Example Google Drive ruby API usage with google-api-client version 0.9.pre4 authenticating with a service account

google-drive-example.rb

ENV['GOOGLE_APPLICATION_CREDENTIALS'] = "#{ENV['HOME']}/google-service-account.json"
scopes =  ['https://www.googleapis.com/auth/drive']
drive = Google::Apis::DriveV2::DriveService.new

auth_client = Google::Auth.get_application_default(scopes).dup
auth_client.sub = '[email protected]'
drive.authorization = auth_client
report_folders = drive.list_files(q: "title = 'Reports'")
raise "Expected 1 folder called 'Reports', found #{report_folders.items.count}" if report_folders.items.count != 1
parent_id = report_folders.items[0]
source = StringIO.new("Content")
file_metadata = {title: 'test.txt', parents: [parent_id]}
inserted_metadata = drive.insert_file(file_metadata, upload_source: source, content_type: 'text/plain')