Arvados

Currently, Keepstore responds to both HEAD and GET requests the same way, with a full data block.

If the server responded to HEAD requests properly, with just a report of success or failure, it would permit writing applications to check whether a block exists at the destination. That would be a significant performance improvement to tools like arv-copy, which cannot efficiently resume copying a collection if interrupted.

Tim Pierce wrote:

Currently, Keepstore responds to both HEAD and GET requests the same way, with a full data block.

If the server responded to HEAD requests properly, with just a report of success or failure, it would permit writing applications to check whether a block exists at the destination. That would be a significant performance improvement to tools like arv-copy, which cannot efficiently resume copying a collection if interrupted.

I don't think HEAD could enable this functionality unless the permission system is disabled. (But obeying the HTTP specification is a good idea anyway.)

tomclegg@shell:~$ time curl --head -H "Authorization: OAuth2 $ARVADOS_API_TOKEN" "http://keep6.c97qk.arvadosapi.com:25107/a59f44608b780c968af43da75cc9d6e8+67108864+Ad9785dc3247c083f49c7524690e140659bfef7b3@56fdbbaa" 
HTTP/1.1 200 OK
Content-Length: 67108864
Content-Type: application/octet-stream
Date: Fri, 18 Mar 2016 00:11:29 GMT

real    0m2.036s
user    0m0.000s
sys     0m0.014s