submit-social-housing-lettings-and-sales-data/app/services/storage_service.rb

class StorageService
  attr_reader :configuration

  def initialize(paas_config_service, paas_instance_name)
    @paas_config_service = paas_config_service
    @paas_instance_name = paas_instance_name.to_sym
    @configuration = create_configuration
    @client = create_client
  end

  def list_files(folder)
    @client.list_objects_v2(bucket: @configuration.bucket_name, prefix: folder)
           .flat_map { |response| response.contents.map(&:key) }
  end

  def get_file_io(file_name)
    @client.get_object(bucket: @configuration.bucket_name, key: file_name)
           .body
  end

  def write_file(file_name, data)
    @client.put_object(
      body: data,
      bucket: @configuration.bucket_name,
      key: file_name,
    )
  end

private

  def create_configuration
    unless @paas_config_service.config_present?
      raise "No PaaS configuration present"
    end
    unless @paas_config_service.s3_buckets.key?(@paas_instance_name)
      raise "#{@paas_instance_name} instance name could not be found"
    end

    bucket_config = @paas_config_service.s3_buckets[@paas_instance_name]
    StorageConfiguration.new(bucket_config[:credentials])
  end

  def create_client
    credentials =
      Aws::Credentials.new(
        @configuration.access_key_id,
        @configuration.secret_access_key,
      )
    Aws::S3::Client.new(
      region: @configuration.region,
      credentials: credentials,
    )
  end
end

class StorageConfiguration
  attr_reader :access_key_id, :secret_access_key, :bucket_name, :region

  def initialize(credentials)
    @access_key_id = credentials[:aws_access_key_id]
    @secret_access_key = credentials[:aws_secret_access_key]
    @bucket_name = credentials[:bucket_name]
    @region = credentials[:aws_region]
  end

  def ==(other)
    @access_key_id == other.access_key_id &&
      @secret_access_key == other.secret_access_key &&
      @bucket_name == other.bucket_name &&
      @region == other.region
  end
end