Hackage.Security.Client.Verify

Verification monad

data Verify a

Verification monad

The verification monad is similar to ResourceT in intent, in that we can register handlers to be run to release resources. Unlike ResourceT, however, we maintain _two_ handlers: a cleanup handler which is run whether or not verification succeeds, and a finalisation handler which is run only if verification succeeds.

• Cleanup handlers are registered using acquire, and are guaranteed to run just before the computation terminates (after the finalisation handler).
• The finalisation handlers are run only when verification succeeds, and can be registered with ifVerified. Finalisation can be used for instance to update the local cache (which should only happen if verification is successful).

Instances

Monad Verify

Defined in Hackage.Security.Client.Verify

Methods

(>>=) :: Verify a -> (a -> Verify b) -> Verify b

(>>) :: Verify a -> Verify b -> Verify b

return :: a -> Verify a

fail :: String -> Verify a

Functor Verify

Defined in Hackage.Security.Client.Verify

Methods

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

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

Applicative Verify

Defined in Hackage.Security.Client.Verify

Methods

pure :: a -> Verify a

(<*>) :: Verify (a -> b) -> Verify a -> Verify b

liftA2 :: (a -> b -> c) -> Verify a -> Verify b -> Verify c

(*>) :: Verify a -> Verify b -> Verify b

(<*) :: Verify a -> Verify b -> Verify a

MonadIO Verify

Defined in Hackage.Security.Client.Verify

Methods

liftIO :: IO a -> Verify a

runVerify :: (Finaliser -> Finaliser) -> Verify a -> IO a

Run an action in the Verify monad

acquire :: IO a -> (a -> IO ()) -> Verify a

Acquire a resource and register the corresponding cleanup handler

NOTE: Resource acquisition happens with exceptions masked. If it is important that the resource acquistion can be timed out (or receive other kinds of asynchronous exceptions), you will need to use an interruptible operation. See http://www.well-typed.com/blog/2014/08/asynchronous-exceptions/ for details.

ifVerified :: IO () -> Verify ()

Register an action to be run only if verification succeeds

Specific resources

openTempFile

Arguments

:: FsRoot root

=> Path root

Temp directory

-> String

Template

-> Verify (Path Absolute, Handle)

Create a short-lived temporary file

Creates the directory where the temp file should live if it does not exist.

Re-exports

liftIO :: MonadIO m => IO a -> m a

Lift a computation from the IO monad.