How to set access-control-allow-origin in webrick under rails?

Rails 3.1

class ApplicationController < ActionController::Base
  protect_from_forgery
  after_filter :set_access_control_headers

  def set_access_control_headers
    headers['Access-Control-Allow-Origin'] = '*'
    headers['Access-Control-Request-Method'] = '*'
  end
end

Rails 4 (http://edgeguides.rubyonrails.org/security.html#default-headers)

In config/application.rb:

config.action_dispatch.default_headers.merge!({
  'Access-Control-Allow-Origin' => '*',
  'Access-Control-Request-Method' => '*'
})

If you're on Rails 2 just add this to your application contoller.

before_filter :set_access

def set_access
  @response.headers["Access-Control-Allow-Origin"] = "*"
end

Obviously changing "*" to something a little less open would be a good idea.