ascii-progress-0.3.0.0: bin/DownloadExample.hs

import           Control.Monad.IO.Class       (MonadIO, liftIO)
import           Data.ByteString              (ByteString)
import qualified Data.ByteString              as ByteString (length)
import           Data.ByteString.Char8        as ByteString (unpack)
import           Data.Conduit                 (ConduitM, await, yield, ($$+-),
                                               ($=+))
import           Data.Conduit.List            (sinkNull)
import           Network.HTTP.Conduit         (http, parseUrl, responseBody,
                                               responseHeaders, withManager)
import           Network.HTTP.Types           (hContentLength)
import           System.Console.AsciiProgress

main :: IO ()
main = withManager $ \manager -> displayConsoleRegions $ do
    -- Start the request
    req <- parseUrl "https://i.imgur.com/8CJGhZQ.gif"
    res <- http req manager
    -- Get the Content-Length and initialize the progress bar
    let Just cl = lookup hContentLength (responseHeaders res)
    pg <- liftIO $ newProgressBar def { pgTotal = read (ByteString.unpack cl)
                                      , pgWidth = 100
                                      , pgOnCompletion = Just "Download done"
                                      }
    -- Consume the response updating the progress bar
    responseBody res $=+ updateProgress pg $$+- sinkNull
    -- Force the progress bar to complete
    liftIO $ complete pg

updateProgress :: MonadIO m => ProgressBar -> ConduitM ByteString ByteString m ()
updateProgress pg = await >>= maybe (return ()) (\chunk -> do
    let len = ByteString.length chunk
    liftIO $ tickN pg len
    yield chunk
    updateProgress pg)