importfeed: git-annex becomes a podcatcher in 150 LOC

Annex/Branch.hs

@@ -21,6 +21,7 @@ module Annex.Branch (
 	change,
 	commit,
 	files,
+	withIndex,
 ) where
 
 import qualified Data.ByteString.Lazy.Char8 as L

Annex/Direct.hs

@@ -35,7 +35,7 @@ stageDirect :: Annex Bool
 stageDirect = do
 	Annex.Queue.flush
 	top <- fromRepo Git.repoPath
-	(l, cleanup) <- inRepo $ Git.LsFiles.stagedDetails [top]
+	(l, cleanup) <- inRepo $ Git.LsFiles.stagedOthersDetails [top]
 	forM_ l go
 	void $ liftIO cleanup
 	staged <- Annex.Queue.size

Command/AddUrl.hs

@@ -1,6 +1,6 @@
 {- git-annex command
  -
- - Copyright 2011 Joey Hess <joey@kitenet.net>
+ - Copyright 2011-2013 Joey Hess <joey@kitenet.net>
  -
  - Licensed under the GNU GPL version 3 or higher.
  -}
@@ -61,10 +61,7 @@ start relaxed optfile pathdepth s = go $ fromMaybe bad $ parseURI s
 perform :: Bool -> String -> FilePath -> CommandPerform
 perform relaxed url file = ifAnnexed file addurl geturl
   where
-	geturl = do
-		liftIO $ createDirectoryIfMissing True (parentDir file)
-		ifM (Annex.getState Annex.fast <||> pure relaxed)
-			( nodownload relaxed url file , download url file )
+	geturl = next $ addUrlFile relaxed url file
 	addurl (key, _backend)
 		| relaxed = do
 			setUrlPresent key url
@@ -80,12 +77,23 @@ perform relaxed url file = ifAnnexed file addurl geturl
 					stop
 				)
 
-download :: String -> FilePath -> CommandPerform
-download url file = do
+addUrlFile :: Bool -> String -> FilePath -> Annex Bool
+addUrlFile relaxed url file = do
+	liftIO $ createDirectoryIfMissing True (parentDir file)
+	ifM (Annex.getState Annex.fast <||> pure relaxed)
+		( nodownload relaxed url file
+		, do
 			showAction $ "downloading " ++ url ++ " "
+			download url file
+		)
+
+download :: String -> FilePath -> Annex Bool
+download url file = do
 	dummykey <- genkey
 	tmp <- fromRepo $ gitAnnexTmpLocation dummykey
-	stopUnless (runtransfer dummykey tmp) $ do
+	showOutput
+	ifM (runtransfer dummykey tmp)
+		( do
 			backend <- chooseBackend file
 			let source = KeySource
 				{ keyFilename = file
@@ -94,8 +102,10 @@ download url file = do
 				}
 			k <- genKey source backend
 			case k of
-			Nothing -> stop
-			Just (key, _) -> next $ cleanup url file key (Just tmp)
+				Nothing -> return False
+				Just (key, _) -> cleanup url file key (Just tmp)
+		, return False
+		)
   where
 	{- Generate a dummy key to use for this download, before we can
 	 - examine the file and find its real key. This allows resuming
@@ -119,7 +129,7 @@ download url file = do
 			downloadUrl [url] tmp
 		
 
-cleanup :: String -> FilePath -> Key -> Maybe FilePath -> CommandCleanup
+cleanup :: String -> FilePath -> Key -> Maybe FilePath -> Annex Bool
 cleanup url file key mtmp = do
 	when (isJust mtmp) $
 		logStatus key InfoPresent
@@ -133,7 +143,7 @@ cleanup url file key mtmp = do
 	maybe noop (moveAnnex key) mtmp
 	return True
 
-nodownload :: Bool -> String -> FilePath -> CommandPerform
+nodownload :: Bool -> String -> FilePath -> Annex Bool
 nodownload relaxed url file = do
 	headers <- getHttpHeaders
 	(exists, size) <- if relaxed
@@ -142,10 +152,10 @@ nodownload relaxed url file = do
 	if exists
 		then do
 			let key = Backend.URL.fromUrl url size
-			next $ cleanup url file key Nothing
+			cleanup url file key Nothing
 		else do
 			warning $ "unable to access url: " ++ url
-			stop
+			return False
 
 url2file :: URI -> Maybe Int -> FilePath
 url2file url pathdepth = case pathdepth of

