happstack-static-routing-0.4.0: Support for static URL routing with overlap detection for Happstack.

Safe HaskellNone



Support for static routing tables in Happstack. The routing tables are order independent as long as:

  • if any two handlers overlap, one of them handles a more specific path than the other. The more specific handler is then tried first.

Routing tables are constructed from dir, path, remainingPath, choice, and (for now) param.

A routing table is compiled by using compile. The result is an overlap report, and a prefix tree that is used to efficiently dispatch requests by means of dispatch.

See the file src/Happstack/StaticRouting/Test.hs in the distribution for examples.



data Route a Source

Static routing tables consisting of handlers of type a.


compile :: (MonadIO m, HasRqData m, ServerMonad m, FilterMonad Response m) => Route (m Response) -> Either String (m (Maybe Response))Source

Compile routes or return overlap report. Returns 'Left e' in case of order-dependent overlap between handlers, where e describes the overlap. Returns 'Right h', where h is a compiled handler that returns Nothing in case no matching handler was found, otherwise 'Just response'.

choice :: [Route a] -> Route aSource

Combine several route alternatives into one.

dir :: String -> Route a -> Route aSource

Pop a path element if it matches the given string.

path :: forall m hm h r r'. Path m hm h r => Method -> (m r -> hm r') -> h -> Route (hm r')Source

Expect the given method, and exactly n more segments, where n is the arity of the handler.

class Path m hm h r | h r -> mSource

Support for varying number of arguments to path handlers.


Path m hm (m r) r 
(FromReqURI v, ServerMonad hm, Path m hm h r) => Path m hm (v -> h) r 

remainingPath :: Method -> h -> Route hSource

Expect zero or more segments.