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Route Filters

a.k.a Responding to different url paths

Happstack provides a variety of ways to match on parts of the request and respond appropriately. One simple system is the use of the guard functions in SimpleHTTP.

Matching on static path segments

Other Routing Filters

SimpleHTTP includes a number of other useful routing filters, such as:

nullDir :: (ServerMonad m, MonadPlus m) => m ()

check that there are no path segments remaining

host :: (ServerMonad m, MonadPlus m) => String -> m a -> m a

match on a specific host name in the Request

withHost :: (ServerMonad m, MonadPlus m) => (String -> m a) -> m a

Lookup the host header and pass it to the handler.

uriRest :: (ServerMonad m) => (String -> m a) -> m a

Grab the rest of the URL (dirs + query) and passes it to your handler

anyPath :: (ServerMonad m, MonadPlus m) => m r -> m r

Pop any path element and ignore when choosing a 'ServerPartT' to handle the request.

trailingSlash :: (ServerMonad m, MonadPlus m) => m ()

Guard which checks that the Request URI ends in /. Useful for distinguishing between foo and foo/

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