git-annex/Utility/Url.hs
2017-08-17 11:00:48 -04:00

367 lines
11 KiB
Haskell

{- Url downloading.
-
- Copyright 2011-2014 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
{-# LANGUAGE CPP #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE FlexibleContexts #-}
module Utility.Url (
closeManager,
managerSettings,
URLString,
UserAgent,
UrlOptions,
mkUrlOptions,
check,
checkBoth,
exists,
UrlInfo(..),
getUrlInfo,
assumeUrlExists,
download,
downloadQuiet,
parseURIRelaxed,
matchStatusCodeException,
) where
import Common
import Utility.Tmp
import qualified Build.SysConfig
import Network.URI
import Network.HTTP.Types
import qualified Data.CaseInsensitive as CI
import qualified Data.ByteString as B
import qualified Data.ByteString.UTF8 as B8
import Control.Monad.Trans.Resource
import Network.HTTP.Conduit hiding (closeManager)
-- closeManager is needed with older versions of http-client,
-- but not new versions, which warn about using it. Urgh.
#if ! MIN_VERSION_http_client(0,4,18)
import Network.HTTP.Client (closeManager)
#else
closeManager :: Manager -> IO ()
closeManager _ = return ()
#endif
#if ! MIN_VERSION_http_client(0,5,0)
responseTimeoutNone :: Maybe Int
responseTimeoutNone = Nothing
#endif
managerSettings :: ManagerSettings
#if MIN_VERSION_http_conduit(2,1,7)
managerSettings = tlsManagerSettings
#else
managerSettings = conduitManagerSettings
#endif
{ managerResponseTimeout = responseTimeoutNone }
type URLString = String
type Headers = [String]
type UserAgent = String
data UrlOptions = UrlOptions
{ userAgent :: Maybe UserAgent
, reqHeaders :: Headers
, reqParams :: [CommandParam]
, applyRequest :: Request -> Request
}
instance Default UrlOptions
where
def = UrlOptions Nothing [] [] id
mkUrlOptions :: Maybe UserAgent -> Headers -> [CommandParam] -> UrlOptions
mkUrlOptions defuseragent reqheaders reqparams =
UrlOptions useragent reqheaders reqparams applyrequest
where
applyrequest = \r -> r { requestHeaders = requestHeaders r ++ addedheaders }
addedheaders = uaheader ++ otherheaders
useragent = maybe defuseragent (Just . B8.toString . snd)
(headMaybe uafromheaders)
uaheader = case useragent of
Nothing -> []
Just ua -> [(hUserAgent, B8.fromString ua)]
(uafromheaders, otherheaders) = partition (\(h, _) -> h == hUserAgent)
(map toheader reqheaders)
toheader s =
let (h, v) = separate (== ':') s
h' = CI.mk (B8.fromString h)
in case v of
(' ':v') -> (h', B8.fromString v')
_ -> (h', B8.fromString v)
addUserAgent :: UrlOptions -> [CommandParam] -> [CommandParam]
addUserAgent uo ps = case userAgent uo of
Nothing -> ps
-- --user-agent works for both wget and curl commands
Just ua -> ps ++ [Param "--user-agent", Param ua]
{- Checks that an url exists and could be successfully downloaded,
- also checking that its size, if available, matches a specified size. -}
checkBoth :: URLString -> Maybe Integer -> UrlOptions -> IO Bool
checkBoth url expected_size uo = do
v <- check url expected_size uo
return (fst v && snd v)
check :: URLString -> Maybe Integer -> UrlOptions -> IO (Bool, Bool)
check url expected_size = go <$$> getUrlInfo url
where
go (UrlInfo False _ _) = (False, False)
go (UrlInfo True Nothing _) = (True, True)
go (UrlInfo True s _) = case expected_size of
Just _ -> (True, expected_size == s)
Nothing -> (True, True)
exists :: URLString -> UrlOptions -> IO Bool
exists url uo = urlExists <$> getUrlInfo url uo
data UrlInfo = UrlInfo
{ urlExists :: Bool
, urlSize :: Maybe Integer
, urlSuggestedFile :: Maybe FilePath
}
deriving (Show)
assumeUrlExists :: UrlInfo
assumeUrlExists = UrlInfo True Nothing Nothing
{- Checks that an url exists and could be successfully downloaded,
- also returning its size and suggested filename if available. -}
getUrlInfo :: URLString -> UrlOptions -> IO UrlInfo
getUrlInfo url uo = case parseURIRelaxed url of
Just u -> case parseurlconduit (show u) of
Just req -> catchJust
-- When http redirects to a protocol which
-- conduit does not support, it will throw
-- a StatusCodeException with found302.
