Re: .ics export violates RFC2445

[Carsten Dominik <carsten.dominik@gmail.com>]

On Apr 29, 2008, at 7:16 PM, Adam Spiers wrote:

>>> Also, it would be great if a UID field could be generated for each
>>> event, perhaps by checksumming the contents of the event in some  
>>> way.
>>> The RFC says:
>>>
>>> Conformance: The property MUST be specified in the "VEVENT",
>>> "VTODO", "VJOURNAL" or "VFREEBUSY" calendar components.
>>>
>>>   -- http://tools.ietf.org/html/rfc2445#section-4.8.4.7
>>>
>>> The checksum would ensure that the UID field only changes when the
>>> event details check, which would be a first step towards helping
>>> synchronisation systems.  I'm vaguely suspicious that the lack of  
>>> UIDs
>>> currently confuses Google Calendar too.
>>
>> A UID may be good.  However I think changing the UID when changing  
>> the
>> entry would be bad, because this would exactly *disable*  
>> synchronization.
>> To synchronize, you must know which entries to compare, and this is  
>> only
>> possible with a persistent UID.
>
> Doh - you are right of course.
>
>> I guess we could create one, but this UID would then have to be  
>> stored
>> in the entry, as a property.  Exporting to ical again must then re- 
>> use the
>> old uid each time.
>>
>> My org-id.el in the contrib directory allows already to create unique
>> identifiers, and it would be easy enough to include the domain to  
>> make
>> them truely unique, wordwide.
>>
>> However, right now I am hesitating to force a property drawer onto
>> every entry that ever is exported to iCalendar.  But as an option,  
>> this might
>> really be good and eventually allow true synchronization.
>
> I understand your hesitation - as an option that sounds perfect.

Please get the latest GIT version of Org.  Then set the variable

(setq org-icalendar-force-UID t)

and try to export to iCalendar.

Right now, I am only forcing and using the ID for VEVENT.  I am not  
using it for VTODO, because I am not sure if it is allowed to have the  
same UID for a VEVENT and a VTODO, if they originate from the same  
entry in a database?  Do you or anyone else know what the rules are  
for this?

- Carsten