Auto-refreshing XOAuth token system for Google

0_usage.md

Usage

Simple as XOauthSession.access_token.

First time usage, either create a yaml file yourself or:

Setup your app at Google developer console. There you follow the menu "APIs & auth" > "Credentials". Click "Create new Client ID" and select "Installed Application" and then "Other". Download oauth2.py and execute the following with the credentials of the Google Developer console.

python oauth2.py --generate_oauth2_token --client_id=<client_id> --client_secret=<client_secret>

Follow its instructions and use the tokens there to create your initial yaml file.

require "xoauth_session"
XOauthSession.new("client_id", "client_secret", "refresh_token", nil, nil).save

This will create a file like the following:

--- !ruby/struct:XOAuthSession
client_id: <client_id>
client_secret: <client_secret>
refresh_token: <refresh_token>
access_token: <access_token>
expires_at: 2015-06-03 20:21:29.350315000 +02:00

xoauth_session.rb

require "httparty"
require "yaml"

class XOAuthSession < Struct.new(:client_id, :client_secret, :refresh_token, :access_token, :expires_at)

  def self.access_token
    load.access_token
  end
  
  def self.load
    YAML.load_file("xoauth_session.yml")
  end

  def save
    File.open("xoauth_session.yml", "w") { |f| f.write(to_yaml) }
  end

  def access_token
    refresh_access_token if super.nil? || Time.now.to_i >= expires_at.to_i
    super
  end

  def refresh_access_token
    response = HTTParty.post("https://accounts.google.com/o/oauth2/token",
      body: {
        client_id: client_id,
        client_secret: client_secret,
        refresh_token: refresh_token,
        grant_type: "refresh_token"
      },
      headers: {
        "Content-Type" => "application/x-www-form-urlencoded"
      }
    )
    raise "Error Response: #{response.code}" if response.code != 200
    self.expires_at = Time.now + response.parsed_response["expires_in"].to_i
    self.access_token = response.parsed_response["access_token"]
    save
  end

end