module Happstack.Helpers.Redirect where 

import Happstack.Server
import Control.Monad.Trans

import Happstack.Helpers.ParseRequest

{- | 
redirectPath def path rq = ...

eg, redirectPath (fail "horribly) "/path/to/page" will redirect to
  or http://localhost:5001/path/to/page depending on whether it is servin in online environemnt
  or for local development on port 5001
  Could produce an error if the hostname can't be determined for some reason (malformed headers?)
redirectPath :: (MonadIO m) => WebT m Response -> String -> Request -> WebT m Response
redirectPath def p rq = do
  case modRewriteAppUrl p rq of
    Left _ -> def
    Right au -> redirectToUrl au

{- |
Escape a serverPartT handler by redirecting somewhere

Basically a wrapper around supplied seeOther function, which doesn't quite do what I want
redirectToUrl :: MonadIO m => String -> WebT m Response
redirectToUrl url = seeOther url $ toResponse ()