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authorGravatar Joey Hess <joeyh@joeyh.name>2015-03-27 10:22:32 -0400
committerGravatar Joey Hess <joeyh@joeyh.name>2015-03-27 10:22:36 -0400
commitb1483ee577dded9e00f8d82d52a806ee02888b2c (patch)
treead16d663918d043320587a5b2aa6539cd61e7397 /Utility
parentbe1f27f20455080471472afbc48763e668c6b97b (diff)
Work around curl bug when asked to download an empty url to a file.
In this situation, curl -o exits successfully without creating the output file. There was already a workaround for curl file:/// but I did not realize this also affected regular url downloads. To fix it, pre-create the destination file before starting curl. Since we cannot always know the size of an url before trying to download it, let's always do this. Note that since curl is told -C -, we have to consider if this makes curl try to do a ranged download, which might fail on some servers where a regular download would have succeeded. My testing indicates this isn't a problem; since the file is empty, curl seems to not try to do a ranged download. Original report: https://github.com/datalad/datalad/issues/79 Curl bug report: https://github.com/bagder/curl/issues/183
Diffstat (limited to 'Utility')
-rw-r--r--Utility/Url.hs11
1 files changed, 6 insertions, 5 deletions
diff --git a/Utility/Url.hs b/Utility/Url.hs
index ddf5eea40..07be955e2 100644
--- a/Utility/Url.hs
+++ b/Utility/Url.hs
@@ -209,9 +209,6 @@ download' quiet url file uo =
case parseURIRelaxed url of
Just u
| uriScheme u == "file:" -> do
- -- curl does not create destination file
- -- for an empty file:// url, so pre-create
- writeFile file ""
curl
| otherwise -> ifM (inPath "wget") (wget , curl)
_ -> return False
@@ -240,8 +237,12 @@ download' quiet url file uo =
- the remainder to download as the whole file,
- and not indicating how much percent was
- downloaded before the resume. -}
- curl = go "curl" $ headerparams ++ quietopt "-s" ++
- [Params "-f -L -C - -# -o"]
+ curl = do
+ -- curl does not create destination file
+ -- if the url happens to be empty, so pre-create.
+ writeFile file ""
+ go "curl" $ headerparams ++ quietopt "-s" ++
+ [Params "-f -L -C - -# -o"]
go cmd opts = boolSystem cmd $
addUserAgent uo $ reqParams uo++opts++[File file, File url]
quietopt s