diff options
Diffstat (limited to 'Utility/Url.hs')
| -rw-r--r-- | Utility/Url.hs | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/Utility/Url.hs b/Utility/Url.hs index e10b8a92a..efd6ad16d 100644 --- a/Utility/Url.hs +++ b/Utility/Url.hs @@ -7,6 +7,7 @@ module Utility.Url ( URLString, + check, exists, canDownload, download, @@ -14,6 +15,7 @@ module Utility.Url ( ) where import Control.Applicative +import Control.Monad import qualified Network.Browser as Browser import Network.HTTP import Network.URI @@ -23,16 +25,28 @@ import Utility.Path type URLString = String -{- Checks that an url exists and could be successfully downloaded. -} -exists :: URLString -> IO Bool +{- Checks that an url exists and could be successfully downloaded, + - also checking that its size, if available, matches a specified size. -} +check :: URLString -> Maybe Integer -> IO Bool +check url expected_size = handle <$> exists url + where + handle (False, _) = False + handle (True, Nothing) = True + handle (True, s) = expected_size == s + +{- Checks that an url exists and could be successfully downloaded, + - also returning its size if available. -} +exists :: URLString -> IO (Bool, Maybe Integer) exists url = case parseURI url of - Nothing -> return False + Nothing -> return (False, Nothing) Just u -> do r <- request u HEAD case rspCode r of - (2,_,_) -> return True - _ -> return False + (2,_,_) -> return (True, size r) + _ -> return (False, Nothing) + where + size = liftM read . lookupHeader HdrContentLength . rspHeaders canDownload :: IO Bool canDownload = (||) <$> inPath "wget" <*> inPath "curl" |