Command/ImportFeed.hs

@@ -0,0 +1,148 @@
+{- git-annex command
+ -
+ - Copyright 2013 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Command.ImportFeed where
+
+import Text.Feed.Import
+import Text.Feed.Query
+import Text.Feed.Types
+import qualified Data.Set as S
+import qualified Data.Map as M
+import Data.Char
+
+import Common.Annex
+import Command
+import qualified Utility.Url as Url
+import Logs.Web
+import qualified Option
+import qualified Utility.Format
+import Utility.Tmp
+import Command.AddUrl (addUrlFile, relaxedOption)
+
+data ToDownload = ToDownload
+	{ feed :: Feed
+	, item :: Item
+	, location :: URLString
+	}
+
+mkToDownload :: Feed -> Item -> Maybe ToDownload
+mkToDownload f i = case getItemEnclosure i of
+	Nothing -> Nothing
+	Just (enclosureurl, _, _) -> Just $ ToDownload f i enclosureurl
+
+def :: [Command]
+def = [notBareRepo $ withOptions [templateOption, relaxedOption] $
+	command "importfeed" (paramRepeating paramUrl) seek
+		SectionCommon "import files from podcast feeds"]
+
+templateOption :: Option
+templateOption = Option.field [] "template" paramFormat "template for filenames"
+
+seek :: [CommandSeek]
+seek = [withField templateOption return $ \tmpl ->
+	withFlag relaxedOption $ \relaxed ->
+	withWords $ start relaxed tmpl]
+
+start :: Bool -> Maybe String -> [URLString] -> CommandStart
+start relaxed opttemplate = go Nothing
+  where
+  	go _ [] = stop
+  	go cache (url:urls) = do
+		showStart "importfeed" url
+		v <- findEnclosures url
+		if isJust v then showEndOk else showEndFail
+		case v of
+			Just l | not (null l) -> do
+				knownurls <- getknownurls cache
+				mapM_ (downloadEnclosure relaxed template knownurls) l
+				go (Just knownurls) urls
+			_ -> go cache urls
+
+	defaulttemplate = "${feedtitle}/${itemtitle}.${extension}"
+	template = Utility.Format.gen $ fromMaybe defaulttemplate opttemplate
+
+	{- This is expensive, so avoid running it more than once. -}
+	getknownurls (Just cached) = return cached
+	getknownurls Nothing = S.fromList <$> knownUrls
+
+findEnclosures :: URLString -> Annex (Maybe [ToDownload])
+findEnclosures url = go =<< downloadFeed url
+  where
+	go Nothing = do
+		warning $ "failed to parse feed " ++ url
+		return Nothing
+	go (Just f) = return $ Just $
+		mapMaybe (mkToDownload f) (feedItems f)
+
+{- Feeds change, so a feed download cannot be resumed. -}
+downloadFeed :: URLString -> Annex (Maybe Feed)
+downloadFeed url = do
+	showOutput
+	liftIO $ withTmpFile "feed" $ \f h -> do
+		ifM (Url.download url [] [] f)
+			( parseFeedString <$> hGetContentsStrict h
+			, return Nothing
+			)
+
+{- Avoids downloading any urls that are already known to be associated
+ - with a file in the annex. -}
+downloadEnclosure :: Bool -> Utility.Format.Format -> S.Set URLString -> ToDownload -> Annex ()
+downloadEnclosure relaxed template knownurls enclosure
+	| S.member url knownurls = noop
+	| otherwise = do
+		dest <- liftIO $ feedFile template enclosure
+		showStart "addurl" dest
+		ifM (addUrlFile relaxed url dest)
+			( showEndOk
+			, showEndFail
+			)
+  where
+  	url = location enclosure
+
+{- Generate a unique filename for the feed item by filling 
+ - out the template.
+ -
+ - Since each feed url is only downloaded once,
+ - if the file already exists, two items with different urls
+ - has the same title. A number is added to disambiguate.
+ -}
+feedFile :: Utility.Format.Format -> ToDownload -> IO FilePath
+feedFile template i = makeUnique 0 $
+	Utility.Format.format template $ M.fromList
+		[ field "feedtitle" $ getFeedTitle $ feed i
+		, fieldMaybe "itemtitle" $ getItemTitle $ item i
+		, fieldMaybe "feedauthor" $ getFeedAuthor $ feed i
+		, fieldMaybe "itemauthor" $ getItemAuthor $ item i
+		, fieldMaybe "itemsummary" $ getItemSummary $ item i
+		, fieldMaybe "itemdescription" $ getItemDescription $ item i
+		, fieldMaybe "itemrights" $ getItemRights $ item i
+		, fieldMaybe "itemid" $ snd <$> getItemId (item i)
+		, field "extension" $ takeExtension $ location i
+		]
+  where
+	field k v = 
+		let s = map sanitize v in
+		if null s then (k, "none") else (k, s)
+	fieldMaybe k Nothing = (k, "none")
+	fieldMaybe k (Just v) = field k v
+
+	sanitize c
+		| isSpace c || isPunctuation c || c == '/' = '_'
+		| otherwise = c
+
+makeUnique :: Integer -> FilePath -> IO FilePath
+makeUnique n file =
+	ifM (isJust <$> catchMaybeIO (getSymbolicLinkStatus f))
+		( makeUnique (n + 1) file
+		, return file
+		)
+  where
+  	f = if n == 0
+		then file
+		else
+			let (d, base) = splitFileName file
+			in d </> show n ++ "_" ++ base

