gapp-auth-sinatra.rb

require 'rubygems'
require 'gdata'
require 'sinatra'

def is_gapp_user?(user, password)
  client = GData::Client::GMail.new
  begin
    token = client.clientlogin(user, password)
    return token
  rescue GData::Client::AuthorizationError
    return false
  end
end

use Rack::Auth::Basic do |username, password|
  is_gapp_user?(username, password)
end

get '/' do
  "Hello"
end