Network.CGI.Monad

Internal stuff that most people shouldn't have to use. This module mostly deals with the internals of the CGIT monad transformer.

CGI monad class

class Monad m => MonadCGI m where

The class of CGI monads. Most CGI actions can be run in any monad which is an instance of this class, which means that you can use your own monad transformers to add extra functionality.

Methods

cgiAddHeader :: HeaderName -> String -> m ()

Add a response header.

cgiGet :: (CGIRequest -> a) -> m a

Get something from the CGI request.

Instances

Monad m => MonadCGI (CGIT m)

CGI monad transformer

newtype CGIT m a

The CGIT monad transformer.

Constructors

CGIT

Fields

unCGIT :: ReaderT CGIRequest (WriterT Headers m) a

Instances

MonadTrans CGIT

MonadCatch m => MonadError SomeException (CGIT m)

Monad m => Monad (CGIT m)

(Functor m, Monad m) => Functor (CGIT m)

MonadThrow m => MonadThrow (CGIT m)

MonadCatch m => MonadCatch (CGIT m)

MonadIO m => MonadIO (CGIT m)

Monad m => MonadCGI (CGIT m)

(Typeable1 m, Typeable a) => Typeable (CGIT m a)

type CGI a = CGIT IO a

A simple CGI monad with just IO.

runCGIT :: Monad m => CGIT m a -> CGIRequest -> m (Headers, a)

Run a CGI action.

Request info

data CGIRequest

The input to a CGI action.

Constructors

CGIRequest

Fields

cgiVars :: Map String String

Environment variables.

cgiInputs :: [(String, Input)]

Input parameters. For better laziness in reading inputs, this is not a Map.

cgiRequestBody :: ByteString

Raw request body. To avoid memory leaks, this is the empty string if the request body has been interpreted as inputs in application/x-www-form-urlencoded or multipart/form-data format.

Instances

Show CGIRequest

Error handling

throwCGI :: (MonadCGI m, MonadThrow m) => SomeException -> m a

Throw an exception in a CGI monad. The monad is required to be a MonadIO, so that we can use throwIO to guarantee ordering.

catchCGI :: (MonadCGI m, MonadCatch m) => m a -> (SomeException -> m a) -> m a

Catches any expection thrown by a CGI action, and uses the given exception handler if an exception is thrown.

tryCGI :: (Functor m, MonadCGI m, MonadCatch m) => m a -> m (Either SomeException a)

Catches any exception thrown by an CGI action, and returns either the exception, or if no exception was raised, the result of the action.

handleExceptionCGI :: (MonadCGI m, MonadCatch m) => m a -> (SomeException -> m a) -> m a

Deprecated: Use catchCGI instead.

Deprecated version of catchCGI. Use catchCGI instead.