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|
{- Url downloading.
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Utility.Url (
exists,
download,
get
) where
import Control.Monad (liftM)
import Control.Monad.State (liftIO)
import qualified Network.Browser as Browser
import Network.HTTP
import Network.URI
import Types
import Messages
import Utility
type URLString = String
{- Checks that an url exists and could be successfully downloaded. -}
exists :: URLString -> IO Bool
exists url =
case parseURI url of
Nothing -> return False
Just u -> do
r <- request u HEAD
case rspCode r of
(2,_,_) -> return True
_ -> return False
{- Used to download large files, such as the contents of keys.
- Uses curl program for its progress bar. -}
download :: URLString -> FilePath -> Annex Bool
download url file = do
showOutput -- make way for curl progress bar
-- Uses the -# progress display, because the normal one is very
-- confusing when resuming, showing the remainder to download
-- as the whole file, and not indicating how much percent was
-- downloaded before the resume.
liftIO $ boolSystem "curl" [Params "-L -C - -# -o", File file, File url]
{- Downloads a small file. -}
get :: URLString -> IO String
get url =
case parseURI url of
Nothing -> error "url parse error"
Just u -> do
r <- request u GET
case rspCode r of
(2,_,_) -> return $ rspBody r
_ -> error $ rspReason r
{- Makes a http request of an url. For example, HEAD can be used to
- check if the url exists, or GET used to get the url content (best for
- small urls). -}
request :: URI -> RequestMethod -> IO (Response String)
request url requesttype = Browser.browse $ do
Browser.setErrHandler ignore
Browser.setOutHandler ignore
Browser.setAllowRedirects True
liftM snd $ Browser.request
(mkRequest requesttype url :: Request_String)
where
ignore = const $ return ()
|