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 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.

Instances

Functor Route

Methods

fmap :: (a -> b) -> Route a -> Route b

(<$) :: a -> Route b -> Route a

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

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 a

Combine several route alternatives into one.

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

Pop a path element if it matches the given string.

param :: Route a -> Route a

Pop a path element, and store it to use with handler

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

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 -> m

Support for varying number of arguments to path handlers.

Minimal complete definition

pathHandler, arity, canBeApplied

Instances

Path m hm (m r) r

Methods

pathHandler :: (m r -> hm r') -> m r -> hm r'

arity :: hm r -> m r -> Int

canBeApplied :: hm r -> m r -> [String] -> Bool

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

Methods

pathHandler :: (m r -> hm r') -> (v -> h) -> hm r'

arity :: hm r -> (v -> h) -> Int

canBeApplied :: hm r -> (v -> h) -> [String] -> Bool

remainingPath :: Method -> h -> Route h

Expect zero or more segments.