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|
{- Url downloading.
-
- Copyright 2011,2013 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE CPP #-}
module Utility.Url (
URLString,
check,
exists,
download,
get
) where
import Common
import Network.URI
import qualified Network.Browser as Browser
import Network.HTTP
import Data.Either
import qualified Build.SysConfig
type URLString = String
type Headers = [String]
{- Checks that an url exists and could be successfully downloaded,
- also checking that its size, if available, matches a specified size. -}
check :: URLString -> Headers -> Maybe Integer -> IO Bool
check url headers expected_size = handle <$> exists url headers
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.
-
- For a file: url, check it directly.
-
- Uses curl otherwise, when available, since curl handles https better
- than does Haskell's Network.Browser.
-}
exists :: URLString -> Headers -> IO (Bool, Maybe Integer)
exists url headers = case parseURIRelaxed url of
Just u
| uriScheme u == "file:" -> do
s <- catchMaybeIO $ getFileStatus (unEscapeString $ uriPath u)
case s of
Just stat -> return (True, Just $ fromIntegral $ fileSize stat)
Nothing -> dne
| otherwise -> if Build.SysConfig.curl
then do
output <- readProcess "curl" curlparams
case lastMaybe (lines output) of
Just ('2':_:_) -> return (True, extractsize output)
_ -> dne
else do
r <- request u headers HEAD
case rspCode r of
(2,_,_) -> return (True, size r)
_ -> return (False, Nothing)
Nothing -> dne
where
dne = return (False, Nothing)
curlparams =
[ "-s"
, "--head"
, "-L"
, url
, "-w", "%{http_code}"
] ++ concatMap (\h -> ["-H", h]) headers
extractsize s = case lastMaybe $ filter ("Content-Length:" `isPrefixOf`) (lines s) of
Just l -> case lastMaybe $ words l of
Just sz -> readish sz
_ -> Nothing
_ -> Nothing
size = liftM Prelude.read . lookupHeader HdrContentLength . rspHeaders
{- Used to download large files, such as the contents of keys.
-
- Uses wget or curl program for its progress bar. (Wget has a better one,
- so is preferred.) Which program to use is determined at run time; it
- would not be appropriate to test at configure time and build support
- for only one in.
-}
download :: URLString -> Headers -> [CommandParam] -> FilePath -> IO Bool
download url headers options file =
case parseURIRelaxed url of
Just u
| uriScheme u == "file:" -> do
-- curl does not create destination file
-- for an empty file:// url, so pre-create
writeFile file ""
curl
| otherwise -> ifM (inPath "wget") (wget , curl)
_ -> return False
where
headerparams = map (\h -> Param $ "--header=" ++ h) headers
wget = go "wget" $ headerparams ++ [Params "-c -O"]
{- 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. -}
curl = go "curl" $ headerparams ++ [Params "-L -C - -# -o"]
go cmd opts = boolSystem cmd $
options++opts++[File file, File url]
{- Downloads a small file.
-
- Uses curl if available since it handles HTTPS better than
- the Haskell libraries do. -}
get :: URLString -> Headers -> IO String
get url headers = if Build.SysConfig.curl
then readProcess "curl" $
["-s", "-L", url] ++ concatMap (\h -> ["-H", h]) headers
else case parseURI url of
Nothing -> error "url parse error"
Just u -> do
r <- request u headers GET
case rspCode r of
(2,_,_) -> return $ rspBody r
_ -> error $ rspReason r
{- Uses Network.Browser to make 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).
-
- This does its own redirect following because Browser's is buggy for HEAD
- requests.
-}
request :: URI -> Headers -> RequestMethod -> IO (Response String)
request url headers requesttype = go 5 url
where
go :: Int -> URI -> IO (Response String)
go 0 _ = error "Too many redirects "
go n u = do
rsp <- Browser.browse $ do
Browser.setErrHandler ignore
Browser.setOutHandler ignore
Browser.setAllowRedirects False
let req = mkRequest requesttype u :: Request_String
snd <$> Browser.request (addheaders req)
case rspCode rsp of
(3,0,x) | x /= 5 -> redir (n - 1) u rsp
_ -> return rsp
addheaders req = setHeaders req (rqHeaders req ++ userheaders)
userheaders = rights $ map parseHeader headers
ignore = const noop
redir n u rsp = case retrieveHeaders HdrLocation rsp of
[] -> return rsp
(Header _ newu:_) ->
case parseURIReference newu of
Nothing -> return rsp
Just newURI -> go n $
#if defined VERSION_network
#if ! MIN_VERSION_network(2,4,0)
#define WITH_OLD_URI
#endif
#endif
#ifdef WITH_OLD_URI
fromMaybe newURI (newURI `relativeTo` u)
#else
newURI `relativeTo` u
#endif
{- Allows for spaces and other stuff in urls, properly escaping them. -}
parseURIRelaxed :: URLString -> Maybe URI
parseURIRelaxed = parseURI . escapeURIString isAllowedInURI
|
