Get matched route in ActionM using capture

[kt0d]

When using regex to match a route, I am able to later retrieve matched path with param "0", as in example described here:

https://hackage.haskell.org/package/scotty-0.12/docs/Web-Scotty.html#v:regex

Can this be done if I match a route using capture?

[jfraudeau]

It's not possible in the current state of things. As the original pattern is turned into a WAI middleware, see :

scotty/Web/Scotty/Route.hs

Lines 86 to 108 in dc66aa0

	addroute :: (ScottyError e, MonadIO m) => StdMethod -> RoutePattern -> ActionT e m () -> ScottyT e m ()
	addroute method pat action = ScottyT $ MS.modify $ \s -> addRoute (route (routeOptions s) (handler s) (Just method) pat action) s
	route :: (ScottyError e, MonadIO m) => RouteOptions -> ErrorHandler e m -> Maybe StdMethod -> RoutePattern -> ActionT e m () -> Middleware m
	route opts h method pat action app req =
	let tryNext = app req
	{- |
	We match all methods in the case where 'method' is 'Nothing'.
	See https://github.com/scotty-web/scotty/issues/196
	-}
	methodMatches :: Bool
	methodMatches =
	case method of
	Nothing -> True
	Just m -> Right m == parseMethod (requestMethod req)
	in if methodMatches
	then case matchRoute pat req of
	Just captures -> do
	env <- liftIO $ catch (Right <$> mkEnv req captures opts) (\ex -> return . Left $ ex)
	res <- evalAction h env action
	maybe tryNext return res
	Nothing -> tryNext
	else tryNext

It should be possible to add the orignal pattern to ActionEnv

What do you think @ocramz ? This could be a nice new feature, I could see myself using it for logging and metrics metadata

[ocramz]

Agreed this would be nice to have !