gem 'carrierwave-aws'

CarrierWave.configure do |config|
  config.storage    = :aws
  config.aws_bucket = ENV.fetch('S3_BUCKET_NAME')
  config.aws_acl    = 'public-read'

  # Optionally define an asset host for configurations that are fronted by a
  # content host, such as CloudFront.
  config.asset_host = 'http://example.com'

  # The maximum period for authenticated_urls is only 7 days.
  config.aws_authenticated_url_expiration = 60 * 60 * 24 * 7

  # Set custom options such as cache control to leverage browser caching
  config.aws_attributes = {
    expires: 1.week.from_now.httpdate,
    cache_control: 'max-age=604800'
  }

  config.aws_credentials = {
    access_key_id:     ENV.fetch('AWS_ACCESS_KEY_ID'),
    secret_access_key: ENV.fetch('AWS_SECRET_ACCESS_KEY'),
    region:            ENV.fetch('AWS_REGION') # Required
  }

  # Optional: Signing of download urls, e.g. for serving private
  # content through CloudFront.
  config.aws_signer = -> (unsigned_url, options) { Aws::CF::Signer.sign_url unsigned_url, options }
end

class MyUploader < Carrierwave::Uploader::Base
  # Storage configuration within the uploader supercedes the global CarrierWave
  # config, so be sure that your uploader does not contain `storage :file`, or
  # AWS will not be used.
  storage :aws

  # You can find full list of custom headers in AWS SDK documentation on
  # AWS::S3::S3Object
  def download_url(filename)
    url(response_content_disposition: %Q{attachment; filename="#{filename}"})
  end
end