[web-devel] [Yesod] getBy404.

I'd like to support getBy404 as like as get404 on yesod framework. getBy404 ukey = do mres <- getBy ukey case mres of Nothing -> lift notFound Just res -> return res for example, on wiki site, the resource url include wikiname as key(String) not id (Int). In this situation, getBy404 are frequently encountered. How about this?