[Bug-wget] Discussion for [PATCH] Removing "Range" header from HEAD method

[Bykov Aleksey]

Greetings all.

Please leave Your's suggestion, commentaries or anything other about this
variant of patch to SUBJ.

* Solves - Sometimes (and unstable) at least download.microsoft.com return  
"HTTP 416" instead of "HTTP 200" when "-cN" keys are used. So downloads  
breaks with false "The file is already fully retrieved; nothing to do.".  
Bugreport posted at  
http://lists.gnu.org/archive/html/bug-wget/2013-03/msg00066.html . In  
attachment - patch3_data.zip - log for repeatly launched commands "wget  
-cd -a wget_cd.log URL" "wget -cdN -a wget_cdN.log URL". From seven tries  
in wget_cdN.log first five was failed. After - all works correct.
* Application range - all systems
* Description and backgrounding - Now if "-N" key is used, Wget send  
request to server with "HEAD" method. If "HTTP 200" returned, then  
compares "Last-Modifed" with filedate and "Content-Lenght" and with  
filesize. If differ, then redownload with "GET" method. "-c" keys add  
"Range" header to both "HEAD" and "GET".
During experiment with CURL (that is more applicable as test instrument)  
find that bug appeared if during request "HEAD" method used with "Range"  
headers. Bug is on server size (because Wget and CURL with same request  
get same reply) and unstable (it's disappeared after several tries to  
download). During quick studies of "RFC 2616"  
http://www.w3.org/Protocols/rfc2616/rfc2616.html i can't find mention  
about this combination of headers. So i decide to just remove/break  
possibility of this combination.
* Principe - just additional check for "Range" headers usage.
* Testing status - looks like work. Because of bug is server size and  
disappeared/appeared randomly, i can't be sure about it removing.
* Possible limitation - unknown for me.

Thanks in advise
Sorry for bad English.

--
Best regars, Alex

0003-Remove-Range-header-from-HEAD-method-to-prevent-fals.patch
Description: Binary data

patch3_data.zip
Description: Zip archive