gistfile1.rb

  
    def url_for_oauth_code(options = {})
        # for permissions, see http://developers.facebook.com/docs/authentication/permissions
        permissions = options[:permissions]
        scope = permissions ? "&scope=#{permissions.is_a?(Array) ? permissions.join(",") : permissions}" : ""
        display = options.has_key?(:display) ? "&display=#{options[:display]}" : ""

        callback = options[:callback] || @oauth_callback_url
        raise ArgumentError, "url_for_oauth_code must get a callback either from the OAuth object or in the options!" unless callback

        # Creates the URL for oauth authorization for a given callback and optional set of permissions
        "https://#{GRAPH_SERVER}/oauth/authorize?client_id=#{@app_id}&redirect_uri=#{callback}#{scope}#{display}"
      end