Carrierwave: Encoding::UndefinedConversionError (“\xFF” from ASCII-8BIT to UTF-8)

Question

I'm trying to upload multiple files to a record called Post , with a json attribute called images , using Carrierwave. But when I try to save the record, I get this error:

  (0.5ms)  ROLLBACK
Completed 401 Unauthorized in 15ms (ActiveRecord: 0.8ms)
Encoding::UndefinedConversionError ("\xFF" from ASCII-8BIT to UTF-8):

I've used Carrierwave before and I never got this error. I checked if anyone's had this problem, before, and I didn't find much. This question suggested the activesupport-json_encoder gem, but this gem isn't compatible with Rails 5. Also suggested were the force_encoding method and using a "wb" flag when saving the file, but the Carrierwave code has no place to implement those suggestions.

Here's the code I have:

form

<%= form_for @post, :html => {multipart: true}, do |f| %>
  <%= f.file_field :images, multiple: true %>
  <%= f.submit "submit" %>
<% end %>

posts controller

  ...
  private
    def post_params
      params.require(:post).permit({images: []})
    end
end

posts migration

  ...
  create_table :posts do |t|
    t.json :images
    ...

posts uploader

class ImageUploader < CarrierWave::Uploader::Base
  include CarrierWave::MiniMagick

  storage :fog

  def fix_exif_rotation
    manipulate! do |img|
      img.tap(&:auto_orient)
    end
  end

  process :fix_exif_rotation
  process :resize_to_fit => [800, 56000]

  version :thumb do
    process resize_to_fit: [300, 56000]
  end
end

Answer 1

My guess would be that you need to use :string instead of :json in the ActiveRecord::Migration .

class AddImagesToGallery < ActiveRecord::Migration
  def change
    add_column :galleries, :images, :string, array: true, default: [] # add images column as array
  end
end

You can check following How to: Add more files and remove single file when using default multiple file uploads feature for more.

EDIT - added the reason

The reason why you are getting this error is that the gem activesupport-json_encoder (the one PR is hanging there from 2014) is no longer maintained and is not compatible with rails 5.x.