[Owncloud] Sync Client needs server help

[Klaas Freitag]

Hi,

one of the biggest shortcomings of the sync client currently is that it 
does a full scan of its the ownCloud directories via webdav to query the 
last modified times. That causes load and other trouble. It would be 
great to find out if something has changed server side more cheaply.

We have the file system cache which also has the mod times in the 
database. My idea is now, instead of querying every single file, I just 
issue a HEAD request on the top sync directory and get the latest 
modtime of all files in that dir back. If that is younger than the one I 
know, I have to do a sync.

I know that it could be even more cool, ie. delivering the list of files 
back etc. but lets do small steps. Doing just one HEAD instead of 
querying the whole tree already will be great.

The implementation seems easy: Just get all database id's of the fscache 
table entries below the top directory of the sync dir and do kind of
SELECT MAX(mtime) FROM fscache WHERE id in ( list-of-all-ids-in dir );
That should be fast enough.

My question now is: How do we do that? Should we have another app called 
/files/sync? Or do we want to enhance the WebDAV server to be able to do 
the described logic if a HEAD request on a dir comes in?

I think the latter is more "within the concept" of doing the sync via 
WebDAV, OTOH a sync app could be useful anyway for other sync related 
server support.

What do you think?

Thanks,

Klaas