Happstack.StaticRouting

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.

Documentation

data Route a

Static routing tables consisting of handlers of type a.

compile :: (MonadIO m, HasRqData m, ServerMonad m, MonadPlus m) => Route (m a) -> (m a, Maybe String)

Compile routes, also return possible overlap report. If the overlap report is Nothing, the routing table is order independent. If the overlap report is Just s, then s is a textual representation of all the paths that are order dependent, suitable for a warning message.

choice :: [Route a] -> Route a

Combine several route alternatives into one.

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

Pop a path element if it matches the given string.

path :: forall m hm h a b. Path m hm h a => Method -> (m a -> hm b) -> h -> Route (hm b)

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

class Path m hm a b | a b -> m hm

Support for varying number of arguments to path handlers.

Instances

Path m hm (m b) b

(FromReqURI d, ServerMonad hm, MonadPlus hm, Path m hm a b) => Path m hm (d -> a) b

remainingPath :: Method -> h -> Route h

Expect zero or more segments.

param :: String -> Route a -> Route a

DEPRECATED. Expect a specific parameter to be present.