Stream.purs

module Util.Stream where

import Prelude
import Control.Monad.Aff (Aff, makeAff)
import Control.Monad.Eff (Eff)
import Control.Monad.Eff.Exception (EXCEPTION, Error)
import Control.Monad.ST (ST, newSTRef, modifySTRef, readSTRef, runST)
import Data.Monoid (class Monoid)
import Node.Encoding (Encoding(..))
import Node.Stream (Read, Readable, Stream, onData, onError, onEnd, onDataString)

readFullString :: forall w eff. Readable w (err :: EXCEPTION | eff) -> Aff (err :: EXCEPTION | eff) String
readFullString stream = makeAff handleData where
    handleData :: (Error -> Eff (err :: EXCEPTION | eff) Unit) -> (String -> Eff (err :: EXCEPTION | eff) Unit) -> Eff (err :: EXCEPTION | eff) Unit
    handleData onErr onSuccess = runST do
        ref <- newSTRef ""
        onError stream onErr
        onEnd stream do
            value <- readSTRef ref
            onSuccess value
        onDataString stream UTF8 \str -> do
            modifySTRef ref $ flip (<>) str
            pure unit
        pure unit