From 50ea37515411228f2a9eea96a01bd219457bbb11 Mon Sep 17 00:00:00 2001
From: Derek Higgins <derekh@redhat.com>
Date: Thu, 3 Oct 2013 22:18:08 +0100
Subject: [PATCH] Ignore empty files returned by curl

In cases where servers ignore the Modified time, curl cancels the
download, outputs a http 200 and leaves the output file untouched, we
don't want this empty file.

Fixes bug #1234926

Change-Id: I05b0dd95dcd53ca50d88ec07f2f1ee9958b6adb7
---
 elements/cache-url/bin/cache-url | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/elements/cache-url/bin/cache-url b/elements/cache-url/bin/cache-url
index 09ec48c9..3ac19369 100755
--- a/elements/cache-url/bin/cache-url
+++ b/elements/cache-url/bin/cache-url
@@ -36,8 +36,16 @@ fi
 
 rcode=$(curl -L -o $tmp -w '%{http_code}' $url $time_cond)
 if [ "$rcode" = "200" ] ; then
-    echo $success
-    mv $tmp $dest
+    # In cases where servers ignore the Modified time,
+    # curl cancels the download, outputs a 200 and leaves
+    # the output file untouched, we don't want this empty file.
+    if [ -n "$time_cond" -a ! -s $tmp ] ; then
+        echo "Ignoring empty file returned by curl. Using locally cached $url"
+        rm -f $tmp
+    else
+        echo $success
+        mv $tmp $dest
+    fi
 elif [ "$rcode" = "304" ] ; then
     echo "Server copy has not changed. Using locally cached $url"
     rm -f $tmp