[horde] Active sync: multiple calendars?

[Jan Schneider]

Zitat von Michael J Rubinsky <mrubinsk at horde.org>:

> Quoting Gunnar Wrobel <wrobel at horde.org>:
>
>> Quoting Michael J Rubinsky <mrubinsk at horde.org>:
>>
>>> Quoting Andreas Ntaflos <daff at pseudoterminal.org>:
>>>
>>>> Hi,
>>>>
>>>> is it possible to access and sync multiple Horde calendars (on the same
>>>> user account) with the new ActiveSync plugin? Or is this not supported
>>>> by design or specification?
>>>
>>> By specification. The AS protocol does not support multiple  
>>> calendars for a single user.
>>
>> But shouldn't there be ways to aggregate calendars? I'm pretty  
>> certain the ActiveSync support on the Kolab server allows selecting  
>> several.
>
> Sure, it would be possible to essentially combine all events from  
> multiple calendars into a single AS collection. However, there are a  
> number of issues that I ran into while trying to do this when I  
> originally wrote the library:
>
> There is no way to differentiate the calendars on the client (AS  
> only supports a single "calendar" folder) so no calendar names, no  
> horde-centric calendar colors (in fact some clients might color the  
> events based on the tags) - all events look like they are in the  
> user's "main" calendar.
>
> There is no way to mark events as read only, no way to map back an  
> event to the calendar it came from in the case that multiple  
> calendars may have the same event uid (though this is not specific  
> to AS), and no way on the client to select the calendar to add a new  
> event to (all events are assumed to be on the user's "main"  
> calendar). This last point _might_ also cause issues with both event  
> invitations and recurring event exceptions on calendars other than  
> the user's "main" calendar (don't have code or protocol docs in  
> front of me at the moment to verify this one).
>
> There would also be issues when a user changes which calendars they  
> want included after the initial setup (would basically require the  
> user or admin to explicitly reset the AS account to force a complete  
> replacement sync). For example - a user initially sets up two  
> calendars, but then decides to remove one. All the events from the  
> second calendar will still be present on the device. Similarly,  
> adding a second calendar would not sync the events that were  
> created/modified prior to the last successful sync time.
>
> Yes, some of these issues could be at least partially worked around  
> by e.g., limiting the calendars allowed to be synched to calendars  
> owned by the user, or adding user pref for the calendar to use when  
> creating new events on an AS device, but these rather feel like  
> hacks instead of implementations.
>
> If in fact kolab does allow this, I'd be interested in both how the  
> kolab/activesync connector implements this and how robust this  
> actually is. If you have any links to code or similar, I'd love to  
> take a look. This is a sore point for me as well though even if we  
> get minimal support for this, would likely not help me since it's  
> calendars I have read only access to that I need to include (see  
> note above about read only issues).
>
> Also, it's worth noting that I'm aware that Google's "activesync"  
> support allows this - but this is not true activesync; they have  
> added features to the protocol and these only work if using a Google  
> client, not a generic activesync client.

All what you said could be applied to contacts too, where we allow  
several sources. In fact, synching several calendars can be  
implemented transparently, i.e. for both SyncML and ActiveSync,  
analogous to address books.

Jan.

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