Network.Wai.Trans

Simple utilities for embedding a monad transformer stack in an Application or Middleware - with MiddlewareT, your transformer stack is shared across all attached middlewares until run. You can also lift existing Middleware to MiddlewareT, given some extraction function.

Documentation

type ApplicationT m = Request -> (Response -> m ResponseReceived) -> m ResponseReceived

Isomorphic to Kleisli (ContT ResponseReceived m) Request Response

type MiddlewareT m = ApplicationT m -> ApplicationT m

Lift and Run

liftApplication

Arguments

:: MonadBaseControl IO m stM

=> Extractable stM

=> Application

To lift

-> ApplicationT m

liftMiddleware

Arguments

:: MonadBaseControl IO m stM

=> Extractable stM

=> Middleware

To lift

-> MiddlewareT m

runApplicationT

Arguments

:: MonadBaseControl IO m stM

=> Extractable stM

=> ApplicationT m

To run

-> m Application

runMiddlewareT

Arguments

:: MonadBaseControl IO m stM

=> Extractable stM

=> MiddlewareT m

To run

-> m Middleware

Monad Morphisms

hoistApplicationT

Arguments

:: Monad m

=> Monad n

=> (forall a. m a -> n a)

To

-> (forall a. n a -> m a)

From

-> ApplicationT m

-> ApplicationT n

hoistMiddlewareT

Arguments

:: Monad m

=> Monad n

=> (forall a. m a -> n a)

To

-> (forall a. n a -> m a)

From

-> MiddlewareT m

-> MiddlewareT n

Exception Catching

catchApplicationT

Arguments

:: MonadCatch m

=> Exception e

=> ApplicationT m

-> (e -> ApplicationT m)

Handler

-> ApplicationT m

catchMiddlewareT

Arguments

:: MonadCatch m

=> Exception e

=> MiddlewareT m

-> (e -> MiddlewareT m)

Handler

-> MiddlewareT m