[Owncloud] Sync Client needs server help

[Evert Pot]

> 
> I understand the concept and indeed its good. It's very near to what I want to implement, with the only difference that instead of the hash sums, I'd like to use the mtimes, as csync does. Why do we think thats a benefit: Well, based on the mtimes its decideable which version is newer. Moreover, the mtime is already a natural meta data in each file system, so we do not have to add something new. That given, csync runs without server support by now.
> 
> What is missing is the propagation of the mtimes from individual files and directories to their parent directory. If we do that with the ownCloud server support, I think we will have the same benefits that you described above. As we have the data in a database server side we will be able to retrieve the data fast.

Does this mean that if I run this on a machine with an incorrect date (in the future) I could potentially wipe out the entire server state?
I think using the modification time is a flawed idea.. The way dropbox handles this is, imho the better way..

* Always assume that the server state is the current state.
* Clients have a hash of the last known server-state
* When clients pushes a new version of a file, they include the last known hash (much like If-Match:, but it wouldn't have to be enforced)
* If the client attempts to do an update with an old hash, make a duplicate of the previous server state as a conflicted copy.

> 
>> 
>> Note that there is a related RFC - http://tools.ietf.org/html/rfc6578 -
>> however I'm not confident that the approach outlined there is quite right.
> Do you know if its implemented in a WebDAV server already?

I'm currently working on a plugin for this :)

Evert