" => nil).find_each do |instance|
      next if instance.send(@attribute).attached?

      id = file_id(instance.send("#{@attribute}_id"))
      next unless Easymovie::Aws.bucket.object(id).exists?
      tmp_file = Tempfile.new

      # Download the S3 file to our temp file
      Easymovie::Aws.s3.client.get_object(
        response_target: tmp_file.path,
        bucket: Easymovie::Aws.bucket.name,
        key: id
      )

      # Find content_type of S3 file using ImageMagick
      # Verify if the model has the content_type column otherwise infers using MiniMagick
      content_type = instance.try(:"#{@attribute}_content_type") || MiniMagick::Image.new(tmp_file.path).mime_type

      # Attach tmp file to our User as an ActiveStorage attachment
      filename = instance.try(:"#{@attribute}_filename") || "file.#{content_type.split('/').last}"
      instance.send(@attribute).attach(
        io: tmp_file,
        filename: filename,
        content_type: content_type
      )

      if instance.send(@attribute).attached?
        instance.save # Save our changes to the instance
        puts "- migrated #{@mode} #{@attribute}'s file for instance ##{instance.id}."
      else
        puts "- \e[31mFailed to migrate the file for #{@model} instance ##{instance.id} with Refile id #{instance.send("#{@attribute}_id")}\e[0m"
      end

      tmp_file.close
    end
  end

  private

  def file_id(id)
    return id if id.match('store/')
    "store/#{id}"
  end
end