[sync] Deleting attributes on the client

[Gunnar Wrobel]

Hi!

I'm currently testing SyncML support with Horde CVS HEAD based on a
Kolab backend (IMAP based data storage). The SyncML part is based on
SQL though. Clients are a Blackberry and a Nokia 6120c.

In general both work fine wich is nice :) But I'm unable to delete
attributes on either of the clients (e.g. removing an e-mail address
or a phone number in an already synchronized addressbook entry on the
client). The data remains present on the server after removing the
attribute and synchronizing.

This seems to come down to a problem with data exchange via
vCard/iCalendar. I'm not certain how things are supposed to work.

Both clients will send vCard/iCalendar data wich contains only
attributes that actually have a value on the client. So if I delete an
attribute in a vCard it won't be mentioned in the update message from
the client.

As te vCard has been exchanged between client and server before Turba
will fetch the old entry and overwrite any attributes provided by the
client on this addressbook entry.

As I deleted the attribute the change will be missed by the server.

Turba will delete an attribute if the attribute is provided with an
empty string as value. Is this the intended behaviour? Meaning that
the client update must indicate removal of an attribute by sending the
attribute with an empty value?

As the clients don't do that I would need to use a client specific
converter but that would be fine. I'm just wondering whether that is
the intended mode of action. In fact using vCards/iCalendars as method
of data exchange seems somewhat limited in that context. But that
would be a SyncML limitation then.

Thanks!

Cheers,

Gunnar

-- 
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E-mail : p at rdus.de                                 Dr. Gunnar Wrobel
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