Heroku Maintenance Mode

config.ru

# $ heroku maintenance:on
# $ heroku maintenance:off
# side-effect for any GETs during and then after Maintenance Mode ...
# the maintenance page stays cached (in place of the real ones) - until: Cmd + Shift + R

require 'rubygems'

if ENV['MAINTENANCE_MODE']
  
  require 'rack'
  require 'rack/maintenance'
  require 'rack-rewrite'
  
  html = "index.html"
  path = File.join('public', 'maintenance')
  file = File.join(path, html)
  
  use Rack::Static,
    :urls => ["/#{html}",
              "/images",
              "/stylesheets"],
    :root => path
  use Rack::Maintenance,
    :file => file
  use Rack::Rewrite do
    send_file /.*/, file, :if => Proc.new { |rack_env|
      File.exists?(file) && rack_env['REQUEST_URI'] !~ /\.(css|jpg|png)/
    }
  end
  
else

# run App

end