Command/Indirect.hs

@@ -59,7 +59,7 @@ perform = do
 	setDirect False
 
 	top <- fromRepo Git.repoPath
-	(l, clean) <- inRepo $ Git.LsFiles.stagedDetails [top]
+	(l, clean) <- inRepo $ Git.LsFiles.stagedOthersDetails [top]
 	forM_ l go
 	void $ liftIO clean
 	next cleanup

Git/LsFiles.hs

@@ -12,6 +12,7 @@ module Git.LsFiles (
 	modified,
 	staged,
 	stagedNotDeleted,
+	stagedOthersDetails,
 	stagedDetails,
 	typeChanged,
 	typeChangedStaged,
@@ -69,16 +70,24 @@ staged' ps l = pipeNullSplit $ prefix ++ ps ++ suffix
 	prefix = [Params "diff --cached --name-only -z"]
 	suffix = Param "--" : map File l
 
-{- Returns details about files that are staged in the index
- - (including the Sha of their staged contents),
- - as well as files not yet in git. -}
+{- Returns details about files that are staged in the index,
+ - as well as files not yet in git. Skips ignored files. -}
+stagedOthersDetails :: [FilePath] -> Repo -> IO ([(FilePath, Maybe Sha)], IO Bool)
+stagedOthersDetails = stagedDetails' [Params "--others --exclude-standard"]
+
+{- Returns details about all files that are staged in the index. -}
 stagedDetails :: [FilePath] -> Repo -> IO ([(FilePath, Maybe Sha)], IO Bool)
-stagedDetails l repo = do
+stagedDetails = stagedDetails' []
+
+{- Gets details about staged files, including the Sha of their staged
+ - contents. -}
+stagedDetails' :: [CommandParam] -> [FilePath] -> Repo -> IO ([(FilePath, Maybe Sha)], IO Bool)
+stagedDetails' ps l repo = do
 	(ls, cleanup) <- pipeNullSplit params repo
 	return (map parse ls, cleanup)
   where
-	params = [Params "ls-files --others --exclude-standard --stage -z --"] ++
-		map File l
+	params = Params "ls-files --stage -z" : ps ++ 
+		Param "--" : map File l
 	parse s
 		| null file = (s, Nothing)
 		| otherwise = (file, extractSha $ take shaSize $ drop 7 metadata)

