Switched from the old haskell HTTP library to http-conduit.

The hoary old HTTP library was only used when checking if an url exists,
when curl was not available. It had many problems, including not supporting
https at all.

Now, this is done using http-conduit for all urls that it supports. Falls
back to curl for any url that http-conduit doesn't like (probably ftp etc,
but could also be an url that its parser chokes on for whatever reason).

This adds a new dependency on http-conduit, but webdav support already
indirectly depended on that, and the s3-aws branch also uses it.

This opens up the possibility of using http-conduit for large file
downloads, but for now I've left it using wget/curl.

This commit was sponsored by Paul Tötterman.

4 files changed, 72 insertions, 88 deletions

diff --git a/Utility/Url.hs b/Utility/Url.hs
index 4137a5d8b..073e36821 100644
--- a/Utility/Url.hs
+++ b/Utility/Url.hs
@@ -1,6 +1,6 @@
 {- Url downloading.
  -
- - Copyright 2011,2013 Joey Hess <joey@kitenet.net>
+ - Copyright 2011-2014 Joey Hess <joey@kitenet.net>
  -
  - License: BSD-2-clause
  -}
@@ -21,10 +21,11 @@ module Utility.Url (
 
 import Common
 import Network.URI
-import qualified Network.Browser as Browser
-import Network.HTTP
-import Data.Either
+import Network.HTTP.Conduit
+import Network.HTTP.Types
 import Data.Default
+import qualified Data.CaseInsensitive as CI
+import qualified Data.ByteString.UTF8 as B8
 
 import qualified Build.SysConfig
 
@@ -34,16 +35,43 @@ type Headers = [String]
 
 type UserAgent = String
 
-data UrlOptions = UrlOptions
+data BaseUrlOptions = BaseUrlOptions
 	{ userAgent :: Maybe UserAgent
 	, reqHeaders :: Headers
 	, reqParams :: [CommandParam]
 	}
 
-instance Default UrlOptions
+instance Default BaseUrlOptions
   where
 	def = UrlOptions Nothing [] []
 
+data UrlOptions = UrlOptions
+	{ urlOptions :: BaseUrlOptions
+	, applyRequest :: Request -> Request
+	}
+
+mkUrlOptions :: BaseUrlOptions -> UrlOptions
+mkUrlOptions uo = UrlOptions uo applyrequest
+  where
+	applyrequest = \r -> r { requestHeaders = requestHeaders r ++ addedheaders }
+	addedheaders = uaheader ++ otherheaders
+	uaheader = case userAgent uo of
+		Nothing -> []
+		Just ua -> [(hUserAgent, B8.fromString ua)]
+	otherheaders = map toheader (reqHeaders uo)
+	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 (UrlOptions 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
@@ -60,33 +88,26 @@ check url expected_size = go <$$> exists url
 		Nothing -> (True, True)
 
 {- 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.
- -}
+ - also returning its size if available. -}
 exists :: URLString -> UrlOptions -> IO (Bool, Maybe Integer)
 exists url uo = 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
+	Just u -> case parseUrl (show u) of
+		Just req -> existsconduit req `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
+				s <- catchMaybeIO $ getFileStatus (unEscapeString $ uriPath u)
+				case s of
+					Just stat -> return (True, Just $ fromIntegral $ fileSize stat)
+					Nothing -> dne
+			| Build.SysConfig.curl -> do
 				output <- catchDefaultIO "" $
 					readProcess "curl" $ toCommand curlparams
 				case lastMaybe (lines output) of
-					Just ('2':_:_) -> return (True, extractsize output)
+					Just ('2':_:_) -> return (True, extractlencurl output)
 					_ -> dne
-			else do
-				r <- request u HEAD uo
-				case rspCode r of
-					(2,_,_) -> return (True, size r)
-					_ -> return (False, Nothing)
+			| otherwise -> dne
 	Nothing -> dne
   where
 	dne = return (False, Nothing)
@@ -98,19 +119,28 @@ exists url uo = case parseURIRelaxed url of
 		, Param "-w", Param "%{http_code}"
 		] ++ concatMap (\h -> [Param "-H", Param h]) (reqHeaders uo) ++ (reqParams uo)
 
