CarrierWave複数画像のアップロード

#前提
carrierwave用のカラム image:stringがある状態

teminal

$ rails g model Post title:string body:text image:string
$ rails db:migrate

#実装

###Gemインストール

Gemfile

gem 'carrierwave'

terminal

$ bundle install

###CarrierWaveのアップローダー作成

terminal

$ rails g uploader image

app/uploaders/image_uploader.rb に下記ファイルが作成される。

image_uploader.rb

class ImageUploader < CarrierWave::Uploader::Base
  # Include RMagick or MiniMagick support:
  # include CarrierWave::RMagick
  # include CarrierWave::MiniMagick

  # Choose what kind of storage to use for this uploader:
  storage :file
  # storage :fog

  # Override the directory where uploaded files will be stored.
  # This is a sensible default for uploaders that are meant to be mounted:
  def store_dir
    "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  end

  # Provide a default URL as a default if there hasn't been a file uploaded:
  # def default_url(*args)
  #   # For Rails 3.1+ asset pipeline compatibility:
  #   # ActionController::Base.helpers.asset_path("fallback/" + [version_name, "default.png"].compact.join('_'))
  #
  #   "/images/fallback/" + [version_name, "default.png"].compact.join('_')
  # end

  # Process files as they are uploaded:
  # process scale: [200, 300]
  #
  # def scale(width, height)
  #   # do something
  # end

  # Create different versions of your uploaded files:
  # version :thumb do
  #   process resize_to_fit: [50, 50]
  # end

  # Add a white list of extensions which are allowed to be uploaded.
  # For images you might use something like this:
  # def extension_whitelist
  #   %w(jpg jpeg gif png)
  # end

  # Override the filename of the uploaded files:
  # Avoid using model.id or version_name here, see uploader/store.rb for details.
  # def filename
  #   "something.jpg" if original_filename
  # end
end

Postモデルに先ほど作成したImageUploaderと紐付け。

post.rb

  # 追加
  mount_uploaders :image, ImageUploader
  serialize :image, JSON

####controllerの編集
ストロングパラメーターに複数ファイルのアップロード属性を許可する

posts_controller.rb

  def post_params
    params.require(:post).permit(:title, :body, { image: [] })
  end

####viewの編集
複数枚選択できるようにする。

new.html.erb

 #追加 multiple: true
 <%= f.file_field :image, multiple: true %>

最後に複数枚表示できるようにする。

index.html.erb

 <% @post.image.each do |image| %>
   <%= image_tag(image.url) %>
 <% end %>