examples/lines_url.hs

   1 {-# LANGUAGE OverloadedStrings #-}
   2 -- https://gist.github.com/michaelt/88e1fac12876857deefe
   3 -- following
   4 -- https://gist.github.com/gelisam/c769d186493221d7ebbe and associated controversy.
   5
   6 module Main where
   7
   8 import Prelude hiding (lines)
   9 import Lens.Family
  10 import Pipes
  11 import Pipes.Group
  12 import Pipes.HTTP
  13 import Pipes.Text
  14 import Pipes.Text.Encoding
  15 import Pipes.Text.IO (toHandle,stdout)
  16 import qualified System.IO as IO
  17 import Data.Functor (void)
  18 import qualified Data.Text as T
  19
  20 main = do
  21   req <- parseUrl "https://gist.github.com/gelisam/c769d186493221d7ebbe"
  22                 -- "http://www.example.com"
  23                 -- "http://www.gutenberg.org/files/10/10-h/10-h.htm"
  24   withManager tlsManagerSettings $ \m ->
  25     withHTTP req m $ \resp ->  void $ runEffect $
  26       number_lines_of (responseBody resp ^. utf8 . lines) >-> toHandle IO.stdout
  27
  28 number_lines_of :: Monad m => FreeT (Producer Text m) m r -> Producer Text m r
  29 number_lines_of  = number_loop (1 :: Int) where
  30   number_loop n free = do
  31     fproducer <- lift $ runFreeT free
  32     case fproducer of
  33       Pure badbytes -> do
  34         yield $ T.pack "\n"
  35         return badbytes -- these could be inspected ...
  36       Free p -> do
  37         yield $ T.pack ("\n" ++ show n ++ "  ")
  38         next_free <- p
  39         number_loop (n+1) next_free