Ruby Quickstart

Complete the steps described in the rest of this page to create a simple Ruby command-line application that makes requests to the Google Calendar API.

Prerequisites

To run this quickstart, you need the following prerequisites:

  • Ruby 2.0 or greater
  • A Google account with Google Calendar enabled

Step 1: Turn on the Google Calendar API

Click this button to create a new console project and automatically enable the Google Calendar API:

Enable the Google Calendar API

This opens a new dialog. In the dialog, do the following:

  1. Select + Create a new project.
  2. Download the configuration file.
  3. Move the downloaded file to your working directory and ensure it is named credentials.json.

Step 2: Install the Google Client Library

Run the following command to install the library:

gem install google-api-client -v '~> 0.8'

See the library's installation page for the alternative installation options.

Step 3: Set up the sample

Create a file named quickstart.rb in your working directory and copy in the following code:

calendar/quickstart/quickstart.rb
require 'google/apis/calendar_v3'
require 'googleauth'
require 'googleauth/stores/file_token_store'
require 'fileutils'

OOB_URI = 'urn:ietf:wg:oauth:2.0:oob'.freeze
APPLICATION_NAME = 'Google Calendar API Ruby Quickstart'.freeze
CREDENTIALS_PATH = 'credentials.json'.freeze
# The file token.yaml stores the user's access and refresh tokens, and is
# created automatically when the authorization flow completes for the first
# time.
TOKEN_PATH = 'token.yaml'.freeze
SCOPE = Google::Apis::CalendarV3::AUTH_CALENDAR_READONLY

##
# Ensure valid credentials, either by restoring from the saved credentials
# files or intitiating an OAuth2 authorization. If authorization is required,
# the user's default browser will be launched to approve the request.
#
# @return [Google::Auth::UserRefreshCredentials] OAuth2 credentials
def authorize
  client_id = Google::Auth::ClientId.from_file(CREDENTIALS_PATH)
  token_store = Google::Auth::Stores::FileTokenStore.new(file: TOKEN_PATH)
  authorizer = Google::Auth::UserAuthorizer.new(client_id, SCOPE, token_store)
  user_id = 'default'
  credentials = authorizer.get_credentials(user_id)
  if credentials.nil?
    url = authorizer.get_authorization_url(base_url: OOB_URI)
    puts 'Open the following URL in the browser and enter the ' \
         "resulting code after authorization:\n" + url
    code = gets
    credentials = authorizer.get_and_store_credentials_from_code(
      user_id: user_id, code: code, base_url: OOB_URI
    )
  end
  credentials
end

# Initialize the API
service = Google::Apis::CalendarV3::CalendarService.new
service.client_options.application_name = APPLICATION_NAME
service.authorization = authorize

# Fetch the next 10 events for the user
calendar_id = 'primary'
response = service.list_events(calendar_id,
                               max_results: 10,
                               single_events: true,
                               order_by: 'startTime',
                               time_min: Time.now.iso8601)
puts 'Upcoming events:'
puts 'No upcoming events found' if response.items.empty?
response.items.each do |event|
  start = event.start.date || event.start.date_time
  puts "- #{event.summary} (#{start})"
end

Step 4: Run the sample

Run the sample using the following command:

ruby quickstart.rb

The first time you run the sample, it will prompt you to authorize access:

  1. The sample will attempt to open a new window or tab in your default browser. If this fails, copy the URL from the console and manually open it in your browser.

    If you are not already logged into your Google account, you will be prompted to log in. If you are logged into multiple Google accounts, you will be asked to select one account to use for the authorization.

  2. Click the Accept button.
  3. The sample will proceed automatically, and you may close the window/tab.

Notes

  • Authorization information is stored on the file system, so subsequent executions will not prompt for authorization.
  • The authorization flow in this example is designed for a command-line application. For information on how to perform authorization in a web application, see Using OAuth 2.0 for Web Server Applications.

Further reading

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