(matchStatusCodeException (== found302))
(existsconduit req)
(const (existscurl u))
`catchNonAsync` (const dne)
-- http-conduit does not support file:, ftp:, etc urls,
-- so fall back to reading files and using curl.
Nothing
| uriScheme u == "file:" -> do
let f = unEscapeString (uriPath u)
s <- catchMaybeIO $ getFileStatus f
case s of
Just stat -> do
sz <- getFileSize' f stat
found (Just sz) Nothing
Nothing -> dne
| Build.SysConfig.curl -> existscurl u
| otherwise -> dne
Nothing -> dne
where
dne = return $ UrlInfo False Nothing Nothing
found sz f = return $ UrlInfo True sz f
curlparams = addUserAgent uo $
[ Param "-s"
, Param "--head"
, Param "-L", Param url
, Param "-w", Param "%{http_code}"
] ++ concatMap (\h -> [Param "-H", Param h]) (reqHeaders uo) ++ (reqParams uo)
extractlencurl s = case lastMaybe $ filter ("Content-Length:" `isPrefixOf`) (lines s) of
Just l -> case lastMaybe $ words l of
Just sz -> readish sz
_ -> Nothing
_ -> Nothing
extractlen = readish . B8.toString <=< firstheader hContentLength
extractfilename = contentDispositionFilename . B8.toString
<=< firstheader hContentDisposition
firstheader h = headMaybe . map snd .
filter (\p -> fst p == h) . responseHeaders
existsconduit req = do
mgr <- newManager managerSettings
let req' = headRequest (applyRequest uo req)
ret <- runResourceT $ do
resp <- http req' mgr
-- forces processing the response before the
-- manager is closed
liftIO $ if responseStatus resp == ok200
then found
(extractlen resp)
(extractfilename resp)
else dne
liftIO $ closeManager mgr
return ret
existscurl u = do
output <- catchDefaultIO "" $
readProcess "curl" $ toCommand curlparams
let len = extractlencurl output
let good = found len Nothing
let isftp = or
[ "ftp" `isInfixOf` uriScheme u
-- Check to see if http redirected to ftp.
, "Location: ftp://" `isInfixOf` output
]
case lastMaybe (lines output) of
Just ('2':_:_) -> good
-- don't try to parse ftp status codes; if curl
-- got a length, it's good
_ | isftp && isJust len -> good
_ -> dne
#if MIN_VERSION_http_client(0,4,30)
parseurlconduit = parseUrlThrow
#else
parseurlconduit = parseUrl
#endif
-- Parse eg: attachment; filename="fname.ext"
-- per RFC 2616
contentDispositionFilename :: String -> Maybe FilePath
contentDispositionFilename s
| "attachment; filename=\"" `isPrefixOf` s && "\"" `isSuffixOf` s =
Just $ reverse $ drop 1 $ reverse $
drop 1 $ dropWhile (/= '"') s
| otherwise = Nothing
headRequest :: Request -> Request
headRequest r = r
{ method = methodHead
-- remove defaut Accept-Encoding header, to get actual,
-- not gzip compressed size.
, requestHeaders = (hAcceptEncoding, B.empty) :
filter (\(h, _) -> h /= hAcceptEncoding)
(requestHeaders r)
}
{- Download a perhaps large file, with auto-resume of incomplete downloads.
-
- Uses wget or curl program for its progress bar and resuming support.
- Which program to use is determined at run time depending on which is
- in path and which works best in a particular situation.
