addurl --fast: Verifies that the url can be downloaded (only getting its head), and records the size in the key.

Backend/URL.hs

@@ -24,5 +24,9 @@ backend = Backend {
 	fsckKey = Nothing
 }
 
-fromUrl :: String -> Key
+fromUrl :: String -> Maybe Integer -> Key
-fromUrl url = stubKey { keyName = url, keyBackendName = "URL" }
+fromUrl url size = stubKey
+	{ keyName = url
+	, keyBackendName = "URL"
+	, keySize = size
+	}

Command/AddUrl.hs

@@ -15,6 +15,7 @@ import qualified Backend
 import qualified Command.Add
 import qualified Annex
 import qualified Backend.URL
+import qualified Utility.Url as Url
 import Annex.Content
 import Logs.Web
 import qualified Option
@@ -55,7 +56,7 @@ perform url file = ifAnnexed file addurl geturl
 download :: String -> FilePath -> CommandPerform
 download url file = do
 	showAction $ "downloading " ++ url ++ " "
-	let dummykey = Backend.URL.fromUrl url
+	let dummykey = Backend.URL.fromUrl url Nothing
 	tmp <- fromRepo $ gitAnnexTmpLocation dummykey
 	liftIO $ createDirectoryIfMissing True (parentDir tmp)
 	stopUnless (downloadUrl [url] tmp) $ do
@@ -70,7 +71,10 @@ download url file = do
 
 nodownload :: String -> FilePath -> CommandPerform
 nodownload url file = do
-	let key = Backend.URL.fromUrl url
+	(exists, size) <- liftIO $ Url.exists url
+	unless exists $
+		error $ "unable to access url: " ++ url
+	let key = Backend.URL.fromUrl url size
 	setUrlPresent key url
 	next $ Command.Add.cleanup file key False
 

debian/changelog

@@ -20,6 +20,8 @@ git-annex (3.20120124) UNRELEASED; urgency=low
   * Fix teardown of stale cached ssh connections.
   * When checking that an url has a key, verify that the Content-Length,
     if available, matches the size of the key.
+  * addurl --fast: Verifies that the url can be downloaded (only getting
+    its head), and records the size in the key.
 
  -- Joey Hess <joeyh@debian.org>  Tue, 24 Jan 2012 16:21:55 -0400