Google Auth Library for Ruby

Description

This is Google's officially supported ruby client library for using OAuth 2.0
authorization and authentication with Google APIs.

Install

Be sure https://rubygems.org/ is in your gem sources.

For normal client usage, this is sufficient:

$ gem install googleauth

Example Usage

require 'googleauth'

# Get the environment configured authorization
scopes =  ['https://www.googleapis.com/auth/cloud-platform',
           'https://www.googleapis.com/auth/compute']
authorization = Google::Auth.get_application_default(scopes)

# Add the the access token obtained using the authorization to a hash, e.g
# headers.
some_headers = {}
authorization.apply(some_headers)

Application Default Credentials

This library provides an implementation of
application default credentials for Ruby.

The Application Default Credentials provide a simple way to get authorization
credentials for use in calling Google APIs.

They are best suited for cases when the call needs to have the same identity
and authorization level for the application independent of the user. This is
the recommended approach to authorize calls to Cloud APIs, particularly when
you're building an application that uses Google Compute Engine.

User Credentials

The library also provides support for requesting and storing user
credentials (3-Legged OAuth2.) Two implementations are currently available,
a generic authorizer useful for command line apps or custom integrations as
well as a web variant tailored toward Rack-based applications.

The authorizers are intended for authorization use cases. For sign-on,
see Google Identity Platform

Important notes

If you accept a credential configuration (credential JSON/File/Stream) from an
external source for authentication to Google Cloud, you must validate it before
providing it to any Google API or library. Providing an unvalidated credential
configuration to Google APIs can compromise the security of your systems and data.
For more information, refer to Validate credential configurations from external
sources.

Example (Web)

require 'googleauth'
require 'googleauth/web_user_authorizer'
require 'googleauth/stores/redis_token_store'
require 'redis'

client_id = Google::Auth::ClientId.from_file('/path/to/client_secrets.json')
scope = ['https://www.googleapis.com/auth/drive']
token_store = Google::Auth::Stores::RedisTokenStore.new(redis: Redis.new)
authorizer = Google::Auth::WebUserAuthorizer.new(
  client_id, scope, token_store, '/oauth2callback')


get('/authorize') do
  # NOTE: Assumes the user is already authenticated to the app
  user_id = request.session['user_id']
  credentials = authorizer.get_credentials(user_id, request)
  if credentials.nil?
    redirect authorizer.get_authorization_url(login_hint: user_id, request: request)
  end
  # Credentials are valid, can call APIs
  # ...
end

get('/oauth2callback') do
  target_url = Google::Auth::WebUserAuthorizer.handle_auth_callback_deferred(
    request)
  redirect target_url
end

Example (Web with PKCE)

Proof Key for Code Exchange (PKCE) is an RFC that aims to prevent malicious operating system processes from hijacking an OAUTH 2.0 exchange. PKCE mitigates the above vulnerability by including code_challenge and code_challenge_method parameters in the Authorization Request and a code_verifier parameter in the Access Token Request.

require 'googleauth'
require 'googleauth/web_user_authorizer'
require 'googleauth/stores/redis_token_store'
require 'redis'

client_id = Google::Auth::ClientId.from_file('/path/to/client_secrets.json')
scope = ['https://www.googleapis.com/auth/drive']
token_store = Google::Auth::Stores::RedisTokenStore.new(redis: Redis.new)
authorizer = Google::Auth::WebUserAuthorizer.new(
  client_id, scope, token_store, '/oauth2callback')


get('/authorize') do
  # NOTE: Assumes the user is already authenticated to the app
  user_id = request.session['user_id']
  # User needs to take care of generating the code_verifier and storing it in
  # the session.
  request.session['code_verifier'] ||= Google::Auth::WebUserAuthorizer.generate_code_verifier
  authorizer.code_verifier = request.session['code_verifier']
  credentials = authorizer.get_credentials(user_id, request)
  if credentials.nil?
    redirect authorizer.get_authorization_url(login_hint: user_id, request: request)
  end
  # Credentials are valid, can call APIs
  # ...
end

get('/oauth2callback') do
  target_url = Google::Auth::WebUserAuthorizer.handle_auth_callback_deferred(
    request)
  redirect target_url
end

Example (Command Line) [Deprecated]