-}
download :: URLString -> FilePath -> UrlOptions -> IO Bool
download = download' False
{- No output to stdout. -}
downloadQuiet :: URLString -> FilePath -> UrlOptions -> IO Bool
downloadQuiet = download' True
download' :: Bool -> URLString -> FilePath -> UrlOptions -> IO Bool
download' quiet url file uo = do
case parseURIRelaxed url of
Just u
| uriScheme u == "file:" -> curl
-- curl is preferred in quiet mode, because
-- it displays http errors to stderr, while wget
-- does not display them in quiet mode
| quiet -> ifM (inPath "curl") (curl, wget)
-- wget is preferred mostly because it has a better
-- progress bar
| otherwise -> ifM (inPath "wget") (wget , curl)
_ -> return False
where
headerparams = map (\h -> Param $ "--header=" ++ h) (reqHeaders uo)
wget = go "wget" $ headerparams ++ quietopt "-q" ++ wgetparams
{- Regular wget needs --clobber to continue downloading an existing
- file. On Android, busybox wget is used, which does not
- support, or need that option.
-
- When the wget version is new enough, pass options for
- a less cluttered download display. Using -nv rather than -q
- avoids most clutter while still displaying http errors.
-}
#ifndef __ANDROID__
wgetparams = concat
[ if Build.SysConfig.wgetunclutter && not quiet
then [Param "-nv", Param "--show-progress"]
else []
, [ Param "--clobber", Param "-c", Param "-O"]
]
#else
wgetparams = [Param "-c", Param "-O"]
#endif
{- 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 = do
-- curl does not create destination file
-- if the url happens to be empty, so pre-create.
writeFile file ""
go "curl" $ headerparams ++ quietopt "-sS" ++
[ Param "-f"
, Param "-L"
, Param "-C", Param "-"
, Param "-#"
, Param "-o"
]
{- Run wget in a temp directory because it has been buggy
- and overwritten files in the current directory, even though
- it was asked to write to a file elsewhere. -}
go cmd opts = withTmpDir "downloadurl" $ \tmp -> do
absfile <- absPath file
let ps = addUserAgent uo $ opts++reqParams uo++[File absfile, File url]
boolSystem' cmd ps $ \p -> p { cwd = Just tmp }
quietopt s
| quiet = [Param s]
| otherwise = []
{- Allows for spaces and other stuff in urls, properly escaping them. -}
parseURIRelaxed :: URLString -> Maybe URI
parseURIRelaxed s = maybe (parseURIRelaxed' s) Just $
parseURI $ escapeURIString isAllowedInURI s
{- Some characters like '[' are allowed in eg, the address of
- an uri, but cannot appear unescaped further along in the uri.
- This handles that, expensively, by successively escaping each character
- from the back of the url until the url parses.
-}
parseURIRelaxed' :: URLString -> Maybe URI
parseURIRelaxed' s = go [] (reverse s)
where
go back [] = parseURI back
go back (c:cs) = case parseURI (escapeURIString isAllowedInURI (reverse (c:cs)) ++ back) of
Just u -> Just u
Nothing -> go (escapeURIChar escapemore c ++ back) cs
escapemore '[' = False
escapemore ']' = False
escapemore c = isAllowedInURI c
hAcceptEncoding :: CI.CI B.ByteString
hAcceptEncoding = "Accept-Encoding"
hContentDisposition :: CI.CI B.ByteString
hContentDisposition = "Content-Disposition"
{- Use with eg:
-
- > catchJust (matchStatusCodeException (== notFound404))
-}
#if MIN_VERSION_http_client(0,5,0)
matchStatusCodeException :: (Status -> Bool) -> HttpException -> Maybe HttpException
matchStatusCodeException want e@(HttpExceptionRequest _ (StatusCodeException r _))
| want (responseStatus r) = Just e
| otherwise = Nothing
matchStatusCodeException _ _ = Nothing
#else
matchStatusCodeException :: (Status -> Bool) -> HttpException -> Maybe HttpException
matchStatusCodeException want e@(StatusCodeException s _ _)
| want s = Just e
| otherwise = Nothing
matchStatusCodeException _ _ = Nothing
#endif