Google Auth Library for Ruby

Homepage
http://www.github.com/googleapis/google-auth-library-ruby
Authors
Tim Emiola
Copyright
Copyright © 2015 Google, Inc.
License
Apache 2.0

Gem Version

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 / Installed App)

Command line and desktop applications should use the Loopback IP redirect flow (http://localhost) as recommended in the OOB Migration Guide.

require "googleauth"
require "googleauth/stores/file_token_store"

LOOPBACK_URI = "http://localhost"

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