[Owncloud] standards based interoperability?

[Brad McEvoy]

>> One immediate point of possible interest is that I've just implemented
>> efficient bi-directional file sync using a new protocol called zsync
>> (similar to rsync, but over http). The protocol is defined here -
>> http://zsync.moria.org.uk/ - but as documented is only server to client.
>> I've extended it to be bi-directional.
> How did you do that? I wonder how this should be working as owncloud is webdav
> only?
The zsync protocol is a http extension, so is easily added to webdav 
servers, as it has been with milton. In fact, because milton is just a 
library used my many server applications, zsync will become 
auto-magically available to a large number of servers as they upgrade.
>
> How do you detect and solve conflicts?
> How do you detect if a file has been removed?
Those are application level concerns, but zsync is simply a transport 
level protocol. We have a separate file sync engine (ie client side) 
which performs crc tracking and filesystem listening to provide the 
application intelligence. Currently proprietary, but should be open 
sourced soon. When combined with a GUI this is feature equivalent with 
dropbox.
> How do you make sure there is no file corruption or loss of contect if an
> error occurs (network loss, segfault)?
There is a full crc check done on the resulting file at the merge, same 
as for rsync.