-	extractsize s = case lastMaybe $ filter ("Content-Length:" `isPrefixOf`) (lines s) of
+	extractlencurl 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
-
--- works for both wget and curl commands
-addUserAgent :: UrlOptions -> [CommandParam] -> [CommandParam]
-addUserAgent uo ps = case userAgent uo of
-	Nothing -> ps
-	Just ua -> ps ++ [Param "--user-agent", Param ua] 
+	
+	extractlen resp = readish . B8.toString =<< headMaybe lenheaders
+	  where
+		lenheaders = map snd $ 
+			filter (\(h, _) -> h == hContentLength)
+				(responseHeaders resp)
+	
+	existsconduit req = withManager $ \mgr -> do
+			let req' = (applyRequest uo req) { method = methodHead }
+			resp <- http req' mgr
+			-- forces processing the response before the
+			-- manager is closed
+			ret <- if responseStatus resp == ok200
+				then return (True, extractlen resp)
+				else liftIO dne
+			liftIO $ closeManager mgr
+			return ret
 
 {- Used to download large files, such as the contents of keys.
  -
@@ -161,52 +191,6 @@ download' quiet url file uo =
 		| quiet = [Param s]
 		| otherwise = []
 
-{- 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.
- -
- - Unfortunately, does not handle https, so should only be used
- - when curl is not available.
- -}
-request :: URI -> RequestMethod -> UrlOptions -> IO (Response String)
-request url requesttype uo = go 5 url
-  where
-	go :: Int -> URI -> IO (Response String)
-	go 0 _ = error "Too many redirects "
-	go n u = do
-		rsp <- Browser.browse $ do
-			maybe noop Browser.setUserAgent (userAgent uo)
-			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 (reqHeaders uo)
-	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
diff --git a/debian/changelog b/debian/changelog
index c55fbabd3..0d884cd81 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -39,6 +39,7 @@ git-annex (5.20140718) UNRELEASED; urgency=medium
   * git-annex-shell sendkey: Don't fail if a remote asks for a key to be sent
     that already has a transfer lock file indicating it's being sent to that
     remote. The remote may have moved between networks, or reconnected.
+  * Switched from the old haskell HTTP library to http-conduit.
 
  -- Joey Hess <joeyh@debian.org>  Mon, 21 Jul 2014 14:41:26 -0400
 
diff --git a/debian/control b/debian/control
index 522b7c5cc..1106bc89d 100644
--- a/debian/control
+++ b/debian/control
@@ -46,6 +46,7 @@ Build-Depends:
 	libghc-dns-dev,
 	libghc-case-insensitive-dev,
 	libghc-http-types-dev,
+	libghc-http-conduit-dev,
 	libghc-blaze-builder-dev,
 	libghc-crypto-api-dev,
 	libghc-network-multicast-dev,
@@ -55,7 +56,6 @@ Build-Depends:
 	libghc-gnutls-dev (>= 0.1.4),
 	libghc-xml-types-dev,
 	libghc-async-dev,
-	libghc-http-dev,
 	libghc-feed-dev (>= 0.3.9.2),
 	libghc-regex-tdfa-dev [!mipsel !s390],
 	libghc-regex-compat-dev [mipsel s390],
diff --git a/git-annex.cabal b/git-annex.cabal
index 097fee4cb..58aac39b3 100644
--- a/git-annex.cabal
+++ b/git-annex.cabal
@@ -96,11 +96,11 @@ Executable git-annex
   Main-Is: git-annex.hs
   Build-Depends: MissingH, hslogger, directory, filepath,
    containers, utf8-string, network (>= 2.0), mtl (>= 2),
-   bytestring, old-locale, time, HTTP, dataenc, SHA, process, json,
+   bytestring, old-locale, time, dataenc, SHA, process, json,
    base (>= 4.5 && < 4.9), monad-control, exceptions (>= 0.5), transformers,
    IfElse, text, QuickCheck >= 2.1, bloomfilter, edit-distance, process,
    SafeSemaphore, uuid, random, dlist, unix-compat, async, stm (>= 2.3),
-   data-default, case-insensitive
+   data-default, case-insensitive, http-conduit, http-types
   CC-Options: -Wall
   GHC-Options: -Wall
   Extensions: PackageImports
@@ -141,8 +141,7 @@ Executable git-annex
     CPP-Options: -DWITH_S3
 
   if flag(WebDAV)
-    Build-Depends: DAV (>= 1.0),
-     http-client, http-types
+    Build-Depends: DAV (>= 1.0), http-client
     CPP-Options: -DWITH_WEBDAV
 
   if flag(Assistant) && ! os(solaris)
@@ -188,7 +187,7 @@ Executable git-annex
   if flag(Webapp)
     Build-Depends:
      yesod, yesod-default, yesod-static, yesod-form, yesod-core,
-     http-types, wai, wai-extra, warp, warp-tls,
+     wai, wai-extra, warp, warp-tls,
      blaze-builder, crypto-api, hamlet, clientsession,
      template-haskell, data-default, aeson, path-pieces,
      shakespeare