Rails 4 carrierwave gem TypeError on assign to uploader

Question

I'm using the carrierwave gem to set up image upload on a nested form. The uploader looks like:

class CarImageUploader < CarrierWave::Uploader::Base

    include CarrierWave::MiniMagick

    if Rails.env.production?
        storage :fog
    else
        storage :file
    end

    def store_dir
        "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
    end

    def default_url
        'default-no-car-pic.png'
    end

    version :thumb do
        process :resize_to_fit => [50, 50]
    end

    def extension_white_list
        %w(jpg jpeg gif png)
    end

end

The model looks like:

class Car < ActiveRecord::Base

    belongs_to :user
    has_one :car_info, dependent: :destroy
    has_one :car_spec, dependent: :destroy
    accepts_nested_attributes_for :car_spec, :car_info

    mount_uploaders :car_images, CarImageUploader

    validates_associated :car_info, :car_spec, presence: true

end

The view form:

<%= form_for @car, html: { multipart: true, class: "form-horizontal" } do |f| %>

    <%= f.fields_for :car_spec do |car_spec_field| %>

        # Fields for car_spec

    <% end %>

    <%= f.fields_for :car_info do |car_info_field| %>

        # Fields for car_info

    <% end %>

    <%= f.label :images %>
    <%= f.file_field :images, multiple: true %>

    <%= f.submit "Add car" %>

<% end %>

The create action in CarsController looks like:

@car = current_user.cars.build(car_params)
@car.car_images = params[:car][:images]

respond_to do |format|
  if @car.save

    format.html { redirect_to @car, notice: 'Car was successfully created.' }
    format.json { render :show, status: :created, location: @car }
  else
    format.html { render :new }
    format.json { render json: @car.errors, status: :unprocessable_entity }
  end
end

This code results in TypeError in CarsController#create can't cast Array to when I submit the form. The car_images field was added to the cars table asjson field. According to the instructions on carrierwave github this is correct, but it is throwing the above error on form submit. What is causing this error and how can I correct the code so that the form will submit?

Dima Melnik Dima Melnik · Accepted Answer · 2015-09-10T05:16:28

I had the same error.

TypeError: can't cast Array to

As said in documentation https://github.com/carrierwaveuploader/carrierwave#multiple-file-uploads you need do migration

rails g migration add_avatars_to_users avatars:json

The problem is in type column json. SQLite3 and MySQL have not this type as it in PostgreSQL. You can migrate it as text

rails g migration add_avatars_to_users avatars:text

For me it's work.

Rails 4 carrierwave gem TypeError on assign to uploader

2 Answers