How to Upload files using Carrierwave Google Storage

We all must have got requirement for uploading files to Google Cloud Storage in our Rails Project for several purposes. Simplest way to do that is by using carrierwave. But the carrierwave gem uses Fog to upload files to google cloud storage. But now we’ve a gem called Carrierwave Google Storage, which uses the official google-cloud gem by Google for Google Cloud Storage, instead of Fog.

Lets start integrating file upload using Carrierwave Google Storage step by step:-

1: Add carrierwave-google-storage gem to your Gemfile

gem 'carrierwave-google-storage'

2: Create carrierwave.rb to your config/inititalizers

CarrierWave.configure do |config|
  config.storage                             = :gcloud
  config.gcloud_bucket                       = 'your-bucket-name'    # Better fetch this from environment variables
  config.gcloud_bucket_is_public             = true
  config.gcloud_authenticated_url_expiration = 600
  config.gcloud_content_disposition          = 'attachment'          # or you can skip this
  
  config.gcloud_attributes = {
    expires: 600
  }
  
  config.gcloud_credentials = {
    gcloud_project: 'gcp-project-name',                              # Better fetch this from environment variables
    gcloud_keyfile: 'path-to-gcp-keyfile.json'                       # Better fetch this from environment variables
  }
end

3: Run following command to create uploader at app/uploaders/avatar_uploader.rb

rails generate uploader Avatar

This will generate following file

class AvatarUploader < CarrierWave::Uploader::Base
  def store_dir
    # Here you can specify your directory path to which your file should get uploaded
  end

  def extension_whitelist
    %w(jpg jpeg gif png) # Here you can whitelist the extensions you want to upload
  end
end

4: Add a string field to your model to mount the uploader by running following migration

rails g migration add_`string_field_name`_to_`your_model` `string_field_name`:string
rails db:migrate

5: Now open your model file and mount the uploader to newly added string field

class User < ActiveRecord::Base
  mount_uploader :string_field_name, AvatarUploader
end

6: Now just save the file in model in following manner

# If from api params
user = User.create(avatar: params[:image_file]) # This will create a user entry with uploaded file in avatar field

# If file is in file system
file = File.new('path/to/file')
user = User.create(avatar: file) # This will create a user entry with uploaded file in avatar field

7: To access uploaded file’s url, use following method

user.avatar.url # This will give you the URL of the uploaded file

References:-

1. CarrierWave
2. Carrierwave Google Storage

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