GHC 9.14.1 · lts/ghc-9.14.x · 7a6c33e · 2026-10-12
Modulewai-extra-3.1.18Haskell2010
Dynamically choose between Middlewares
It's useful when you want some Middlewares applied selectively.
Example: do not log health check calls:
import Network.Wai
import Network.Wai.Middleware.HealthCheckEndpoint
import Network.Wai.Middleware.RequestLogger
app' :: Application
app' =
selectMiddleware (selectMiddlewareExceptRawPathInfo "/_healthz" logStdout)
$ healthCheck appRelevant Middleware for a given Request.
Semigroup MiddlewareSelectionDefined in wai-extra-3.1.18 · Network.Wai.Middleware.SelectMonoid MiddlewareSelectionDefined in wai-extra-3.1.18 · Network.Wai.Middleware.SelectCreate the Middleware dynamically applying MiddlewareSelection.
Use the Middleware when the predicate holds.
Use the Middleware for the given rawPathInfo.
Use the Middleware for all rawPathInfo except then given one.