check

# File actionpack/lib/action_controller/vendor/rack-1.0/rack/auth/openid.rb, line 249
      def check(consumer, session, req)
        oid = consumer.begin(req.GET[@openid_param], @anonymous)
        req.env['rack.auth.openid.request'] = oid
        req.env['rack.errors'].puts(oid.message)
        p oid if $DEBUG

        ## Extension support
        extensions.each do |ext,args|
          oid.add_extension(ext::Request.new(*args))
        end

        session[:openid_param] = req.GET[openid_param]
        return_to_uri = return_to ? return_to : req.url
        session[:return_to] = return_to_uri
        immediate = session.key?(:setup_needed) ? false : immediate

        if oid.send_redirect?(realm, return_to_uri, immediate)
          uri = oid.redirect_url(realm, return_to_uri, immediate)
          redirect(uri)
        else
          confirm_post_params(oid, realm, return_to_uri, immediate)
        end
      rescue ::OpenID::DiscoveryFailure => e
        # thrown from inside OpenID::Consumer#begin by yadis stuff
        req.env['rack.errors'].puts([e.message, *e.backtrace]*"\n")
        return foreign_server_failure
      end