Nice approach++. I also generally do this stuff in auto() as well but not that way. I may adopt that myself. It's quite direct.

Update: Oh, but I would change part of it.

   $c->response->redirect('/login/'.$c->request->path);
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Should be-

   $c->response->redirect($c->uri_for('/login', $c->request->path));
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Redirects are supposed to be absolute URIs (per the HTTP spec) and even though most stuff accommodates the relative ones there is at least one real world bug: I've seen them do freaky stuff in mod_perl; internally redispatching to an unrelated part of the app. That was a drag to track down.