importfeed: Avoid downloading a redundant item from a feed whose guid has been downloaded before, even when the url has changed.

To support this, always store itemid in metadata; before this was only done
when annex.genmetadata was set.

Command/ImportFeed.hs

@@ -73,7 +73,7 @@ perform opts cache url = do
 	v <- findDownloads url
 	case v of
 		[] -> do
-			feedProblem url "bad feed content"
+			feedProblem url "bad feed content; no enclosures to download"
 			next $ return True
 		l -> do
 			ok <- and <$> mapM (performDownload opts cache) l
@@ -96,21 +96,32 @@ data ToDownload = ToDownload
 
 data DownloadLocation = Enclosure URLString | QuviLink URLString
 
+type ItemId = String
+
 data Cache = Cache
 	{ knownurls :: S.Set URLString
+	, knownitems :: S.Set ItemId
 	, template :: Utility.Format.Format
 	}
 
 getCache :: Maybe String -> Annex Cache
 getCache opttemplate = ifM (Annex.getState Annex.force)
-	( ret S.empty
+	( ret S.empty S.empty
 	, do
 		showSideAction "checking known urls"
-		ret =<< S.fromList <$> knownUrls
+		(is, us) <- unzip <$> (mapM knownItems =<< knownUrls)
+		ret (S.fromList us) (S.fromList (concat is))
 	)
   where
 	tmpl = Utility.Format.gen $ fromMaybe defaultTemplate opttemplate
-	ret s = return $ Cache s tmpl
+	ret us is = return $ Cache us is tmpl
+
+knownItems :: (Key, URLString) -> Annex ([ItemId], URLString)
+knownItems (k, u) = do
+	itemids <- S.toList . S.filter (/= noneValue) . S.map fromMetaValue 
+		. currentMetaDataValues itemIdField 
+		<$> getCurrentMetaData k
+	return (itemids, u)
 
 findDownloads :: URLString -> Annex [ToDownload]
 findDownloads u = go =<< downloadFeed u
@@ -191,12 +202,18 @@ performDownload opts cache todownload = case location todownload of
   where
 	forced = Annex.getState Annex.force
 
-	{- Avoids downloading any urls that are already known to be
+	{- Avoids downloading any items that are already known to be
 	 - associated with a file in the annex, unless forced. -}
 	checkknown url a
-		| S.member url (knownurls cache) = ifM forced (a, return True)
+		| knownitemid || S.member url (knownurls cache)
+			= ifM forced (a, return True)
 		| otherwise = a
 
+	knownitemid = case getItemId (item todownload) of
+		-- only when it's a permalink
+		Just (True, itemid) -> S.member itemid (knownitems cache)
+		_ -> False
+
 	rundownload url extension getter = do
 		dest <- makeunique url (1 :: Integer) $
 			feedFile (template cache) todownload extension
@@ -211,8 +228,10 @@ performDownload opts cache todownload = case location todownload of
 						checkFeedBroken (feedurl todownload)
 					else do
 						forM_ ks $ \key ->
-							whenM (annexGenMetaData <$> Annex.getGitConfig) $
-								addMetaData key $ extractMetaData todownload
+							ifM (annexGenMetaData <$> Annex.getGitConfig)
+								( addMetaData key $ extractMetaData todownload
+								, addMetaData key $ minimalMetaData todownload
+								)
 						showEndOk
 						return True
 
@@ -275,6 +294,12 @@ extractMetaData i = meta
 	tometa (k, v) = (mkMetaFieldUnchecked k, S.singleton (toMetaValue v))
 	meta = MetaData $ M.fromList $ map tometa $ extractFields i
 
+minimalMetaData :: ToDownload -> MetaData
+minimalMetaData i = case getItemId (item i) of
+	(Nothing) -> emptyMetaData
+	(Just (_, itemid)) -> MetaData $ M.singleton itemIdField 
+		(S.singleton $ toMetaValue itemid)
+
 {- Extract fields from the feed and item, that are both used as metadata,
  - and to generate the filename. -}
 extractFields :: ToDownload -> [(String, String)]
@@ -296,12 +321,18 @@ extractFields i = map (uncurry extractField)
 	feedauthor = getFeedAuthor $ feed i
 	itemauthor = getItemAuthor $ item i
 
+itemIdField :: MetaField
+itemIdField = mkMetaFieldUnchecked "itemid"
+
 extractField :: String -> [Maybe String] -> (String, String)
-extractField k [] = (k, "none")
+extractField k [] = (k, noneValue)
 extractField k (Just v:_)
 	| not (null v) = (k, v)
 extractField k (_:rest) = extractField k rest
 
+noneValue :: String
+noneValue = "none"
+
 {- Called when there is a problem with a feed.
  - Throws an error if the feed is broken, otherwise shows a warning. -}
 feedProblem :: URLString -> String -> Annex ()

Logs/Web.hs

@@ -21,7 +21,6 @@ module Logs.Web (
 
 import qualified Data.ByteString.Lazy.Char8 as L
 import qualified Data.Map as M
-import Data.Tuple.Utils
 
 import Common.Annex
 import qualified Annex
@@ -70,7 +69,7 @@ setUrlMissing uuid key url = do
 		logChange key uuid InfoMissing
 
 {- Finds all known urls. -}
-knownUrls :: Annex [URLString]
+knownUrls :: Annex [(Key, 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
@@ -80,10 +79,13 @@ knownUrls = do
 	Annex.Branch.withIndex $ do
 		top <- fromRepo Git.repoPath
 		(l, cleanup) <- inRepo $ Git.LsFiles.stagedDetails [top]
-		r <- mapM (geturls . snd3) $ filter (isUrlLog . fst3) l
+		r <- mapM getkeyurls l
 		void $ liftIO cleanup
 		return $ concat r
   where
+	getkeyurls (f, s, _) = case urlLogFileKey f of
+		Just k -> zip (repeat k) <$> geturls s
+		Nothing -> return []
 	geturls Nothing = return []
 	geturls (Just logsha) = getLog . L.unpack <$> catObject logsha
 

debian/changelog

@@ -8,6 +8,10 @@ git-annex (5.20150328) UNRELEASED; urgency=medium
   * Fix GETURLS in external special remote protocol to strip
     downloader prefix from logged url info before checking for the
     specified prefix.
+  * importfeed: Avoid downloading a redundant item from a feed whose
+    guid has been downloaded before, even when the url has changed.
+  * importfeed: Always store itemid in metadata; before this was only
+    done when annex.genmetadata was set.
 
  -- Joey Hess <id@joeyh.name>  Fri, 27 Mar 2015 16:04:43 -0400
 

doc/git-annex-importfeed.mdwn

@@ -21,7 +21,7 @@ importing e.g., youtube playlists.
 
 * `--force`
 
-  Force downoading urls it's seen before.
+  Force downoading items it's seen before.
 
 * `--template`
 

doc/git-annex.mdwn

@@ -792,7 +792,8 @@ Here are all the supported configuration settings.
   In particular, it stores year and month metadata, from the file's
   modification date.
 
-  When importfeed is used, it stores additional metadata from the feed.
+  When importfeed is used, it stores additional metadata from the feed,
+  such as the author, title, etc.
 
 * `annex.queuesize`
 

doc/todo/podcatching_handling_updated_files.mdwn

@@ -11,6 +11,8 @@ known items, it could instead build a `Map (Either URlString GUID) Key`.
 
 This would at least prevent the duplication, when the feed has guids.
 
+> [[done]] --[[Joey]]
+
 It would be even nicer if the old file could be updated with the new
 content. But, since files can be moved around, deleted, tagged, etc,
 that only seems practical at all if the file is still in the directory