require 'google/api_client/client_secrets'
require 'google/api_client/auth/installed_app'
require 'google/api_client/auth/storages/file_store'
require 'google/api_client/auth/storage'

require 'google/apis/drive_v2'

TOKEN_FILE = 'token5.json'
SECRETS_FILE = 'client_secrets.json'

token_store = Google::APIClient::FileStore.new(TOKEN_FILE)
storage = Google::APIClient::Storage.new(token_store)
storage.authorize
authorization = storage.authorization

if (!authorization || authorization.expired?)
  client_secrets = Google::APIClient::ClientSecrets.load(SECRETS_FILE)
  flow = Google::APIClient::InstalledAppFlow.new(
    :client_id => client_secrets.client_id,
    :client_secret => client_secrets.client_secret,
    :scope => 'https://www.googleapis.com/auth/drive.metadata.readonly',
    :port => 5000)

  authorization = flow.authorize(storage)
end

drive = Google::Apis::DriveV2::DriveService.new
drive.authorization = authorization
files = drive.list_files

files.items.each do |file|
  puts file.title
end