pretty printing HTML with Conduit

pretty-html-conduit.hs

{-# LANGUAGE NoMonomorphismRestriction #-}

-- build-depends: base >= 4.7 && < 5, xml-conduit, text, conduit, transformers, resourcet, html-conduit, conduit-extra

module Lib
where

import qualified Text.XML.Stream.Parse as P
import qualified Text.XML.Stream.Render as R
import qualified Data.Conduit.List as CL
import qualified Data.Text as T
import qualified Data.Text.IO as T
import Control.Monad.IO.Class (liftIO)
import Control.Monad.Trans.Resource (runResourceT)
import Data.Conduit
import Data.Conduit.Binary (sourceFile)
import Text.HTML.DOM (eventConduit)

-- this uses the XML parser; you'll get staircasing because entities
-- like <img>, <link> and <meta> are not auto-closed.
test3 :: IO ()
test3 = (runResourceT . runConduit)
            $   P.parseFile (P.def { P.psDecodeEntities = P.decodeHtmlEntities }) "input.html"
            =$= R.prettify
            =$= R.renderText R.def
            =$= CL.mapM_ (\x -> liftIO (T.putStr x))

-- uses `eventConduit` which uses HTML auto-closing conventions.
test4 :: IO ()
test4 = (runResourceT . runConduit)
            $   sourceFile "input.html"
            =$= eventConduit
            =$= R.prettify
            =$= R.renderText R.def
            =$= CL.mapM_ (\x -> liftIO (T.putStr x))