# File lib/rack/auth/openid.rb, line 70
      def check(session, oid_url, env)
        consumer = ::OpenID::Consumer.new session, OIDStore
        oid = consumer.begin oid_url
        return auth_fail unless oid.status == ::OpenID::SUCCESS
        @options.each do |ns,s|
          next unless ns.is_a? String
          s.each {|k,v| oid.add_extension_arg(ns, k, v) }
        end
        r_url = @options.fetch :return do |k| request.url end
        t_url = @options.fetch :trust
        env['rack.auth.openid.status'] = oid
        return 303, {'Location'=>oid.redirect_url( t_url, r_url )}, []
      end