Authenticate via OAuth to the Google Drive API and list all files in the account

gdrive_filelister.rb

# Given a client_secrets.json file, authenticate via OAuth to the
# Google Drive API and list all files in the account.

# Setup:
## gem install google-api-client
## Under Google Developers Console, enable the Drive API and Drive SDK.
### Under Credentials > OAuth, create a new client ID.
#### This provides the client_secrets.json.
#### The Redirect URI must exactly match what the app actually sends.

# Docs:
## Example Ruby gdrive app
https://developers.google.com/drive/web/examples/ruby#setting_up_the_client_id_client_secret_and_other_oauth_20_parameters
## cloud console API tool
https://cloud.google.com/console/project/apps~neon-fort-486/apiui/api/drive/method/drive.files.list
## gdrive SDK parents API; good luck getting the item's folder's name
https://developers.google.com/drive/v2/reference/parents/get



require 'google/api_client'
require 'google/api_client/client_secrets'
require 'google/api_client/auth/installed_app'


def retrieve_all_files(client)

  # Retrieve a list of File resources.
  #
  # @param [Google::APIClient] client
  #   Authorized client instance
  # @return [Array]
  #   List of File resources.

  drive = client.discovered_api('drive', 'v2')
  result = Array.new
  page_token = nil
  begin
    parameters = {}
    if page_token.to_s != ''
      parameters['pageToken'] = page_token
    end
    api_result = client.execute(
                   :api_method => drive.files.list,
                   :parameters => parameters)
    puts "Page status: #{api_result.status}"
    if api_result.status == 200
      files = api_result.data
      result.concat(files.items)
      page_token = files.next_page_token
    else
      puts "An error occurred: #{result.data['error']['message']}"
      page_token = nil
    end
  end while page_token.to_s != ''
  result
end

# Initialize the client.
client = Google::APIClient.new(
           :application_name => 'filelister',
           :application_version => '0.0.1')

# Load client secrets from ./client_secrets.json.
client_secrets = Google::APIClient::ClientSecrets.load

# Run installed application flow. Check the samples for a more
# complete example that saves the credentials between runs.
flow = Google::APIClient::InstalledAppFlow.new(
         :client_id => client_secrets.client_id,
         :client_secret => client_secrets.client_secret,
         :scope => ['https://www.googleapis.com/auth/drive'])

client.authorization = flow.authorize

files = retrieve_all_files(client)