GHC 10.0.0.20260917 · lts/ghc-10.0.x · 8fef28d · 2026-11-02
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.