cgi-3001.1.6.0: A library for writing CGI programs Source code Contents Index

Network.CGI.Monad Portability non-portable Stability experimental Maintainer bjorn@bringert.net

Contents CGI monad class CGI monad transformer Request info Error handling

Description

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

Synopsis

class Monad m => MonadCGI m where cgiAddHeader :: HeaderName -> String -> m () cgiGet :: (CGIRequest -> a) -> m a newtype CGIT m a = CGIT { unCGIT :: (ReaderT CGIRequest (WriterT Headers m) a) } type CGI a = CGIT IO a runCGIT :: Monad m => CGIT m a -> CGIRequest -> m (Headers, a) data CGIRequest = CGIRequest { cgiVars :: (Map String String) cgiInputs :: [(String, Input)] cgiRequestBody :: ByteString } throwCGI :: (MonadCGI m, MonadIO m) => Exception -> m a catchCGI :: CGI a -> (Exception -> CGI a) -> CGI a tryCGI :: CGI a -> CGI (Either Exception a) handleExceptionCGI :: CGI a -> (Exception -> CGI a) -> CGI a

CGI monad class

class Monad m => MonadCGI m where Source

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 () Source Add a response header. cgiGet :: (CGIRequest -> a) -> m a Source Get something from the CGI request. Instances Monad m => MonadCGI (CGIT m)

CGI monad transformer

newtype CGIT m a Source

The CGIT monad transformer. Constructors CGIT unCGIT :: (ReaderT CGIRequest (WriterT Headers m) a) Instances MonadTrans CGIT MonadError Exception (CGIT IO) Monad m => Functor (CGIT m) Monad m => Monad (CGIT m) Monad m => MonadCGI (CGIT m) MonadIO m => MonadIO (CGIT m) (Typeable1 m, Typeable a) => Typeable (CGIT m a)

type CGI a = CGIT IO a Source

A simple CGI monad with just IO.

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

Run a CGI action.

Request info

data CGIRequest Source

The input to a CGI action. Constructors CGIRequest 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, MonadIO m) => Exception -> m a Source

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 :: CGI a -> (Exception -> CGI a) -> CGI a Source

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

tryCGI :: CGI a -> CGI (Either Exception a) Source

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 :: CGI a -> (Exception -> CGI a) -> CGI a Source

Deprecated version of catchCGI. Use catchCGI instead.

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