Sinatra Ajax File Upload

Valums script at http://valums.com/ajax-upload/ works like a charm in sinatra route you would require something like

  get :upload do
    render "/test/upload", :layout => false
  end
  post :upload do
    logger.debug params
    newf = File.open("public/post.jpg", "wb")
    newf.write(request.body.read)
    '{success:true}'
  end