rails: in app billing server verify

rails_in_app_billing.rb

ISSUER = '362508889713-np8nvipb8cank17t68i4ekggvcm3ogd5.apps.googleusercontent.com'
APP_NAME = 'ossumapp'  # This value didn't seem to matter.  I think it is for logging
APP_VERSION = '0.9.0'     # This value didn't seem to matter.  I think it is for logging
GOOGLE_API_KEY = 'AIzaSyAVMfAxfWmHaUzVy8IXjuGpM9U3ciW81cU'
  class Billing
   def self.google_api_client
    @@google_client ||= Google::APIClient.new(
      application_name:    APP_NAME,
      application_version: APP_VERSION
    ).tap do |client|

      # Load the key downloaded from the Google Developer Console
      if ENV['GOOGLE_API_KEY'].nil?
        puts "Be sure that you have ENV['GOOGLE_API_KEY'] defined in your environment."
        return
      end
      key = OpenSSL::PKey::RSA.new GOOGLE_API_KEY, 'notasecret'

      # Initialize the connection
      client.authorization = Signet::OAuth2::Client.new(
        :token_credential_uri => 'https://accounts.google.com/o/oauth2/token',
        :audience => 'https://accounts.google.com/o/oauth2/token',
        :scope => 'https://www.googleapis.com/auth/androidpublisher',
        :issuer => ISSUER,
        :signing_key => key)
      client.authorization.fetch_access_token!
    end
  end

  def self.test_server(package_name, product_id, token)
    # Get the client
    client = self.google_api_client

    # Discover the subscriptions API
    publisher = client.discovered_api('androidpublisher', 'v2')

    # Make the API call
    result = client.execute(
      :api_method => publisher.purchases.products.get,
      :parameters => {'packageName' => package_name, 'productId' => product_id, 'token' => token}
    )
    puts result
    result
  end
end