Rails redirect using post emulation

redirect.rb

# This code isn't safe; at least add escaping to the url and the params.
class ActionController::Base
  def redirect_using_post(url, params)
    render :text => %Q{<form action="#{url}">#{params.map{|k,v| %Q{<input type=
hidden" name="#{k}" value="#{v}" />}}.join('')}</form><script>document.forms[0].submit()</script>}
  end
end