GitAnnex.hs

@@ -57,6 +57,9 @@ import qualified Command.Ungroup
 import qualified Command.Vicfg
 import qualified Command.Sync
 import qualified Command.AddUrl
+#ifdef WITH_FEED
+import qualified Command.ImportFeed
+#endif
 import qualified Command.RmUrl
 import qualified Command.Import
 import qualified Command.Map
@@ -91,6 +94,9 @@ cmds = concat
 	, Command.Lock.def
 	, Command.Sync.def
 	, Command.AddUrl.def
+#ifdef WITH_FEED
+	, Command.ImportFeed.def
+#endif
 	, Command.RmUrl.def
 	, Command.Import.def
 	, Command.Init.def

Logs/Web.hs

@@ -1,6 +1,6 @@
 {- Web url logs.
  -
- - Copyright 2011 Joey Hess <joey@kitenet.net>
+ - Copyright 2011, 2013 Joey Hess <joey@kitenet.net>
  -
  - Licensed under the GNU GPL version 3 or higher.
  -}
@@ -11,12 +11,21 @@ module Logs.Web (
 	getUrls,
 	setUrlPresent,
 	setUrlMissing,
+	urlLog,
+	urlLogKey,
+	knownUrls
 ) where
 
+import qualified Data.ByteString.Lazy.Char8 as L
+
 import Common.Annex
 import Logs.Presence
 import Logs.Location
 import Types.Key
+import qualified Annex.Branch
+import Annex.CatFile
+import qualified Git
+import qualified Git.LsFiles
 
 type URLString = String
 
@@ -24,8 +33,24 @@ type URLString = String
 webUUID :: UUID
 webUUID = UUID "00000000-0000-0000-0000-000000000001"
 
+urlLogExt :: String
+urlLogExt = ".log.web"
+
 urlLog :: Key -> FilePath
-urlLog key = hashDirLower key </> keyFile key ++ ".log.web"
+urlLog key = hashDirLower key </> keyFile key ++ urlLogExt
+
+{- Converts a url log file into a key.
+ - (Does not work on oldurlLogs.) -}
+urlLogKey :: FilePath -> Maybe Key
+urlLogKey file
+	| ext == urlLogExt = fileKey base
+	| otherwise = Nothing
+  where
+  	(base, ext) = splitAt (length file - extlen) file
+	extlen = length urlLogExt
+
+isUrlLog :: FilePath -> Bool
+isUrlLog file = urlLogExt `isSuffixOf` file
 
 {- Used to store the urls elsewhere. -}
 oldurlLogs :: Key -> [FilePath]
@@ -58,3 +83,21 @@ setUrlMissing key url = do
 	addLog (urlLog key) =<< logNow InfoMissing url
 	whenM (null <$> getUrls key) $
 		logChange key webUUID InfoMissing
+
+{- Finds all known urls. -}
+knownUrls :: Annex [URLString]
+knownUrls = do
+	{- Ensure the git-annex branch's index file is up-to-date and
+	 - any journaled changes are reflected in it, since we're going
+	 - to query its index directly. -}
+	Annex.Branch.update
+	Annex.Branch.commit "update"
+	Annex.Branch.withIndex $ do
+		top <- fromRepo Git.repoPath
+		(l, cleanup) <- inRepo $ Git.LsFiles.stagedDetails [top]
+		r <- mapM (geturls . snd) $ filter (isUrlLog . fst) l
+		void $ liftIO cleanup
+		return $ concat r
+  where
+	geturls Nothing = return []
+  	geturls (Just logsha) = getLog . L.unpack <$> catObject logsha

Utility/Url.hs

@@ -130,6 +130,9 @@ download' quiet url headers options file =
  -
  - 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 -> Headers -> RequestMethod -> IO (Response String)
 request url headers requesttype = go 5 url

debian/changelog

@@ -7,6 +7,7 @@ git-annex (4.20130724) UNRELEASED; urgency=low
     Like drop, dropunused checks remotes, and honors the global
     annex.numcopies setting. (However, .gitattributes settings cannot
     apply to unused files.) 
+  * importfeed can be used to import files from podcast feeds.
   * Add status message to XMPP presence tag, to identify to others that
     the client is a git-annex client. Closes: #717652
   * webapp: When creating a repository on a removable drive, set

debian/control

@@ -48,6 +48,7 @@ Build-Depends:
 	libghc-xml-types-dev,
 	libghc-async-dev,
 	libghc-http-dev,
+	libghc-feed-dev
 	ikiwiki,
 	perlmagick,
 	git,

doc/git-annex.mdwn

@@ -190,6 +190,19 @@ subdirectories).
 