The Google Auth OOB flow has been discontiued on January 31, 2023. The OOB flow is a legacy flow that is no longer considered secure. To continue using Google Auth, please migrate your applications to a more secure flow. For more information on how to do this, please refer to this OOB Migration guide.

require 'googleauth'
require 'googleauth/stores/file_token_store'

OOB_URI = 'urn:ietf:wg:oauth:2.0:oob'

scope = 'https://www.googleapis.com/auth/drive'
client_id = Google::Auth::ClientId.from_file('/path/to/client_secrets.json')
token_store = Google::Auth::Stores::FileTokenStore.new(
  :file => '/path/to/tokens.yaml')
authorizer = Google::Auth::UserAuthorizer.new(client_id, scope, token_store)

user_id = ENV['USER']
credentials = authorizer.get_credentials(user_id)
if credentials.nil?
  url = authorizer.get_authorization_url(base_url: OOB_URI )
  puts "Open #{url} in your browser and enter the resulting code:"
  code = gets
  credentials = authorizer.get_and_store_credentials_from_code(
    user_id: user_id, code: code, base_url: OOB_URI)
end

# OK to use credentials

Example (Service Account)

scope = 'https://www.googleapis.com/auth/androidpublisher'

authorizer = Google::Auth::ServiceAccountCredentials.make_creds(
  json_key_io: File.open('/path/to/service_account_json_key.json'),
  scope: scope)

authorizer.fetch_access_token!

You can also use a JSON keyfile by setting the GOOGLE_APPLICATION_CREDENTIALS environment variable.

export GOOGLE_APPLICATION_CREDENTIALS=/path/to/service_account_json_key.json

require 'googleauth'
require 'google/apis/drive_v3'

Drive = ::Google::Apis::DriveV3
drive = Drive::DriveService.new

scope = 'https://www.googleapis.com/auth/drive'

authorizer = Google::Auth::ServiceAccountCredentials.from_env(scope: scope)
drive.authorization = authorizer

list_files = drive.list_files()

3-Legged OAuth with a Service Account

This is similar to regular service account authorization (see this answer for more details on the differences), but you'll need to indicate which user your service account is impersonating by manually updating the sub field.

scope = 'https://www.googleapis.com/auth/androidpublisher'

authorizer = Google::Auth::ServiceAccountCredentials.make_creds(
  json_key_io: File.open('/path/to/service_account_json_key.json'),
  scope: scope
)
authorizer.update!(sub: "email-to-impersonate@your-domain.com")

authorizer.fetch_access_token!

Example (Environment Variables)

export GOOGLE_ACCOUNT_TYPE=service_account
export GOOGLE_CLIENT_ID=000000000000000000000
export GOOGLE_CLIENT_EMAIL=xxxx@xxxx.iam.gserviceaccount.com
export GOOGLE_PRIVATE_KEY="-----BEGIN PRIVATE KEY-----\n...\n-----END PRIVATE KEY-----\n"

require 'googleauth'
require 'google/apis/drive_v3'

Drive = ::Google::Apis::DriveV3
drive = Drive::DriveService.new

# Auths with ENV vars:
# "GOOGLE_CLIENT_ID",
# "GOOGLE_CLIENT_EMAIL",
# "GOOGLE_ACCOUNT_TYPE", 
# "GOOGLE_PRIVATE_KEY"
auth = ::Google::Auth::ServiceAccountCredentials
  .make_creds(scope: 'https://www.googleapis.com/auth/drive')
drive.authorization = auth

list_files = drive.list_files()

Storage

Authorizers require a storage instance to manage long term persistence of
access and refresh tokens. Two storage implementations are included:

• Google::Auth::Stores::FileTokenStore
• Google::Auth::Stores::RedisTokenStore

Custom storage implementations can also be used. See
token_store.rb for additional details.

Supported Ruby Versions

This library is supported on Ruby 3.0+.

Google provides official support for Ruby versions that are actively supported
by Ruby Core—that is, Ruby versions that are either in normal maintenance or
in security maintenance, and not end of life. Older versions of Ruby may
still work, but are unsupported and not recommended. See
https://www.ruby-lang.org/en/downloads/branches/ for details about the Ruby
support schedule.

License

This library is licensed under Apache 2.0. Full license text is
available in LICENSE.

Contributing

See [CONTRIBUTING][contributing].

Support

Please
report bugs at the project on Github. Don't
hesitate to
ask questions
about the client or APIs on StackOverflow.