I have a rails app I built for an old site I converted from another cms (in a non-rails language, hehe). Most of the old pages are mapped to the new pages using routes.rb. But there are still a few 404s.

I am a rails newb so I'm asking if there are any advanced ways to handle 404s. For example, if I was programming in my old language I'd do this:

• Get the URL (script_name) that was being accessed and parse it.
• Do a lookup in the database for any keywords, ids, etc found in the new URL.
• If found, redirect to the page (or if multiple records are found, show them all on a results page and let user choose). With rails I'd probably want to do :status => :moved_permanently I'm guessing?
• If not found, show a 404.

Are there any gems/plugins or tutorials you know of that would handle such a thing, if it's even possible. Or can you explain on a high level how that can be done? I don't need a full code sample, just a push in the right direction.

PS. It's a simple rails 3 app that uses a single Content model.