 	git annex import /media/camera/DCIM/
 
+* importfeed [url ...]
+
+  Imports the contents of podcast feeds. Only downloads files whose
+  urls have not already been added to the repository before, so you can
+  delete, rename, etc the resulting files and repeated runs won't duplicate
+  them.
+
+  Use --template to control where the files are stored.
+  The default template is '${feedtitle}/${itemtitle}${extension}'
+  (Other available variables: feedauthor, itemauthor, itemsummary, itemdescription, itemrights, itemid)
+
+  The --relaxed and --fast options behave the same as they do in addurl.
+
 * watch
 
   Watches for changes to files in the current directory and its subdirectories,

doc/install/fromscratch.mdwn

@@ -21,6 +21,7 @@ quite a lot.
   * [UUID](http://hackage.haskell.org/package/uuid)
   * [regex-tdfa](http://hackage.haskell.org/package/regex-tdfa)
   * [extensible-exceptions](http://hackage.haskell.org/package/extensible-exceptions)
+  * [feed](http://hackage.haskell.org/package/feed)
 * Optional haskell stuff, used by the [[assistant]] and its webapp
   * [stm](http://hackage.haskell.org/package/stm)
     (version 2.3 or newer)

doc/tips/downloading_podcasts.mdwn

@@ -0,0 +1,44 @@
+You can use git-annex as a podcatcher, to download podcast contents.
+No additional software is required, but your git-annex must be built
+with the Feeds feature (run `git annex version` to check).
+
+All you need to do is put something like this in a cron job:
+
+`cd somerepo && git annex importfeed http://url/to/podcast http://other/podcast/url`
+
+This downloads the urls, and parses them as RSS, Atom, or RDF feeds.
+All enclosures are downloaded and added to the repository, the same as if you
+had manually run `git annex addurl` on each of them.
+
+git-annex will avoid downloading a file from a feed if its url has already
+been stored in the repository before. So once a file is downloaded,
+you can move it around, delete it, `git annex drop` its content, etc,
+and it will not be downloaded again by repeated runs of
+`git annex importfeed`. Just how a podcatcher should behave.
+
+## templates
+
+To control the filenames used for items downloaded from a feed,
+there's a --template option. The default is
+`--template='${feedtitle}/${itemtitle}${extension}'`
+
+Other available template variables:  
+feedauthor, itemauthor, itemsummary, itemdescription, itemrights, itemid
+
+## catching up
+
+To catch up on a feed without downloading its contents,
+use `git annex importfeed --relaxed`, and delete the symlinks it creates.
+Next time you run `git annex addurl` it will only fetch any new items.
+
+## fast mode
+
+To add a feed without downloading its contents right now,
+use `git annex importfeed --fast`. Then you can use `git annex get` as
+usual to download the content of an item.
+
+## distributed podcastching
+
+A nice benefit of using git-annex as a podcatcher is that you can
+run `git annex importfeed` on the same url in different clones
+of a repository, and `git annex sync` will sync it all up.

git-annex.cabal

@@ -65,6 +65,9 @@ Flag TestSuite
 Flag TDFA
   Description: Use regex-tdfa for wildcards
 
+Flag Feed
+  Description: Enable podcast feed support
+
 Executable git-annex
   Main-Is: git-annex.hs
   Build-Depends: MissingH, hslogger, directory, filepath,
@@ -154,6 +157,10 @@ Executable git-annex
     Build-Depends: dns
     CPP-Options: -DWITH_DNS
 
+  if flag(Feed)
+    Build-Depends: feed
+    CPP-Options: -DWITH_FEED
+
 source-repository head
   type: git
   location: git://git-annex.branchable.com/