src/Main.hs

   1 {-# LANGUAGE DoAndIfThenElse #-}
   2 module Main
   3 where
   4
   5 import Control.Concurrent.ParallelIO (stopGlobalPool)
   6 import System.Directory (doesFileExist)
   7 import System.IO (
   8   Handle,
   9   IOMode (WriteMode),
  10   hPutStrLn,
  11   openBinaryFile,
  12   stderr,
  13   stdout
  14   )
  15
  16 import CommandLine (show_help)
  17 import Configuration (Cfg(..), get_cfg)
  18 import LWN.Article (real_article_path)
  19 import LWN.HTTP (get_login_cookie)
  20 import LWN.Page (epublish, page_from_url)
  21
  22
  23 -- | If we're given an empty path, return a handle to
  24 --   'stdout'. Otherwise, open the given file and return a read/write
  25 --   handle to that.
  26 get_output_handle :: FilePath -> IO Handle
  27 get_output_handle path =
  28   if (null path) then
  29     return stdout
  30   else
  31     openBinaryFile path WriteMode
  32
  33
  34 argument_is_file :: Cfg -> IO Bool
  35 argument_is_file cfg = do
  36   path <- real_article_path (article cfg)
  37   doesFileExist path
  38
  39 main :: IO ()
  40 main = do
  41   cfg' <- get_cfg
  42   aif <- argument_is_file cfg'
  43   cfg  <- case aif of
  44            False -> get_login_cookie cfg'
  45            True  -> return cfg'
  46
  47   page <- page_from_url cfg (article cfg)
  48   case page of
  49     Just p -> do
  50       output_handle <- get_output_handle (output cfg)
  51       epublish p output_handle
  52     Nothing -> do
  53       hPutStrLn stderr "ERROR: could not parse an LWN page from the given URL."
  54       _ <- show_help
  55       return ()
  56
  57   -- Necessary, for some reason.
  58   stopGlobalPool