prawnto question: how to attach a pdf (from a show action) in the mailer


I have vacancies, I want to recommend, and if wanted directly attache
as pdf.

You get the PDF with e.g. /vacancies/9887.pdf
How can I attach some thing in a mail?

Whats the best pratice here?
Sending through Rack?
Streaming / self calling HTTP URI and attach it?

I tried even to do something like this:

  # Forward via Email
  def forward
    render_to_string :action => "show"
    pdf = response.body
    @vacancy = Vacancy.find_by_vacancy_number(params[:vacancy_number])
    if NotificationMailer.recommendation(@vacancy, params[:email],
(params[:pdf] == 'true'), params).deliver
      flash[:notice] = 'The Job offer has been sent.'
      flash[:notice] = 'The Job offer could not be sent'
    redirect_to :action => :show, :id => params[:vacancy_number]

Thanks for any clue!